Lithologic Reservoirs

The Zhujiang Formation reservoirs in Baiyun Sag of Pearl River Mouth Basin attained a high degree of attention at home and abroad because of its large scale, typical structures of submarine fan, excellent reservoirs and huge exploration potential. Based on the analysis of various primary sedimentary structures and palaeontology in W and H gas fields, it is believed that the Zhujiang Formation was deposited by submarine fan dominated by debris flows. The submarine fan was divided into three subfacies which were inner fan, middle fan and outer fan, and further divided into channel, inter-channel and lobe microfacies. Many depositional types were identified, which were grain flow, debris flow, proximal and distal turbidity currents. Based on the detailed analysis of the features of various gravity flows and their distributions, the submarine model comprised of “source, drains, and sinks” was established.

Deposition characteristics, recognition mark and form mechanism of mass transport deposits in terrestrial lake Basin

PAN Shuxin， ZHENG Rongcai， WEI Pingsheng， WANG Tianqi， CHEN Bintao， LIANG Sujuan

2013, Vol.25(2): 9–18 Abstract ( 510 ) PDF (1562 KB) ( 717 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.002

Extensive mass transport deposits （MTDs） distributed in continental margin have became new filed of gravity flow exploration and development. In order to understand the sedimentary and distribution characteristics of the MTDs which deposited in depression and faulted basins, Songliao Basin and Erlian Bain are chosen as the research object. Based on integrated analysis of seismic, core and laboratory test data, sedimentary features and distribution pattern of MTDs were studied systematically. Gravity flow deposits can be divided into MTDs and turbidite. MTDs are different from turbidities in terms of sedimentary structure, concentration, flow pattern, rheology characteristics and seismic response. MTDs belong to laminar flow with solid and bingham fluid characteristics simultaneously and include movement and emplacement by elastic deformation and brittle deformation and plastic deformation. Besides the common massive sandstone, MTDs also form synsedimentary deformation structures or soft-sedimentary deformation structures, such as convolute bedding, slumping deformation structure, boudinage and microfaults, as well as shale boulder. Turbidite belongs to turbulence which forms grained beddings. Seismic profile reveals that thick layer of MTDs are characterized by chaotic, mounded, and transparent seismic reflection, and thin layer of MTDs have eye-shaped reflection structure. MTDs not only have the particle size distribution characteristics of gravity flow, but also have the particle size distribution characteristics of traction current. MTDs are more widely distributed than turbidite in the study area, have more layers and larger monolayer thickness, and have better reservoir performance. The study shows that MTDs are new areas for terrestrial lacustrine gravity flow exploration.

Reservoir characteristics of N₂² and N₂¹ in Yingdong Oilfield, Qaidam Basin

HUANG Yeqiu，SONG Guangyong，WANG Bo，LI Senming，WANG Yanqing，HUANG Geping

2013, Vol.25(2): 19–25 Abstract ( 527 ) PDF (800 KB) ( 848 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.003

The sandstone reservoirs of N22 and N21 in Yingdong Oilfield are characterized by much and thin layers and fine-grained,which play an important part on hydrocarbon distribution. Based on core, thin section, scanning electron microscope, mercury penetration and X-ray diffraction, reservoir characteristics and main controlling factors of N22 and N21 sandstones in Yingdong Oilfield were systematically studied. The result shows that: ①N22 and N21 sandstones are lithic arkose, mainly of fine-grained sandstone and siltstone, with medium compositional maturity and high textural maturity. Matrix content is low, and as the main type of cement, calcite content is moderate. Diagenesis of the sandstone reservoir is weak. ②the main reservoir space is primary intergranular pore, followed by dissolved pores and intragranular crack. Pore structure of reservoir includes three major types: medium pore and throat, large pore and medium throat, large pore and coarse throat. ③High quality reservoir in the study area is attributed to shallow burial condition. Microfacies, sandstone texture and cement content are key factors to distinguish good porosity and permeability sandstone. Compaction is the main factor for porosity-losing processes, and calcite cementation comes next. ④the reservoir in Yingdong Oilfield can be subdivided into four classes,and class Ⅰ, Ⅱ and Ⅲ are commercial, while Class Ⅳ is noncommercial and requiring improvements. It is suggested that while there is sandstone there is reservoir, and the key of exploration is searching sedimentary facies of high quality.

Sedimentary types and evolution characteristics of Putaohua reservoir in Yushulin-Zhaozhou area, Songliao Basin

FU Xiandi， WANG Shengnan， ZHANG Liang， ZHAO Qinghai， CONG Lin

2013, Vol.25(2): 26–30 Abstract ( 607 ) PDF (681 KB) ( 486 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.004

Based on the technologies of thin section identification, particle size analysis, core observation, logging analysis and physical property analysis, this paper studied the reservoir petrology characteristics, sedimentary structure characteristics, logging facies characteristics, physical properties and oil-bearing properties in in Yushulin-Zhaozhou area of Songliao Basin. The results show that the Putaohua reservoir in Yushulin-Zhaozhou area is fluvial delta facies, which can be further divided into eight microfacies, including distributary channel, natural levee, crevasse splay, interdistributary bay, subaqueous distributary channel, subaqueous interdistributary bay, frontal sheet sand and predelta mud. According to the analysis of the vertical sequence of single well, sedimentary microfacies and the relation between reservoir oil-bearing properties and microfacies types, it is believed that Putaohua reservoir experienced early base level falling and later base level ascending evolution, and microfacies types control the reservoir oil-bearing properties. This research result can provide technical support for the further efficient exploration and development in this area.

Seismic facies identification in Sungang area, Biyang Sag

XIAO Xue， YANG Lei， WANG Xu

2013, Vol.25(2): 31–35 Abstract ( 553 ) PDF (640 KB) ( 496 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.005

In order to understand the sedimentary characteristics in Sungang area of Biyang Sag, the typical seismic facies and the planar characteristics of seismic facies of the study area were studied by using the seismic facies identification method. Based on the corresponding relation of seismic facies and sedimentary facies, instantaneous frequency planar graph, palaeogeomorphology and the single well facies of some wells, the planar graphs of seismic facies were translated into the planar graphs of sedimentary facies. By the study, four typical seismic facies in the study area were identified, including sphenoid foreset facies, oblique foreset facies, imbricate progradation facies and subparalleling sheet facies. In the northern study area, there are vast braideddelta front subfacies of the different period in the upper sub-member and the lower position of sand groupⅠof He 3 member. In the southern study area, there is only one leafy sand body of fan delta front in the upper sub-member of sand groupⅠof He 3 member, and two leafy sand bodies of fan delta front in the lower position of sand groupⅠof He 3 member.

Structural characteristics of Chaoshui Basin

ZHAO Hongbo， HE Xinrui， WANG Xiaoye， GU Daohui

2013, Vol.25(2): 36–40 Abstract ( 449 ) PDF (617 KB) ( 632 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.006

In order to clarify the fault distribution characteristics, the connection between the faults, and that the deposition whether is controlled by the fault system, a number of geological sections and the fault distribution map formed in different geological periods were drawn up. The study result shows that the Chaoshui Basin experienced four times of tectonic movement, and formed complex structural features in deferent tectonic movement. In Early-Middle Jurassic, it formed a series of EW strike normal faults, which control deposition in some degree. In Late Jurassic, it formed a series of EW strike abnormal faults, which have no effect on deposition. In Early Cretaceous, there only formed some smallsize of normal faults in Chenjiaxinjing sag, which have little effect on deposition. In Cenozoic, there formed a series of thrust faults, and some normal faults formed in Early-Middle Jurassic were reversed. The evolution of the basin includes the rift basin period of Early-Middle Jurassic, the depression period of the Late Jurassic, the uplifting and atrophy period from the end of the Late Jurassic to Cretaceous, and the transformation die period of the Himalayan tectonic movement in the Cenozoic. The source bed, reservoir and caprock in the basin developed well, so there are good conditions for forming structural traps in the Chaoshui Basin. It will be the next exploration work to looking for structural traps along the fault zone.

Reservoir characteristics of Callovian-Oxfordian in Chashgui area, Amu Darya Basin

WANG Qiang，FEI Huaiyi，LIU Henian，CHENG Xubin，WU Lei，WANG Xingzhi

2013, Vol.25(2): 41–48 Abstract ( 672 ) PDF (1036 KB) ( 611 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.007

Chashgui Gas Field is one of the gas fields supplying gas to the Central Asia Natural Gas Pipeline. Limited by the low coring recovery rate and low drilling success ratio in early period, the reservoir characteristics of Callovian Oxfordian in Chashgui area is unclear, which causes difficulty in exploration evaluation and gas field development. Based on petrology analysis of the core data, slice arbitration, core physical property and pore structure, and combined with the previous achievements, this paper studied the characteristics of Callovian-Oxfordian reservoir in Chashgui Gas Field. The result shows that the reservoir property is middle to low porosity and low permeability, and the reservoir is mainly of middle to small pore and small throat. The reservoir in this area was divided into 3 types, and the characteristics of each type of reservoir were studied. The rock type, sedimentary facies and diagenesis have important effect on the reservoir development. These recognitions can provide basis for the evaluation and development of the gas field, and provide reference for the progressive exploration in surrounding area.

Reservoir characteristics and formation mechanism of Lower Permian Shan 2 member in northern Zizhou area, Ordos Basin

XU Xing， LI Wenhou

2013, Vol.25(2): 49–54 Abstract ( 490 ) PDF (769 KB) ( 504 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.008

Based on the analysis of cast slices, scanning electron microscope, mercury injection test and well logging, this paper studied the physical properties and formation mechanism of Shan 2 member in northern Zizhou area, Ordos Basin. The result shows that the reservoir of Shan 2 member mainly developed quartz sandstone and lithic sandstone.The reservoir spaces are mainly intergranular pores and dissolved pores of P1sh23, and micropores of P1sh22 and P1sh21 reservoirs. The reservoir belongs to low porosity and low permeability reservoir. Delta front subaqueous distributary channel is the main facies belt for forming reservoirs. The reservoir properties are controlled by sedimentation, diagenesis, pore structure types and its combination patterns. The physical properties were mainly reduced by compaction press-solution and cementation.

Technology of lithologic reservoir description in fan delta: A case study from Yingzijie area

LI Guodong， BAI Weiwei， SUN Jinlei， HUANG Yuyan

2013, Vol.25(2): 55–59 Abstract ( 414 ) PDF (607 KB) ( 586 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.009

There are many factors restrict the exploration and development of subtle reservoir in the deep lake area. The accurate description of reservoir distribution is the important factors of oil and gas exploration and development. Taking the exploration in Yingzijie area as an example, through the research of seismic facies division and sand body identification, we formed the “five steps” method for reservoir description of lithologic reservoirs in fan delta, which includes using seismic frequency extension to identify reservoir, using seismic response to show characteristics, using seismic facies to define zones, using multi-well joint constrained inversion to determine fine sand bodies and using frequency divider to interpret boundary. The exploration practice shows that this technology has good effect, and can be used to establish models of seismic wave form for different type of sand bodies, show the contact relationship of crosswise sand, confirm the facies configuration of delta front and prodelta, and predict favorable zones of lithologic reservoir.

Application of prestack simultaneous inversion to the prediction of carbonate reservoirs

GU Mingfeng，XU Meiru，ZHOU Jingao，NI Chao，XIN Yongguang，HAO Yi

2013, Vol.25(2): 60–64 Abstract ( 528 ) PDF (583 KB) ( 839 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.010

The reservoir at the top of Leikoupo Formation in Central Sichuan Basin has the characters of low porosity and low permeability. Well log data shows that the P-impendence of gas-bearing dolomites is similar with tense limestone. Therefore, traditional method is incapable to discriminate porous dolomite and tense limestone. For resolving this problem, first, this paper conducted sensitivity analysis by using log cross-plot technique to find out rock physical parameters which are sensitive to reservoir and fluids, and then calculated the sensitive parameters such as λρ, μρ and vP/vS by pre-stack simultaneous inversion and predicted the favorable reservoirs. The results fit well with the drilling data, which shows that this method is feasible in complex carbonate reservoir prediction.

Logging identification and application of Carboniferous volcanic rocks in Zhongguai uplift, Junggar Basin

SHANG Ling， XIE Liang， YAO Weijiang， DANG Yufang， LIANG Zeliang

2013, Vol.25(2): 65–69 Abstract ( 657 ) PDF (711 KB) ( 634 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.011

Lithology is the base of reservoir evaluation and oil and gas exploration. Volcanic reservoir is characterized by complex and changeful lithologies, which makes the exploration and development difficult. Based on the data of rock slice, logging, core, rock fragments of Carboniferous volcanic rocks in Zhongguai uplift, this paper analyzed the main rock types, established the chart of lithology and electricity, and combining with the conventional logging crossplot methods to identify lithology, summarized the conventional logging response characteristics of the lithologies of volcanic rocks.

Origin of AVO anomaly of Jamieson Formation in deepwater area of Outer Browse Basin, Australia

JIN Li， LUO Zhongqiang， LI Ping

2013, Vol.25(2): 70–75 Abstract ( 460 ) PDF (959 KB) ( 554 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.012

Based on core thin sections analysis and regional sedimentary settings, this paper carried out a comprehensive analysis of the exploration of Jamieson Formation inW-1 well in Outer Browse Basin, Australia. The result shows that Jamieson Formation is a set of Aptian-Cenomanian bio-siliceous rock to be of rich radiolarians and diatoms, and micro-porosity developed inside the foraminifer. The bio-siliceous rock is at a phase of early diagenetic B between opal A to opal CT transition with substantive micro-pores survived and is of high-bounded porosity and low density. The false gas-bearing reservoir in CMR log and AVO anomaly are caused by such petrographic characteristics. In fact, the bio-siliceous rock of Jamieson Formation is poor reservoir. Similar cases with false-DHI are not uncommon, especially in the shallow targets in deep-water and should be take notice of exploration.

Preliminary study on wave field separation of seismic reflection wave and scattered wave

CHEN Keyang， YANG Wei， WU Qingling， FAN Xingcai， LI Lailin， LIU Zhenkuan

2013, Vol.25(2): 76–81 Abstract ( 464 ) PDF (1020 KB) ( 940 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.013

Compared with seismic reflection wave, the seismic scattered wave has better ability to descript the formation details, therefore, we carried out the exploratory study on the separation method of seismic scattered wave and reflection wave. The paper analyzed the wave field characteristic difference and similarity between the reflection wave and the scattered wave, and put forward a new idea and scheme based on the diffusion filter of thermal conductivity equation to achieve the multi-scale separation of the reflection wave energy and the scattered wave energy according to the basic thermal conductivity theory. Taking the pre-stack migration data of practical 3D seismic project as examples, this paper carried out wave field separation processing of the reflection wave and scattered wave. The result shows that the proposed method can relatively separate the reflection wave and scattered wave, and they can respectively reflect the macroscopic and microscopic features of formation. The computation results are accurate and reliable, in which the S/N of the scattered wave energy is relatively poor, but it can reflect the fracture and heterogeneous geologic body edge, and it is more effective to descript the microscopic detail features covered by conventional seismic reflection wave energy. Therefore, the proposed method can provide an important reference value for practical seismic data processing.

Dynamic productivity prediction model for fracturing wells in low permeability gas reservoir

XIONG Jian，LIU Xiangjun，CHEN Zhen

2013, Vol.25(2): 82–85 Abstract ( 446 ) PDF (415 KB) ( 691 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.014

Based on the steady seepage theory, according to the change characteristics of gas seepage rule after fracturing, considering the gas PVT parameters change with formation pressure, and combining with material balance equation, this paper derived and established a dynamic productivity prediction model for infinite conductivity vertically fractured wells in low permeability reservoir with non-linear seepage, and analyzed the effect of non-linear seepage characteristics and production on gas well productivity. The result shows that the greater the start-up pressure gradient and deformation coefficient of permeability are, the more the stable production period decreases, and the longer the production life is, the slower the formation pressure decline. The larger the slippage factor is, the more the stable production period increases, and the shorter the production life is, the faster the formation pressure decline. The greater the gas production rate is, the more the stable production period decreases, and the shorter the production life is, the faster the formation pressure decline. The bottom hole pressure has less effect on the variation law of the gas well productivity.

Feasibility study of air foam flooding low temperature oxidation process in“three low” reservoir: A case study from Tang 80 block in Ganguyi Oilfield

ZHANG Xinchun，YANG Xingli，SHI Xiaowei

2013, Vol.25(2): 86–91 Abstract ( 611 ) PDF (345 KB) ( 581 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.015

The air foam flooding technology is of low-cost and high-profile drive capacity, and has broad application prospects in “three low” reservoir in Ganguyi Oilfield, which is characterized by strong heterogeneity, lack of water and low well production. In order to validate low temperature oxidation feasibility of air foam flooding, and ensure the safety of air injection, through researching application status of this technology, studying indoor dynamic and static low temperature oxidation simulation experiment and actual field test detection, this paper studied oil and air oxidation in different pressures and different temperatures, also monitored and analyzed the oxygen content in field test. The result shows that low temperature oxidation reactions can occur in this “three-low” reservoir and the reaction rate is intensified with increasing pressure.

Application of cumulative oil/steam ratio method to proved reserves evaluation of steam huff and puff in heavy oil reservoir

HUANG Xiangguang

2013, Vol.25(2): 92–94 Abstract ( 474 ) PDF (298 KB) ( 391 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.016

Liaohe oil province is mainly of heavy oil. In the SEC reserves evaluation method, it has not mentioned the reserves evaluation method of steam huff and puff in heavy oil reservoir. This paper proposed a new method based on the cumulative oil production and cumulative steam injection volume to obtain the proved reserves. This method introduces steam injection volume and oil production of the steam huff and puff in heavy oil reservoir. Taking Du 229 block in Liaohe oil province as an example, the calculation result proves the applicability and practicability of this method, which can provide reference for other fields.

Study on pressure gradient and producing degree of water flooding reserves in square inverted nine-spot well pattern

LI Biao， TANG Hai， LU Dongliang

2013, Vol.25(2): 95–99 Abstract ( 452 ) PDF (477 KB) ( 557 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.017

According to Non-Darcy flow theory and potential superposition principle, this paper deduced pressure gradient distribution law at the normal production in square inverted nine-spot well pattern, and applied the result to the studies of effective injection-production system formation conditions and producing degree of water flooding reserves in square inverted nine-spot well pattern. Taking actual oilfield as an example, this paper studied the rule that producing degree of water flooding reserves changes with injection-production differential pressure variation, which can provide theory basis for adjustment well deployment in square inverted nine-spot well pattern.

Study on formation damage with water flooding for ultra-low permeability reservoir in Xinjiang Oilfield

XU Haofei， MA Hongwei2 YIN Xiangrong， ZHAO Xubin， LIU Xuegong， LAI Nanjun

2013, Vol.25(2): 100–106 Abstract ( 617 ) PDF (691 KB) ( 612 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.018

Because of the special characteristics of pore throat, the suspended solids content and the scaling tendency of foreign fluids are strictly limited with water flooding for ultra-low permeability reservoir. How to reduce the degree of formation damage with water flooding to protect pore throat, that will be the critical to efficient development of ultra-low permeability reservoir. Taking a block of Xinjiang Oilfield as an example, by analyzing the reservoir sensitivities and scaling tendency, this paper defined the damage factors of formation with water flooding. The result shows that the reservoir exhibits medium to strong water sensitivity, serious salt sensibility and medium to strong alkali sensitivity, the scale is serious for oilfield injection water, injected water will produce insoluble that will damage the water injection pipeline and reservoir pore throat. Thus, in the water flooding development process of ultra-low permeability reservoir, we need to not only focus on reservoir protection, but also limit the quality of injected water so as to effectively protect reservoirs and lay the foundation for long-term efficient development.

Study on a single point deliverability formula of horizontal wells in Sulige Gas Field

ZHONG Jiajun， TANG Hai， LU Dongliang， ZHANG Zongda， LI Donglin

2013, Vol.25(2): 107–111 Abstract ( 660 ) PDF (315 KB) ( 775 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.019

The horizontal well deliverability is one of the important parameters of the oil （gas） field and the theoretical basis for oil （gas） wells production proration. For low （special low） permeability oil （gas） field, the single point deliverability testing is a fast and effective way to determine the capacity of the oil （gas） wells. It only needs a stable point of the test data to determine the oil （gas） well capacity and it is simpler, less time-consuming and more economical compared with the back pressure well testing and the modified isochronal test. It is significant to develop the single point deliverability formula for Sulige Gas Field with low （special low） permeability of the gas reservoir capacity analysis. This paper applied gas reservoir numerical simulation method and selected the typical wells in Sulige Gas Field to establish the gas reservoir single well model, achieved single point method productivity formula with binomial deliverability equation, and verified the results of the formula. As a result, the formula has the high precision in the Sulige Gas Field of the capacity analysis of horizontal wells.

Coalbed methane is adsorption gas underground

LI Chuanliang， PENG Chaoyang， ZHU Suyang

2013, Vol.25(2): 112–115 Abstract ( 711 ) PDF (577 KB) ( 733 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.020

Coalbed methane development is growing fast. However, the occurrence state of coalbed methane is still in query, for which a study was conducted in this paper. Source rock of mudstone has a small amount of organic material, which can only absorb quite small amount of methane recoverable without economic value. However, coal has a large amount of organic material, which can absorb a large amount of methane recoverable with economic value. Organic material of coal rock is polarized weak on molecules, is likely to adsorb methane molecules with weak polarization. The strongly polarized minerals in coal rock are likely to adsorb water molecules with strong polarization. Coal rock consists of matrix block and fractures, which can be called fractured mudstone. The methane in free gas generated in matrix migrated to fractures and was lost away, and finally only adsorption gas was stored and kept. It needs to produce water and decrease formation pressure to develop coalbed methane. Pressure drawdown can degas the formation water, and desorb adsorption methane, and generate free gas. Then free gas migrates to fractures and will be produced to surface. There is critical production pressure for coalbed methane development. The process of coalbed methane production does not have diffusion phenomena.

Research advance in exploration and development of shale gas

ZHANG Xiaolong， ZHANG Tongwei， LI Yanfang， YAN Jianping， ZHANG Mingjie， HU Peiqing

2013, Vol.25(2): 116–122 Abstract ( 883 ) PDF (467 KB) ( 1326 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.021

Shale gas is one of unconventional gas resources and stores in organic rich shales and mudstones as free gas and absorbed gas in pores developed in organic matter and mineral matrix. Shale gas accumulation is considered as a cumulative gas charging within organic rich shales, and the organic rich shales serve as gas source, reservoir and seals. The gas origin in shale gas reservoirs could be thermogenic, biogenic or the mixing of both. The feature of low porosity （<10%） and low permeability （μD～nD） in shales requires hydraulic fracturing to enhance pore connectivity for achieving commercial gas production. A success of shale gas development in the United States is a typical model of comprehensive integrating between shale gas geological characterization and petroleum engineering technologies. Shale gas exploration in China is in its early stage but shows a great resource potential. The low-level shale gas survey, immature technologies for shale gas development, unclear understanding of main controlling factors of shale gas reservoirs, the lack of the theory and model of shale gas accumulation are challenging issues for shale gas success in China.

A comment on research methods of fault sealing capacity

ZHANG Xinshun， WANG Jianping， LI Yajing， WU Hongzhu

2013, Vol.25(2): 123–128 Abstract ( 692 ) PDF (388 KB) ( 902 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2013.02.022

Fault plays an essential role in oil and gas accumulation, so the analysis of fault sealing capacity is quite important. There are many methods, but it’s still so hard for these methods to evaluate the fault sealing capacity accurately and widely. As a result, before we select an appropriate method and hence improve the reliability of results, we must make clear about the using condition and the key steps of different methods. This paper summarized the most frequently-used methods and their trains of thought proposed by the academician at home and abroad, and then analyzed the relevant basic datasets, key steps, merits and demerits, using conditions and the relative reliability of each method. The qualitative evaluation of fault sealing capacity has 12 respects, including direction of faults, size of faults throw, sand/strata ratio and so on. While the quantitative evaluation methods are mainly based on quantitative calculation of the normal stress on fault plane, shale smear factor and fluid pressure of mudstone. Presently, the SGR method put forward by Yielding is most mature and widest used in many methods. From the known area or some other area with similar geological character nearby, we can get the appropriate parameter or the evaluation standard of the special method, and then the unknown fault sealing capacity can be analyzed.