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Published in last 1 year | In last 2 years| In last 3 years| All| Most Downloaded in Recent Month | Most Downloaded in Recent Year| Most Downloaded in Recent Year Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Development Status of High-efficiency Rock-breaking and Speed-increasing Technologies for Deep Shale Gas Horizontal Wells ZHU Xiaohua, LI Rui, LIU Weiji, LI Zhilin, LU Dengyun Journal of Southwest Petroleum University(Science & Technology Edition)    2023, 45 (4): 1-18.   DOI: 10.11885/j.issn.1674-5086.2021.04.05.01 Abstract （356）   HTML （230）    PDF（pc） （2990KB）（821）       Knowledge map    Save At present, China has basically formed the economic exploitation of shallow shale gas engineering technology system, and is moving towards deep layer (more than 3 500 m) exploitation. Deep shale gas has great development potential with rich reserve. But the problems of slow drilling speed and high cost caused by high hardness, high plasticity and high abrasiveness of deep rock are very prominent. Therefore, the efficient rock breaking methods and influencing factors in deep shale gas drilling are introduced. We analyze and summarize the efficient transmission technology of reducing friction and torsion in deep shale gas horizontal wells to improve bit breaking power; and we analyze and summarize new technologies of bit and tooth with strong attacking power and longer service, technology of rock breaking parameter enhancement by using speed-raising tool to assist bit and speed-raising tool-bit parameter matching technology that is suitable for deep shale gas, and briefly describe several new non-mechanical and efficient rock breaking methods, aiming to providing a reference for future economic and efficient exploration and development of deep shale gas. Reference | Related Articles | Metrics Select Optimization Study of the Horizontal Well and Injection-production Pattern in an Ultra-low-permeability Reservoir FAN Jianming, QU Xuefeng, WANG Chong, ZHANG Qingzhou, WANG Xuanru 西南石油大学学报(自然科学版)    2018, 40 (2): 115-128.   DOI: 10.11885/j.issn.1674-5086.2017.03.22.03 Abstract （197）   HTML    PDF（pc） （1891KB）（733）       Knowledge map    Save This study forms the basic principle of an injection-production well design for a horizontal well in an ultra-lowpermeable reservoir based on the understanding of the breakthrough, effect analysis, and mining rule of the horizontal well in an ultra-low-permeable reservoir to solve the problem of stable production. The following points are discussed:(1) the expanding range of the three-dimensional space of an artificial pressure crack is the foundation of the injection-production pattern design; (2) the direction of the well arrangement is perpendicular to the maximum principal stress; (3) the lateral displacement of the well network is the main supplementary energy; (4) the well spacing, distance, and horizontal section length should be optimized to improve the water flooding control area ratio; and (5) spacing must be reduced and an effective use of the gap between the reserves must be realized to improve the intensity of the single section. The technical direction and policy of further improving the development effect of horizontal wells are put forward based on the basic principles of the injection-production well pattern design along with the combination of field statistics and theoretical analysis to (1) improve the level of the single segment output; (2) improve the level of the well network pressure and optimize the well spacing for 500-600 m (the horizontal segment lengths of the reservoirs of the I, Ⅱ, and Ⅲ classes were 500-550 m, 450-500 m, and 400-450 m, respectively, and the reservoir row spacings of the I, Ⅱ, and Ⅲ classes were 150, 120~130, and 100~120 m, respectively; (3) optimize the water injection intensity of the single well using the technique of low and moderate water injection; and (4) determine the reasonable initial output of the horizontal well using the relationship between the amount of deposit, distance, and velocity of the water line. The reasonable production flow pressure injection was slightly greater than the saturation pressure before the water injection was effective, and was not less than 2/3 of the saturated pressure. Reference | Related Articles | Metrics Select Application of Fracturing Construction Curve in Fracture Evaluation of Deep Shale Gas Horizontal Wells YAN Jianping, LAI Siyu, GUO Wei, LIAO Maojie, HUANG Yi Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (5): 1-18.   DOI: 10.11885/j.issn.1674-5086.2022.10.18.04 Abstract （129）   HTML （15）    PDF（pc） （7210KB）（249）       Knowledge map    Save Shale gas horizontal wells usually do not have coring and electrical imaging scales, which makes it difficult to identify fractures. The fracturing operation curve can reflect the fracturing effect and the development of natural fractures before fracturing. Taking the deep shale gas formation of Block Y101 in Luzhou, southern Sichuan as an example, according to the type and characteristics of the fracturing operation curve in the sand-carrying fluid stage, the logging response characteristics of the fracture layer and the matrix layer before the fracturing of the horizontal well are calibrated. The wavelet transform is used to extract the high-frequency weak signal reflecting the fracture information to establish the wavelet comprehensive coefficient ( WI), the crossplot is used to select six parameter indexes sensitive to the fracture response, the analytic hierarchy process and the fuzzy mathematics method are used to construct the fracture evaluation comprehensive coefficient ( FI), and the relationship between different fracturing operation curve types and logging information is further combined to realize the identification and development level evaluation of horizontal well fracture layers. The results show that the fracturing construction curve of the sand-carrying fluid stage has a descending type (I), a descending stable type (II), a stable type (III), and an ascending type (IV). Among them, when the natural gamma high value, the compensated neutron and the density increase significantly, the acoustic time difference increases with the “jagged” cycle jump, the double lateral shows a “positive difference” and WI≥0.18， FI≥0.430, the fracturing construction curve is a descending type, and the fracture is well developed (F–A grade); When 0.390≤ FI<0.430, there are both downward type and downward stable type, and the fractures are more developed (F–B grade); when 0.350≤ FI<0.390, it is a descending stable type, and the fractures are generally developed (F–C grade). Reference | Related Articles | Metrics Select Analysis of Policy and Enlightenment on Treatment of Fracturing Fluid in Shale Gas Production Between China and the United States CHEN Xuezhong, LU Youchang, WU Yiyi, MA Lili Journal of Southwest Petroleum University(Science & Technology Edition)    2021, 43 (5): 212-219.   DOI: 10.11885/j.issn.1674-5086.2021.02.25.02 Abstract （215）   HTML （5）    PDF（pc） （1453KB）（398）       Knowledge map    Save Fracturing flowback fluid is complex in composition and difficult in treatment because it is rich in chemical additives and is affected by formation water and cuttings. Based on the comparison of relevant regulations on water environmental protection and fracturing flowback fluid treatment in shale gas development between China and the United States, we find out the following problems in the environmental supervision of shale gas development in China:the unified coordination organization for the environmental supervision of shale gas development has not yet been formed; the environmental regulations and standards related to shale gas development are not perfect; the basic scientific research is weak. Therefore, the countermeasures of shale gas fracturing fluid management in China are establishing on a sound regulatory system and carrying out the entire process environmental supervision, improving basic scientific research, and enhancing the technology and management system. Reference | Related Articles | Metrics Select PERFORMANCE EVALUATION OF ENCAPSULATED BREAKER IN FRACTURING FLUIDS WU Min YIE Yan 西南石油大学学报(自然科学版)    2002, 24 (6): 68-70.   DOI: 10.3863/j.issn.1000-2634.2002.06.020 Abstract （948）      PDF（pc） （234KB）（1001）       Knowledge map    Save An encapsulated breaker is composed of particles that are coated with a waterproof coating , which can reduce releasing rate of the breaker. The encapsulated breaker can be used in fracturing treatment at higher concentrations and has littleinfluence on viscosities of fracturing fluid. Laboratory study on performance of the encapsulated breaker has been conducted by comparing with other products from abroad and home , which has indicated a method and results of rheological properties of the fracturing fluid. Related Articles | Metrics Select Evaluation of Uncertainties for Pore-pressure Taking Eaton Method asan Example Zang Yanbin;Wang Ruihe;Wang Zizhen;Zhang Rui;He Yingming; 西南石油大学学报(自然科学版)    2012, 34 (4): 55-61.   Abstract （478）      PDF（pc） （670KB）（851）       Knowledge map    Save In view of the difficulties the uncertainty of pore-pressure brought to the drilling engineering design and construction， the concept of pore pressure uncertainty is present，and the calculation model for pore pressure uncertainty is derivated for Eaton method. An example is analyzed using synthesis data from PG block in northeast Sichuan region. The method presented here gives the range and main influencing factors of pore pressure uncertainty，and the influence law of related factors to uncertainty. The calculated results are in correspondence with actual mud density and the results of gas production test，which proves that the evaluation method of pore pressure uncertainty is feasible，the results has high accuracy and validity. Related Articles | Metrics Select Advances in the Interface Detection of Gas-liquid Two-phase Pipe-flow Research JIANG Junze, YONG Qiwei, QIAN Haibing, JIANG Xinsheng, HUANG Yanqi Journal of Southwest Petroleum University(Science & Technology Edition)    2021, 43 (2): 138-148.   DOI: 10.11885/j.issn.1674-5086.2020.03.05.02 Abstract （343）   HTML （10）    PDF（pc） （637KB）（601）       Knowledge map    Save The accuracy detection of the interface is not only the basis of the mechanics analysis, but also a powerful measure for the investigation of two-phase flow. Gas-liquid occurs widely in the energy, power, chemical engineering, petroleum and aviation, and there is an obvious topological and transient interface which is difficult to be detected accurately. The paper has summarized the interface detection technology and numerical simulation method.The decetion technology includes capacitance, conductivity, optical, ray, heat acoustic, nuclear magnetic resonance; the WMS, PT and PIV technologies are developed in recent years which enhance the precision of the interface detection; the numerical simulation includes PIC, MAC, ALE, VOF, Level Set, and so on. The methods are compared and analyzed with the advantages and boundedness, and some strategy and tendency are proposed, which may provide some references for the two-phase flow investigation. Reference | Related Articles | Metrics Select A Review of the Application Progress of Machine Learning in Oil and Gas Industry MIN Chao, DAI Boren, ZHANG Xinhui, DU Jianping Journal of Southwest Petroleum University(Science & Technology Edition)    2020, 42 (6): 1-15.   DOI: 10.11885/j.issn.1674-5086.2020.06.05.03 Abstract （868）   HTML （72）    PDF（pc） （1130KB）（1455）       Knowledge map    Save With the rise of deep learning in recent years, machine learning has been further developed in the oil and gas field. However, due to the particularity and complexity of the oil and gas industry, there is no training sample base suitable for deep learning, nor a targeted model establishment and selection method system. In addition, the uninterpretability of methods such as deep learning leads to the high dependence of learning models on the environment, which restricts the popularization and application of machine learning in the oil and gas industry. Starting from the development stage of machine learning, this paper introduces the major breakthroughs and problems in the application of machine learning in various fields of oil and gas industry. Then, suggestions are given on the processing methods and sample building of different types of data in the oil and gas industry, and how to carry out model adaptability analysis, etc. Finally, the development potential and research direction of machine learning in oil and gas artificial intelligence are proposed. Reference | Related Articles | Metrics Select May Downward Flow of Oil and Gas Occur? A Discussion with Mr. Wang Yongshi LI Chuanliang, LIU Donghua Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (5): 170-182.   DOI: 10.11885/j.issn.1674-5086.2024.05.08.01 Abstract （112）   HTML （11）    PDF（pc） （1215KB）（186）       Knowledge map    Save In response to whether downward flow of oil and gas occurs in petroleum geology, based on the relevant theories of flow mechanics in porous media, the migration and accumulation mechanism of oil and gas and the formation mechanism of formation overpressure were deeply studied through theoretical analysis. The main understandings were obtained as follows: firstly, migration is different from flow, flow requires differential pressure drive, migration does not require differential pressure drive, and oil and gas migration is a discrete flow or droplet flow under buoyancy; secondly, oil and gas can migrate upwards, and downward flow of oil and gas will not occur due to the lack of driving force; thirdly, the laboratory experiments did not simulate underground conditions, with a large pressure difference and a high flow velocity, indicating oil and gas flow rather than oil and gas migration; fourthly, the mudstone formation is an open formation and there is no overpressure and formation water can balance formation pressure through flow; fifthly, oil and gas are separated and surrounded by formation water, and overpressure can occur and the overpressure is balanced by capillary pressure; sixthly, there is no upper source-lower reservoir model, and the source rock may not necessarily be located directly below the oil and gas reservoir. Lateral upward migration can also achieve the formation of oil and gas reservoirs. Reference | Related Articles | Metrics Select Investigation Advances in Rheological Properties of Water Based Foam Jing Jiaqiang;Dai Kemin;Yang Lu;An Yunpeng;Zhao Chuandong 西南石油大学学报(自然科学版)    2013, 35 (1): 173-178.   Abstract （361）      PDF（pc） （465KB）（1033）       Knowledge map    Save Water based foams have been widely used in oil well drilling，foam flooding，mineral flotation and other fields. Because of the complexity and instability of their own structure，the exact description of their rheological properties should consider various factors such as liquid film drainage，gas diffusion，foam mass and structure，foam compressibility，wall slip， bubble size compared with measuring system，environment temperature and pressure and so on. This leads to no generally accepted theory for their rheological behavior. A widely available method of controlling the wall slip is to increase surface roughness of the flow channels such as rotor surface or pipe wall during the experimental investigation，and some theoretical modification methods deduced from some appropriate hypotheses have a better adaptability. The volume equalized constitutive equation assumes that the friction factor of foam flow in pipe is a constant，which can solve the difficulty of its pressure drop calculation due to the foam compressibility to some extent. It is widely believed that the foam rheological properties can be satisfactorily described by power law or Herschel-Bulkley models，but the existence of“yield stress”for the aqueous foams is being disputed due to different measurement conditions. Related Articles | Metrics Select Organic Volume Proportion in Shale: Concept, Measurement Method and Significance YOU Lijun, FAN Daoquan, KANG Yili, ZHOU Yang, CHEN Yang Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (2): 1-14.   DOI: 10.11885/j.issn.1674-5086.2022.07.15.03 Abstract （226）   HTML （219）    PDF（pc） （2473KB）（174）       Knowledge map    Save Total Organic Content is an essential index for evaluating the oil and gas production capacity of shale, which has an impact on porosity and gas content and is also a key parameter for evaluating the ``geological sweet spot" of shale reservoir. However, TOC cannot reflect the distribution, connectivity, spatial proportion of organic matter and its influence on oil and gas flow and reservoir transformation. Through data sorting and analysis, the concept of Organic Volume Proportion was clarified and gave and analyzed the advantages and disadvantages of five calculation methods, including the formula method, scanning electron microscopy estimation method, CT scanning method, low-field NMR measurement method, and rock physics model method. The significance of organic matter volume content to developing organic-rich shale oil and gas is also discussed. The Organic Volume Proportion refers to the volume of organic matter per unit volume of shale. It is expressed as a percentage, which strengthens the importance of organic pores in shale gas reservoir evaluation and development, and enriches the evaluation parameter system of shale oil and gas reservoirs. Organic matter is the weak structural point or weak structural plane of shale, the characteristics of OVP bridge the geological sweet spot and engineering sweet spot indicators, the solubility and spatial proportion of organic matter lay the foundation for the new idea of ``removal material and increment permeability" in oil and gas reservoirs. When organic matter is taken as the object of dissolution, a small amount of organic matter dissolution will greatly increase the reservoir reconstruction volume. Reference | Related Articles | Metrics Select Predicting the Diffusive Front of Supercritical CO 2 in Tight Oil Reservoirs WEI Bing, SHANG Jing, PU Wanfen, Kadet VALERIY, ZHAO Jinzhou 西南石油大学学报(自然科学版)    2020, 42 (2): 94-102.   DOI: 10.11885/j.issn.1674-5086.2019.10.30.02 Abstract （247）   HTML    PDF（pc） （697KB）（1188）       Knowledge map    Save Most of researchers claim that supercritical CO 2 diffusion is one of the key considerations for CO 2 huff-puff EOR in tight reservoirs. In this paper, a matrix-fracture model was designed and applied to measuring the diffusion coefficient of supercritical CO 2 in saturated oil cores using pressure decay method. The influence of reservoir conditions such as pressure and core petroproperties on the diffusion coefficient and concentration distribution of supercritical CO 2 was comprehensively investigated, and a method predicting CO 2 concentration field and diffusion front was established. The experimental results showed that the diffusion coefficient of supercritical CO 2 in the tight core (0.06 mD) is in the order of 10 -12 m 2/s. The diffusion coefficient was found to increase with the increase of the initial gas injection pressure before finally leveling off after a certain pressure. The maximum diffusion coefficient occured around the critical pressure point. In addition, the diffusion coefficient increased with the increase of matrix permeability and porosity, whereas it decreased with the increase of core tortuosity. After 900 days, diffusion in tight reservoirs, the diffusion front only advanced 0.095 m. Therefore, it is rational to neglect the diffusing effect of CO 2 in the field operation cycle of CO 2 injection in tight reservoirs. In the later stage of diffusion, the concentration gradient of CO 2 became low leading to gradual decrease of diffusion. Reference | Related Articles | Metrics Select STUDY ON THE SYNTHESIS AND POUR-POINT DEPRESSING PROPERTIES OF EVA GRAFT COPOLYMER GUO Shu-feng GUAN Zhong-yuan HU Xing-qi WU Li-juan 西南石油大学学报(自然科学版)    2009, 31 (6): 143-147.   DOI: 10.3863/j.issn.1674-5086.2009.06.032 Abstract （822）      PDF（pc） （463KB）（967）       Knowledge map    Save On the basis of analyzing characteristics of Daqing crude oil and according to mechanism of PPD,the graft copolymer of EVA and octadecyl maleimide is synthesized.The graft copolymer has an optimal effect of pour point depressing for the Daqing crude oil when it is synthesized under the conditions that the mole ratio of EVA and octadecyl maleimide is 1∶20,mass fraction peroxidation benzoin formyl is 2.5%,polymerization time is 6h,and the polymerization temperature is 90℃.When 100mg/kg of the graft copolymer was added into Daqing crude oil,the pour point was reduced by 15℃.The infrared spectrograms of octadecylamine,maleic anhydride,octadecyl maleimide indicate that the reaction product of dodecylamine and maleic anhydride is dodecylmaleimide.The NMR spectral diagrams of EVA and its graft copolymers show that the reaction of EVA and dodecylmaleimide has taken place indeed,and the grafted percentage reaches to 6.7%. Related Articles | Metrics Select Application and Prospect of Fluid Mobility in Oilfield Development TAN Fengqi, MA Chunmiao, LI Xiankun, JING Yuqian Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (1): 1-20.   DOI: 10.11885/j.issn.1674-5086.2022.06.18.02 Abstract （191）   HTML （26）    PDF（pc） （10022KB）（387）       Knowledge map    Save The study on fluid mobility in micro-pore-throat is of great significance for accurate evaluation and efficient development of the reservoir, and it is also the necessary basis for enhanced oil recovery of oil-gas reservoir. According to the differences of research objects, the research methods of fluid mobility in pore throats are divided into three dimensions: mineral composition, pore structure and fluid production. NMR technology can quickly and accurately determine the commonly used movable fluid parameters such as movable fluid saturation, movable fluid porosity and irreducible water saturation, and then effectively evaluate and predict the productivity of various oil and gas reservoirs. At present, the major oil fields at home and abroad have adopted the method of combining NMR with other experimental means to determine the production law of fluid in the reservoir, and have achieved good application results in different types of reservoirs such as tight glutenite, carbonate rock, coal seam and oil shale. In addition, in order to achieve effective exploration and development of different types of oil and gas resources, it is necessary to clarify the control factors of fluid mobility in the reservoir. Based on the existing research results, the control factors of fluid mobility can be divided into macro and micro aspects. The macro factors include sedimentary environment, diagenesis and lithofacies type, while the micro factors include pore throat structure, reservoir physical properties, mineral composition, water film thickness and other factors. At present, although the research methods of fluid mobility have been abundant and have achieved good application results in the evaluation of different types of oil and gas resources, further research and exploration are needed for greater accuracy and wider coverage in its application. In the future development, new ideas and methods such as pore network model, reservoir numerical simulation, multi parameter evaluation index, simultaneous geochemical parameters and so on can be comprehensively applied so as to deeply reveal the percolation mechanism of movable fluid in the micro-pore-throat, and continuously improve the accuracy of comprehensive evaluation of movable fluid, to provide geological basis for the rational formulation of reservoir development plan, and to promote the efficient development of the petroleum industry. Reference | Related Articles | Metrics Select COMPARATIVE STUDY ON DYNAMICS BEHAVIORS OF THE FULL DRILLSTRING BETWEEN GAS DRILLING AND MUD DRILLING LIN Tie-jun LIAN Zhang-hua ZHANG Jun-liang WEI Chen-xing CHEN Shi-chun; 西南石油大学学报(自然科学版)    2011, 33 (1): 139-143.   DOI: 10.3863/j.issn.1674-5086.2011.01.025 Abstract （846）      PDF（pc） （538KB）（889）       Knowledge map    Save The movement of the full drillstring is a very complex nonlinear dynamical process.It is impossible to get very much perfect analytic solution and there is high cost of experiment.Thus，based on elasticsplastic mechanics，rock mechanics and drilling string mechanics and the drilling data of some gas well，this paper successfully establishes the complex nonlinear dynamics finite element 3D realtime drilling model of several kilometerslong irregular borehole，and real conditions are considered，such as mutual action between drill bit and rock，unknown contact between tapered drillstring and hole，effect of complicated 3D well trajectories (azimuth angle，deviation angle) and real drilling parameters (WOB，rotating speed).The timevarying data at each point on the long drillstring can be obtained after simulated，including displacement，axial force，stress，bending moment，torque，vibration，and contact force.These data are processed to obtain the perilous stress zones，the severe abrasion areas，the lowest fatigue life section which possibly lead to failure and difference between gas drilling and mud drilling，which can provide theoretical foundations for the application of drillstring failure and prevention.Furthermore，it is useful of this model to study drilling string mechanics，hole deviation control and equipment in air drilling. Related Articles | Metrics Select A SYNTHESIS OF 2 OCTYL DODECYL ETHER DING Wei JING Hui YU Tao QU Guang-miao SUN Ying 西南石油大学学报(自然科学版)    2011, 33 (1): 144-146.   DOI: 10.3863/j.issn.1674-5086.2011.01.026 Abstract （832）      PDF（pc） （360KB）（664）       Knowledge map    Save 2octyl dodecyl ether is synthesized from solid sodium hydroxide，Guerbet alcohol and epichlorohydrin by phasetransfer catalysistetrabutyl ammonium.Effects of molar ratio of raw materials，amount of catalyst，reaction temperature and reaction time on the yield of 2octyl dodecyl ether are discussed.The final determined optimum conditions are that n(Guerbet alcohol)∶ n(epichlorohydrin)∶ n(Solid caustic soda)=1.00∶ 1.15∶ 1.20，the amount of catalyst is 0.05(relative to alcohol molar ratio)，reaction temperature and time are at 50℃ for 4 hours.Under these conditions，2octyl dodecyl ether can be obtained at 79.8% yield rate.The epoxy value measured by hydrochloric acidacetone method is 0.232.The final product structure is confirmed by infrared spectroscopy. Related Articles | Metrics Select Ground Stress Field Inversion and Fracture Prediction Based on MLR-ANN Algorithm ZHANG Bohu, HU Yao, WANG Yan, CHEN Wei, LUO Chao Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (3): 1-12.   DOI: 10.11885/j.issn.1674-5086.2022.08.20.01 Abstract （117）   HTML （15）    PDF（pc） （3743KB）（149）       Knowledge map    Save Shale gas reservoirs are deeply buried in China, and the distribution law of ground stress is complex due to tectonic movement. It is difficult for traditional methods to reflect the magnitude and direction distribution of regional in-situ stress accurately. A coupling algorithm of multiple linear regression and artificial neural network is proposed to invert the shale gas reservoir and surrounding ground stress in Changning-Jianwu Block, southern Sichuan. Using the comprehensive fracture coefficient method, the reservoir fractures are predicted and the fracture development areas are divided. The in-situ stress in the study area is mainly compressive stress, and the direction is about NE115°. The stress around the fault caused by tectonic movement is relatively concentrated, and shear cracks are easy to develop. The cracks are mainly developed and medium developed. The study area has a high degree of fracture development in the upper part of the Wufeng Formation and the structural fault near the bottom of the Longmaxi Formation. The research results have important reference value for well pattern arrangement, fracturing optimization design and casing damage prevention of shale gas extraction. Reference | Related Articles | Metrics Select ULTRALOW TEMPERATURE BREAKER ON CROSSLINKED HPG FRACTURING FLUIDS BY BORANE Chen Fu Yan Xing zhong Lin Tan Fang 西南石油大学学报(自然科学版)    1999, 21 (2): 74-76.   DOI: 10.3863/j.issn.1000-2634.1999.02.21 Abstract （904）      PDF（pc） （235KB）（975）       Knowledge map    Save It is necessary to solve the problem of fracturing fluids being broken in shallow and low temperature reservoirs. Catalysts under low temperature accelerate the breaking capabilities of ammonium persulfate (APS), enzyme and encapsulated breaker. By testing viscosity losses of hydroxyprophyl guar(HPG) crosslinked by borane, some APS/catalysts systems and microencapsulated breaker have been screened at 50℃. Results have been shown that the HPG fracturing fluids can be completely destroyed by APS/catalysts. Related Articles | Metrics Select Research Progress of the Ultrasonic Detection in Phase Behavior of Fluidsin Porous Media Chen Hao;Yang Shenglai;Yu Donghai;Li Fangfang;Zhang Xing 西南石油大学学报(自然科学版)    2013, 35 (1): 67-73.   Abstract （385）      PDF（pc） （385KB）（1024）       Knowledge map    Save So far，the study of the phase behavior of hydrocarbon fluids has been relatively mature. It could supply corresponding theoretical guidance and technical support for the efficient development of the oil and gas reservoirs. However，the effect of porous media on phase behavior mostly is ignored. Therefore，it is crucial to study the phase behavior of fluids in porous media with due consideration of the interactions of the fluids and porous media. With the further development in this field，advantages of the ultrasonic detection such as no limit of pressure and temperature，no effect on fluid compositions，low cost and no harm to human beings have received increasingly attention and the technique is gradually being used in phase behavior of fluids in porous media. In this paper，with reference to abundant literature at home and abroad，detection mechanism of the ultrasonic wave is described briefly and research advances of the ultrasonic detection in phase behavior of gas hydrates and condensate gas system is summarized emphatically. And，the existing problems and future research of this technique are also identified. Related Articles | Metrics Select Optimization of Injection Technique of Corrosion Inhibitor in CO 2-flooding Oil Recovery ZHANG Deping, MA Feng, WU Yule, DONG Zehua 西南石油大学学报(自然科学版)    2020, 42 (2): 103-109.   DOI: 10.11885/j.issn.1674-5086.2019.05.08.01 Abstract （197）   HTML    PDF（pc） （767KB）（1161）       Knowledge map    Save Severe downhole corrosion occurred during Jilin CO 2 flooding in an oilfield in Jilin due to the high pressure of CO 2, high concentration of saline water and sulfate reducing bacteria (SRB) in the produced fluid. Currently, addition of corrosion inhibitors is one of the common methods to protect the oil well and tubes. Through studies of corrosion mechanism and main factor analysis, the effects of inhibitor type, concentration, and injection technique on their filed inhibition efficiency and long-term durability were investigated, aiming at lowering the cost of corrosion management. Then a suitable injection regulation of inhibitor is proposed based on the filed situation in order to improve the long-term efficacy of inhibitor. Injection optimization tests indicate that the corrosion rate has been decreased to <0.076 mm/a. This optimized injection technique of inhibitor not only increases the service life of downhole device and tubes but also decrease the cost of corrosion management. Reference | Related Articles | Metrics Select Mechanism of Organic Matter Enrichment in the Wufeng Formation–Longmaxi Formation Shale in the Upper Yangtze Platform CHEN Lei, DONG Jianhua, HU Yue, JI Yubing, REN Guanbao Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (5): 66-79.   DOI: 10.11885/j.issn.1674-5086.2022.08.26.02 Abstract （42）   HTML （3）    PDF（pc） （17708KB）（144）       Knowledge map    Save The study takes the shale at the bottom of the Wufeng–Longmaxi Formation in the Upper Yangtze Platform as the research object. The organic matter enrichment mechanism of this set of black shale was studied through the test of organic carbon content, major, trace and rare earth elements and other data. The results show that: the shale at the bottom of the Wufeng–Longmaxi Formation in the study area was deposited in a passive continental margin setting with tectonic stability, which was conducive to the enrichment of organic matter; different geological factors exert varying degrees of control over organic matter enrichment, wherein paleoproductivity has shown a non-significant impact on the organic matter enrichment in the bottom shales of the Wufeng–Longmaxi Formation. Conversely, terrestrial input has produced a diluting effect to some extent; during the sedimentation period of the bottom shales in the Wufeng–Longmaxi Formation, the environmental conditions were characterized by dysoxic-anoxic and moderately stagnant settings, which were highly favorable for the accumulation and preservation of organic matter. However, due to a slightly more open water body environment during the deposition period at the base of the Longmaxi Formation compared to that of the Wufeng Formation, there exists a certain degree of difference in the controlling influence of the water body environment on the preservation of organic matter in the two sets of black shales from both formations. The organic matter enrichment in the two sets of shales from the Wufeng Formation and Longmaxi Formation exhibits distinct differences. The organic matter enrichment of the shale of the Wufeng Formation is controlled by productivity-retention environment, and the organic matter enrichment of the shale at the bottom of the Longmaxi Formation is controlled by conservation-open-upwelling ocean current. Reference | Related Articles | Metrics Select Study on the Change of Fluid Production of High Water-cut Stage in Different Producing System Liu Huanle1, Wu Zexin2*, Zhang Bo3, Wu Xiaoyu4 西南石油大学学报(自然科学版)    2015, 37 (1): 123-127.   DOI: 10.11885/j.issn.1674-5086.2012.10.18.01 Abstract （344）   HTML    PDF（pc） （363KB）（827）       Knowledge map    Save In order to further master change law of liquid production when the oilfield enter a period of high water cut production， we study on the change of liquid production in different production system. Based on actual oil production and water drive curve of this block in recently years，according to actual production needs of oilfield，the change of oil production of high water-cut stage in different producing system will be obtained by theoretical derivation when the liquid production is fixed. At the same time，the change of liquid production is studied when the oil production is fixed or reduced at a certain speed. This theory can realize quantification about the change of liquid production. Take a certain block in a true oilfield for example，on the basis of water-flood characteristic curve that is suitable for this block，the change of liquid production of high water-cut stage in different producing system will be obtained by actual data，and provide strongly theoretical guidance for decision-makers. At the same time，this method can be used to other blocks，which has wide application prospects. Reference | Related Articles | Metrics Select Mechanisms of Fluid-rock Interaction and Systems of Soaking in Shale Gas Reservoir: A Research Review YANG Zhaozhong, DU Huilong, YI Liangping, LI Xiaogang, GOU Liangjie Journal of Southwest Petroleum University(Science & Technology Edition)    2023, 45 (6): 80-94.   DOI: 10.11885/j.issn.1674-5086.2022.05.04.02 Abstract （121）   HTML （11）    PDF（pc） （2081KB）（203）       Knowledge map    Save The production practice of shale gas reservoirs shows that soaking the well can significantly increase the initial production after fracturing operation. However, there is a lack of a comprehensive review and summary of the existing literature when it comes to which scientific-soaking system should be selected in a specific situation. Based on the research results of domestic and foreign scholars on the mechanism of reservoir reconstruction and damage, model, influencing factors and engineering process of fluid-rock reaction during shale gas well soaking, we systematically summarize the yield-increasing mechanism and the existing soaking system. The results show that the fluid rock reaction is the essence of soak production under reservoir conditions, and the degree of fluid-rock reaction is the key to formulate soaking system. The interaction of fluid-rock during well soaking can both contribute and damage the reservoir. The transformation of the reservoir includes the initiation and expansion of micro fractures and gas liquid imbibition displacement; the damage to the reservoir includes solid phase plugging during fluid-rock reaction and water phase trap caused by fracturing fluid intrusion. Establishing an unknown bridge between fluid-rock interaction and effective pore structure parameters of reservoir is the key to the study of the systems of soaking. In view of the cross scale and highly nonlinear problems that restrict the research on fluid-rock interaction, the author proposed an effective fracture characterization model based on molecular dynamics and an industrial artificial intelligence optimization model for shale gas well soak. Reference | Related Articles | Metrics Select Experience of Efficient Fracturing of Shale Gas in North America and Enlightenment to China Zeng Fanhui, Guo Jianchun, Liu Heng, Xiao Yong 西南石油大学学报(自然科学版)    2013, 35 (6): 90-98.   DOI: 10.3863/j.issn.1674–5086.2013.06.012 Abstract （261）      PDF（pc） （455KB）（1046）       Knowledge map    Save Shale gas as an important unconventional resource，is essential for our energy security and supply，but the shale reservoir is of low porosity and extra-low permeability characteristics，and hydraulic fracturing is needed to obtain the desired economic output. We summarized the advanced technology used in American shale gas exploitation in the paper. Based on the shale gas reservoir characteristics and technology development of China，we also discussed the directions of large-scale development of shale gas in China. The results indicate that economical development of north American shale gas benefited from the advanced reservoir evaluation，horizontal drilling and hydraulic fracturing. And we also further evaluated the latest developments in north American shale gas，including reservoir evaluation，fracturing material and design optimization，production evaluation. In addition，discussion of technology adaptability and basic principles of various technologies are presented. In order to improve the development of shale gas in China，from exploration to development，we should learn from combining advanced experience with our reservoir features to carry out science and technology research，such as whole optimization of exploration and development，the volume fracturing mechanism and related technology，the evaluation of negative effects of shale gas development. Reference | Related Articles | Metrics Select Researches on Relationship Between Production Allocation and Decline Rate of Gas Wells in Sulige Gas Field LI Peng, FAN Qianqian, HUO Minghui, ZHENG Lanian, YUE Jun 西南石油大学学报(自然科学版)    2020, 42 (1): 126-132.   DOI: 10.11885/j.issn.1674-5086.2018.12.07.01 Abstract （194）   HTML    PDF（pc） （566KB）（1025）       Knowledge map    Save To determine the rational production allocation for gas wells with a certain initial decline rate, Arps decline curve analysis was used to clarify the positive proportionality between new well production allocation and its initial daily decline rate, assuming that the initial production allocation of the gas wells is not affected by their final cumulative gas production. The initial daily decline rate was then converted into the initial annual decline rate to determine the relationship between the gas well production allocation and the initial annual decline rate, and a theoretical chart was established for the degrees of reduction in gas well production and in the initial annual decline rate, which can be used to guide the rational production allocation of new gas wells and determine the workload for gas field capacity building. This study demonstrated that, in reducing production allocation to reduce gas well decline, the magnitude of reduction in gas well decline rate is related to the magnitude of the initial annual decline rate and the magnitude of the reduction in production allocation, rather than the absolute value of the reduction in production allocation. The larger the initial annual decline of the gas wells, the more significant is the reduction in gas well decline through reduction of production allocation. The opposite is observed for gas wells with relatively small initial annual decline, whose reduction decline is not significant through reduction of production allocation. Reference | Related Articles | Metrics Select The Adsorption and Desorption of Coal Bed Methane: A Review ZHU Suyang, DU Zhimin, LI Chuanliang, PENG Xiaolong, WANG Chaowen 西南石油大学学报(自然科学版)    2017, 39 (4): 104-112.   DOI: 10.11885/j.issn.16745086.2015.11.12.05 Abstract （302）   HTML    PDF（pc） （2437KB）（1172）       Knowledge map    Save In this study, we investigated progress in the following three aspects of coal bed methane(CBM) research:adsorption theory and experiments, the effects of water on adsorption and desorption, and liquid-solid adsorption theory. We summarized the achievements of gas phase adsorption theory in studying CBM adsorption, and, in particular, the influence of water. In addition, existing complications in gas phase adsorption theory with regards to CBM adsorption were analyzed, and the new liquid phase adsorption theory and CBM compound desorption model built on its basis were introduced. Different water phases have a variable impact on CBM adsorption. When water saturation is low in the coal sample, equilibrium moisture in the gas phase can significantly reduce the amount of CBM adsorbed. As water saturation reaches critical levels, water content has little effect on the amount of CBM adsorbed. Upon further increase in water content in the coal sample, liquid-state water in the injected coal sample increases the quantity of CBM adsorbed. The occurrence of CBM is not in agreement with the existing gas phase adsorption model. In contrast, the liquid phase adsorption model explains both the hydrocarbon generation condition of coal in an aqueous environment and the absence of critical desorption pressure in gas phase adsorption. Under the conditions of liquid phase adsorption, the desorption of CBM is a compound desorption process controlled by both gas phase and liquid phase desorption. Reference | Related Articles | Metrics Select Research Progress on Functionalization Nanocarbons for Enhanced Oil Recovery LIU Rui, CHEN Zezhou, GAO Shi, PU Wanfen, DU Daijun Journal of Southwest Petroleum University(Science & Technology Edition)    2024, 46 (1): 64-75.   DOI: 10.11885/j.issn.1674-5086.2022.06.13.02 Abstract （130）   HTML （9）    PDF（pc） （2390KB）（184）       Knowledge map    Save Owing to their amphiphilic, and high aspect ratio, functionalization nanocarbons display multifaceted properties of surfactant, molecular film, colloid, liquid crystal molecule and polymer, stimulating their unique advantages and application potential application in enhanced oil recovery. This paper summarizes the common and unique characteristics of the structures and properties of the nanocarbons composing of 1D carbon nanotube and 2D graphene, the preparation methods, and their functionalization routes. The lipophilic-hydrophilic tailoring modification for nanocarbons on harsh reservoir temperature and salinity is proposed. Guided by the universal problem of low sweep efficiency and low micro-displacement efficiency of water flooding reservoirs, the absorption and self-assembly mechanisms of functionalization nanocarbons at water/oil and water/rock interfaces are analyzed, and multi-dimensional characterizations and information-based physical simulations of functionalization nanocarbons are summarized. Based on the nano-scale molecular and cross-scale characteristics and water/oil/rock interface effects, the coupled enhanced oil recovery mechanisms of functionalization nanocarbons on enhancing sweep volume and improving displacement efficiency are elucidated. The papers ends with a critical and perspective outline on the existing problems in the large-scale application of functionalization nanocarbons and their route to the low-carbon cost for enhanced oil recovery. Reference | Related Articles | Metrics Select Reflection on Domestic and Foreign Research Status of Subsurface Safety Valves and Their Domestication LIU Wei, YANG Song, MAI Yu, WANG Yimin, JIANG Shikai 西南石油大学学报(自然科学版)    2018, 40 (3): 164-174.   DOI: 10.11885/j.issn.1674-5086.2016.08.02.02 Abstract （276）   HTML    PDF（pc） （2504KB）（910）       Knowledge map    Save Motivated by the insufficient research and development of subsurface safety valves in China, the structure and classification methods of subsurface safety valves are introduced, and oil tube recovery products from four global oil-service companies and domestic enterprises are analyzed. The comparison shows that foreign companies have characteristic structures and functions of subsurface safety valves but share similar core technologies. The products can adapt to different well depths, temperatures, and pressures; however, domestic products are only applicable for shallow wells and low-pressure environments. The latest research conditions of subsurface safety valves in both China and foreign countries are studied, and the comparative analysis shows that foreign research mainly focuses on the safe reliability and functional diversity, while domestic research only focuses on the preliminary design and either indoor or outdoor detection. Eventually, key technologies of the urgent settlement of the domestication of subsurface safety valves, as well as solutions and thoughts are proposed by considering the present technical state of subsurface safety valves in China. Reference | Related Articles | Metrics Select Modeling of the Reservoir Architecture of Thin Interbedded Deposits MOU Zhonghai, LIU Xue, CHANG Lin, SU Qiu, WU Qianran 西南石油大学学报(自然科学版)    2020, 42 (3): 1-12.   DOI: 10.11885/j.issn.1674-5086.2018.11.21.06 Abstract （254）   HTML    PDF（pc） （28644KB）（2002）       Knowledge map    Save Taking the braided river deltas of the Q6 Block in the Kunbei Oilfield in the Qaidam Basin as an example, this study investigated methods to model the architecture of thin interbedded reservoir sandstones. Traditional methods are based on the relatively maximum values of natural gamma measurements and (or) positive spontaneous potential abnormalities to determine the boundaries of sub-layers. Meanwhile, the sub-layer division based on the tangent points of reflected and diffracted wavefronts can more accurately depict the thickness and depth of reservoir layers, insulating layers, and interlayers. The interlayers in the study area are dominated by localized mudstones. Hence, two parameters, the thickness of low-permeability layers and permeability return level, were adopted to identify the interlayers. This enhanced the model accuracy. Because the braided river deltas were under the hydrodynamic control of both river and lake waves and the strata are characterized by thin interbedded low-inclination sand-mudstones, this study proposes that strict data control, hierarchical modeling and reservoir layer/interlayer nesting should be included to construct an architectural model of the thin interbedded deposits. Subsequently, an architectural model for the braided river deltas of the Q6 Block in the Kunbei region was established. Analysis of the relationships between the architectural units of the model shows that there are four types of architecture in the target layers. They are lateral stitching, lateral separation, progradation, and accretion. Among them, the lateral stitching and vertical accretion modes of the sand bodies are the most developed. Compared to the traditional modeling method, the proposed method is more advantageous and sensible for thin interbedded deposits. Reference | Related Articles | Metrics Select Calculation of Strength Design of Casing Strings He Shiming 西南石油大学学报(自然科学版)    1997, 19 (1): 53-59.   DOI: 10.3863/j.issn.1000-2634.1997.01.011 Abstract （990）      PDF（pc） （303KB）（1060）       Knowledge map    Save This paper discusses the principle of triaxial stress design of casing strings, deduces the strength formula of triaxial stress, and analyzes the overall external loads applied on the casing string.The modified equal safety coefficient method is put forward on the basis of equal scatter coeffi- cient method. The new method is more reasonable than equal safety coefficient method when dealing with external loads, and it improves the design procedure. Based on the proposed method and in combination with the practice of oilfields, the software for strength design of casing string is developed and has been widely used in oilfields. Related Articles | Metrics Select Research Progress, Challenge and Prospect of Nanoscale Oil-displacing Materials for Enhanced Oil Recovery ZHANG Chenjun, JIN Xu, YUAN Bin, ZHANG Lei, ZHENG Shaojing Journal of Southwest Petroleum University(Science & Technology Edition)    2023, 45 (1): 55-70.   DOI: 10.11885/j.issn.1674-5086.2022.04.27.03 Abstract （487）   HTML （29）    PDF（pc） （1589KB）（446）       Knowledge map    Save This review summarizes the research progress of nanoscale oil-displacing materials developed by various researchers, describes the application effect of silica nanoparticles, metal-oxide nanomaterials, polymer nanospheres and carbon nanomaterials, analyses the physical and chemical properties of existing nanoscale oil-displacing agents and their EOR mechanism in porous reservoir media, including nanometer-size effect, wettability alteration, structural disjoining pressure, mobility ratio improvement, and predicts the potential of nanoscale oil-displacing materials in high water cut reservoir, low permeability reservoirs, tight oil and shale oil in China. In addition, the review points out the challenges and research direction in the process of oilfield development, such as testing methods, accuracy of mathematical model, material versatility, economy and industrial production, and provides a theoretical and experimental basis for their large-scale application in EOR. Reference | Related Articles | Metrics Select Annular Aerated Gas-lift Reverse Circulation Drilling Technology and Key Parameters Design LI Qian, ZHANG Xiaolin, LI Zhengtao, LI Juan, DAI Feng Journal of Southwest Petroleum University(Science & Technology Edition)    2021, 43 (4): 35-43.   DOI: 10.11885/j.issn.16745086.2021.04.29.01 Abstract （222）   HTML （5）    PDF（pc） （1736KB）（434）       Knowledge map    Save Using gas lift reverse circulation drilling technology to solve the leakage problem of Changning shale gas surface drilling, it is necessary to solve the problems of conventional gas lift reverse circulation drilling technology, such as open wellhead and inaccurate bottom hole pressure control. Therefore, on the basis of conventional gas-lift reverse circulation drilling technology, a new annular aerated gas-lift reverse circulation drilling technology is designed. The new technology is equipped with rotary blowout preventer, drill pipe cock and other tools, which has well control ability. By adjusting key construction parameters such as gas injection rate and drilling fluid displacement, bottom hole pressure is controlled to reduce drilling leakage. Based on the multiphase flow theory, the calculation model of bottom hole pressure for annular aerated gas-lift reverse circulation drilling technology is established. The influence of key construction parameters on bottom hole pressure is analyzed, and the design method of key parameters is established. The key construction parameters are optimized within the scope of safety window to ensure safe drilling. The results show that the bottom hole pressure first decreases and then rises with the increase of gas injection rate, and there is a critical gas injection rate; the bottom hole pressure rises with the increase of well depth; the bottom hole pressure rises with the increase of drilling fluid displacement. The field test was carried out in the surface drilling of a well in Changning. Compared with the lost circulation formation in the same section, the lost circulation was reduced by 83.6% using the conventional drilling technology. The research results provide a new technical measure to solve the problem of lost circulation in the surface drilling of Changning shale gas in Sichuan. Reference | Related Articles | Metrics Select NEW METHOD OF CALCULATING WELLBORE TEMPERATURE IN GAS WELLS Mao Wei Liang Zheng 西南石油大学学报(自然科学版)    1999, 21 (1): 56-58(6.   DOI: 10.3863/j.issn.1000-2634.1999.01.014 Abstract （886）      PDF（pc） （272KB）（916）       Knowledge map    Save Knowing the temperature distribution in gas well is of great importance to gas well design and dynamic analysis; accurate prediction of wellbore temperature distribution can improve the accuracy of wellbore pressure prediction. Based on energy conservation law, a mathematical model for calculating wellbore temperature distribution in a gas well has been developed. This model assumes steady-state heat transfer inside the wellbore and transient heat transfer in the adjacent formation. Data from the literature are used to testify the validity of the model. Results indicate that the temperature distribution predicted by the model agrees well with the measured data. Related Articles | Metrics Select THE RESEARCH AND APPLICATION OF PERMEABILITY, POROSITY AND NET OVERBURDEN PRESSURE LAWS WU Fan SUN Li-juan HE Jiang 西南石油大学学报(自然科学版)    1999, 21 (4): 23-25.   DOI: 10.3863/j.issn.1000-2634.1999.04.007 Abstract （1101）      PDF（pc） （245KB）（1286）       Knowledge map    Save Studying the variation of porosity, permeability and the net overburden pressure in formation, can guide the development and modification of oilfields, to statistical and analysis and research on the natural core data of Zhongyuan oilfield by using the newly introduced cmx-300, the core automatic analyzer developed in late 1980’and applied to study high-pressure porosity and permeability were made. The research shows that the relationship between formation porosity, permeability and net overburden pressure is closely related to univariate quadratic equation; when porosity matches net overburden pressure with exponent relationship, the presented physical significance is clearer, the accuracy requirement can be met and the compressibility of rocks can gained automatically. The compressibility and average hydraulic radius of the rocks is exponential is put forward; the ratio of permeability under the net overburden pressure and ground permeability is only related to the value of the overburden pressure, but nothing to do with the surface permeability. Related Articles | Metrics Select Effects of Morphology of Hydraulic Fractures on Acid Etching Behaviors and Fluid Diversion Capacity GOU Bo, LI Xiao, MA Huiyun, ZHOU Changlin 西南石油大学学报(自然科学版)    2019, 41 (3): 80-90.   DOI: 10.11885/j.issn.1674-5086.2018.10.28.01 Abstract （368）   HTML    PDF（pc） （3571KB）（873）       Knowledge map    Save At present, most simulations of hydraulic fractures are conduced based on the assumption of smooth parallel plates, ignoring the effects of the morphology of the fractures on acid etching behaviors and fluid diversion capacity. A self-developed device named "acid pressure test system for fracture fluid diversion" was used to simulate smooth and rough fractures, respectively, with smooth and rough plates to study the characteristics of acid etching behaviors and diversion capacity of the two types of fracture morphology with different acid injection volumes and periods. The results show that the tortuosity of the fracture profile increased after acid etching for smooth fractures, whereas the opposite was observed for rough fractures, as acid etching reduced the peaks and deepened the troughs. Increasing the acid injection volume or period led to significantly larger change in elevation, fracture width, acid dissolution amount, and diversion capacity for rough fractures than for smooth fractures, whereas the former had not only better retention ability of fluid diversion, but also higher sensitivity to changes in acid injection parameters. In conclusion, the assumption of rough plates is beneficial for realistically evaluating the diversion capacity of acid pressure fractures under reservoirs, thus improving the targetedness of the acid pressure scheme design and the acid pressure effect. Reference | Related Articles | Metrics Select Quantitative Evaluation of Single Well’s Water Breakthrough Types in theTahe Fractured-vuggy Reservoir Long xu;Li Peng;Kang Zhihong;Niu Yujing;Cui Wenbin 西南石油大学学报(自然科学版)    2012, 34 (4): 127-134.   Abstract （490）      PDF（pc） （833KB）（708）       Knowledge map    Save The reservoir types in Tahe oilfield consist of cave，fracture，crack-cave，cave-fracture and fracture-vuggy，which makes the problems complicated in the actual production，such as violent water flooding，stop ping blowout，production decline and invalid coning water. We can evaluate the effect of different reservoir types or engineering measures on production through the analysis of water flooding curve changes. The following two methods of water breakthrough speed were commonly evaluated：1）evaluating water breakthrough speed quantitively according to the shape of production curve，and dividing oil wells into types of slow rising，sudden rising and ，water and intermittent rising etc. 2）evaluating water breakthrough speed of single well or wells simplely using the watercuts in two points of time. Based on the disadvantage of the conventional methods， this paper makes a careful analysis in oil production curve，and forms a new dual water curves to analyze the well’s dynamic production. By using a new evaluation parameter-water/oil ration(the slope of the fitting line，k)，we evaluate the speed of water breakthrough quantitively. At last，the authors classified the water breakthrough types of the wells in No.4 block，in Tahe Oilfield. Related Articles | Metrics Select Prediction and Application of the Shaft Friction Coefficient Based on Drill-string Dynamics SONG Wei, HU Zhongzhi, ZHOU Yan, SHEN Yuanyuan, WEI Na 西南石油大学学报(自然科学版)    2020, 42 (1): 84-90.   DOI: 10.11885/j.issn.1674-5086.2018.07.19.04 Abstract （206）   HTML    PDF（pc） （789KB）（1071）       Knowledge map    Save Accurate prediction and control of friction torque during the design and construction of drilling phases can prevent drilling accidents, and the shaft friction coefficient is a key factor in predicting friction torque. Therefore, we predicted the friction coefficients for the casing and open-hole sections for highly-deviated well drilling based on a calculation model for friction torque. This was based on drill-string dynamics and data from a near-bit, multi-parameter measuring instrument. The results were successfully applied to the analysis and control of friction torque in the third-spud drilling stage of adjacent wells of the same type. The field application results revealed that the friction coefficient of the actual drill casing was 0.27~0.29, and the friction coefficient of the open hole was 0.39~0.41, both of which are higher than the empirical values. The error between the predicted and actual values of the hook load and the torque of the case satisfied the construction accuracy requirements. The friction torque during actual drilling was monitored in real time to detect abnormal changes based on the friction torque prediction chart, which ensured smooth construction of the well. The results provide a scientific basis for optimizing drilling equipment and the well profile of highly deviated wells, and for planning the on-site drilling construction. Reference | Related Articles | Metrics Select STREATHEN GAS INJECTION FOR ENHANCED OIL RE COVERY Li Shi-lun Guo Ping DaiLei Sun Lei 西南石油大学学报(自然科学版)    2000, 22 (3): 41-45.   DOI: 10.3863/j.issn.1000-2634.2000.03.011 Abstract （1616）      PDF（pc） （176KB）（1163）       Knowledge map    Save Enhance Oil Recovery (EOR)is one of the permanent top-ics in research on Oil/gas reservoir development. Because of low oil price, the demand for chemical drive is keeping decreasing and for gas drives increasing. The reservoirs in East China oil fields are non-marine deposits with Serious heterogeneity and high viscosity crudes, Water Cut increases very fast, recovery by water drive is relatively low, only 33%.The reserve discov- ered recently is difficult to produce because of low permeability of the reservoirs and high viscosity of the crudes, streathening gas injection for enhanced oil recovery has become an urgent strategy in on shore petroleum industry development. China launched the evaluation in the second time on tertiary recovery potential in 1998.By statistics, the geological reserve suitable for gas injection(CO2) miscible flooding is over 10.57×108 tons. By combination of foreign experience and the analysis and evaluation on China’s tertiary recovery potential, it is recog-nized that the oil fields in east china oil- bearing provinces should streathen non-gas drive and the oil field in west china should be hydrocarbon drive dominant. The key to gas drive is gas resource, the discovery of CO2resource should be placed at-tention to, and the technology to generate N2and CO2, inject and sperate N2should be probed. The development of compres-sion facility-home made, pilot tests of gas drive and dry gas recycle for gas condensate reservoir with rich condensates should be speeded up. Related Articles | Metrics Select Processing Method to the Data of Relative Permeability in Unsteady State Displacement Dong Dapeng 西南石油大学学报(自然科学版)    2014, 36 (6): 110-116.   DOI: 10.11885/j.issn.1674-5086.2012.08.30.07 Abstract （326）   HTML    PDF（pc） （362KB）（693）       Knowledge map    Save JBN method is compared with Jones′ graphical technique by formula deriving and converting. It is concluded that the essential difference between the two methods is the different reference permeability of the rock. When calculating relative permeability，oil permeability at irreducible water saturation is a more suitable reference than the flowing ability of oil and water. The author made a comparison among Polynomial function，logarithmic function and exponential function when fitting average water saturation and total injection volume. The result shows that logarithmic function and exponential function have good fitting accuracy if piecewise fitting is carried out. Furthermore，oil ratio calculated by these two fitting function is more reasonable. We obtain similar oil relative permeability but quite different water relative permeability when using different functions to fit 1/Qi and 1/(IQi). Linear function，polynomial function and power function are compared，and the result calculated by power function is more reasonable. Reference | Related Articles | Metrics Select Molecular Simulation for Inorganic Salts Inhibition Mechanism on Illite Hydration LIU Meiquan, PU Xiaolin, ZHANG Qian, SU Junlin Journal of Southwest Petroleum University(Science & Technology Edition)    2021, 43 (4): 81-89.   DOI: 10.11885/j.issn.16745086.2021.04.29.15 Abstract （240）   HTML （9）    PDF（pc） （1281KB）（311）       Knowledge map    Save In order to study the microscopic mechanism of illite hydration expansion and the mechanism of inorganic salt inhibitors, two illite crystal models (1M-tv and 1M-cv), which are common in oil and gas reservoirs, were established through molecular simulation technology. Furthermore, molecular dynamics method was used to study the microscopic distribution of illite interlayer particles and the hydration parameters of inorganic salt cations entering the interlayer. The results show that the interlayer spacing of illite increases with the number of adsorbed water molecules. It reaches saturation when the number of molecules is 20; 1M-tv configuration is more prone to hydration expansion than 1M-cv configuration; K + and Ca 2+ are the smallest hydration numbers and hydration radius of monovalent cations and divalent cations, respectively. In addition, K + can be embedded in the silicon-oxygen six-membered ring of the tetrahedral sheet, making it difficult for ion exchange to occur, which can effectively prevent water molecules from entering the inside of the illite crystal structure. The experimental results well verify the inhibition of KCl and CaCl 2 on illite hydration expansion. The results have important theoretical significance for the study of shale anti sloughing mechanism and drilling fluid hydration inhibitor. Reference | Related Articles | Metrics