Lithologic Reservoirs

Multiple platform margins developed in Ordovician in TarimBasin, but their reservoirs have significant differences. Statistics data show that reservoir performance of high-angle platform margin is much better than lower-angle platform margin in the aspects of thin section, porosity and logging scales. The angle of foreslope has a positive correlation with the reservoir-layer thickness ratio in platform margin reservoir. High-angle platform margin reef-shoal suffered intense exposure and meteoric water leaching and early pores is favorable for later burial dissolution. So the reservoirs in highangle platform margin reef-shoal have the characteristics of larger thickness and good quality. Low-angle platform margin reef-shoal needs additional conditions to develop good reservoirs, such as fracture, hydrothermal fluid and dolomitization.

Research on oil accumulation law in combination of lower source rock and upper reservoir in small fault depression lake basin：An example from K₁d in main central rifts of Haita Basin

FU Guang， HAN Na

2011, Vol.23(5): 5–8 Abstract ( 373 ) PDF (496 KB) ( 430 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.002

Based on the dissection of oil reservoirs and the study of space matching relation between oil reservoirs and oil accumulation conditions, it is considered that oil reservoirs are mainly fault oil reservoirs in main central rifts of Haita Basin, and mainly distributed in reversal structures and around long-term developing faults. Oil accumulation and distribution of K1d are mainly controlled by the following factors: ①Distribution areas of K1n1 source rock control the areas of oil accumulation and distribution ofK1d;②Reversal structures are favorable places for oil accumulation of K1d; ③Sand bodies of braided delta front provide favorable reservoir space for oil accumulation of K1d; ④Long-term developing faults not only provide pathways for oil migration ofK1n1 toK1d, but also provide structural background for oil accumulation of K1d. Oil accumulation models of K1d are that oil from K1n1 migrated to K1d by long-term developing faults under the action of buoyancy and accumulated in fault block or fault-lithologic traps in and around reversal structures.

Hydrocarbon migration law and model of Chang 9 reservoir in Jiyuan area, Ordos Basin

LIU Xianyang，DENG Xiuqin，ZHAO Yande，ZHANG Xuefeng，HAN Tianyou

2011, Vol.23(5): 9–15 Abstract ( 367 ) PDF (1099 KB) ( 430 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.003

The research means and methods of reservoir geochemistry, reservoir geology and sedimentology are applied to discuss the hydrocarbon sources, migration mechanism, dynamics and accumulation pattern of Chang 9 reservoir in Jiyuan area. The result shows that the crude oil of Chang 9 reservoir comes primarily fromthe high-quality hydrocarbon source rocks ofChang 7 reservoir, ofwhich the hydrocarbon migrated downward and accumulated in Chang 9 reservoir. The main dynamic ofChang 7 hydrocarbon migrating to Chang 9 reservoir is mainly fromthe abnormal high pressure of Chang 7 hydrocarbon source rock hydrocarbon pressurization and excess pressure difference between Chang 7 and Chang 9 reservoir. The vertical superposition and lateral connecting sand bodies and the fractures formed in the regional tectonic activity are the favorable migration path for connectingChang 7 high-quality hydrocarbon source rocks with Chang 9 reservoir.

Characteristics of Chang 7-Chang 9 reservoir group of Triassic in Wuqi and Dingbian area

YU Bo

2011, Vol.23(5): 16–20 Abstract ( 438 ) PDF (637 KB) ( 516 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.004

In order to study the reservoir characteristics ofChang 7-Chang 9 reservoir group in Wuqi and Dingbian area of Ordos Basin, the data of thin section, grain size, mercury penetration and physical properties are used to analyze the petrology, pore configuration, physical properties of the reservoir. The effects of sedimentation and diagenesis on reservoir properties are also studied. The result shows that the reservoirs of Chang 7-Chang 9 reservoir group are mainly of lithic arkose, the pores are mainly corroded intergranular pores, the porosity ranges from8% to 12%, and the permeability ranges from 0.1mD to 1mD. Compaction makes the primary pores decrease, cementation not only damages the primary pores, but alsomakes the secondary dissolved pores suffer damage, and dissolution improves the reservoir properties.

Study on diagenesis of Jurassic sandstone reservoirs in Lunnan area, Tarim Basin

XU Xiongfei， WANG Jiawei， YANG Bo， XING Yi， ZHOU Guobao， CAO Ronghao

2011, Vol.23(5): 21–27 Abstract ( 402 ) PDF (2165 KB) ( 419 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.005

Based on cast slice, scanning electronic microscope, X-diffraction, cathodoluminescence and physical properties, combined with previous researhes, the diagenesis of Jurassic sandstone reservoirs in Lunnan area, Tarim Basin is analyzed, and the types of diagenesis are defined. The study on diagenetic evolutionary series shows that the diagenetic evolution of Jurassic sandstone has already been in B stage of early diagenesis to initial period of A stage of late diagenesis, with the latter being the majority. Compaction destroyed the primary pore structure of Jurassic sandstone intensively. The strong dissolution of feldspar particles at the A stage of late diagenesis made the dissolved pores develop in Lower Jurassic sandstone reservoirs, which constitutes the necessary space for oil and gas accumulation. The intergranular micropores developed in illite, chlorite, illite-smectite mixed-layer greatly improved the reservoir performance ofMiddle and Upper Jurassic sandstone.

Microscopic pore structure characteristics of Chang 6 reservoir in H area of Ansai Oilfield

ZHENG Yanrong， QU Hongjun， FENG Yangwei， WANG Yun， WANG Li， LI Min

2011, Vol.23(5): 28–32 Abstract ( 485 ) PDF (673 KB) ( 539 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.006

Pore structure has an important effect on reservoir properties. By thin section analysis, SEM, mercury injection method, the microscopic pore structure characteristics of Chang 6 reservoir in H area of Ansai Oilfield are studied. The result shows that Chang 6 reservoir belongs to lowporosity and ultra-lowpermeability reservoir in H area of Ansai Oilfield. The main pore types of the reservoir include intergranular dissolved pore, residual intergranular pore and intragranular dissolved pore. The pore and throat have good sorting and general communication. The carillary pressure curve is divided into Ⅰ, Ⅱ, Ⅲ, Ⅳ types according to the characteristic parameters of pore structure. The type Ⅱ and Ⅲ are the main types in the study area. With capillary pressure curve changing from Ⅰ type to Ⅳ type, the driving pressure and Pc50 increase gradually, and Rc50 and average pore throat radius decrease gradually, which reflects that pore structure and reservoir property change from good to poor. By comprehensive research of the relationship between characteristic parameters of pore structure and property parameters, it is shown that reservoir property is the result of driving pressure, Pc50, structural coefficient and so on.

Analysis of reservoir conditions of Meso-Neoproterozoic in Huapi Anticline

QU Yongqiang，ZHANG Huquan，LIU Liqin，WANG Hailong

2011, Vol.23(5): 33–37 Abstract ( 372 ) PDF (419 KB) ( 645 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.007

Through the analysis of source-reservoir-seal assemblage of Meso-Neoproterozoic in northern Hebei, combined with the field observation of Huapi Anticline, it is considered that the combination of Hongshuizhuang, Tieling and Xiamaling Formation is the most favorite source-reservoir-seal assemblage in northern Hebei area. Huapi Anticline reservoir formed during Triassic period, and the upper Tieling Formation and above at the top of the anticline were eroded. Therefore, Huapi Anticline is an ancient anticline oil pool.

Using fluid inclusion to redefine gas accumulation stages of Xujiahe Formation in Hexingchang area

FENG Jierui，LENG Jigao，ZHU Li，ZHANG Yong，SUN Haiwei

2011, Vol.23(5): 38–42 Abstract ( 439 ) PDF (506 KB) ( 996 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.008

Based on the analysis of 230 inclusion samples of the second and fourth members of Xujiahe Formation in Hexingchang area, the characteristics of hydrocarbon inclusion and hydrocarbon-bearing salt water inclusion combining with burial history are used to define the gas reservoir formation time. The process of hydrocarbon accumu-lation in the study area is as following：The two main peak homogenization temperatures of the fourth member of Xujiahe Formation ranges from 77 ℃ to 98 ℃ and from 118 ℃ to 120 ℃ respectively, and the corresponding hydrocarbon accumu-lation stages are middle-late stage of Middle Jurassic and middle stage of Late Jurassic, with the former as the main accumulation stage; The main peak homogenization temperatures of the second member of Xujiahe Formation ranges from 95 ℃ to 106.1 ℃, from 119.8 ℃ to 127.1 ℃ and from 134.5℃ to 140.1 ℃ respectively, and the corresponding hydrocarbon accumulation stages are from the late stage of Late Triassic to the early stage of Early Jurassic and late stage ofMiddle Jurassic.

Research on diagenetic sealing of Nanbaijiantan fault in northwestern margin of Junggar Basin

PENG Wenli，CUI Dian，WU Kongyou，LIU Zhenyu

2011, Vol.23(5): 43–48 Abstract ( 435 ) PDF (1095 KB) ( 514 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.009

From the point of sealing mechanism，the factors that affect the closure property of fault are smear effect, fragmentation and diagenesis. Diagenesis is the dominant factor for the gradually closed effect of quiescent fault. Diagenesis types that affect the closure property of faults are compaction and packing action, as well as cementation, which are all constructive for the closure property of faults. Based on the seismic, well logging and testing data, combined with core and rock slice observation, the quantitative calculation method is applied to carry out the study on the diagenesis of Nanbaijiantan fault in northwestern margin of Junggar Basin. The result shows that because of the strong compaction and packing action, as well as cementation, the faulted zone in Nanbaijiantan has lower porosity and permeability, and the fault has good closure property. Through structure division of faulted zone, combined with core and rock slice observation, it is considered that the influence area of diagenetic sealing in the study area ranges from 50 to 80 meters.

Reservoir diagenesis characteristics of Jurassic Badaowan Formation in Che-Guai area, Junggar Basin

ZHANG Shuncun， ZHONG Weijun， LIANG Zeliang， LU Xinchuan， JIA Yanyan， SHI Jian

2011, Vol.23(5): 49–55 Abstract ( 439 ) PDF (961 KB) ( 613 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.010

Based on well-core observation, slice, SEM, logging data and stable isotope analysis, the reservoir accumulating space types of Jurassic Badaowan Formation in Che-guai area, northwestern margin of Junggar Basin, are well studied. It is considered that conglomerate in the study area mainly developed primary intergranular pores, secondary intragranular dissolved pore and structural fractures; sandstones in the study area mainly developed primary intergranular pores, secondary intergranular dissolved pore and intragranular dissolved pore. The diagenesis characteristics of compaction, cementation and dissolution are studied. Conglomerate and sandstone of Jurassic Badaowan Formation are in stages A and B of late diagenetic stage. In addition, different diagenesis have different influential mechanism on reservoir space types and physical properties. Compaction can decrease the reservoir accumulating space, and makes the reservoir physical properties become worse. On the one hand, cementation can fill up the reservoir accumulating space, and make the reservoir physical properties become worse, on the other hand, it can support grain skeleton and decrease the influence of compaction, meanwhile, it can provide material for dissolution at the late diagenetic stage. Dissolution is a constructive communicating diagenesis, and it can produce secondary pores and fractures.

Oil and Gas accumulation characteristics of nearshore subaqueous fan in Hongze Sag

ZHANG Tao， ZHANG Shiying

2011, Vol.23(5): 56–59 Abstract ( 487 ) PDF (619 KB) ( 612 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.011

The sedimentary system types and contribution are controlled by tectonic features in Hongze Sag. The steep slope zone in the southeast develops nearshore subaqueous fan sedimentary system. The exploration practice reveals that the difference among different parts of nearshore subaqueous fan is obvious. The accumulation conditions and characteristics of different subfacies are studied in order to clarify the main exploration direction of nearshore subaqueous fan. The result shows that fan foot is composed of compacted glutenite rocks and reservoir can not be easily accumulated. The midfan and fanhead are interbedded by sandstone and mudstone. The sandstone has good reservoir capacity and it is updip pinchouting in mature lacustrine source rocks, so it can form a variety of tectonic-lithologic and lithologic reservoirs. Therefore, the midfan and lower-fan are the main exploration target zones of nearshore subaqueous fan.

Application of grey system theory to reservoir valuation of Putaohua Oilfield in northern Songliao Basin

WANG Yajing， GUO Shaobin

2011, Vol.23(5): 60–63 Abstract ( 507 ) PDF (443 KB) ( 522 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.012

The application of grey systemtheory to reservoir evaluation is introduced. The hierarchical-cluster analysis is firstly adopted to select relatively independent evaluation parameters, and six parameters are selected out of ten parameters, including variation coefficient, shale content, effective thickness, oil saturation, porosity and permeability. And then correlation analysis of grey systemtheory is used to determine the weight coefficient of each parameter. Based on calculation of the indexes for comprehensive evaluation of reservoir, inflection-point method is adopted to determine the classifying thresholds for the comprehensive evaluation of reservoir, and then conduct comprehensive quantitative evaluation. Good evaluation effects have been achieved. There are mainly type I and II reservoir in northern Putaohua Oilfield, and type II and III reservoir in southern Putaohua Oilfield.

Evolution model of sedimentary facies in the sequence framework of Changxing Formation in Dianjiang-Wanxian area, Sichuan Basin

GUO Chuan，LI Guorong，ZHOU Bin，LI Tingli，XIE Fachuan，DONG Wenyu

2011, Vol.23(5): 64–68 Abstract ( 568 ) PDF (783 KB) ( 607 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.013

After integration analysis of outcrop, core, logging and seismic data, it is recognized that Upper PermianChangxing Formation is carbonate platform deposition in Dianjiang-Wanxian area, Sichuan Basin. Because of E-mei taphrogeny, two platforms and two trenches developed in Dianjiang-Wanxian area. Based on the establishment of third-order sequence framework, the distribution of sedimentary facies is studied. It is considered that there is a carbonate platform system during the Changxing period in Dianjiang-Wanxian area, which is controlled by Kaijiang-Liangping trench and includes open platform, platform edge and ramp facies. Reef, bioclastic shoal and tidal flat facies developed in the platform edge during the high system tract period of the two third-order sequences of Changxing Formation are favorable facies belts. And only a little reef and shoal developed in platform edge during the transgression systemtract period of the upper third-order sequence. Being affected by regression, reef and shoal moved to the east-north of the study area.

Fracture prediction of Daanzhai member in Langzhong-Nanbu area, northern Sichuan

WANG Shilin，QIN Qirong，SU Peidong，FAN Xiaoli，LI Le

2011, Vol.23(5): 69–72 Abstract ( 498 ) PDF (608 KB) ( 570 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.014

The geological condition in Langzhong-Nanbu area in northern Sichuan is complex. The reservoir of Daanzhai member is thin and super tight with its pores, holes and fractures as main storage and permeation spaces. The development of the fractures is the main factors for controlling the reservoir productivity. The great differences in reservoir productivity among the adjacent wells in the same set of reservoir reflect that the reservoir heterogeneity is strong and it is mainly controlled by the development of fractures. Based on core, logging and oil testing, the method of rock fracturing approximation degree, curvature method and seismic trace discontinuity detection method are used to predict the fractures, and the accuracy of fracture prediction which is depended on the 2D seismic data is well enhanced. The quantitative study by using the weight value to judge the fracture development is carried out, which provides basis for seeking the favorable reservoir and deploying drilling site.

Application of AVO technology to hydrocarbon detection in Tiejianglu area

XU Liying， FANG Bingzhong， SUN Lixu， JIANG Dezhi， LI Dechun

2011, Vol.23(5): 73–77 Abstract ( 418 ) PDF (786 KB) ( 642 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.015

The lithologic-stratigraphic reservoirs of Shahejia Formation in Tiejianglu slope belt have complex oil/ water relationship. The prestack seismic data with relative amplitude preservation contain more information about lithology and fluid than the poststack seismic data. Therefore, the prestack seismic data can be used for hydrocarbon detection. The primary application of prestack seismic data of Aki & Richards and Shuey approximate expressions based on Zoeppritz equation in hydrocarbon detection is introduced. AVO forward modeling is conducted to define fluid-corresponding AVO abnormity, then to identify AVO abnormity across well point trace gather, and finally to interpret AVO multi-attribute body, thus to find abnormal hydrocarbon distribution zones and guide the exploration deployment in the study area.

Recognition of gravity flow deposits with log data and its implications

CUI Weiping， YANG Yuqing

2011, Vol.23(5): 78–81 Abstract ( 402 ) PDF (744 KB) ( 516 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.016

The deposits of sudden event gravity flowwhich are not only rigid and compact but also have characteristics of thin thickness and complex sedimentation type are generally mingled with normal deposits, which makes the recognition of lithology and fluid property very difficult with conventional log data. According to core observation, it is considered that the first member of Liushagang Formation in W oilfield which is the important oil-bearing series developed large amount of various types of gravity flowdeposits. Based on the analysis of depositional characteristics, the methods of crossplot and logging curve shape are proposed to distinguish effectively the the event gravity flow deposits fromthe normal deposits by using the high precision gamma ray and density curve of subaerial core scanning. Finally the oil possibility and physical property of the gravity flowdeposits are evaluated, and the result shows that distal turbidite is the favorable exploration and development target and two possible oil-bearing turbidite sand bodies are pointed out, which provides basis and supports for further evaluation and tapping the potential of the oilfield.

Application of S-transformation to recognition of low-amplitude structure:An example from Lu 10-Lu 6 well area in hinterland of Junggar Basin

BAI Xiaoyin， GUO Juanjuan， CHEN Yongbo， WANG Bin， HUANG Yu

2011, Vol.23(5): 83–86 Abstract ( 417 ) PDF (673 KB) ( 612 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.017

In the Lu10-Lu 6 well area in hinderland of Junggar Basin, the recognition of low-amplitude structure is the main task to seek lowstructural-lithologic reservoir, which is similar toLuliangOilfield. The Hutubihe Formation, one of the major reservoirs in the study area, developed braided river sand bodies, its seismic event has poor lateral continuity, and there are fewwells that unevenly distributed in this area, so it is difficult to trace horizons of low-amplitude structure precisely. The time-frequency analysis technique of S-transformation is used to establish the time-frequency response model of seismic cycle in S domain. Based on the joint calibration of two-dimensional spectrum and sedimentary cycle of single well, the isochronous sedimentary framework of the entire work area is built up. Finally, according to accurate horizon tracingwhich is controlled by the isochronous sedimentary framework, six low-amplitude structural traps are found, the total area is 221 km2, and twowells are optimized. The real drilling result proves the validity and practicability.

Pre-stack reverse-time noise suppressing method based on Laplacian operator

CHEN Keyang

2011, Vol.23(5): 87–95 Abstract ( 482 ) PDF (1605 KB) ( 988 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.018

Low frequency noise is the main problem of the pre-stack reverse-time migration section. The figure noise removal mechanism based on Laplacian operator and the raising mechanism of the pre-stack reverse-time migration are analyzed. Laplacian operators are used to carry out the pre-stack reverse-time noise suppressing experiments in stacking image domain, common imaging domain and common shot domain respectively, and the results are compared with highpass filter method. The numerical simulation results show that the low-frequency reverse-time migration noise is mainly caused by the inaccuracy of migration velocity, and other reasons of low-frequency reverse-time migration noise are the inconsistency of wavelet form between numerical simulating wavelet and numerical records and the application of the correlation type reverse-time imaging condition. The noise suppressing effects based on the Laplacian operator in the above different domains are obvious, and the result in common shot domain is the best. The above methods in three domains are better than that of the conventional high-pass filter method, the formation detail characteristics of the processed section are clearer, and the horizontal cophasal axes of the common imaging gather are correctly depicted.

Fracture prediction of the bottom of T1 f 4 in Huanglongchang structure,northeastern Sichuan Basin

SHAO Xiaozhou， QIN Qirong， FAN Xiaoli， SHI Lichuan

2011, Vol.23(5): 96–100 Abstract ( 437 ) PDF (558 KB) ( 583 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.019

According to the regional tectonic evolution in northeastern Sichuan Basin, Huanglongchang structure is the result ofmultiphase tectonic movements, and it is mostly affected by the force from NE to SWduring the late Himalayan movement. The finite element method and Mohr-Coulomb criterion are used to predict the fractures at the bottomof T1 f 4 in Huanglongchang structure. The result shows that the fractures are well developed in structural high and nearby, two sides of fault, as well as the intersections of faults. Underwent two periods of tectonic stress, six groups of fractures are formed in Huanglongchang structure, and the main trends of these fractures are NW, NE, NNE and NNW.

Research methods of fault sealing

REN Sen-lin， LIU Lin， XU Lei

2011, Vol.23(5): 101–105 Abstract ( 498 ) PDF (802 KB) ( 651 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.020

Faults play a dual role in hydrocarbon migration and accumulation, which provides migration paths or close hydrocarbon, so that the evaluation of fault sealing has a great significance in oil and gas exploration and development. There are manyways to study fault sealing at present, and they can be summarized as lithology, mechanics, fluid nature, fluid inclusions and comprehensive evaluation. These different research methods and some study cases fromexperts are selected to elaborate the principles, characteristics and application of various types of research methods in detail, in order to evaluate fault sealing reasonably.

Development effect evaluation and strategy of horizontal wells in multilayer edge water reservoir in Sudan

RAO Liangyu， WU Xianghong， LI Xianbing， LI Xiangling

2011, Vol.23(5): 106–110 Abstract ( 524 ) PDF (491 KB) ( 513 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.021

In order to solve the problems of large increase of water-cut and increasingly decline of horizontal well production in multilayer edge water reservoir in Sudan, the reservoir is studied by integrate multi-discipline knowledge, and the development performance of horizontal well in various water cut stage is evaluated by using dimension less oil rate and dimensionless cumulative production and monthly incremental ratio of water cut. The results show that horizontal well is the essential technology that can stabilize production and control water cut in high water cut stage of multilayer edge water reservoir, Sudan. The well location, produced fluid intension and reservoir heterogeneity are the major controlling factors for water cut increasing, and the well location, produced fluid intension, reservoir pressure maintenance and formation protection situation are the major controlling factors for production decline. The development strategy is to strengthen horizontal well optimization design in early stage, and lift liquid and water shutoff to stabilize oil production and control water cut, inject water in due time to maintain reservoir pressure and strengthen formation protection in mid-later stage, in order to increase individual productivity and improve the development performance ofmultilayer edge reservoir.

Research on clay mineral features and sensitivity damage in Triassic sandstone reservoir in Lungu 7 well field

OUYANG Chuanxiang， DENG Zhiying， ZHANG Wei

2011, Vol.23(5): 111–114 Abstract ( 434 ) PDF (439 KB) ( 569 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.022

The reservoir in Lungu 7 well field in Tarim Oilfield belongs to middle to high porosity and middle to high permeability reservoir. In order to research some of those damage factors in the process of mining, based on the rock properties and mineral composition characteristics, the sensitivity test evaluation method is applied to analyze the sensitivity damage mechanism of Triassic reservoir in Lungu 7 well field. The result shows that velocity sensitive damage does not necessarily exist in the middle-high porosity and permeability reservoir with high content of kaolinite. The velocity sensitive damage caused by kaolinite which is outputed by feldspar dissolution and limited in particle feldspar is smaller, but the alkali sensitive damage is larger. Illite which outputs on the clastic particle surface in the form of capsule has a little velocity sensitive damage. illite-smectite mixed-layer with a slice of pore filling type output mainly causes water sensitivity effect. It is considered that Triassic reservoir in Lungu 7 well field has the characteristics ofmedium-strong alkali sensitivity, mediumwater sensitivity, mediumweak dilute sensitivity and no velocity sensitivity.

Characteristics and genesis of formation water in Daniudi Gas Field, Ordos Basin

QIN Wei， LI Zhongdong， ZHENG Zhenheng， ZHAO Jiancheng

2011, Vol.23(5): 115–120 Abstract ( 469 ) PDF (544 KB) ( 680 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.023

Based on the analysis of the enrichment and deficit of ion in the formation water, combined with the previous research, the gensis of formation water in Taiyuan, Shanxi and Lower Shihezi Formation in Daniudi Gas Field is analyzed. The result shows that the formation water in the study area is controlled by sedimentary environment, waterrock interaction, fluid mixing and evaporation effect. The formation water in each formation has high content of Br - , Ca 2+ and Sr 2+ , and little content of Mg 2+ and Na + . The enrichment of Br - in Lower Shihezi Formation and the chemical similarity of the formation water in different formations indicate the existence of water mixing.Much acid water fromcoal measures has an important effect on reservoir diagenesis.

Research on Triassic interbeds in block one of Tahe Oilfield

LIU Hailei， DAI Junsheng， YIN He， JIA Kaifu

2011, Vol.23(5): 121–126 Abstract ( 453 ) PDF (749 KB) ( 541 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.05.024

According to the geological characteristics of Triassic reservoir in block one of Tahe Oilfield, the logging data of 37 wells in this area are dealt with, and the distribution of interbeds is studied. The study area is divided into 3 oil layer groups, 11 sublayers, 10 interlayers and 26 interbeds. The distribution of interlayers and interbeds is described, and the relationship between interbeds and the remaining oil distribution are analyzed. The result shows that the interlayers between the main reservoirs extend a long distance with the stable thickness and a enrichment of remaining oil at the bottom, and the distribution frequency and density of the interbeds in the main reservoirs are high with a high level of remaining oil.