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Table of Content

    20 April 2011, Volume 33 Issue 2
    专家论坛
    CHEMICAL FLOODING RECOVERY MECHANISM OF NATURAL CORES
    WANG De-min WANG Gang XIA Hui-fen YANG Shu-ren WU Wen-xiang
    2011, 33(2):  1-11.  DOI: 10.3863/j.issn.1674-5086.2011.02.001
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    Results of Newtonian Fluids flooding very homogeneous porous media show the displacement efficiencyof the system is determined by the capillary number of the driving fluid. The experience gained from chemicalflooding natural cores and reservoirs that are all micro-heterogeneous or macro-heterogeneous to some degree showsthat displacement efficiency is influenced, besides capillary number, by many other factors. Newtonian Fluids donot haveelasticproperties; when flooding, there is no change in the wettability of the system; there is no imbibition;emulsions are not formed; and there is no alteration of thegeometry of the pores. However, when chemicallyflooding, elasticity markedly effects the displacement efficiency; change in wettability could occur; emulsions welloften show up, and from core and field tests data, emulsions significantly increases the recovery, emulsions canincrease the volumetric sweep oftheporoussystems and markedly alter the phase permeability behavior and water cut. The wettability will change and imbibition will occur; pore geometry alteration by solution and precipitation will happen, which influences the permeability, imbibition and recovery. The above factors all markedly influence
    the displacement efficiency of the system, especially when many factors act jointly. The concept of ultimate and economical displacement efficiency and its effect on the selection of actual field flooding systems is analyzed(Many papers analyze ultimate displacement efficiency. however, in oil field, usually economical displacement efficiency is more important). Besides capillary number, the above factors should be considered when developing and selecting chemicals and flooding systems. The above insights can further deepen our knowledge of the mechanism of chemical flooding, promote further research in this area and form better criteria for designing, developing, screening and selecting EOR chemicals and flooding systems in oil field.
    地质勘探
    SOURCE ROCK FEATURES AND EVALUATION OF TRIASSIC STRATA IN THE CEN-TRAL JUNGGAR BASIN
    WANG Bin;WU Ming WANG Xu-long ZHANG Yue-qian CAO Jian
    2011, 33(2):  12-20.  DOI: 10.3863/j.issn.1674-5086.2011.02.002
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    According to the organic geochemical and petrological analyses on Triassic mudstones from Well MS 1,the organic matter abundance, type and maturity are revealed. And the hydrocarbon generative potential is addressed
    and evaluated. The results show that the organic matter abundance is between 0.17%~9.11% and the average value is 1.62%, reaching the standard of high-quality source rock. The organic matter are mainly derived from higher plant, the kerogen type is from II2 to III. The organic matter has gone into mature stage. Thus, the Triassic mud-stones are favorable for hydrocarbon(especially gas)generation. Considering that the source rock potential of the Triassic strata has not been well constrained, this study provides a new reference information for regional oil and gas exploration nationally and internationally.

    THE PETROPHYSICS CHARACTERIZATION OF CLASTIC RESERVOIR AND THE ME-THODS OF LITHOLOGY
    CHEN Gong-yang ZHOU Yan-li HU Yong
    2011, 33(2):  21-27.  DOI: 10.3868/j.issn.1674-5086.2011.02.03
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    The analysis of the petrophysics characterization of clastic reservoir shows that the variation of P-wave velocity was controlled by the sedimentation and diagenesis, and therefor leads to the regular variation of acoustic impedance. The sedimentation was mainly represented by the grain size, sorting and shale content, and the diagenesis mainly includes the compaction,pressolution and cementation. Using the method of classic single impedance threshold only resolves the vertical variation of acoustic impedance. As a result, the paper proposes a more effective method of impedance threshold volume. Through studying example, using the new method can explain the acoustic impedance accurately, which has played good effect in solving the uncertainty of the sand explanation because the areal variation of acoustic impedance caused by the deposition.
    GEOLOGICAL REGIONAL SELECTION AND AN EVALUATION METHOD OF RESOUR-CE POTENTIAL OF SHALE GAS
    LI Yan-Jun;LIU Huan LIU Jia-Xia CAO Li-Chun JIA Xue-Cheng
    2011, 33(2):  28-34. 
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    With the quickening step of China’s shale gas exploration and development, the establishment of evaluation criteria of shale gas and the evaluation method of specific geological constituencies has become the prerequisite
    and foundation of exploration and development. The optimization of favorable area can provide an important basis for further decision-making of the exploration and further study. According to a large number of foreign shale gas exploration and development cases, the main geological characteristics of shale gas are summarized. Based on the shale gas development practice of foreign countries, geological and geochemical parameters and the specific geo-
    logical conditions of domestic basins, six evaluating parameters for selecting favorable shale gas area are optimized according to their generating capacities, storage capacities and easy exploitations. At the same time, the evaluating index is defined, and the grading standards are established. Meanwhile, a simulation of the application of the evaluation method in selecting the favorable geological zones has been carried out in a certain region of a basin. Finally,the common quantitative calculation methods of shale gas potential are summarized systematically. Considering the complex geological backgrounds of China and the status that shale gas is less explored and developed, the analogy method and volume method are recommended to be used comprehensively to calculate the resources.

    GEOLOGICAL REGIONAL SELECTION AND AN EVALUATION METHOD OF RESOUR-CE POTENTIAL OF SHALE GAS
    LI Yan-Jun;LIU Huan LIU Jia-Xia CAO Li-Chun JIA Xue-Cheng
    2011, 33(2):  35-42. 
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    With the quickening step of China’s shale gas exploration and development, the establishment of evaluation criteria of shale gas and the evaluation method of specific geological constituencies has become the prerequisite
    and foundation of exploration and development. The optimization of favorable area can provide an important basis for further decision-making of the exploration and further study. According to a large number of foreign shale gas exploration and development cases, the main geological characteristics of shale gas are summarized. Based on the shale gas development practice of foreign countries, geological and geochemical parameters and the specific geo-
    logical conditions of domestic basins, six evaluating parameters for selecting favorable shale gas area are optimized according to their generating capacities, storage capacities and easy exploitations. At the same time, the evaluating
    index is defined, and the grading standards are established. Meanwhile, a simulation of the application of the evalu-
    ation method in selecting the favorable geological zones has been carried out in a certain region of a basin. Finally,
    the common quantitative calculation methods of shale gas potential are summarized systematically. Considering the
    complex geological backgrounds of China and the status that shale gas is less explored and developed, the analogy
    method and volume method are recommended to be used comprehensively to calculate the resources.
    THE CHARACTERISTICS OF SEQUENCE STRATIGRAPHY AND DEPOSITIONAL SYS-TEMS OF THE PALAEOGENE DONGYING FORMATION IN LIAOZHONG SAG
    LI Quan LIN Chang-song WU wei WANG jun YU Li-sha
    2011, 33(2):  43-50. 
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    According to the high-resolusion sequence stratigraphy theory and method, the Dongying strata in the Liaozhong Sag has been divided into three 3rd order sequences and six 4th order sequences based on the integrated
    study on cores, well logs, cryptogam and seismic data. Several kinds of depositional systems have been identified,such as alluvial fan /fan delta deposits, fluvial and delta deposits, incised valley filling, sea-gull deposit, floodingm basin deposit, lacustrine deposit, gravity or turbidity flow deposit, and so on. The best favorable sequence place for lithology exploration such as turbidity system and subsea apron are identified based on the complication of the 4th order sequence. The position is the bottom of the 4th order sequence and the top of the 3rd order sequence of SQd2 and SQd3. Through the analysis of the characteristics and positions of the depositional system, it can be concluded that the types and position of the depositional system are controlled by palaeostructure and palaeoclimate.

    CHARACTERISTICS OF PERMITTIVITY OF CORES AND ITS APPLICATION IN FLU-IDS IDENFICATION
    LIU Hong-qi;a DENG You-ming QIU Chun-ning a GUO Zhao-xue;b LIU Jing
    2011, 33(2):  51-54. 
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    Complex electrical well logging has been widely used in many oilfields. It is a powerful method for the low-resistivity, water-flooded and residual oil zone. However, frequency dispersion and incorrecte calculation of the real and image part of complex resistivity are the main reasons that restrict its development. The principle of complex resistivity logging are studied in this paper, and it is found that permittivity of the rocks and formation fluids have more distinguished response than resistivity of them. The previous experiments have been proved that the permittivity decreased with the distance square between two poles. Based on the results of the experiments, the new equations to calculate the saturation and salinity of formation water have been established, in addition, a circute that used to detect capacitivity is designed. The new method has been shown available for identifing the fluid by the oilfield data.
    CHARACTERISTIC OF DIAGENESIS AND SECONDARY POROSITY OF NORTHERNGLUTENITE IN NORTHERN DONGYING SAG
    YANG Yuan-liang;
    2011, 33(2):  55-60. 
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    Based on the analysis of thin section, SEM and the reservoir property data, the digenesis and characteristics of the development of the secondary porosity in the glutenite of northern Dongying Sag are studied. Glutenite
    fans such as nearshore subaqueous fan, deep water turbidite fan are developed in the northern part of Dongying Sag. They have a low maturity in composition and structure. Glutenite reservoir has experienced many kinds of
    diagenesis, such as compaction, cementation, dissolution and so on. Mechanical compaction is the main compaction. Cementations are mainly carbonate cementation, quartz overgrowth and clay minerals cementation. Dissolution comprises carbonate cementation content dissolution, feldspar particles and limestone debris dissolutions. Accordingt the characteristics of vitrinite reflectance, fluid inclusion thermometry, and clay minerals mixed-layer proportion,it is ascertained that the glutenite has experienced stage A and B of the early diagenesis, and stage A of the middlediagenesis. At the same time, the pores have experienced an evolutionary process from primary to secondary. In this area, secondary pore mainly develops in the range of 1 650~2 450m. Compared with Binnan and Shengtuo area,secondary porosity in Lijin is less developed.
    ANALYSIS ON STRUCTURAL DEFORMATION STAGES AND DYNAMIC GENESIS OFTRUST BELT IN LONGMEN MOUNTAIN
    DAI Jian-quan
    2011, 33(2):  61-67. 
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    Through abundant field surveys, the structural elements which can reflect the deformation trace of paleostructural stress field such as Beichuan-yingxiu fault, foreland fault, are summarized and analyzed. Then, the structural stages and mechanical properties of structural trace are analyzed. Thus, the structural deformation history and stress history are recovered. The result shows that the Longmen Mountain has witnessed more than ten times of structural deformations with different directions and different stress properties. Combined with the theory of regional tectonics, dynamic interpretation is performed in this article.
    RESERVOIR PARAMETER PREDICTION BY MULTI-ATTRIBUTE BASED ON HYBRIDLEARNING ALGORITHM OF FEED-FORWARD NETWORK
    WU Qiu-bo;WU Yuan WANG Yun-cheng
    2011, 33(2):  68-72. 
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    When applying the feed-forward network to describe the nonlinear relationship between seismic attributes and reservoir parameters, the classical error back propagation(BP)learning algorithm has slow convergence and
    is easy to fall into local minima, and has many other deficiencies. This paper researches a new reservoir parameter prediction technique by seismic multi-attribute which is based on the integration of particle swarm optimization
    (PSO)algorithm and BP algorithm of the feed-forward network. PSO is agroup random search evolutionary computation technique, has a faster convergence rate and strong global search ability; BP algorithm is essentially a gradient descent algorithm, focusing on local search. Hybrid algorithm trains network by PSO and BP alternatively. That is, when the learning error energy of PSO in required generation has not changed, using BP for local search disturbances. Function approximation test and practical reservoir parameter prediction experiment illustrate the hybrid learning method has a short training time, high efficiency and reliability, and has good prospect.

    INFLUENCES OF CLAY MINERALS ON PHYSICAL PROPERTIES OF TIGHT SAND-STONES OF XUJIAHE FORMATION IN GUANG’AN AREA
    SONG Li-hong;ZHU Ru-kai ZHU De-sheng SUI Shao-qiang ZHOU Chuan-min
    2011, 33(2):  73-78. 
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    Clay minerals are widely distributed in the T3x, they are important source rocks and cement in tight sandstones, and they are the main controlling factors of the qualities of reservoirs. Based on the appraisal of the core
    thin section, clay minerals in sandstone are analyzed comprehensively and systematically by using SEM and X-ray.The result shows that the chlorite rim which is developed in the early stage of diagenesis can prohibit the overgrowth of quartz, so it is very important for the preservation of primary porosity. Authigenic illite seriously reduces porosity and permeability by cutting the primary and second intergranular pores into micro-pores. Authigenic kaolinite often forecasts secondary pore development zones which are only founded in T3x6 member.
    AN ANALYSIS OF THE MAIN CONTROLLING FACTORS OF THE RESERVOIR FOR-MATION OF UPPER TRIASSIC YANCHANG FORMATION IN ORDOS BASIN
    LI Song HU Zong-quan YIN Wei LIU Zhen PAN Gao-feng
    2011, 33(2):  79-83. 
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    It is concluded that there are favorable conditions for oil accumulation in Zhenjing Area through the detailed analysis of many aspects of the Upper Triassic Yanchang Formation in Ordos Basin, such as hydrocarbon source conditions, reservoir conditions, reservoir-cap rock combination and the type trap. The research results of the controlling factors of oil reservoirs and the enrichment regularity indicate that the tectonic evolution controls
    oil reservoir adjusting direction, old oil reservoir migrates to the north-east direction. Organic matter abundance distribution of hydrocarbon source rocks controls the oil accumulation. The area where the organic matter abun-
    dance is more than 1 percent has favorable conditions for oil accumulation. The favorable deposit belts control the enrichment of oil and the underwater distributary channel of deltaicfront subfacies are close to hydrocarbon sources,
    and have better sand body physical properties and a large thickness, making it a favorable site for the accumulation of petroleum. The dynamic reduction of fluid controls the migration direction of petroleum in reservoring time.
    The bigger the dynamic reduction of fluid is, the more petroleum will be accumulated. The fracture serves as the migration channels for the hydrocarbon enrichment, and the porosity increasing caused by the fracture will further affect the hydrocarbon enrichment.

    THE LOGGING EFFECTIVENESS EVALUATION OF COMPLEX CARBONATE RESER-VOIRS
    ZHANG Shang-hua;SIMA Li-qiang YAN Qi-bin ZHAO Hui LIU Ji-yan
    2011, 33(2):  84-88. 
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    The effectiveness of fracture largely depends on fracture apertures and radial extension. Formation microresistivity image logging can effectively identify the fracture, but it can not judge radial extension. Using formation micro-resistivity imaging logging with ARI logging can determine the effectiveness of fracture. In the absence of advanced logging technology, the use of differences of dual lateral logging can also be used to determine the effectiveness of fractures. For the carbonate rock reservoir with the complex pore structure, layered strata, isolated cavity strata, conventional logs response characteristics alone will often lead to the wrong interpretation. Conclusions must be based on reservoir geological characteristics to make an reasonable assessment of reservoir effectiveness.
    EVOLUTION AND DEPOSITING RESPONSE IN DUNHUA BASIN
    CHEN Xiao-hui ZHANG Ting-shan XIE Xiao-an WANG Hai-feng LAN Guang-zhi
    2011, 33(2):  89-94. 
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    Dunhua Basin is located in the middle of Dunhua Mishan Graben. And it is a rift-fault depression superposed basin which is controlled by the Dunhua Mishan fracture zone. A series of tectonic system transitions happens
    during the Mesozoic and Cenozoic period in the Dunhua Mishan fracture zone. The transitions starts in the Late Triassic. In the Late Jurassic, it is compressional; during the Cretaceous–Paleogene, it has a left-lateral displacementand a certain scale of extension; there is a compression in the lat e Paleogene, which then turns into the extensionstate again after Neogene. The evolution of Dunhua Mishan fracture zone plays a controlling role in the gener ation,development and evolution of the Dunhua basin. The evolution of the Dunhua Basin in the Mesozoic–Cenozoic period is: the compressional orogeny, strike slip & pull-apart and the initial rifting stage in Late Jurassic–Early Cretaceous (rift development stage); the inversion, uplifting and exhumation stage in Late Cretaceous-Paleocene;rift basin development stages in the Eocene–Oligocene period and Depression and basalt eruption stage after the Neogene. Different evolution stages have different deposition response characteristics.
    A CALCULATION METHOD FOR RELATIVE PERMEABILITY CURVE OF STRESS SEN-SITIVE
    DENG Yong;PENG Guang-ming
    2011, 33(2):  95-98. 
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    For the stress sensitive reservoir, the change of reservoir pressure can result in the decline of porosity and permeability and affect the flow feature and rule, so the relative permeability curves’ shape will change. The prerequisite of reservoir engineering research is to obtain the relative permeability curves under different reservoir pressure. The pore network technology is one of the effective methods to predict and calculate relative permeability.Based on the technology and considering the stress sensitivity, the dynamic models of pore’s microscopic structure characteristic parameters are established, the variation of relative permeability curves under the change of reservoir
    pressure is calculated and the experiment data is fitted. It is verified that the method can be used for the calculation of relative permeability for the stress sensitive reservoir, and the necessary parameter can be given for the study of
    reservoir engineering.
    SEQUENCE BOUNDARY IDENTIFICATION OF NEOGENE SHAWAN FORMATION INCHEPAIZI AREA IN JUNGGAR BASIN
    YANG Shao-chun LUO Hai-ning YE Guang-hui ZHANG Shi-qi XIANG Kui
    2011, 33(2):  99-103. 
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    Based on the sequence stratigraphy theory, through the comprehensive analysis of geological, seismic,drilling, logging and outcrops of Neogene Miocene Shawan group strata of Chepaizi Area in the Junggar Basin,
    Neogene Shawan group can be divided into two third-sequences from the bottom to the top: N1SSQ1 and N1SSQ2.A total of 3 third-sequence boundaries are identified. Through identifying and comparing the unconformity surface,conformity, the initial lake flooding surface and the largest lake flooding surface, etc., beginning with the study of sequence division, the identifying characteristics of the system tract and parasequence sets boundary are analyzed deeply, the isochronous sequence stratigraphic framework of the study area is set up.
    石油与天然气工程
    STUDY ON PRODUCTION DECLINE MODEL IN SULFUR DEPOSITION RESERVOIR
    LIU Yong-liang XU Yan-xia XU Yan-mei HUANG Wei-gang LIU Bin
    2011, 33(2):  104-108. 
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    In the previous studies, the data of the high sulfur gas reservoir development research are difficult to obtain in the actual operation. Considering sulfur deposition near wellbore, the mathematical model of production decline in sulfur deposition composite gas reservoir is established. The production decline Blasingame type curves of single gas well in high sulfur gas reservoir are drawn with Stefest numeric inversion. Then, the characteristics of curves and influence factors are discussed. The non-dimensional production decline integral derivative curves concave down deeper at middle period of production decline curves with the growth of sulfur saturation. When the sulfur saturation increases to 50%, the integral derivative curves sink to the deepest level and the integral derivative value is minimum. The smaller the radius of sulfur deposition is, the earlier the flattish stage of the non-dimensional
    production decline curves will appear. A straight line with slope of -1 is emerged in both the integral and integral derivative curves at late period of the production decline curves, which is the indication of harmonic decline. The
    study findings are superior to the pressure build up test, therefore, this study is of great value in the exploration and development of gas reservoir with high sulfur.
    STUDY ON WELL PATTERN ADJUSTMENT METHOD OF FRACTURED LOW-PERMEA-BILITY OIL RESERVOIR
    GAO Ming;SONG Kao-ping ZHANG Ying-zhi YANG Er-long WANG Wei-guo
    2011, 33(2):  109-114. 
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    Based on the fracture development characteristics and water flooding development performance of Fuyang Formation in Dong16 Block of Daqing Yushulin Oilfield and combined with the saturation distribution of remainin
    oil in present Block, the effect of fracture on remaining oil distribution and the development effect is analyzed, which provides evidence for the injection-production system adjustment. According to the characteristics of Fault Block
    Dong160 and Fault Block Sheng371, 4 sets of infill programs are designed and the development prediction index is optimized. The results show that fracture is in the same direction with well line in Fault Block Dong160 and effective
    displacement can not be established between oil and water well lines, so the well spaces should be shorten. After infilling wide spacing and small row spacing the linear water injection is formed. In Fault Block Sheng371 fracture
    direction is at the angel of 12.5? to well line direction and effective displacement can be established between oil and water well lines. The optimized Program 4 in which the triangular gravity infilling is selected to change flow field direction is more beneficial to exploit remaining oil enriched areas.
    STUDY ON THE FLOWING PERFORMANCE OF GAS WELLS IN DUAL-POROSITY DE-FORMABLE FRACTAL RESERVOIRS
    FAN Huai-cai;LI Xiao-pingi;DOU Tian-cai CHEN Jun YUAN Fu-feng
    2011, 33(2):  115-120. 
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    In the process of developing the deformed double porosity media reservoirs, the rock stress-sensitivity will apparently effect the performance of development. In this paper, the deformed double porosity mathematic
    model is established and the permeability stress-sensitivity is presented on the basis of considering double porosity media and deformable performance of rock. Through Laplace transformation, the Laplace space analytic solution
    has been obtained and converted into real space solution by means of the numerical inversion of Stehfest and the solution of the mathematic model is obtained. On the basis of the varying relation between the dimensionless rate and dimensionless time, the influence of the storativity ratio, the interporosity flow parameter, the dimensionless stresssensitivity and skin coefficient on gas well flux dynamic characteristics has been analyzed. The research result is
    of actual significance to develop deformed double porosity media reservoirs reasonably and to ensure the normal production of the gas wells or reservoir.
    STUDY ON THE VISUAL MODELING OF WATER FLOODING IN CARBONATE FRAC-TURE-CAVITY RESERVOIR
    WANG Lei;DOU Zhi-lin LIN Tao ZHAO Hai-yang LUO Juan
    2011, 33(2):  121-124. 
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    :This paper focuses on the research of water flooding mechanism in fracture-cavern reservoirs by visualized physical simulation. The effects of different injection fluids, injection directions and injection angles on flooding, and the oil and water distributions before and after water injection are obtained directly. The experiment of gas injection to enhance oil recovery has also been conducted. The results indicate that the location of fractures and caverns has a significant impact on water flooding, and gravity differentiation plays an important role in the fracture-cavern model. The formation and distribution of remaining oil is mainly affected by channel irregularity and gravitational capture. Residual oil mainly distributes in the“attic storey”, in which the top caves and head of bottom caves the residual oil is difficult to flood. They are also the main displacement space of gas injection. Once the water channel was formed during the displacement, remaining oil in caves would be difficult to displace. Changing the way of water injection or injection media, such as gas injection, is possible to further displace the remaining oil in caves, so that to enhance the recovery. Sequent gas injection experiments demonstrate that remaining oil in the attic storey can be driven obviously by changing the way of gas injection.
    ANALYSIS OF ADAPTABILITY OF WELL NETWORK TO ADVANCED WATER INJEC-TION IN LOW PERMEABLE RESERVOIR
    WANG Jing-yao MA De-sheng LI Jun JIANG You-wei ZHAO Man-ping
    2011, 33(2):  125-128. 
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    Based on the analysis of 5 experimrntal areas of advanced water injection, adaptability of well well network in thye study area is numerically simulated with the analysis method of balancing between injection and production and by combining theoretical and dunamic analysis of study area. After analyzing the relationship between pressure and number ratio of oil well and water well, between contra output of liquid and number ratio oil well and water well, formation pressure and production fluid index with water absorption and that water percentage of different well network and output degree. The authors clarify the influence of well network on formation pressure, oil producing rate and increase of water percentage. The analysis reveals that formation pressure monotone decrease with the increasing of ration of oil and water well, and that fluid production can be increased by adjusting well
    network and there is no clear relationship between well network and increasing in water percentage.
    FORECAST MODEL OF LOCATION OF SULFUR DEPOSITION IN THE WELL BOREOF HIGH SULFUR GAS WELL
    FU De-kui GUO Xiao DU Zhi-min DENG Sheng-hui LIU Lin-qing
    2011, 33(2):  129-132. 
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    During the course of production of high sulfur gas well, temperature and pressure falls continually along well bore, solubility of sulfur particles in gas phase declines, and sulfur particle precipitate in well bore from gas phase
    after running up to saturation state if velocity of gas is less than critical sustaining velocity of particle, sequentially resulting in blockage of gaseous flow channel. Gas well production may halts when sulfur deposition became severe. In this paper, an integrated forecast model of sulfur deposition in high sulfur gas well is presented by coupling pressure and temperature forecasting model, critical sustaining velocity model of particle and model of solubility of
    sulfur particles in gas phase. A case analysis is carried out in well-L. The result shows that, with production decrease,gaseous velocity gradually declines, and therefore, area of sulfur deposition steps up along borehole after production
    declines to critical production.
    RESEARCH ON LABORATORY EXPERIMENTS OF CO2 DRIVE IN ULTRA-LOW PER-MEABILITY RESERVOIR
    LIU Shu-xia
    2011, 33(2):  133-136. 
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    Aiming at the following problems in the ultra-low permeability reservoir in Daqing external field, such as big residual potential, poor infilling effect, low oil recovery ratio of water flooding, the CO2 flooding technology of the ultra-low permeability reservoir is put forward. Through the slim tube experiment and the CO2 displacement experiment of natural core, the minim miscibility pressure of CO2 and oil of Gaotaizi Oilfield is obtained. The displacement effects of CO2 flooding on ultra-low permeability reservoir are evaluated. Laboratory study results show that CO2 flooding can be applied in Gaotaizi reservoir, and good displacement effects can be obtained. When the air permeability of natural core is 0.51 mD, the CO2 flooding can enhance oil recovery for more than 8 percentages after water flooding. It is feasible to carry out CO2 flooding in ultra-low permeability reservoir.
    THE APPLICATION OF AHP METHOD IN WELL CONTROL RISK EVALUATION BYCONTROLLABLE FACTOR ANALYSIS
    LIU Gang JIN Ye-quan LI Feng YU Hai-xia
    2011, 33(2):  137-141. 
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    There are many factors that trigger the well control risk. Therefore, the assessment job about the degree of influence on well control incentives is a basic work that may reduce the well control accident and damage. Analytic
    hierarchy process is an effective evaluation method. Based on the review of related references, this paper establishes a three-level evaluation index system of controllable incentives. By using the basic principles of AHP method to build a weight model, the analysis on controllable factors induced ell control risk is done and weight values of each incentive are figured out. It provides exemplary theoretical basis for identification and prevention of controllable
    factor induced well control risk, and supplies reference on the well control risk preventing.
    BENCH SCALE EXPERIMENTAL STUDY OF AIR INJECTION IN XI11-72 WELL FIELDOF BEIR OILFIELD
    WANG Yan-qiu;SUN Jian-song
    2011, 33(2):  142-146. 
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    The water displacement efficiency in Beir Oilfield is low, especially the ultra-low permeable reservoir in Xi 11-72 well field. The paper studies the feasibility of air injection in the well field by bench scale experimental study, and draws the conclusion that the displacement efficiency could be advanced by air injection. The displacement efficiency of air injection can reach 57.14% when injecting 15 PV, while the water displacement efficiency is 34.95%. In slim line low-temperature oxidation experimentation and combustion tube high temperature oxidation experimentation, oxygen is exhausted in large quantities and low-temperature oxidation occurs. So the method of air injection can be adopted in the reservoir of Xi 11-72 Well Field of Beir Oilfield.
    油气化学工程
    RESEARCH REVIEW OF DIRECT SYNTHESIS OF DIMETHYL CARBONATE FROMCARBON DIOXIDE
    NING Ying-nan TANG Hao MAO Guoliang
    2011, 33(2):  147-151. 
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    Dimethyl carbonate(DMC)is one of the fastest growing environmentally benign chemical products. In recent years, people have put more attention to the route of direct synthesis DMC from CO2 and CH3OH. This paper mainly discusses the principle for catalyst design and the action mechanism of different catalyst. The effect of promoter, absorbent agent and reaction condition to catalyst activity and selectivity are reviewed.
    APPLICATION OF K2CO3/AL2O3 SOLID ALKALINE CATALYSTS TO REMOVE ACIDFROM CRUDE OIL BY ESTERIFICATION
    WU Yan WANG Hao ZHONG Ting GUO Ying-ying XIONG Min
    2011, 33(2):  152-156. 
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    Developing esterification catalysts with high performance is considered to be a key factor to improve the efficiency of catalytic esterification. Compared with the conventional acidic esterification catalysts, the solid alkaline catalysts show better anti-poisoning property and higher stability. A series of alumina-supported K2CO3 catalyst is prepared by pore volume impregnation method and used in the esterification reaction to remove acid from crude oil. The property of catalysts is characterized by XRD and N2 adsorption-desorption. Hammett indicator and benzene carboxylic acid titration method are used to measure the basicity strength and basicity amount distribution on the
    catalysts. The effects of K2CO3 content on catalysts’ property and deacidfication activity are investigated and the esterification reaction conditions are studied. It is shown that the poor dispersed multilayer K2CO3 crystallites are formed on the catalyst which contains 25% K2CO3, causing a great decrease of specific surface area and pore volume of catalyst. The total basicity amount (H–>9.3) and weak basicity amount (9.3increased with the increase of K2CO3 loading until it reaches 20%, and if the increase continues, it will lead to the decrease of basic sites. The results also indicated that the weak basic sites with 9.3major contribution to the catalyst’s deacidfication activity. The catalyst loaded with 20% K2CO3 has the greatest
    amount of weak basic sites and thus the highest catalytic activity. It can remove 97.8% acid of Liaohe high acidity crude oil and the acid value of crude oil can be decreased from 11.17 mgKOH/g to 0.25 mgKOH/g under the optimal
    reaction conditions of reaction temperature 200 ℃, reaction time 2 h, catalyst and glycol mass fraction 1% and 2%, respectively. Moreover, the K2CO3/Al2O3 catalyst shows good repeated-use performance.
    PROGRESS OF INITIATING SYSTEM FOR SYNTHESIS OF ACRYLAMIDE-BASED PO-LYMERS
    CHEN Qiu-shi KANG Qi-jun;LI Hua-bing;
    2011, 33(2):  157-160. 
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    The new initiating system for synthesis of acrylamide-based polymers has attracted much attention and been the focus of increasing polymer molecular weight in recent years. The performance of polymerization, charac-teristic and range of application of aqueous azo initiator has been investigated and the aqueous azo initiators can be used for the preparation of high molecular weight acrylamide-based polymers and its derivatives, which demonstrates
    abroad application prospect. The effect of difunctional initiator and amino functional monomer on molecular weight are also discussed. The initiating system of the new kind of cryogenic compound initiators containing potassium
    persulfate, ammonia water, urea, azo-(2-amidinopropane) dihydrochloride, functional monomer MP are believed to be able to be used for the preparation of ultrahigh molecular weight acrylamide-based polymers.
    石油机械工程及其他
    MODELING ON TRIAXIAL COMPRESSIVE STRENGTH OF SANDSTONE BASED ONWELL-LOGGING DATA
    KUANG Yu-chun WANG Ya-ping LIU Yan-jun XIA Wen-yu XU Chun-tang
    2011, 33(2):  161-164. 
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    The compressive strength of rocks is very important to optimization of drill bits selection. Aiming at thesandstones which are frequently encountered in the oil drilling, a triaxial compressive strength model which is based on logging data is put forward. The model is established on the basis of acoustic logging, bulk density, gamma ray counts and the results of uniaxial compressive strength. The experiments’ results about the nature of confining pressure of sandstone mechanics and changes in sandstone porosity are also considered. It is shown that sandstone strength is influenced by confining pressure significantly. With the increasing of lateral pressure, the compressive
    strength is also increased. Porosity is reduced with the increasing of confining pressures, which conforms to the rule of logarithmic function.
    THE RESEARCH OF ESP–GL RELAY LIFTING TECHNOLOGY
    YANG Zhi LI Meng-jie;ZHAO Hai-yang;ZHAO Li-chun JIANG Qing-chun
    2011, 33(2):  165-170. 
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    In order to solve the problems that the individual artificial lift techniques can’t meet the requirement of deep-well pumping, based on the theory of artificial lift techniques and the composite structure of pipe strings,the combination technical schemes and principles are proposed. In view of the virtues of gas-lift technique, thecombination of deep well-pump and gas-lift, especially the combination of electric submersible pump and gas-lift(ESP-GL)has obvious superiority and is fit for the high flow rate deep pumping. The structures of the lift pipe stringsare discussed and implement measures are put forward. In order to overcome side effects of the traditional gas-liftthat could lead to the casing fluid level lowering and influence lower deep-well pump quality, the minor diametertube gas injection technology which can provide condition for combination with other artificial lift techniques isproposed. The calculations carried out by the proposed ESP-GL combination method show that if the ESP dischargerate and lifting pressure head are not changed, the pumping depth of the ESP can reach 6 000 m after relay liftingwhich provides technical support for the high flow rate lifting of the deep zone reservoir; if the depth of ESP is
    unchanged, airlift can enhance the production of gas well.
    博导论评
    STUDY ON THE FORMATION AND EVOLUTION OF GAS ACCUMULATION IN LOW-ER TRIASSIC JIALINGJIANG FORMATION OF SICHUAN BASIN
    XU Guo-sheng HE Yu YUAN Hai-feng YANG Yun-hui MENG Yi-zhang
    2011, 33(2):  171-178. 
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    Based on the analysis of the composition and carbon isotopic characteristics of natural gas, it is confirmed that the natural gas of Jianglingjiang Formation has a large drying coefficient and high thermal evolution, showing an apparent feature that gas always comes from both oil-type and coaliferous source rocks, with an exception existed in Middle Sichuan region, where the accumulational gas is mainly composed by high-mature oil-type gas. The regional tectonic activities and accumulation elements of the whole basin are analyzed in this paper, the accumulation process of Jialingjiang Formation is rebuilt, and the accumulation model of natural gas of typical structural belts in the Middle, Eastern and Southern Sichuan Basin are established separately. It is found that all the Jialingjiang gas pool have experienced a long evolutionary history of ancient oil accumulation, ancient gas accumulation and current gas accumulation, and this process has a close relationship with the Indosinian movement, Yanshan movement and Himalayan movement. The law that Jialingjiang natural gas accumulation follows is as follows:fluid-drive with high
    pressure, cross-layer migration of fluid, condution by fault and fracture, oil cracking to gas accumulation sealed by gypsum layers.