Journal of Southwest Petroleum University(Science & Technology Edition)

Current Situation, Challenges and Countermeasures of China's Energy Transformation and Energy Security Under the Goal of Carbon Neutrality

HOU Meifang

2023, 45(2): 1-10. DOI: 10.11885/j.issn.1674-5086.2023.01.12.02

Asbtract ( 487 )

HTML ( 53)

PDF (1295KB) ( 550 )

References | Related Articles | Metrics

Human society is now in its third stage of energy transformation, with the goal of carbon neutrality and sustainable development, after the first two major energy transformation periods. China's energy development is facing complex situation and severe challenges under the new situation. We must accelerate the low-carbon energy transformation to achieve carbon neutrality, and firmly safeguard the bottom line of energy security at the same time. It is a major issue for China's high-quality energy development to balance energy transformation and energy security. Studies indicate that: 1) the previous two energy transformations were both in line with the traditional law of economic development and accompanied by the industrial revolution. In these two transformations, energy acted as common productive factors, and the energy structure gradually changed under the drive of technology. However, the core reasons of the third energy transformation are to address climate change and guarantee energy security. The ongoing transformation is driven by the strategic measures of sustainable development besides technological development, and it requires multiple efforts. 2) there are lots of risks in China's energy transformation: the total energy consumption is too large, the carbon emission and proportion of coal in energy structure is too high, the domestic production of oil and gas is too low, the dependence ration of overseas oil and gas is too high, and the development of renewable energy is too weak. 3) under the goal of carbon neutrality, China's energy transformation and energy security should focus on "three acceleration": making full use of the advantages of socialist system, speeding up the construction of new energy system through the way of cleaning fossil energy, scaling up renewable energy and developing smart comprehensive energy, speeding up independent innovation of science and technology in the fields of coal, oil, gas and renewable energy, speeding up the implementation of energy conservation.

Characteristics and Main Controlling Factors of High Quality Channel Sandstone Reservoir in Zhongjiang Gas Field

WANG Yongfei, HENG Yong

2023, 45(2): 11-20. DOI: 10.11885/j.issn.1674-5086.2020.11.25.02

Asbtract ( 2035 )

HTML ( 24)

PDF (22504KB) ( 126 )

References | Related Articles | Metrics

The sandstone reservoirs of Shaximiao Formation in Zhongjiang Gas Field are generally poor in physical properties. High quality reservoirs are one of the main factors controlling oil and gas enrichment and high yield. The characteristics and controlling factors of high quality reservoir are studied by casting thin section, scanning electron microscope, X diffraction and core physical property analysis data. The results show that the pore types of high quality reservoirs are mainly intergranular dissolved pores and residual intergranular pores, and the diagenetic facies are mainly chlorite cemented facies and chlorite cemented dissolution facies. Early lining chlorite cementation and late dissolution are the key to the formation of high quality reservoirs. Microfractures caused by structural fracture can improve the seepage capacity of reservoirs and promote the formation of high quality reservoirs. The main distributary channel has strong hydrodynamic conditions, large particle size, less argillaceous content and more developed chlorite film in the early stage, which is more conducive to the formation of high-quality reservoirs. The secondary dissolution pores are developed in the secondary distributary channels with high feldspar content, and the reservoirs have good physical properties. Therefore, the high quality reservoirs are mostly developed in the main distributary channels and some secondary distributary channel microfacies with high feldspar content.

A Study on Seismic Reflection Characteristics of Reservoir Under Complex Lithology Background

DAI Ruixue, XI Cheng, RAN Qi, CHEN Kang, LIANG Han

2023, 45(2): 21-31. DOI: 10.11885/j.issn.1674-5086.2020.11.27.03

Asbtract ( 1486 )

HTML ( 9)

PDF (37094KB) ( 139 )

References | Related Articles | Metrics

51.62$\times$10$^4$ m$^3$ of gas was obtained of the risk explororation Well JT1 from the Canglangpu Formation on the northern slope of the paleouplift in Central Sichuan during test. That is the first breakthrough in oil and gas exploration of Canglangpu Formation in Sichuan Basin. However, as the mixed sedimentary facies, the Canglangpu Formation has complex seismic response characteristics of which results in low degree of geophysical study due to its complex lithology. Thus, the seismic reflection characteristics of lithofacies and seismic response model of reservoirs of Cangchuan Formation in central Sichuan Basin are studied based on the drilling data and seismic data. The results show: 1) Canglangpu Formation in Central Sichuan has five lithofacies-seismic reflection modes, among which uniaxial mode and uniaxial complex wave model are the best seismic facies of carbonate rocks. 2) SOM waveform clustering method and wave impedance recursive inversion verify the accuracy of seismic facies, so the carbonate rocks can be further finely depicted. 3) there are two seismic reflection modes of high-quality reservoirs in Canglangpu Formation on the north slope of the paleouplift in central Sichuan Basin. The seismic reflection model of thin-interbedded reservoir is lithologic interface strong axis with complex wave, the seismic reflection model of thick reservoir is lithologic interface strong axis with bright spot. Comprehensive study shows that there are three favorable areas distribute in the shape of stripe in the NW--SE direction in Canglangpu Formation on the north slope and have good conditions for the formation of lithologic traps, with a total area of 1 270 ${\rm {km}}^2$, which is an important area for further exploration. In this paper, one method for research of seismic reflection characteristics of reservoir under complex lithology background is proposed to provide an effective idea for seismic prediction of thin reservoirs as sedimentary facies.

An Objective Function Optimization Method Based on Multi-frequency Wavelets for Receiver Combination in Seismic Acquisition

PENG Gengxin, XU Feng, XU Kaichi, LIU Fulie, LI Yongjun

2023, 45(2): 32-42. DOI: 10.11885/j.issn.1674-5086.2020.12.14.02

Asbtract ( 1486 )

HTML ( 7)

PDF (22151KB) ( 98 )

References | Related Articles | Metrics

The traditional objective function used to design geophone array parameters often takes single-frequency simple harmonic as the research object, and investigates the local information such as zero point position and suppression band, which does not conform to the actual frequency composition and spatial continuity distribution characteristics of seismic wavelet. Based on the combined energy response of broadband wavelets, using the property that the main bodies of interference waves and seismic reflection signals are continuously distributed in different regions of space, four objective functions with statistical significance are established, each of which has its own emphasis on noise suppression and effective signal protection. Through theoretical analysis, numerical simulation and actual data trial calculation, the differences of different objective functions in noise suppression, reflected signal damage, signal spectrum change and AVO distortion are compared. The analysis shows that the objective function protecting the effective signal, as it has more advantages first can reduce the combined low-pass filtering effect, and has less impact on AVO distortion.

Self-facies-control Pre-stack Inversion Technology for Turbidite Sandstone Reservoir with Complex Fault System

WANG Zongjun, TIAN Nan, FAN Ting'en, GAO Yunfeng

2023, 45(2): 43-57. DOI: 10.11885/j.issn.1674-5086.2021.01.29.01

Asbtract ( 1451 )

HTML ( 2)

PDF (6298KB) ( 129 )

References | Related Articles | Metrics

Turbidite sandstone reservoir is a typical gravity flow deposit, which is characterized by lateral variation, vertical multi-stage superposition and frequent migration. Seismic inversion is one of the main methods for fine reservoir description, but the complex fault system, lateral abrupt variation and overlimit thickness of the reservoir in E Oilfield restrict the accuracy of reservoir inversion and its subsequent application. In order to solve the problem of reservoir prediction in E Oilfield, a self-facies-control pre-stack inversion technology with complex fault system is proposed in this paper. Firstly, the deep learning algorithm based on the fault contact relationship chart library is used to construct the complex fault system model, and then the high-precision seismic stratigraphic framework is constructed. Secondly, a high-precision self-facies-control low-frequency model is built using the self-facies-control low-frequency model construction technology. Finally, under the constraints of high-precision stratigraphic framework and self-facies-control low-frequency model, self-facies-control pre-stack inversion is realized, which effectively improves the accuracy of sand body prediction near the fault, overlimit thick reservoir characterization and reservoir lateral boundary identification. The application in E Oilfield shows that this method has achieved good results. The thickness coincidence rate of the horizontal length of 16 new drilled development wells is 91%.

Research on Transient Flow Model of Gas Reservoir Based on Boundary Element Theory

DENG Bo, LU Zhengyuan, ZHAO Na

2023, 45(2): 58-66. DOI: 10.11885/j.issn.1674-5086.2020.12.16.02

Asbtract ( 1388 )

HTML ( 6)

PDF (3037KB) ( 134 )

References | Related Articles | Metrics

The reserves of gas reservoir in Permian Qixia Formation, Shuangyushi Area of northwestern Sichuan Basin is abundant, and the research on transient flow model is difficult due to the development fractures and complex boundary caused by multi-period tectonic movement. On the basis of fundamental principle of seepage theory, a composite dual-porosity physical and mathematical model for vertical well is established by considering arbitrary shape boundary, and then the fundamental and pressure response solution of vertical well in such composite model is derived by point source function and BEM. Combining the principle of superposition and computer programming techniques, the dimensionless pseudo-pressure and its derivative are obtained under different variables, and the gas flow regimes are divided and the parameters sensitives are analyzed. In the end, a field case of Well Shuangyu001—1 in Qixia Formation, Shuangyushi Area in northwestern Sichuan Basin is applied by the method proposed in this paper, and obtained an excellent agreement. It provides a new method for well test interpretation of this kind of complex gas reservoir.

A Calculation Method of Water Breakthrough Time of 5-Point Well Pattern in Low Permeability Reservoir

LI Chenglong, SUN Pengpeng, WANG Yifei, YANG Guinan

2023, 45(2): 67-76. DOI: 10.11885/j.issn.1674-5086.2021.12.24.02

Asbtract ( 1408 )

HTML ( 3)

PDF (549KB) ( 75 )

References | Related Articles | Metrics

According to the reservoir development characteristics, fluid seepage law and five-point well pattern characteristics of low permeability reservoirs, a water breakthrough time calculation model considering pressure-sensitive effect, variable starting pressure gradient, well spacing, fracture and well spacing angle, fracture length, heterogeneity and other factors is established, and the influence law of different factors on water breakthrough time is analyzed. Compared with the existing results, the water breakthrough time calculation model established in this paper is more comprehensive and fits the actual situation of the mine better. The analysis results show that the larger the ratio of well spacing to row spacing, the stronger the heterogeneity; the longer the fracture length, the smaller the starting pressure gradient and the original formation pressure, the earlier the water breakthrough time. With the increase of fracture and well row angle, the water breakthrough time changes, when the water saturation is between 0.4~0.5, the water breakthrough occurs early. The research results can provide theoretical support for the development adjustment scheme of low permeability fractured reservoirs.

Calculation Model of Hydro-mechanical Coupling for Dynamic Width of Deformable Natural Fracture

PENG Hao, LI Qian, GAO Jiajia, YIN Hu, CHEN Yifan

2023, 45(2): 77-86. DOI: 10.11885/j.issn.1674-5086.2020.10.28.02

Asbtract ( 1354 )

HTML ( 5)

PDF (1506KB) ( 113 )

References | Related Articles | Metrics

Aiming at the fact that existing models for calculating the dynamic width of natural fractures fail to consider the compression deformation of the fracture under the net flow pressure in the fracture,the model of hydro-mechanical coupling for dynamic width of natural fracture is studied.Firstly,according to the deformation law of natural fracture wall and the net flow pressure equation in the fracture,a hydro-mechanical coupling leakage dynamic model is established,by which the geometric control equations of the leakage rate and the invasion velocity of the leakage front distance are obtained;then,the self-adaptive search method is used to calculate the equivalent average width of the natural fracture,and the initial width of the natural fracture is obtained based on the volume equivalent principle.The solution method of the natural fracture shape coefficient is established by combining the geometric control equations of leakage rate and the initial width;finally,according to the geometric governing equation of the invasion velocity of the leakage front distance,the natural fracture shape constraint is solved to obtain the normal stiffness,and then the model of hydro-mechanical coupling for dynamic width of natural fracture is obtained.The model of hydro-mechanical coupling for dynamic width of natural fracture has been verified on-site and the calculation results are in good agreement with the on-site measured data.Only the drilling fluid performance,the lost circulation rate sequence and the lost volume sequence measured on-site are needed to predict the dynamic width of natural fractures,which is convenient for on-site application.

Wellbore Stability Analysis of Drilling Fluid Invading Hydrate Reservoir

WANG Lei

2023, 45(2): 87-96. DOI: 10.11885/j.issn.1674-5086.2022.03.29.03

Asbtract ( 1409 )

HTML ( 7)

PDF (1710KB) ( 140 )

References | Related Articles | Metrics

During the drilling of marine gas hydrate reservoirs, the drilling fluid easily invades the gas hydrate wellbore, causing the collapse and instability of the wellbore. The coupling effect of the collapse pressure of the gas hydrate formation and the hydrate phase equilibrium pressure at low temperature is an important influencing factor. Therefore, it is of great significance for the smooth exploitation of marine gas hydrate to carry out the evaluation experiment of the wellbore stability of hydrate reservoir under the action of low temperature drilling fluid system, and to study the mechanism of gas hydrate wellbore instability caused by drilling fluid invasion. The hydrate cores are prepared by simulating the temperature and pressure at the depth of the ocean, and by injecting drilling fluids of different systems, the temperature, pressure, mechanical characteristic parameters and hydrate mass abundance changes in the gas hydrate cores are monitored, and different conditions are studied. Wellbore stability under influence. The research shows that as the drilling fluid temperature increase, the peak strength near the wellbore after the invasion decrease. Large hydrate mass abundance also causes the fluctuation of hydrate core parameters. Compared with the uninvaded core, the stress peak point of the core decrease by 13.95% on average after 5 min of intrusion.

Calculation of the Investigation Radius of Producing Well Through Power Law Heavy Oil Sand Reservoir

XIE Mingying, LIU Guotao, YAN Zhenghe, SHI Zhengnan, SUN Xiaona

2023, 45(2): 97-106. DOI: 10.11885/j.issn.1674-5086.2021.02.08.08

Asbtract ( 1377 )

HTML ( 3)

PDF (977KB) ( 67 )

References | Related Articles | Metrics

The investigation radius is an important parameter in oilfield development. However, the well-known formula of the investigation radius is based on the linear fluid flowing in porous medium, so the formula is out of place for nonlinear fluid, such as power-law fluid. Recently the sand oilfields with power law fluid are discovered in the eastern South China Sea. Based on this, a new numerical method is proposed for studying the investigation radius of power-law heavy oil. This new method avoids the problem of trying to obtain the analytical formula of the investigation radius, and it has wider applicability. On the other hand, the well-known formula does not consider the influence of wellbore storage effect and skin effect. With the help of the relative criterion of investigation radius, using Laplace transform and Stehfest numerical inversion, the influence of power-law index, wellbore storage effect and skin effect on investigation radius is studied by a new method here. A formula for calculating the investigation radius with power-law index between 0.80 and 1.00 is proposed, and the unified form of the formula is formed. At the same time, the relationship between investigation radius and bottom hole pressure drop is also explored. The research results have been used for guiding the optimization design well pattern and injection-production well pattern, and good application results are obtained.

Stability of Water Annulus Transportation of Heavy Oil in Horizontal Pipeline

YIN Xiaoyun, SU Ming, ZHOU Xin, ZHANG Liang, JING Jiaqiang

2023, 45(2): 107-116. DOI: 10.11885/j.issn.1674-5086.2020.12.04.01

Asbtract ( 1408 )

HTML ( 1)

PDF (937KB) ( 64 )

References | Related Articles | Metrics

In the present study, simulations for oil-water annular flow through a horizontal pipe were performed by FLUENT software based on VOF two-phase flow model, standard $k-\varepsilon$ turbulence model, and CSF surface tension model. The influences of fluid properties (oil-water density difference, oil-water viscosity ratio, and oil-water interfacial tension) on the distribution of oil-water two-phase and the stability performance of water annulus structure were analyzed. The simulation results indicate that the oil-water properties have no effect on the area-weighted average of the oil volume fraction, which is about 73% in various working conditions. However, they have a significant impact on the volume fraction distribution rules of oil-water two-phase and the stability evaluation indexes of water annulus structure (oil core eccentricity, stable length ratio of annular flow, and pipeline pressure drop). Under the simulated conditions, the oil-water annular flow in a typical eccentric form, where the oil-core located in the upper part of the pipe is wrapped by the upper thin and lower thick water layer. The stability of water annulus is at the best when the oil phase density is 996.4 kg/m$^3$, the oil phase viscosity is 1 743.3 mPa·s, and the oil-water interfacial tension is 22.36 mN/m.

Study on Wellbore Temperature & Pressure and Phase Control in Supercritical Carbon Dioxide Fracturing

WU Lin, LUO Zhifeng, ZHAO Liqiang, YAO Zhiguang, JIA Yucheng

2023, 45(2): 117-125. DOI: 10.11885/j.issn.1674-5086.2021.05.13.01

Asbtract ( 1345 )

HTML ( 7)

PDF (1985KB) ( 112 )

References | Related Articles | Metrics

Supercritical carbon dioxide fracturing fluid is sensitive to temperature and pressure, and accurate prediction of wellbore temperature, pressure and phase state during fracturing directly affects the final fracturing effect. As a result, a transient wellbore temperature and pressure model of supercritical carbon dioxide fracturing considering axial heat conduction, Joule-Thomson effect, expansion/compression work, and frictional heat was established. Based on the model, the effects of injection temperature, displacement, drag reduction effect, and tubing size on the wellbore temperature, pressure and phase state were analyzed. The results show that the decrease of wellbore temperature leads to an increase in carbon dioxide density and a decrease in flow velocity, which causes the wellhead pressure to decrease simultaneously with the wellbore temperature. The higher the injection temperature, the smaller the displacement, the higher the resistance reduction rate, the larger the tubing size, the higher the bottom hole temperature, and the lower the wellhead pressure. Among them, the wellhead temperature increases by 10℃, and the bottom hole temperature increases by about 7℃; the resistance reduction rate increases by 20%, and the wellhead pressure decreases by about 7MPa. Increasing the injection temperature, the cross-sectional area of the flow channel, and reducing the displacement while using the thickener/resistance reducer can promote the carbon dioxide to reach the supercritical state at the bottom of the well. This article has strong guiding significance for the optimization design and field application of supercritical carbon dioxide fracturing.

Research on Overflow Intelligent Warning Technology Based on Downhole Annulus Parameters

GE Liang, TENG Yi, XIAO Guoqing, XIAO Xiaoting, DENG Hongxia

2023, 45(2): 126-134. DOI: 10.11885/j.issn.1674-5086.2021.03.12.03

Asbtract ( 1402 )

HTML ( 4)

PDF (1358KB) ( 113 )

References | Related Articles | Metrics

With the development of oil and gas exploration and development toward complex formations, the risk of blowout during drilling has increased, and overflow is the precursor of blowout, so the early warning of overflow becomes a key direction to well control and safety prevention. Aiming at the problem that the traditional prediction algorithm fails to analyze the severity of overflow and the prediction accuracy is not high when performing overflow warning based on ground parameters, through the study of overflow symptoms and the mechanism of overflow, the annulus electromagnetic flow system and other systems are used to directly measure the underground near the bit, and an overflow intelligent early warning model was established based on artificial intelligence algorithm—Random Forest to classify and predict the severity of overflow. In order to verify the feasibility of the early warning model, a simulation experimental platform was built for testing, and compared with the conventional BP neural network. The results show that the accuracy of this method is as high as 92.68%, and the accuracy of classification prediction is significantly higher than that of the BP neural network. The research results verify the reliability of the random forest model for downhole overflow early warning, which well realizes the early warning of overflow, and provides a safety technical guarantee for drilling, and has good application prospects.

Design of Operating Parameters in MB8 Gas Storage with Edge and Bottom Water

GONG Ruicheng, WANG Aiming, CHEN Fangfang, YU Haitao, LIU Jingun

2023, 45(2): 135-144. DOI: 10.11885/j.issn.1674-5086.2021.06.18.01

Asbtract ( 1324 )

HTML ( 3)

PDF (1808KB) ( 116 )

References | Related Articles | Metrics

The edge-bottom water will affect the injection and production capacity and peak production of gas wells during gas storage operation. There are few cases of underground gas storage building from medium-strength edge-bottom water gas reservoirs at home and abroad. In accordance with the medium intensity edge-bottom water in Wellblock MB8, the formation water will make influence on storage capability when building a gas storage. We evaluate well type by optimizing of gas-water characteristics of injection-production wells, assess gas storage capacity by material balance equation of water drive gas reservoir, analyze well injection-production capacity considering gas-water two phase seepages, and study edge-bottom water transport conditions in the process of injection-production with numerical simulation method. The study shows that it is feasible to transform underground gas storage in Wellblock MB8, and the influence of edge and bottom water on gas storage operation can be reduced by increasing the number of wells, reducing the injection and production of single well, and by optimizing the well location. Considering the influence of edge and bottom water, the effective working gas in MB8 gas storage is 170 million cubic meters, the reasonable number of injection and production wells is 20, and the operating pressure range from 8.1$\sim$10.9 MPa.

A Review of Offshore Associated Gas Researches and Submarine Associated Gas Storage

LI Qian, ZHOU Xipeng, JIANG Huifeng, MAO Yaling, LUO Xiao

2023, 45(2): 145-158. DOI: 10.11885/j.issn.1674-5086.2021.01.04.03

Asbtract ( 1114 )

HTML ( 5)

PDF (726KB) ( 138 )

References | Related Articles | Metrics

Aiming at the waste of resources and environmental pollution caused by combustion or discharge of associated gas in offshore oilfields, this paper has carried out research work on the treatment and utilization of associated gas in offshore oilfields. In the research, the existing associated gas processing technology, transportation methods, receiving terminal, etc. are introduced and compared in detail, and the key technologies involved in the associated gas processing method are examined, and focus and direction of future researches on the processing method and technology of marine associated gas is proposed. Focus and development direction. Then, considering small output, high processing cost and insufficient energy supply in the treatment of associated gas in offshore oilfields, we propose the construction and design of submarine associated gas storage using offshore oil and gas reservoir, with reference to onshore natural gas storage, and the gas injection and production process of offshore associated gas storage is established. This research discusses the related technology of associated gas treatment in detail, and proposes to build a submarine associated gas storage to solve the problem of associated gas treatment and utilization in offshore oilfields. The research can be referred to by peer researchersand is of great significance for protecting the environment and improving energy efficiency.

A Study on the Functional Reliability of Underwater Floating Body Considering the Wear of Joint Clearance

HE Kongde, HU Hao, FANG Zifan, YANG Weihua, LIU Shaopeng

2023, 45(2): 159-169. DOI: 10.11885/j.issn.1674-5086.2020.10.22.03

Asbtract ( 1427 )

HTML ( 3)

PDF (6072KB) ( 64 )

References | Related Articles | Metrics

Aiming at the problem in system functional reliability caused by the wear of joint clearance between the cable and structure of cable-anchored underwater floating body, a system dynamic model considering the ideal hinge and the wear of joint clearance is established based on the method of Archard adhesion wear calculation and reliability calculation. The dynamic equation and the functional reliability are solved by the multi-scale method and Newmark-$\beta$ method. On this basis, the reliability of surging displacement and roll angle is studied. The results show that with the increase of wear, the contact force of the connection reaches 12.0 times and 5.5 times of the ideal hinge value. When the wear volume is greater than 1.5 mm, the mean value and peak value of the rolling angle of floating body caused by the uncertainty contact state are both greater than the ideal articulated state, and the reliability decreases sharply. When the wear volume is greater than 1.82 mm, the reliability is less than 90%. In the state of clearance contact, the reliability of the transverse surging displacement of the floating body will decrease to a certain extent.

CFD Simulation and Optimization of Electric Submersible Pump Considering the Effect of Heavy Oil Viscosity

LIU Yonghui, XIE Zaixiang, ZHOU Yuchi, PENG Zhenhua, LIU Zhongbo

2023, 45(2): 170-177. DOI: 10.11885/j.issn.1674-5086.2021.04.13.06

Asbtract ( 1430 )

HTML ( 4)

PDF (1701KB) ( 145 )

References | Related Articles | Metrics

Electric submersible pump (ESP) is one of the most common artificial lift techniques. However, when it is applied to heavy oil wells, due to the influence of high viscosity, the performance curves of ESP deviates from the common ones, which caused the effective application window of ESP. Therefore, the centrifugal pump's structural parameters are designed under water flow condition, which is difficult to adapt to the high viscosity environment of heavy oil wells. In view of the above problems, based on the computational fluid dynamics (CFD) numerical simulation method, we study the pressurization characteristics of ESP under the high viscosity condition. The results show that with the increase of fluid viscosity, the frictional force increases, and the interaction effect also shows an increase trend. However, the pressure difference between the impeller inlet and the diffuser outlet decreases, which leads to the flow rate decrease. Meanwhile, the flow regime inside ESP changes from turbulent flow to laminar flow, and recirculation flow area inside the impeller and diffuser blades decrease. Under the same viscosity condition, the head of centrifugal pump decreases with the increase of displacement. Under the same liquid flow rate, the head of centrifugal pump decreases significantly with the increase of viscosity. Based on factor analysis, by taking the effect of viscosity into consideration, the structural parameters of the centrifugal pump are optimized. The optimal structures are as follows: inlet width is 16.6 mm, blade number is 6 pieces, outlet width is 21.9 mm, and blade inclusion angle is 60o. Compared with the original centrifugal pump, when the viscosity is 400 mPa·s, under the submersible electric pump works in allowable flow rate range, the maximum increase of head is 28%.

A Study on Mechanistic Prediction Model of Gathering Pipelines in CO$_2$ Environment

JIANG Hongye, LIU Yingxue, HE Sha, LUO Jiqing, XU Taolong

2023, 45(2): 178-188. DOI: 10.11885/j.issn.1674-5086.2020.11.20.01

Asbtract ( 1460 )

HTML ( 1)

PDF (2781KB) ( 108 )

References | Related Articles | Metrics

CO$_2$ flooding technology has been widely used in major oil fields because of its ability to significantly improve reservoir recovery. However, the increase of CO$_2$ content in the produced fluid leads to serious corrosion of ground gathering and transportation pipelines. In order to solve the problem of CO$_2$ corrosion of ground gathering and transportation pipelines, the CO$_2$ corrosion rate prediction research under the influence of corrosion product film is carried out. Based on the corrosion thermodynamics and kinetics theory, considering the multifield coupling effects such as fluid flow, electrochemical reaction and mass transfer process, the influence factors of corrosion product film on the diffusion coefficient of ion mass transfer are introduced, and a new corrosion prediction mechanism model is proposed based on the work of Nesic et al, and the chemical, electrochemical and mass transfer calculations are improved. The prediction results of the model are compared and verified by using the experimental data in the literature. The results show that the corrosion prediction model is in good agreement with the experimental data. In the presence of corrosion product film, the corrosion prediction rate can be effectively revised, which further improves the applicability and accuracy of CO$_2$ corrosion prediction mechanistic model, and provides some reference for the design of oil and gas production, processing and transportation pipeline and related facilities.

Table of Content