Lithologic Reservoirs

Seismic reservoir is a boundary science，which is based on seismic data，geology，logging，drilling，testing，oil extracting and analysis assay data，to study the change of reservoir lithology，appearance characteristics，space types， pr0perties and fluid features in three．dimensional space and build reservoir mode1．Seismic reservoir is suitable for every stages of the hydrocarbon exploration and development．It is under the guidance of sedimentology，reservoir geology and seismology ，and based on the organic combination of seismic data，geology and logging．Logging analysis， seismic reservoir prediction，reservoir fluid prediction，reservoir modeling and 3D visualization are the key technologies for seismic reservoir．The greatest advantage of seismic reservoir is that it extends the reservoir parameters into 3D space in the range of seismic resolution and can'ies out reservoir modeling and 3D visualization．

Volcanic oil and gas reservoir geology：Thinking and forecast

ZHU Rukai，MAO Zhiguo，GUO Hongli，WANG Jun

2010, Vol.22(2): 7–13 Abstract ( 529 ) PDF (521 KB) ( 762 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.002

The volcanic reservoir in China is characterized by rich residual resources and large potential of petroleum exploration，and will be an important field for the future oil and gas exploration and development．The research emphases of volcanic reservoir are lithology，lithofacies classification，the naming standardization，the formation and evolution mechanism，and the main controlling factors for reservoir development，among which the development characteristics and distribution rule of volcanic reservoir are the key．Th e geology of volcanic reservoir is a comprehensive geological subject to study the tectonic setting,genetic type，characters，formation，evolution，geometric shape， distribution rule of the volcanic reservoir，and the reservoir research method and description technique，as well as the reservoir evaluation and prediction．The development of the volcanic reservoir geology is helpful to the establishment of theory system and method system and the development of deep research of volcanic reservoir．Th e research key fields of volcanic reservoir in sedimentary basins in China include：lithology characteristics and distribution，the diagenesis type and evolution sequence，the origin mechanisms of the weathering crust reservoir,inner buried hill reservoir and fractured reservoir,the evaluation and prediction technique，and the geological modeling an d development reservoir evaluation of volcanic reservoir．

Carbonate seismic reservoir

ZHANG Huquan，WEI Pingsheng，PAN Jianguo，SUN Dong，WANG Hongbin

2010, Vol.22(2): 14–17 Abstract ( 538 ) PDF (380 KB) ( 1001 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.003

Carbonate seismic reservoir is a branch subject of seismic reservoir．The particularity，research approach， content，method and key techniques of carbonate seismic reservoir are briefly expounded．And it is proposed that carbonate seismic reservoir is the key of great breakthrough for carbonate reservoir exploration and development，which will promote the development of carbonate reservoir exploration．

Application of carbonate seismic reservoir to reef-beach complex exploration in Tazhong area

WANG Hongbin，ZHANG Huquan，WEI Pingsheng，SUN Dong，WANG Zhenqing，LI Chuang

2010, Vol.22(2): 18–23 Abstract ( 595 ) PDF (796 KB) ( 573 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.004

Under the guidance of the theory and technology of carbonate seismic reservoir，combined with the controlling factors for the fracture-cave reservoirs，the technologies of impression method paleogeomorphic restoring， wave equation forward modeling,seismic facies waveform classification，multiattribute wel1．to seismic integration porosity inversion and pre-stack anisotropy fracture prediction are applied to portray fracture-cave reservoirs of reef beach complex of Upper Ordovician in No．1 slope break belt in Tazhong area,which could satisfy the deman d of the exploration and development integration．

Characteristics of reef and shoal facies reservoir of Upper Permian Changxing Formation in Wubaiti area，eastern Sichuan Basin

WEN Huaguo，ZHENG Rongcai，DANG Lurui，ZHENG Chao，ZHAO Can，WANG Pengfei

2010, Vol.22(2): 24–31 Abstract ( 553 ) PDF (1315 KB) ( 651 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.005

The characteristics and genesis of Changxing Formation reservoir in Wubaiti area are studied．The result indicates that intracrystalline pores，intercrystalline solution pores，super large dissolved pores and caves supply the prominent reservoir space．Th e reservoir rocks are mainly grain dolomite，reef dolomite and crystal dolomite．The reservoir property is generally poor and it is attributed into fracture-pore reservoir with low porosity and medium permeability． The development of reservoir of Changxing Formation is generally controlled by microfacies and diagenesis．The reef and shoal facies of the platform edge which developed in the period of sustained transgression controlled the distribution of the reservoir．Reef platform shallows，framework reef and binding reef are favorab le microfacies for reservoir space． Diageneses including dolomitization and dissolution are primarily beneficial to the reservoir quality．Excellent reservoir is always associated th the multistage burial dolomitization，early dissolution，mi ddle dissolution at middle—anadiagenetic stage，late dissolution at anadiagenetic stage and hydrogen sulfuric acid dissolution related with TSR．

Accumulation mechanism of composite reservoir of Upper Triassic Yanchang Formation in northwestern Ordos Basin

LI Yuanhao，ZHANGMingji，WANG Xiujuan，DU Yuguo

2010, Vol.22(2): 32–36 Abstract ( 535 ) PDF (464 KB) ( 484 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.006

The Yanehang Formation in northwestern Ordos Basin is one of the most important exploration area which mainly developed lacustrine delta deposition．The Chang 7 oil shale is the source rock which produced high pressure during the main period of hydrocarbon generation．The overpressure is the main dynamic force for the oil migration to the low perm eability reservoirs through microfraetures faults and superposed sands．The Chang 7 sourae rock is characterized by continuous hydrocarbon-generation，episodic hydrocarbon expulsion and muhipoint injection．The source rocks firstly expeHed down to the lower reservoirs and then to the upper reservoirs according to the homogenization temperature and diagenesis and the secondary migration is mainly vertical and short lateral migration．The thickness of downward expulsion is 10 meter and the upper is 30 meter．The ratio of the upper and down hydrocarbon expulsion amount ofchang 7 is about 3:1．

Carbonate reservoir characteristics of Upper Sinian Dengying Formation in western middle Yangtze

LI Pengfei，LI Jianming，SI Shanghua，ZHANG Yan

2010, Vol.22(2): 37–42 Abstract ( 448 ) PDF (522 KB) ( 504 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.007

The Dengying Formation of Upper Sinian in western middle Yangtze is characterized by preferable exploration prospect and low degree of prospecting．Based on the SUl~aae outcrop，the reservoir characteristics are studied．The result shows that dolomite is the main reservoir rock in the study area．The pore types of dolomite reservoir are mainly intercrystal pore，dissolved pore and intra-gravel pore．The pore structure can be divided into three categories：large pore and medium throat，large pore and small throat，microcrack and microthroat，an d among them the large pore and small throat is the main type．The reservoir zoning evaluation result indicates that the reservoir condition in Zhangjiajie— Sancha area are the best，followed by Liantuo inYichang-Pengshui in Chongqing areas，and it is the worst in Wangcun of Yongshun—Yangjiaping in Shimen areas．

Research on diagenesis of Upper Triassic Chang 8 reservoir in Jiyuan area of Ordos Basin

HE Yanxiang， HUANG Sijing， HU Zuowei， LAN Yefang， HUANG Peipei

2010, Vol.22(2): 42–47 Abstract ( 427 ) PDF (457 KB) ( 415 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.008

The thin section，cathodoluminescence and scanning electron microscopy are applied to analyze the petrological characteristics，diagenesis，authigenic minerals and pore development of Chang 8 reservoir sandstone in Jiyuan area．The result shows that the reservoir rock consists of feldspathic lithic sandstone and lithic arkose with low compositional maturity．The main authigenic minerals include kaolinite，chlorite，illite，calcite，quartz and soda feldspar． The content of kaolinite reflects the development degree of secondary porosity．Chlorite and silica have protective efect on primary porosity of the reservoir,and illite has negative efect on the porosity and permeability．Authigenic calcite which generated in the early stage is favorable for reservoir properties，and a large number of calcite cement pores generated in the later stage have negative efect on the reservoir properties．

Sequence stratigraphy of Cambrian in Bachu—Tazhong area，Tarim Basin

LIU Yanting，FU Heng，CHEN Ji，FANG Xiaolu，HUANG Cheng，JIA Wei

2010, Vol.22(2): 48–53 Abstract ( 514 ) PDF (489 KB) ( 587 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.009

Cambrian has been an important research aspect during the oil and gas exploration of deep carbonate in Tarim Basin．Based on the analysis of lithostratigraphy，logging stratigraphy，biostratum and seismic stratigraphy， Cambrian in Bachu-Tazhong area of Tarim Basin is divided into three second—order sequences．SSQ1 corresponds to Lower Cambrian，SSQ2 corresponds to Middle Cambrian，and SSQ3 corresponds to Upper Cambrian．These three second-order sequences developed wellin Bachu area．while only SSQ2 and SSQ3 developed in Tacan 1 well which iS located in the uplift in Tazhong area．The forming of second．order sequence is controlled by the cyclicity of tectonic evolution，which demonstrates that Cambrian experienced 3 times of large transgression—regression and 3 phase of vertically depositional evolution：tidal fiat—restricted platform—evaporation platform of Early Cambrian。 to open platform— evaporation platform of Middle Cambrian，and restricted platform of Late Cambrian．

Diagenesis and porosity evolution of carbonate reservoirs in Samandepe Gas Field，Turkmenistan

DONG Xia，ZHENG Rongcai，WU Lei，CHEN Renjin，YANG Rui，LI Fengjie

2010, Vol.22(2): 54–61 Abstract ( 457 ) PDF (1138 KB) ( 681 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.010

Based on field section measurement，we1l core observation and thin section identification，the diagenesis and porosity evolution of carbonate reservoirs in Samandepe Gas Field，Turkmenistan are synthetically studied．The destructive diageneses are mainly cementation，compaction-pressure solution，silication，anhydritization，sicilianitization and secondary mineral filling,while the constructive diageneses aYe mainly dolomitization，reerystallization，dissolution and fracturing，which results in the basic characteristics of the reservoir that has the combination of a variety of primary secondary porosity types such as organicvisceral pores，intergranular pores，intragranular pores，moldic pores， intercrystal pores，superlarge dissolved pores，dissolved caverns and fractures．On the basis of the reconstruction of diagenetic sequence，the restoration of porosity evolution respectively experienced the following phases：primary pores， residually primary pores，residually primary pores overlapping secondary pores，secondary pores overlapping primary pores·

Reservoir characteristics of Huanglong Formation in the marginof southern Daba Mountain

CHEN Haoru，ZHENG Rongcai，WEN Huaguo，LUO Qinglin，ZHANG Haijie，YU Yang

2010, Vol.22(2): 62–68 Abstract ( 431 ) PDF (678 KB) ( 455 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.011

The gas reservoir of carboniferous Huanglong Formation in the margin of southern Daba Mountain is the main producing formation. Based on core observation, cast thin section identification, core properties, pore structure data, combined with the previous comprehensive view, the reservoir characteristics of Huanglong Formation are analyzed. The lithology of Huanglong Formation is mainly micrite-powder limestone, containing bioclastic microcrystalline limestone, removing dolomitizetion fine-grained limestone, residual crystal powder-fine grained dolomite and karst breccia. The diageneses favorable for reservoir development are mainly dolomitization,recrystallization, fracturing and unique karstification in the study area. The effects of rock type, dolomitization and karstification on the reservoir development ofHuanglong Formation are discussed.

Sequence stratigraphy and typical seismic facies in one exploration block of Bengal Fan

WU Jiapeng,WANG Yingmin，MA Guiming， GONG Chenglin，ZHANG Lei，LIU Zengqin

2010, Vol.22(2): 69–73 Abstract ( 502 ) PDF (404 KB) ( 681 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.012

The study area is located in the deep-water area,with water depth beneath 2 000 m，so it is dificult to recognize the sequence boundary with the seismic termination．Based on sequence stratigraphy theory,seismic facies combining with seismic attribute and~equency division are applied to carry out the sequence stratigraphy division and deposition identification．According to the amplitude characteristics of deep water sedimentary cycles on seismic profiles，the sequence boundaries are identified．LST and T-HST developed in each third-order sequence． Characteristics of the seismic facies and the sedimentary facies are analyzed in the equitime sequence framework． Referred to the sedimentary facies model in the deep water,and integrated with the external configuration and the localization of the five typical seismic facies，it is regarded that the U-shaped facies， dome-shaped facies，parallel seismic facies with high amplitude，parallel seismic facies with mid-low amplitude and tran sparent and chaotic reflecting facies glee respectively on behalf of incised channel，channel-levee complex， turbidite lobes，deep-water mudstone and mass-transport deposits．The distribution characteristics of the typical seismic facies are helpful to the recognition of the sequence boundaries．

Analysis of sequence stratigraphy and sedimentary facies of M aokou Formation in southeastern Sichuan

LUO Peng,LI Guorong,SHI Zejin,ZHOU Dazhi,TANG Hongwei,ZHANG Deming

2010, Vol.22(2): 74–78 Abstract ( 445 ) PDF (503 KB) ( 896 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.013

On the basis of the knowledge of the depositional setting of Maokou Formation in southeastern Sichuan，Combined with outcrop，well log and well logging data，the Maokou Formation is divided into three third-order sequences．According to the research on the lithology,phase sequence and lithologic profile，the sign for identifying and classifying the key sequence surface is expounded，and the characteristics of the every system tracts are summarized．It is believed that the strata at Maokou stage in the study area have the characteristics of rapid tran sgression and slow regression，well sequence comparison and epicontinental platform nature．Therefore，according to the depositional model of epicontinental platform ，the sedimentary facies in the study area can be divided into subtidal low energy zone，subtidal high energy zone，tide flat and lagoon．The sedimentary facies on the vertical and plane profile is described making the system tract a8 unit．Combined with the sequence and the evolution of the sedimentary facies，the depositional model of Maokou Formation is proposed．The beach facies being favorable for reservoir development mainly develops in the high-stand system tract．

Sedimentary system and hydrocarbon enrichment of Yanchang Formation in southern Ordos Basin

LI Shichun,FENG Chaorong,YIN Shijiang

2010, Vol.22(2): 79–83 Abstract ( 454 ) PDF (511 KB) ( 576 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.014

Based on the analysis of hish resolution sequence stratigraphy of Yanchang Formation in southern Ordos Basin，Yanchang Form ation is divided into five long-term cycles and 22 mid-term cycles．The sedimentary system and sand body distribution are studied．There are two provenance systems developed in the northeast and southwest of the study area．The meandering river delta in the northeast deposited in Fuxian-Xunyi-Yijun area，and developed two to three distributary channels．The braided delta in the southwest mainly deposited in Longdong and Zhenjing area,and developed four to five branch channel sand bodies with favorable inherit．The sand bodies in the southwest mainly developed in Chang 8 reservoir，while the sand bodies in the northeast mainly developed in Chang 6 and Chang 2+3 reservoirs．The subaqueous distributary chan nel san d bodies and low—amplitude structures in the southeast are the favorable zones for oil and gas accumulation．

Hydrocarbon accumulation law of lithologic reservoirs of middle Yanchang Formation in Jiyuan area, Ordos Basin

WANG Changyong，ZHENG Rongcai，WANG Chengyu，NIU Xiaobing，XIN Honggang，LIANG Xiaowei

2010, Vol.22(2): 84–89 Abstract ( 483 ) PDF (937 KB) ( 556 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.015

Based on sedimentary characteristics, provenance analysis, sedimentary evolution and reservoir distribution, the reservoir types of middle Yanchang Formation in Jiyuan area, Ordos Basin are studied. The result shows that Chang 8 to Chang 4+5 oil layers ofYanchang Formation are mainly dominated by lithologic reservoirs and lithologic-structural reservoirs, which mainly developed in delta front, subaqueous fan and delta plain close to lakeshore line. The types and distribution of Chang 8 to Chang 4+5 reservoirs in Jiyuan area are mainly controlled by sedimentary provenance. The sand bodies that pinch-out to northeast and southeast are likely to form lithologic reservoirs, and the scale is controlled by the size of sand body. However, the sand bodies that pinch-out to southwest and south only form lithologic-structural reservoirs when superimposed with nose structures, and their scale is controlled by the size of sand body and nose structure at the same time. The sedimentary provenance in the west of the study area are weakened graduallywhile the sedimentary provenance in the north and northeast are strengthened gradually during the deposition stage of Chang 8 to Chang 4+5 oil layers, which causes the change of reservoir types and distribution. It indicates that lithologic reservoirs mainly developed in Chang 8 oil layers, and lithologic-structural reservoirs mainly developed in Chang 7 to Chang 4+5 oil layers.

Study on 3D pre-stack time migration technology：An example from NYS area of Qaidam Basin

ZHANG Tao，HU Ziduo，LIU Wenqing，LU LieQin，SHAO Xichun

2010, Vol.22(2): 90–94 Abstract ( 441 ) PDF (372 KB) ( 365 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.016

The NYS area of Qaidam Basin is characterized by well developed faults and fractures，and complex geological structure．Because of the poor imaging accuracy，the conventional stack imaging method is difficult to salty out the fine interpretation of structure an d fault．Aimed at the tectonic features of NYS area，the parameters of Kirchhof pre-stack migration velocity and migration aperture are optimized，which improves the pre-stack imaging quality and realize fine geological structure interpretation．

Application of edge preserving smoothing to the calculation of seismic coherence cube

ZHAO Yan，HE Zhenhua，HUANG Deji

2010, Vol.22(2): 95–98 Abstract ( 408 ) PDF (458 KB) ( 526 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.017

Seismic coherence cube technique can efectively reveal the lateral changes of strata,such as fault and complex structure．But when the original seismic data volume has 1ower signal to noise ratio，the resolution of the coherence cube is poor because of the influence of the noise．In order to improve the resolution，the edge preserving smoothing(EPS)algorithm is applied to the calculation of the coherence cube，which carries out the processing of edge preserving smoothing to the original seismic data volume before the calculation of the coherence cube．The computing resuh shows that the method could efectively improve the ability of the coherence cube to distinguish the fault from complex structure．

Seismic inversion and prediction of sand bodies in boundary fault zones of Nanyang Sag

LI Guoliang,CAI Jia，GAN Huajun,LIAO Jihua

2010, Vol.22(2): 99–102 Abstract ( 488 ) PDF (548 KB) ( 634 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.018

The boundary fault zones of Nanyang Sag are characterized by weak exploration，and also are the important exploration area for the further exploration．Based on the sequence stratigraphic framework，small sand bodies are identified along the boundary fault zones and the characteristics are described by using seismic data and logging constrained inversion．which indicates the direction for the next step of exploration．This method is significant for the subtle reservoirs exploration in Nanyang Sag and other similar fauh depressed lacustfine basin in the east of China．

Log methods for gas and water zone recognition in Zizhou Gas Field

HOU Wei,YANG Yu，ZHOU Wen,HUANG Dongjie,YANG Yong

2010, Vol.22(2): 103–106 Abstract ( 403 ) PDF (236 KB) ( 778 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.019

Zizhou Gas Field is a lithologic gas reservoir,of which the gas and water distribution is dominated by structure and the alteration of sand body condition．SO all sorts of factors should be considered comprehensively in log recognition of reservoir fluid．The crossplot of resistivity·porosity，apparent porosity and formation water porosity are applied to identify the gas layers，water layers and dry layers of the second member of Shanxi Formation in Zizhou Gas Field．The resuh shows that these methods can effectively distinguish reservoir fluid．The crossplot of resistivity-porosity and form ation water porosity call be used to distinguish gas layers from water layers，and apparent porosity call be applied to distinguish dry layers from gas layers and water layers clearly．The accuracy of these three methods used together in the study area can reach 95％．

Fracture prediction of the second member of Xujiahe Formation of Dayi structure

LI Hu，QIN Qirong，WANG Zhiping，XIANG Junming

2010, Vol.22(2): 107–110 Abstract ( 474 ) PDF (561 KB) ( 461 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.020

Based on the analysis of the tectonic origins and power resources of Dayi strueture．the model of the structural evolution is summed up．2D numerical simulation of the paleotectonic stress field is applied to predict the cracking degree of the rock mass in the study area, to determ ine the relationship between the cracking degree 0f the rock mass and fracture development and to classify the level of fracture development， and then ealTy out the predicti0n of the degree of fracture development，types and occurrences of fracture． The result shows that the fractures in the second member of Xujiahe Formation are well developed in the structural high and nearby as we11 as the fault and nearby．Five groups 0f fractures are formed by the two periods of tectonic stress field， and the main extensional directions 0f these fractures are NW，NE，EW and NS．

Methods for recognizing sequence boundaries by using logging curves in sparse well pattern：A case study from Zhujiang Formation in Pearl River Mouth Basin

XING Wenli,ZHANG Shangfeng，DU Jiayuan,CHEN Weitao,YI Xuefei

2010, Vol.22(2): 111–115 Abstract ( 435 ) PDF (342 KB) ( 427 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.021

The recognition of sequence boundaries is a key problem in sequence stratigraphy．Core，seismic data, palaeontologic correlation and logging data are often applied to recogn ize sequence boundaries．In sparse well pattern， because of the limitation of seismic resolution and the length of the cores，a lot of logging data are needed in order to improve the recogn ition accuracy of sequence boundaries．On the basis of identifying the sequence boundaries of Zhujiang Formation in Pearl River Mouth Basin by diferent methods，such as shape of natural gamma-ray logging curves，acoustic travel time and wavelet analysis，a method for recognizing the sequence boundaries by making full use of well logging information in sparse well pattern is put forward．

An experimental study on injecting noncondensing gas and chemical agent during steam flooding for enhanced oil recovery

ZHANG Xian，LIU Yongjian,CHE Hongchang,WANG Wei

2010, Vol.22(2): 116–119 Abstract ( 501 ) PDF (318 KB) ( 402 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.022

Aimed at the heavy oil reservoir of Yu I group in Jin 45 block，thermostability appraisement and injection parameter optimization for self-produced foaming agent system called DQS are carried out，and then noneondensing gas is injected with DQS to improve displacement eficiency for recovering heavy oil during steam flooding in the physical model experiments．The experiment result of DQS shows that the thermostability is still excellent at 300℃．and the suitable foaming density is 1.2％．If N2 is used as gas source．the gas—liquid ratio should be in the range from 2 to 3 for achieving a relatively large resistance factor and satisfying the requirements of plugging．N2 and CO2 selected as noncondensing gas，is injected respectively with DQS during steam flooding in the experiments．The result shows that both could obviously improve oil displacement eficiency．If N2 is injected with DQS，it is 1 6．7％more than that of steam flooding．If CO2 is injected with DQS it increases by 1 8．1％in comparison with steam flooding．Economic evaluation result shows that C02 is the better choice compared with N2 to be injected with DQS for improving oil displacement eficiency during steam flooding．

The influence of water injection pressure on percolation of low permeability reservoirs

ZHANG Yukun,WANG Weiying,ZHOU Jiangjiang

2010, Vol.22(2): 120–122 Abstract ( 549 ) PDF (266 KB) ( 643 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.023

The percolation rule of fluids in low-permeability reservoirs is the important research field for seepage mechanics．Low permeability reservoirs are characterized by low permeability，fine pore for the oil and water flowing, high fihrational resistance and significant interactions between the solid-liquid interface and liquid-liquid interface． which results in the complexity of the percolation rule．Based on the core flow test，the effects of injection pressure on rock permeability and percolation rules of liquids are analyzed．The result shows that low perm eability reservoirs have the characteristic of non-linear fluid flow through porous medium．The fluid flow speed in the core changes very little with the pressure gradient when the injection pressure is relatively low．It means that the injected water is dificult to enter the formation．When the pressure gradient is larger,there exists all approximate linear relation between flow speed and pressure gradient．Under the condition of invariant overlying pressure and pressure gradient，the higher the injected pressure gets，the higher the perm eability of rocks is．It shows that high pressure water injection will enhance the water injection eficiency under the precondition of the reservoir formation protection．

Study on reservoir classification system and method

SUN Qinhua， LIU Xiaomei， LIU Jianxin， ZHANG JijuanLI Wuguang，SHAO Xianjie，KANG Yuanyuan，SHI Lei，SHAN Yu

2010, Vol.22(2): 123–127 Abstract ( 552 ) PDF (315 KB) ( 1724 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.024

The reservoir classification study is important work for managing scientifically the reservoir and raising the effects of oilfield development．In view of the reservoir characteristic parameters，the reservoirs are classified by cluster analysis method on the basis of the similar relationship of the reservoir features，which overcomes the influence of human factors．According to the attribute value of each category．the discriminant functions are established．The multibank discriminant methods are applied to calculate the probability of the standard type for unknown reservoir,and then the similar degree with the standard one is decided．Thus the type of the unknown reservoir is determined accurately． The result shows that the use of these two kinds of mathematical methods can classify and manage the reservoir scientifically．

Oil and gas distribution can be inverted?

LI Chuanliang

2010, Vol.22(2): 128–132 Abstract ( 632 ) PDF (500 KB) ( 611 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.025

Deep gas reservoirs usually situate at the bottomor the side slope of a syncline. The main feature of deep gas reservoirs is the inversion of gas and water distribution. Actually the deep gas reservoir is not a scientific concept, and the inversion of gas and water can not happen at all. According to the study, the gas and water in a huge container can not be inverted, and gravity separation can make gas and water distribute normally. The gas and water in a uniform capillary can not be inverted, and buoyancy can move the gas upward. The gas and water in a funnel-shape capillary can also not be inverted because there is a stronger driving force tomove gas upward. The inverse funnel-shape capillary can stop the further move of gas upward with the sealing of capillary pressure and make the gas accumulate. In the caprock of conventional structural gas reservoirs and in the surrounding rocks of lithologic reservoirs, there is formation water, but it is not inverted with the gas in the reservoirs. Due to heterogeneity, the traps of physical property form in sandstone formations and the traps of physical property can be anywhere of a formation, but it may not necessarily stay on the top of a structure. The trap of physical property proposed is a scientific concept, and it can replace the deep gas trap and serve the oil and gas exploration better.

Review of comprehensive study methods for seismics—geology

SONG Chuanchun

2010, Vol.22(2): 133–139 Abstract ( 482 ) PDF (892 KB) ( 950 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2010.02.026

During the development of oil and gas exploration technology，seismic stratigraphy，sequence stratigraphy and seismic sediment01 have been successively deve|oped based on the combination of seismic techniques and geology· Seismic stratigraphy is used to discovery the relationships among seismic reflection phase and geologic horizon and sedimentary facies．The sequence stratigraphy is applied to an alyze the genetic relationships am ong seismic reflection characteristics and geol0gical structure，rock deposit．Being a new research method，seismic sedimentology is adopted to find the inherence relations existing among speciM seismic processing,interpretation，seismic attributes and sedimentary charaeteristics．A development tendency of oil and gas exploration is to apply the third-order seismic attributes to identify the seismic reservoirs an d fluids．The basic concept， basic principle， methods and seismics-geology integrated interpretafton are comprehensively expounded，and the applications in continental lacustrine basins are analyzed．As a resuIt．the development tendency of comprehensive technology and methods for seismics-geology is proposed．