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石油勘探与开发（英文）
石油勘探与开发（英文）

双月刊

2096-4803

石油勘探与开发（英文）/Journal Petroleum Exploration and Development
正式出版
收录年代

    Nuclear magnetic resonance experiments on the time-varying law of oil viscosity and wettability in high-multiple waterflooding sandstone cores

    JIA HuZHANG RuiLUO XianboZHOU Zili...
    394-402页
    查看更多>>摘要：A simulated oil viscosity prediction model is established according to the relationship between simulated oil viscosity and geometric mean value of T2 spectrum,and the time-varying law of simulated oil viscosity in porous media is quantitatively characterized by nuclear magnetic resonance(NMR)experiments of high multiple waterflooding.A new NMR wettability index formula is derived based on NMR relaxation theory to quantitatively characterize the time-varying law of rock wettability during waterflooding combined with high-multiple waterflooding experiment in sandstone cores.The remaining oil viscosity in the core is positively correlated with the displacing water multiple.The remaining oil viscosity increases rapidly when the displacing water multiple is low,and increases slowly when the displacing water multiple is high.The variation of remaining oil viscosity is related to the reservoir heterogeneity.The stronger the reservoir homogeneity,the higher the content of heavy components in the remaining oil and the higher the viscosity.The reservoir wettability changes after water injection:the oil-wet reservoir changes into water-wet reservoir,while the water-wet reservoir becomes more hydrophilic;the degree of change enhances with the increase of displacing water multiple.There is a high correlation between the time-varying oil viscosity and the time-varying wettability,and the change of oil viscosity cannot be ignored.The NMR wettability index calculated by considering the change of oil viscosity is more consistent with the tested Amott(spontaneous imbibition)wettability index,which agrees more with the time-varying law of reservoir wettability.
      原文链接:
    • 万方数据
    • 维普

    Experiment of dynamic seepage of tight/shale oil under matrix fracture coupling

    DU MengYANG ZhengmingLYU WeifengLI Zhongcheng...
    403-415页
    查看更多>>摘要：A physical simulation method with a combination of dynamic displacement and imbibition was established by integrating nuclear magnetic resonance(NMR)and CT scanning.The microscopic production mechanism of tight/shale oil in pore throat by dynamic imbibition and the influencing factors on the development effect of dynamic imbibition were analyzed.The dynamic seepage process of fracking-soaking-backflow-production integration was simulated,which reveals the dynamic production characteristics at different development stages and their contribution to enhancing oil recovery(EOR).The seepage of tight/shale reservoirs can be divided into three stages:strong displacement and weak imbibition as oil produced rapidly by displacement from macropores and fractures,weak displacement and strong imbibition as oil produced slowly by reverse imbibition from small pores,and weak displacement and weak imbibition at dynamic equilibrium.The greater displacement pressure results in the higher displacement recovery and the lower imbibition recovery.However,if the displacement pressure is too high,the injected water is easy to break through the front and reduce the recovery degree.The higher the permeability,the greater the imbibition and displacement recovery,the shorter the time of imbibition balance,and the higher the final recovery.The fractures can effectively increase the imbibition contact area between matrix and water,reduce the oil-water seepage resistance,promote the oil-water displacement between matrix and fracture,and improve the oil displacement rate and recovery of the matrix.The soaking after fracturing is beneficial to the imbibition replacement and energy storage of the fluid;also,the effective use of the carrying of the backflow fluid and the displacement in the mining stage is the key to enhancing oil recovery.
      原文链接:
    • 万方数据
    • 维普

    Fine quantitative characterization of high-H2S gas reservoirs under the influence of liquid sulfur deposition and adsorption

    LI TongMA YongshengZENG DaqianLI Qian...
    416-429页
    查看更多>>摘要：In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron mi-croscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1 000 μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposi-tion and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of Type I reservoirs with good physical properties decreased by 16%,and that of Types II and III reservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the dam-age of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.
      原文链接:
    • 万方数据
    • 维普

    Formation damage mechanism and control strategy of the compound function of drilling fluid and fracturing fluid in shale reservoirs

    SUN JinshengXU ChengyuanKANG YiliJING Haoran...
    430-439页
    查看更多>>摘要：For the analysis of the formation damage caused by the compound function of drilling fluid and fracturing fluid,the prediction method for dynamic invasion depth of drilling fluid is developed considering the fracture extension due to shale minerals erosion by oil-based drilling fluid.With the evaluation for the damage of natural and hydraulic fractures caused by mechanical properties weakening of shale fracture surface,fracture closure and rock powder blocking,the formation damage pattern is proposed with consideration of the compound effect of drilling fluid and fracturing fluid.The formation damage mechanism during drilling and completion process in shale reservoir is revealed,and the protection measures are raised.The drilling fluid can deeply invade into the shale formation through natural and induced fractures,erode shale minerals and weaken the mechanical properties of shale during the drilling process.In the process of hydraulic fracturing,the compound effect of drilling fluid and fracturing fluid further weakens the mechanical properties of shale,results in fracture closure and rock powder shedding,and thus induces stress-sensitive damage and solid blocking damage of natural/hydraulic fractures.The damage can yield significant conductivity decrease of fractures,and restrict the high and stable production of shale oil and gas wells.The measures of anti-collapse and anti-blocking to accelerate the drilling of reservoir section,forming chemical membrane to prevent the weakening of the mechanical properties of shale fracture surface,strengthening the plugging of shale fracture and reducing the invasion range of drilling fluid,optimizing fracturing fluid system to protect fracture conductivity are put forward for reservoir protection.
      原文链接:
    • 万方数据
    • 维普

    Extreme massive hydraulic fracturing in deep coalbed methane horizontal wells:A case study of the Linxing Block,eastern Ordos Basin,NW China

    YANG FanLI BinWANG KunjianWEN Heng...
    440-452页
    查看更多>>摘要：Deep coal seams show low permeability,low elastic modulus,high Poisson's ratio,strong plasticity,high fracture initiation pressure,difficulty in fracture extension,and difficulty in proppants addition.We proposed the concept of large-scale stimulation by fracture network,balanced propagation and effective support of fracture network in fracturing design and de-veloped the extreme massive hydraulic fracturing technique for deep coalbed methane(CBM)horizontal wells.This technique involves massive injection with high pumping rate+high-intensity proppant injection+perforation with equal apertures and limited flow+temporary plugging and diverting fractures+slick water with integrated variable viscosity+graded proppants with multiple sizes.The technique was applied in the pioneering test of a multi-stage fracturing horizontal well in deep CBM of Linxing Block,eastern margin of the Ordos Basin.The injection flow rate is 18 m3/min,proppant intensity is 2.1 m3/m,and fracturing fluid intensity is 16.5 m3/m.After fracturing,a complex fracture network was formed,with an average fracture length of 205 m.The stimulated reservoir volume was 1 987×104 m3,and the peak gas production rate reached 6.0×104 m3/d,which achieved efficient development of deep CBM.
      原文链接:
    • 万方数据
    • 维普

    Characteristics of proppant transport and placement within rough hydraulic fractures

    HUANG HaiZHENG YongWANG YiWANG Haizhu...
    453-463页
    查看更多>>摘要：A three-dimensional reconstruction of rough fracture surfaces of hydraulically fractured rock outcrops is carried out by casting process,a large-scale experimental setup for visualizing rough fractures is built to perform proppant transport ex-periments.The typical characteristics of proppant transport and placement in rough fractures and its intrinsic mechanisms are investigated,and the influences of fracture inclination,fracture width and fracturing fluid viscosity on proppant transport and placement in rough fractures are analyzed.The results show that the rough fractures cause variations in the shape of the flow channel and the fluid flow pattern,resulting in the bridging buildup during proppant transport to form unfilled zone,the emergence of multiple complex flow patterns such as channeling,reverse flow and bypassing of sand-carrying fluid,and the influence on the stability of the sand dune.The proppant has a higher placement rate in inclined rough fractures,with a maximum increase of 22.16 percentage points in the experiments compared to vertical fractures,but exhibits poor stability of the sand dune.Reduced fracture width aggravates the bridging of proppant and induces higher pumping pressure.Increasing the viscosity of the fracturing fluid can weaken the proppant bridging phenomenon caused by the rough fractures.
      原文链接:
    • 万方数据
    • 维普

    Effect of perforation density distribution on production of perforated horizontal wellbore

    KAREEM Hasanain J.HASINI HasrilABDULWAHID Mohammed A.
    464-475页
    查看更多>>摘要：To address the issue of horizontal well production affected by the distribution of perforation density in the wellbore,a numerical model for simulating two-phase flow in a horizontal well is established under two perforation density distribution conditions(i.e.increasing the perforation density at inlet and outlet sections respectively).The simulation results are compared with experimental results to verify the reliability of the numerical simulation method.The behaviors of the total pressure drop,superficial velocity of air-water two-phase flow,void fraction,liquid film thickness,air production and liquid production that occur with various flow patterns are investigated under two perforation density distribution conditions based on the numerical model.The total pressure drop,superficial velocity of the mixture and void fraction increase with the air flow rate when the water flow rate is constant.The liquid film thickness decreases when the air flow rate increases.The liquid and air productions increase when the perforation density increases at the inlet section compared with increasing the perforation density at the outlet section of the perforated horizontal wellbore.It is noted that the air production increases with the air flow rate.Liquid production increases with the bubble flow and begins to decrease at the transition point of the slug-stratified flow,then in-creases through the stratified wave flow.The normalized liquid flux is higher when the perforation density increases at the inlet section,and increases with the radial air flow rate.
      原文链接:
    • 万方数据
    • 维普

    Development,challenges and strategies of natural gas industry under carbon neutral target in China

    ZOU CainengLIN MinjieMA FengLIU Hanlin...
    476-497页
    查看更多>>摘要：In the mid-21st century,natural gas will enter its golden age,and the era of natural gas is arriving.This paper re-views the development stages of global natural gas industry and the enlightenment of American shale gas revolution,summa-rizes the development history and achievements of the natural gas industry in China,analyzes the status and challenges of natural gas in the green and low-carbon energy transition,and puts forward the natural gas industry development strategies under carbon neutral target in China.The natural gas industry in China has experienced three periods:start,growth,and leap forward.At present,China has become the fourth largest natural gas producer and third largest natural gas consumer in the world,and has made great achievements in natural gas exploration and development theory and technology,providing impor-tant support for the growth of production and reserves.China has set its goal of carbon neutrality to promote green and sus-tainable development,which brings opportunities and challenges for natural gas industry.Natural gas has significant low-carbon advantages,and gas-electric peak shaving boosts new energy development;the difficulty and cost of development are more prominent.For the national energy security and harmonious development between economy and ecology under the carbon neutral goal,based on the principle of"comprehensive planning,technological innovation,multi-energy complemen-tarity,diversified integration,flexibility and efficiency,optimization and upgrading",the construction of the production-supply-storage-marketing system has to be improved so as to boost the development of the natural gas industry.First,it is necessary to strengthen efforts in the exploration and development of natural gas,making projects and arrangement in key exploration and de-velopment areas,meanwhile,it is urgent to make breakthroughs in key science theories and technologies,so as to increase re-serve and production.Second,it should promote green and innovative development of the natural gas by developing new tech-niques,expanding new fields and integrating with new energy.Third,there is a demand to realize transformation and upgrading of the supply and demand structure of natural gas by strengthening the layout of pipeline gas,liquefied natural gas and the con-struction of underground gas storage,establishing reserve system for improving abilities of emergency response and adjust-ment,raising the proportion of natural gas in the primary energy consumption and contributing to the transformation of energy consumption structure,realizing low-carbon resources utilization and clean energy consumption.
      原文链接:
    • 万方数据
    • 维普

    Geological conditions,genetic mechanisms and accumulation patterns of helium resources

    TAO ShizhenYANG YiqingCHEN YueLIU Xiangbai...
    498-518页
    查看更多>>摘要：Based on the methodology for petroleum systems and through the anatomy and geochemical study of typical helium-rich gas fields,the geological conditions,genesis mechanisms,and accumulation patterns of helium resources in natu-ral gas are investigated.Helium differs greatly from other natural gas resources in generation,migration,and accumulation.Helium is generated due to the slow alpha decay of basement U-/Th-rich elements or released from the deep crust and mantle,and then migrates along the composite transport system to natural gas reservoirs,where it accumulates with a suitable carrier gas.Helium migration and transport are controlled by the transport system consisting of lithospheric faults,basement faults,sedimentary layer faults,and effective transport layers.Based on the analysis of the helium-gas-water phase equilibrium in underground fluids and the phase-potential coupling,three occurrence states,i.e.water-soluble phase,gas-soluble phase and free phase,in the process of helium migration and accumulation,and three migration modes of helium,i.e.mass flow,seepage,and diffusion,are proposed.The formation and enrichment of helium-rich gas reservoirs are controlled by three major factors,i.e.high-quality helium source,high-efficiency transport and suitable carrier,and conform to three accumulation mechanisms,i.e.exsolution and convergence,buoyancy-driven,and differential pressure displacement.The helium-rich gas reservoirs dis-covered follow the distribution rule and accumulation pattern of"near helium source,adjacent to fault,low potential area,and high position".To explore and evaluate helium-rich areas,it is necessary to conduct concurrent/parallel exploration of natural gas.The comprehensive evaluation and selection of profitable helium-rich areas with the characteristics of"source-trap con-nected,low fluid potential and high position,and proper natural gas volume matched with helium's"should focus on the cou-pling and matching of the helium"source,migration,and accumulation elements"with the natural gas"source,reservoir and caprock conditions",and favorable carrier gas trap areas in local low fluid potential and high positions.
      原文链接:
    • 万方数据
    • 维普