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01 June 2011, Volume 32 Issue 3 Previous Issue    Next Issue

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Key Technologies for Discovery of Giant Marine Carbonate Oil-Gas Fields in Tazhong Area, Tarim Basin WANG Zhao-ming, YU Hong-feng, JI Yun-gang, JING Bing, ZHANG Hai-zu 2011, 32 (3):  218-223.  Abstract ( 88 )   PDF (1114KB) ( 337 )   Save The marine carbonate reservoir in Tazhong uplift in Tarim basin is characterized by complicated geology and surface conditions, and its petroleum exploration faces challenges in world-level difficulties. After 15-year researches and practices, the hydrocarbon accumulation theories for marine carbonate reservoirs have been developed, such as the reserves- and hydrocarbon accumulation-controlling theory, the geologic model for multi-origin superimposed and complex fractured-vuggy system, the multi-charging location and multistage large-scale complex mixed sources accumulation theory. The matching technologies for marine petroleum exploration and development are created, including super-deep carbonate rock seismic gathering and processing in desert region, quantitative imagery of fractures and caves, hydrocarbon detection, allocation of high- and stable-production wells, drilling and completion technologies for super-deep and high-temperature carbonate reservoir, and large acid fracturing and alteration technology for fractured-vuggy carbonate reservoir. By means of these theories and technologies, a billion-ton-grade condensate gas field of the Ordovician carbonate reservoirs in Tazhong uplift has been found out, proving the first reef flat complex oil-gas field of Ordovician in China, from which 300 million tons of reserves have been proven basically, and one million-ton productivity has been built up comprehensively. Also, a large scale condensate gas field with interlayer karst of Yingshan formation in the northern slope of Tazhong uplift has been discovered, from which 700 million tons of reserves could be determined, and 4 million-ton productivity construction has been completely started up. These evolutional achievements enrich the marine hydrocarbon theory and promote the progress of the key technologies. References | Related Articles | Metrics

Exploration of Reef-Flat Complex Giant Oil-Gas Field in Tazhong No.1 Slope Break in Tarim Basin: Theory and Technology YANG Hai-jun, HAN Jian-fa, SUN Chong-hao, ZHANG Hai-zu 2011, 32 (3):  224-227.  Abstract ( 92 )   PDF (348KB) ( 290 )   Save To deal with the world-class difficult problems for reef-flat complex (RFC) oil-gas field in Tazhong No.1 slope break, the assorted series of technologies for exploration of the marine carbonate reservoirs are presented, including RFC geologic comprehension modeling technique; RFC quality reservoir seismic prediction technique; RFC large condensate gas pool characterization technique; RFC well location optimum selection technique; super-deep, extra-thermal/pressure reservoir identification, protection and modification technique. The hydrocarbon accumulation geologic theory of RFC large reservoirs is developed, such as the segmentation of platformmargin slope break geologic structure and its control on spatial distribution of RFC, the discovery of largest downhole biohermal group of the Ordovician, the development of large-scale spatial geometry geologic model, the proposition of multi-genetic reservoir improvement, and the development of RFC large condensate gas reservoir geologic models. The deepest and oldest giant condensate gas reservoir in the world has been found out: the RFC giant condensate gas field of the Ordovician is proved as the first one in China, which has reserves of 3×108 t and constructed productivity of 100×104 t in eastern Tarim basin. These exploration and development achievements have enriched the theory and technology for exploration of hydrocarbon accumulation in domestic platform margin energetic facies belts, initiating the novel domains searching for them, being of great significance to be strategically and productively a major explorative area for replacement of resources in Tarim basin. References | Related Articles | Metrics

Depositional Framework of Early-Middle Ordovician in Tazhong-Gucheng Area in Tarim Plate WANG Zhen-yu, HAN Jie, XIONG Yi-xue, SUN Chong-hao, YU Hong-feng 2011, 32 (3):  228-230.  Abstract ( 91 )   PDF (468KB) ( 176 )   Save The core drillings prove that slope facies sediments exist in the Middle-Lower Ordovician in Tazhong area. From the sedimentary characteristics, seismic reflection characteristics and regional stratigraphic thickness changes, this article discusses the depositional framework of the Early-Middle Ordovician in Tazhong and Gucheng areas where two isolated platform margin-slope systems are existed respectively, between which is separated by a relatively low Zhonggu trough. Such a depositional framework discovery is an important significance to exploring and delineating the platform margin high energy facies of the Middle-Lower Ordovician and expanding the oil and gas exploration blocks in these areas. References | Related Articles | Metrics

Determination and Geologic Significance of Yingshan Unconformity of Lower Ordovician in Tazhong Area, Tarim Basin YU Hong-feng, BAI Zhong-kai, DENG Li-ping, JIAO Wei-wei, PAN Yang-yong, ZHAO Yue 2011, 32 (3):  231-234.  Abstract ( 82 )   PDF (427KB) ( 327 )   Save An unconformity exists in Yingshan formation of the Lower Ordovician in Tazhong area, in which significant breakthrough for petroleum exploration has been made. This paper restudies the unconformity by means of unconformity method, geophysics, logging response feature, lithology and colour of cavern sand and shale as well as microfossil information, combining with the results of high-accuracy seismic reservoir prediction and evaluation. It suggests that this large karst unconformity is widely distributed in Tazhong slope area, with good stratified and connected features, being as a favorable reservoir. This study elabrates the key event for hydrocarbon accumulation and petroleum resource extent of the Ordovician carbonate reservoir, hence re-understanding such an unconformity, forming its new strategic idea for carbonate reservoir exploration and extending new domain for petroleum prospecting. References | Related Articles | Metrics

Fossil Record and Growth Sequence of Lianglitag Reef-Flat Complex of Ordovician in Tazhong Area SUN Chong-hao, ZHANG Zheng-hong, WANG Zhen-yu, YU Hong-feng, JI Yun-gang, LI Xin-sheng 2011, 32 (3):  235-238.  Abstract ( 97 )   PDF (436KB) ( 251 )   Save From analysis of the sedimentary setting and lithologic feature, Lianglitag formation of the Ordovician in Tazhong area can be divided into three reef formations, namely, framework reef, reef hill and chalky clay hill, within which fossils are so abundant that they play an important role in serving as a link between past and future. The reef-forming organisms are bacterial algae, calcareous algae, coral, sponge, polyzoa, stromatoporoid, etc., the reef-settled organisms are ostracoda, gastropo, brachiopoda and echinoderm, etc. In evolution stage of the organic reef, the reef-forming organism growing sequence is complete, existing advanced starting reproduction stage-broad reproduction stagedeclining stage. In the process of reef growth, the genus-species, abundance and assemblages appear obvious evolutionary and syngenetic characteristics. The analysis suggests that the reefs in Tazhong are characterized by big thickness of single reef, multiple cycles of development, large-scale multistage reef-flat assemblage, reef rmicrofacies well development and grouping-zoning distribution along the platform margin. The large scale of reef complex shaped by organic reef and grain flat combination provides good fundation for shaping the large scale of reefflat petroleum reservoir in this area. References | Related Articles | Metrics

Strike-Slip Fault System of the Cambrian-Ordovician and Its Oil-Controlling Effect in Tarim Basin WU Guang-hui1, CHENG Li-fang, LIU Yu-kui, WANG Hai, QU Tai-lai, GAO Li 2011, 32 (3):  239-243.  Abstract ( 149 )   PDF (611KB) ( 408 )   Save The analysis of latest 3D seismic data shows that strike-slip fault system occurred in the Cambrian-Ordovician marine carbonate rocks in Tarim basin. The structural styles appeared in flower structure, en echelon structure, pull-apart graben, braided structure, shear fault zone, etc. Multi-stage declinate convergences of the structures formed four evolution stages and distributions of four blocks of strikeslip fault. A series of NE-trending sinistral strike-slip faults developed in the northern slope of Tazhong uplift under the intensive oblique collision by Altym Tagh in the period of late Caledonian to early Hercynian. Controlled by the south Tianshan ocean closure in the late Hercynian, there are NEE-trending compresso-shear faults in the axial part of Tabei uplift and near SN-trending dextral strike-slip faults developed in the southern margin of Tabei uplift. By the Altym Tagh strike-slip fault action in Indosinian-Yanshan movement, the sinistral compresso-shear faults developed in Tadong area (eastern Tarim basin). In late Himalayan, the compresso-shear and strike-slip faults are distributed in Bachu areat under west Kunlun-Pamir oblique squeezing action. It is concluded that the formation and evolution of strikeslip faults are characterized by multiple stages, the faults development by inheritance and segmentation. The strike-slip faults are of great effects on the carbonate reservoirs. The early paleo-reservoirs were destroyed by the strike-slip faults which became the main passageway for late hydrocarbon migration and accumulation. The segmentation of hydrocarbon distribution resulted from the strike-slip faults. References | Related Articles | Metrics

Effect of Fault Activity on Carbonate Reservoir of Yingshan Formation in Tazhong Area, Tarim Basin LV Xiu-xiang, ZHANG Yan-ping, JIAO Wei-wei, YU Hong-feng, BAI Zhong-kai, LIU Dan-dan, ZHAO Yue 2011, 32 (3):  244-249.  Abstract ( 90 )   PDF (545KB) ( 217 )   Save A series of physical and chemical changes took place by the fault activity for Yingshan carbonate reservoir of the Lower Ordovician in Tazhong area. They are the fractures related to the faulting formed in the reservoir near the faults, a high porositypermeability zone, multistage and multi-orientation fractures that improve the carbonate reservoir quality; the fractures as channels for deep fluid migration and various modification processes like solution, metasomatosis and dolomitization; the near-surface fault activity that connected with surface water, deepened the depth of karst, solution and fracture development, thus increasing the effective reservoir spaces. References | Related Articles | Metrics

Fine Study on Yingshan Paleo-Relief of Ordovician in Tazhong Area, Tarim Basin ZHANG Hai-zu, ZHANG Hao-yong, LIU Xin, KE Wei-li, ZHANG Yong 2011, 32 (3):  250-252.  Abstract ( 86 )   PDF (590KB) ( 237 )   Save This paper presents the fine interpretation of seismic horizon, analysis of regional tectonic setting, selection of reference datum, applied analysis of moldic method and residual thickness method, recovery of the paleo-relief and fine sculpture of the paleodrainage pattern of the Ordovician unconformity in Tazhong area. These could be as guidesfor well location arrangement. References | Related Articles | Metrics

The Reef-Flat Weathering Crust Karst and Its Effect on Reservoirs in Tazhong Area, Tarim Basin ZHANG Yun-feng, ZHANG Hai-zu, SUN Chong-hao, JI Yun-gang, HAN Jie, ZHANG Yong 2011, 32 (3):  253-256.  Abstract ( 96 )   PDF (520KB) ( 289 )   Save The carbonate weathering crust of the Upper Ordovician in Tazhong area is characterized by both late diagenetic and near-surfacial karst and penecontemporaneous karst for its outcrop without middle-deep burial or diagenetic environment and its minerals without completely stable conversion, namely, showing non-fabric selectivity dissolved fractures and large caves as well as fabric selectivity dissolved vugs, cast pores and intragranular dissolved pores. In vertical, the crust karst can be divided into superfacial karst zone, vertical percolation dissolved zone, radial flowdissolved zone and groundwater flowzone, with acting thickness of less than 100 m, controlled by reef-flat micro-relief and sea level variation in development. The vuggy layer scale formed by early diagenesis is more expanded by the weathering crust karstification, shaping several new fracture-vug bodies at the top. It is suggested that quality reservoir developed horizons may appear in the reef-flat paleo-relief highs of Lianglitag formation and within 100 mfromthe top. References | Related Articles | Metrics

Development and Evolution Pattern of Paleo-Karst in Slope of Northern Tazhong Area QU Hai-zhou, WANG Fu-huan, WANG Zhen-yu, YU Hong-feng, SUN Chong-hao, ZHANG Yun-feng 2011, 32 (3):  257-261.  Abstract ( 76 )   PDF (465KB) ( 299 )   Save Starting development from Tumuxiuke formation to the end of Lianglitag No.4 member deposition of the Upper Ordovician in slope of northern Tazhong area, the paleo-karst process is so long and its feature is so abundant and obvious that can be comprehensively identified by the characteristics of geology, drilling, conventional logging, imaging logging and seismic data processing. The vertical structure of paleokarst can be divided into surfacial karst zone, vertical percolation zone, radial flow karst zone and deep tranquil flow zone from the top to the bottom, among which the deep tranquil flow zone can be further divided into upper and lower subzones and one transitional zone. With the lowering of paleo relief, the upper karst zone trends to thinning and even undevelopment. Thus the quality of fractured-vuggy reservoir formed by the paleo-karst is controlled by paleo relief and sea level changes. The study suggests that the karst slope is favorable prospecting area, the radial flow karst zone and surfacial karst zone are of best reservoir quality, vertically, and the greatiest potential for petroleum exploration is the Yingshan formation of Lower-Middle Ordovician in the studied area. References | Related Articles | Metrics

Multi-Approach Characterization and Distribution of Ordovician Carbonate Fractures in Tazhong Area, Tarim Basin JU Yan, SUN Xiong-wei, ZHANG Cheng-sen, YU Hong-feng, LIU Xin 2011, 32 (3):  262-266.  Abstract ( 77 )   PDF (233KB) ( 237 )   Save The Ordovician carbonate rock is the main oil producing reservoir in Tazhong area, in which the fractures are important reservoir spaces and seepage channels for oil and gas. Synthesizing the information from cores, well logs, outcrops and seismic data, a suitable method for multi-approach characterization the Ordovician carbonate fractures in Tazhong area is proposed. The study suggests that the distribution of fractures in the Ordovician carbonate rocks is related with the lithology, regional stress field and structural position, and appears in SN zonation, EW blocks and fault control in north slope of Tazhong area, Tarim basin. References | Related Articles | Metrics

The Hydrocarbon Inclusions and Significance of Hydrocarbon Accumulation in Ordovician Reservoirs in Eastern Tazhong Area, Tarim Basin ZHANG Nai, WANG Zhao-ming, YANG Wen-jing, XIAO Zhong-yao, ZHANG Bao-shou, ZHAO Rui-hua, ZHANG Hai-zu, CHEN Yan-gui, XING Yong-liang 2011, 32 (3):  267-271.  Abstract ( 72 )   PDF (594KB) ( 316 )   Save A stage(the Stage-Ⅲ) of hydrocarbon inclusion with strong brown-red fluorescence is discovered in the Ordovician carbonate reservoir in eastern Tazhong area, which is different from the other parts of Tazhong area. There are three stages of hydrocarbon inclusions which contributed to the hydrocarbon accumulation in this area. Based on the composition characteristics, phase diagrams, temperature and pressure of them, it is proved that the Stage-Ⅱ inclusion was formed in late Hercynian movement and the oil originated from the Middle-Upper Ordovician was preserved; the Stage-Ⅳ inclusion formed in late Himalayan movement and the large-scale condensate oil-gas charging decomposing from the Cambrian crude allows the Ordovician oil in Tazhong area to be of mixed feature of Middle-Upper Ordovician and Cambrian oils. This stage condensate charging is the reason for prevalent existence of 25-lower hopane series in oil reservoirs in Tazhong area as the great contributor; and the Stage-Ⅲ formed in Yanshan-early Himalayan movement and high-maturity oil from the Cambrian only accumulated in the Middle-Lower Ordovician and Cambrian reservoirs in eastern Tazhong area, which explains the normal oil reservoir can be found in the eastern Tazhong, while condensate reservoirs have been mainly found in the other areas of Tazhong. References | Related Articles | Metrics

Geochemical Characteristics and Origin of Hydrocarbons from Lower Ordovician in Tazhong Area, Tarim Basin LI Su-mei, XIAO Zhong-yao, LV Xiu-xiang, ZHANG Bao-shou, ZHANG Hai-zu 2011, 32 (3):  272-276.  Abstract ( 82 )   PDF (515KB) ( 228 )   Save Multiple approaches are applied to analysis of the characteristics and origin of the oils from the Lower Ordovician in Tazhong area, Tarim basin. The results show that the oils are primarily condensate oil featured by dominant fractions with low molecular weight and much low content of biomarkers such as steroids and terpenoids, suggesting high-overmature crude oils. It is distinguished from that of the overlying Middle-Upper Ordovician by particularly high-super high dibenzothiophene in aromatics. It is suggested that most of the Lower Ordovician oils are mixed-source oils from both the Cambrian-Lower Ordovician and the Middle-Upper Ordovician with a little higher contribution of the former based on chemical compositions of hydrocarbons and compound-specific carbon isotope of n-alkanes in the oils. It is detected that the Lower Ordovician oils are enriched in mercaptan and long chain alkyl thiolanes. These features together with high H2S content in associated gas as well as high dibenzothiophene in the oils indicate that hydrocarbons from the Lower Ordovician should have suffered some alterations such as thermochemical sulphate reduction (TSR) after accumulation to a certain degree. These might have played an essential role in hydrocarbons alteration and reservoir preservation in this area. References | Related Articles | Metrics

Hydrocarbon Migration and Accumulation of Lower Ordovician in North Slope of Tazhong Low-Swell XU Zhi-ming, ZHANG Hai-zu, WANG Ting-dong, GU Qiao-yuan, LIN Feng, LI Mei, CHEN Li-xin, ZENG Jun 2011, 32 (3):  277-280.  Abstract ( 74 )   PDF (299KB) ( 196 )   Save The Lower Ordovician weathering crust in north slope of Tazhong low-swell is an important channel for petroleum migration and reservoir together with underlying Cambrian as a cap rock. Following the muddy limestone deposit of Lianglitag formation of the Upper Ordovician, the hydrocarbon generated in the Middle-Late Ordovician as peak stage for oil generation in the Cambrian shale source rocks in Manjiaer sag of northern Tazhong area could be trapped effectively. The reservoir-caprock assemblage of the Lower Ordovician formed earlier may be connected with that of underlying Cambrian through faults and fractures, which is a significant natural gas transport layer during Himalayan movement. The Lower Ordovician weathered crust reservoirs linking to the underlying Cambrian reservoir -cap combination by faults and fractures is important gas migration layer during the Himalayan. In the places of suitable sealing conditions such as the fault blocking, compact layer sealing saturated with water and asphaltene sealing formed by early biological degradation, it is believed that natural gas accumulation in continuous distribution could be formed. References | Related Articles | Metrics

Prediction of Carbonate Fractured-Vuggy Reservoir and Hydrocarbon Accumulation Pattern of Yingshan Formation of Lower Ordovician in North Slope of Tazhong Area, Tarim Basin HAN Jian-fa, ZHOU Jin-ming, JING Bing, JIANG Li-hong, YU Hong-feng, HU You-fu, YUAN Jin-ying, SHANG Zhen-guang 2011, 32 (3):  281-284.  Abstract ( 73 )   PDF (431KB) ( 232 )   Save Many reservoir prediction technologies are used for prediction and mapping of Yingshan fractured-vuggy reservoirs' vertical and lateral distributions in Tazhong area, and AVO oil-gas detection technology is applied to adjustment of the fluid property within fractures and caves. Integrating with processing, interpretation and geology, the various well-control reservoir geologic models are developed. The seismic response features of favorable reservoir bodies in high-yielding wells are given. Lots of the seismic information are used to predict reservoirs and hydrocarbon distribution in no well-drilling areas. The fracture and cave system and units are classified combining with palaeo-geomorphology, outcrop lithology, continuity of fractured-vuggy reservoir and later faulting cutting relations. Finally, the water-oil interfaces in fracture and cave units are determined according to drilling and formation test results, and the regional petroleum distribution is discussed and summarized. References | Related Articles | Metrics

Variation of Gas-Oil Ratio in East Test Area in Tazhong No.1 Gas Field, Tarim Basin ZHANG Qiang, YU Hong-feng, BAI Yin, JIANG Yuan, HUANG La-mei, HAN Jie 2011, 32 (3):  285-287.  Abstract ( 97 )   PDF (329KB) ( 192 )   Save Through analyses of the core, well log, geophysical prospecting, test well and production test data, the variation of gas-oil ratio (GOR) of carbonate reservoir of east test area in Tazhong No.1 gas field is reviewed in this paper. The changes with time of the GOR show such four types as the keeping stable, the slow increase, the sustained decrease and the first increase and then decrease. Besed on these, the relationship between the GOR's changes and the reservoir belongs to the apparent homogeneous type, facture system type and dual-porosity medium type. References | Related Articles | Metrics

Application of Fracture-Cave Quantitative Technique to Reserves Study of Carbonate Reservoir in Tazhong Area, Tarim Basin LIU Yun-hong, LIU Yong-lei, LV Dong, AN Hai-ting, XIONG Xing-yin, ZHOU Hong-bo, WANG Xiong-fei, LU Peng-cheng 2011, 32 (3):  288-290.  Abstract ( 93 )   PDF (327KB) ( 261 )   Save The quantitative study from coefficient, parameter and volume determination includes forward modeling analysis, determination of different widths of caves' seismic response feature and amplitude variation and correction template. Integrated with borehole-seismic modeling description technique, the conversion of wave impedance volume into porosity data volume is made. Finally, by description of pore spaces, the quantitative estimation of reservoir space in fracture-vug unit is realized. References | Related Articles | Metrics

A New Method for Evaluation of Single Well-Controlled Dynamic Reserves in Overpressured Gas Reservoir Wang Wei-hong, GUO Yan-dong, LIU Hua 2011, 32 (3):  291-294.  Abstract ( 130 )   PDF (318KB) ( 204 )   Save Rock deformation, varied cock compressibility coefficient and permeability stress- sensibility will occur in the process of overpressured gas reservoir development. The experiment results are used to set up the material balance equation and deformed media gas well productivity equation with consideration of continuous change of the compressibility. By these equations, a new method for matching the production data of gas well and evaluating the well-controlled dynamic reserves in such a gas reservoir. The application results shows that the rock compressibility coefficient and permeability stress-sensitivity of an overpressured gas reservoir has a big effect on calculation of the reserves. If these factors are not considered, the calculated reserves will be lower by 15%~20% than the real reserves. References | Related Articles | Metrics

Study of Surface Ghost Reflection in Shot Process of VSP in Tazhong Area, Tarim Basin BAI Jun-hui, JING Bing, WAN Xiao-ping, DONG Rui-xia, FAN Yang-shuan, ZHANG Ju-min 2011, 32 (3):  295-297.  Abstract ( 71 )   PDF (415KB) ( 250 )   Save This paper presents the surface gholst reflection waves from VSP data in Tazhong desert area with varied relief and analyzes processing approach for deleting multi-ghost relection wave in full attenuation based on the characteristic of such a wave formed by surface structure in process of seismic prospecting or shot in Tazhong area. The study suggests that using VSP processing result integated with well logs can calibrate and recognize the full multi-ghost reflection waves of seismic profile, thus providing proper data volume for geologic researches in this area. References | Related Articles | Metrics

Desert Seismic Data Processing Technology in Tazhong Area, Tarim Basin YUAN Liao, HUANG Guang-jian, LI Dao-shan, JING Bing, LI Guang-peng, GAO Jie 2011, 32 (3):  298-300.  Abstract ( 102 )   PDF (342KB) ( 227 )   Save Tazhong No.1 slope break as a typical karst cavern body is a very favorable domain for hydrocarbon accumulation of the Ordovician carbonate reservoir in Tazhong area, Tarim basin. The feature of fractures and caves is characterized by string beads-like reflection in seismic profile. The methods for prediction of the small-sized caves and fractures developing zones in seismic processing include amplitude-preserved prestack gather processing, noise-removal approach, well-control treatment to improve deconvolution effect in purpose of increasing resolution of the Ordovician inside information. Also, the inside reflection feature of Tazhong Ordovician is further improved using anisotropic prestack time migration technique. References | Related Articles | Metrics

Seismic Reflection Characteristics of High Efficient Wells in Carbonate Reservoirs in Western Tazhong Area, Tarim Basin LIU Xin, JING Bing, SUN Dong, DONG Rui-xia 2011, 32 (3):  301-304.  Abstract ( 118 )   PDF (519KB) ( 267 )   Save The high efficient wells in carbonate fractured-vuggy reservoirs in western Tazhong area are reflected as beads-shaped or sheetshaped strong reflection from the seismic profile. Study on the relationships among the reflection, reservoir type and production performance is of significance for optimizing well location in this area. This paper presents the corresponding relationships among them, including the high efficient well reflection characteristics of the vertical range and horizontal distance of the first wave trough, and the location of effective reservoirs in the seismic profiles, and gives a set of characteristic chart of the wells, based on data from the seismic profiles, engineering anomaly, deliverability test, production performance by means of techniques for numerical simulation and fine calibration of reservoirs. Because the first wave trough is large vertically and the horizontal distance is long, the best location of the high efficient well can be chosen. To drill horiontal wells and explore the non-beads-shaped reservoirs at the same time could be a good method for efficient development of such reservoirs. References | Related Articles | Metrics

Seismic Response Mechanism of Carbonate Caverns and Influence Factors in Tazhong Area LI Sheng-jun, WANG Fu-huan, YONG Xue-shan, LIU Wei-fang, GAO Jian-hu, LI Shi-yin 2011, 32 (3):  305-207.  Abstract ( 96 )   PDF (327KB) ( 275 )   Save The "string beads" reflection characteristic is one of important seismic phenomena in identification of carbonation reservoirs of the Ordovician in Tarim basin. Base on forward modeling of wave equation, the difference models for karst cave shape, observation system, cave mode are designed, and the mechanism and its influence factors of the cavern seismic response are analyzed. The result shows that amplitude of "string beads" response is enhanced with cave width increasing, but the length of "string beads" doesn't change; the amplitude of "string beads" first increases and then decreases with cave height increasing; High-density acquisition has better imaging performance and resolution to the small-sized body compared with the conventional observation system. Different response characteristics are corresponding with different patterns of superimposed caves. These understandings provide a means for studying the relationship between the response mechanism and shape of karst cave and the characteristic of "string beads". References | Related Articles | Metrics

Application of Fourier Spectrum Decomposition Technique to Hydrocarbon Exploration in TZ-45 Wellblock in Tarim Basin HU Tai-ping, JI Yun-gang, PAN Yang-yong, DONG Rui-xia, WU Mei-lian 2011, 32 (3):  308-310.  Abstract ( 77 )   PDF (420KB) ( 176 )   Save Fourier spectrum decomposition technique is widely applied in plane and spacial description of carbonate reservoir in Tazhong area. The tuning amplitude, phase and discrete amplitude data from Fourier spectrum transform (FST) are applied to the fractured-vuggy reservoir description, fault or fracture system carving and reservoir hydrocarbon-bearing detection of Lianglitag formation of the Ordovician in TZ-45 Wellblock in Tazhong area, and good effects have been obtained. References | Related Articles | Metrics

Application of Prestack Interpretation Technique to Ordovician Carbonate Reservoir Prediction in Tazhong Area, Tarim Basin XIONG Xing-yin, HU Tai-ping, LIU Yong-lei, JING Bing, LV Dong, AN Hai-ting, LU Peng-cheng 2011, 32 (3):  311-313.  Abstract ( 67 )   PDF (405KB) ( 200 )   Save Application of prestack interpretation technique to the Ordovician carbonate reservoir direct hydrocarbon detection in reservoirs can get more abundant information about lithology and fluid. It is this technical application that the carbonate reservoir and oil-gas distribution features are understood, and several high and stable production wells are discovered, which provides technical guarantee for the reserves and production incrementation in Tazhong area. References | Related Articles | Metrics

Application of Fracture-Cave Quantitative Technique for Carbonate Reservoir of Yingshan Formation of Lower Ordovician in North Slope of Tazhong Area, Tarim Basin DONG Rui-xia, HAN Jian-fa, ZHANG Yan-ping, YU Hong-feng, JIAO Wei-wei, JI Yun-gang, YU Wen-xia 2011, 32 (3):  314-317.  Abstract ( 79 )   PDF (426KB) ( 197 )   Save In view of geologic models for various reservoirs, integrated with field observing system and seismic geologic conditions in studied area, the numerical simulation is conducted using Tesseral forward software, and the seismic response characteristics of favorable reservoir in highly producing wells. The predicting method for wave impedance inverse seismic attribute is selected through forward studies, analyses of the geophysical response characteristics of all kinds of reservoirs. The corrected wave impedance data body is converted into the porosity data body, followed by getting the effective reservoir spaces of the reservoirs and finally realizing the quantitative description of the effective reservoir spaces. The study shows that highly producing and effective wells are characterized by seismic features of "strong surface plus inside regular beads reflection" and "feeble surface plus inside strong beads reflection". The seismic response characteristics of the carbonate reservoir of the Lower Ordovician weathered crust are dominated by low wave impedance, low velocity, low frequency, strong frequencydivi sion amplitude, strong coherent and intensity attenuation, etc. Through the fracture-cave quantitative sculpture, the total effective reservoir volume is 5.42×108 m3 in Block Zhonggu-8. Exploration practice indicates that the quantitative sculpture of fracture-cave in carbonate reservoir is one of the effective methods to improve the exploration success rate. References | Related Articles | Metrics

Identification of the Carboniferous Volcanic Lithology with Gravitational-Magnetic-Electric Abnormal Information Pattern—An example fromeastern Luliang uplift area in Junggar basin SUO Xiao-dong, ZHANG Sheng, CHEN De-zhi 2011, 32 (3):  318-320.  Abstract ( 89 )   PDF (394KB) ( 281 )   Save Volcanic rocks as an oil-gas reservoir has been approved for the Carboniferous petroleum exploration in the northern Xinjiang. The exploration of eastern Luliang area in Junggar basin reveals that the petrophysical property, the gravitational-magnetic-electric abnormal information and the lithology identification of its volcanic rocks. The study shows that the high- precise gravitational-magnetic-electric data in scale of 1∶50 000 and corresponding special processing methodologies should be applied to identify the regional distribution of the volcanic lithology with density, magnetism and resistivity differences. And the predicted results are more accordant with the real Carboniferous lithology from drilling in this area. References | Related Articles | Metrics

Well Logging Evaluation Technique for Reef-Flat Carbonate Reservoir in Tazhong Area, Tarim Basin LIU Xing-li, ZHANG Gui-bin, JI Yun-gang, ZHANG Cheng-sen, HAN Dong-chun, WU Xing-neng, LIU Yong-lin 2011, 32 (3):  321-324.  Abstract ( 70 )   PDF (406KB) ( 232 )   Save Based on the fracture-vug parameter from electric imaging quantitative processing, conventional well logs and formation testing data as well as crossplot analysis, the quantitative grading standard for various reservoirs is established, and new method of fill-up rate for quantitative evaluation of vuggy reservoir using shale content-areal porosity ratio is proposed. The fluid property discrimination approaches such as gas component analysis, chart analysis, array sonic parameter crossplot, NMR and their suitabilities are studied, by which presents the relationship between logging and seismic attributes of various reservoirs, realizing the integration of microscopic and macroscopic feaures. References | Related Articles | Metrics

Application of Remote Detection Acoustic Reflection Logging to Fractured-Vuggy Carbonate Reservoir Evaluation ZHANG Cheng-sen, XIAO Cheng-wen, LIU Xing-li, GUO Hong-bo, ZHU Deng-chao, WANG Gui-qing 2011, 32 (3):  325-328.  Abstract ( 108 )   PDF (453KB) ( 540 )   Save Remote detection acoustic reflection logging (RDARL) is capable to reflect acoustic impedance anomaly ranging from 3 to 10 meters beside a wellbore in carbonate formation or fractured-vuggy carbonate reservoir. This paper presents the detection principle and its typical response features applied to different types of reservoirs. Through the scale application of RDARL to Tarim carbonate reservoirs, integrated with conventional logging data, the fractured-vuggy developed situations of them beside the wellbores are evaluated. And the acid fracturing test shows that it can reach above 85% in effectiveness, increasing comprehensive capability of evaluating such a reservoir in this basin. References | Related Articles | Metrics

Petroleum Geology and Exploration Potential Analysis in Central Sumatra Basin YANG Lei 2011, 32 (3):  329-331.  Abstract ( 204 )   PDF (362KB) ( 301 )   Save Central Sumatra basin is a back-arc rift basin developed along the edge of the Sunda craton. The basin is very rich in oil and gas resources, the lacustrine shales of Brown Shale formation of the Pematang group of the Paleogene are the principal source rocks, the fluvial and deltaic sandstones of the Sihapas group are the main reservoirs and the overlying shales of the Telisa formation are the main seals in this basin. Essentially there are three source rock facies of the Pematang group, they are deep lacustrine facies, shallow lacustrine facies and carbonaceous marsh facies. The lacustrine facies is oil prone, the carbonaceous marsh facies is gas and condensate prone. The northwestern flanks and offshore in Central Sumatra basin are the targets for future petroleum exploration. References | Related Articles | Metrics