Table of Content

01 August 2005, Volume 26 Issue 4 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Reference Manager ProCite BibTeX RefWorks

Toggle Thumbnails

Petroleum System and Prospecting Targets in Northern Margin of Qaidam Basin ZHOU Yan-ru, YUAN Jian-ying, HE Heng-hua 2005, 26 (4):  345-349.  Abstract ( 94 )   PDF (1196KB) ( 202 )   Save Based on the structural ewolution and goological framework in northern margin rift of Qaidam basin, this paper presents that the overall course of faults development in middle Qaidam is the main power for control ling the superimposition and assemblage of Mesozoic and Cenozoic basins, the deep sodimentary structure of Mesozoic and the reverse structures during Himalayan movement in this rift, and ilustrates that the petroleum system in it is characterized by side-by-side pattern in space and by continuous pattern in time. Furthermore,some countermeasures and saggestions are made,which are of significance for expleration of the rif-lilce reservoirs in this area. References | Related Articles | Metrics

Prospect for Petroleum Exploration in Northern Margin of Qaidam Basin WANG Chang-gui, MA Li-xie 2005, 26 (4):  350-352.  Abstract ( 104 )   PDF (385KB) ( 305 )   Save Since 1955, the petroleum exploration of the northern margin of Qaidam basin has carried out for over 40 years, but no large-scale reserves have been found, except for a middle-sized field named Nanbaxian by the end of 1990s. The oil resources in this area amount to 10x108t, but incremental reserves are seldom discovered, with degree of conversion of oil resources by 3.2%. The reasons for it are as follows: Altun shove fault's destructive effect on petroleum migration in the northem margin; absence of good regional cap rocks; not enough fundamental study work on the Jurassic, and uncontinuity of related prospecting eforts. AIll these add the difficulty for exploration of it. It is suggested that the further exploratory effort should focus on buried or subtle structure and lithologic trap in swell slope, paying attention to restudy of Saishiten piedmont overthrust nappe. References | Related Articles | Metrics

Characteristics of Peculiar State Mineral in Oil-Gas Bearing Province in Northern Margin of Qaidam Basin GAN Gui-yuan, KONG Hong-xi, YU Rui-juan, YAN Xiao-lan, CUI Jun, WANG Ai-min 2005, 26 (4):  353-356.  Abstract ( 82 )   PDF (914KB) ( 326 )   Save The characteristics of peculiar state mineral in oil deposits in the northern margin of Qaidam basin are presented. The distribution of this mineral on oil zones and its eight types of aggregates are ilustrated. The replacement, inclusion and association to oily asphalt as well as feature from scanning electron microscope (SEM) and X-ray analytical result of the peculiar state mineral are studied. Particularly, the characteristics of this mineral on high-yield zone (over 10t per day per well), normal-yield layer (1-l0t per day per ell) and only oil-gas show or extremely low oil production bed are revealed in this paper. References | Related Articles | Metrics

Refined Interpretation of Sequence and! Prediction of Sandbodies in Altun A rea, Qaidam Basin WU Yin-ye, LIU Yun-tian, JIANG Bo, LIU Zhong, LI Jun, CUI Hua-juan 2005, 26 (4):  357-359.  Abstract ( 69 )   PDF (306KB) ( 246 )   Save Combined with refined analysis result of sequence, the seismic prediction technique on reservoir can lead to good results of seismic attribute depending on parasequence under the framework of systems tract. This study shows the prediction of a potential sandbodies distribution of channel turbidite of basin floor fan in the deep lake of Altun area. The braided channel turbidite of middle basin floor fan is characterized by gray and green-grayish sandstone and conglomerate and graveled sandstone with grain-sequence, interbedding with semi-deep and deep lacustrine mudstone. Based on the predicted sandbodies and related structural and oil-generating conditions, the favorable targets for exploration of lithological oil-gas reservoir can be determined. References | Related Articles | Metrics

Sedimentary Provenances and Reservoir Qualities in Southwestern Qaidam Basin LIU Yun-tian, YANG Shao-yong 2005, 26 (4):  360-362.  Abstract ( 72 )   PDF (606KB) ( 211 )   Save Integrating with heavy mineral analysis, the study presents that during E,2 in the southwestern Qaidam basin there exist several sedimentary provenances such as Qigequan- Ahadi, Alaer, Qimantage and Dongchaishan, with heavy mineral assembl ages of eight sub-areas. These provenances are of some diferences in the sedimentary characteristics and facies types: Qigequan-Ahadi is doninated by short-distance and gravity flow deposits; Alaer dominated by medium-fine and fluvial-lacustrine deposits， and Qimantage and Dongchaishan dominated by fine lacustrine deposits or sedimentation. It is predicted that the provenance in the middle part of study area is generally premium in reservoir quality, the north part is secondary, and the southwestern part is poor. References | Related Articles | Metrics

Assessment of Biogenetic Gas R eservoir Potential in Qaidam Basin JIANG Gui-feng, KONG Hong-xi, HOU Ze-sheng, XU Zi-yuan, HU Yong, YUAN Xiu-jun 2005, 26 (4):  363-366.  Abstract ( 91 )   PDF (304KB) ( 206 )   Save Based on the particular geological conditions of forming biogenetic gas reservoir in Qaidam basin, it is calculated from Monte Carlo method that the total resource amount of biogenetic gas is 14755x108m3, integrated with the results obtained from trap geological analysis and basin modeling method. A lso, petroleum assessment system (PASYS) is adopted to evaluate the resource potential of this basin and plays/blocks, and the favorable areas for biogenetic gas prospecting in the near future are Beipo (northern slope) and the Central Depression with corresponding exploration targets, of which the buried structural trap and non -structural trap are the main concern in Qaidam basin. References | Related Articles | Metrics

A bnormal High Pressure Feature in Lenghu-Nanbaxian Structural Belt in Northern Margin of Qaidam Basin GAO Chang-hai, ZHA Ming, WU Kong-you 2005, 26 (4):  367-369.  Abstract ( 138 )   PDF (941KB) ( 334 )   Save Abnommal high pressure is found from Neogene to Jurassic in Lenghu-Nanbaxian structural belt in the northern margin of Qaidam basin, and mostly occurs in undercompaction shale. It was primarily formed by undercompaction, hydrocarbon generation and tectonic compression. The shale caprocks in Jurassic primary hydrocarbon reservoir and Tertiary secondary reservoirs are both abnormal high pressure zones and good pressure-sealed ones, which control the vertical distribution of hydrocarbons. The study shows that the under the abnormal high pressure zone which can be as a good sealing or cap rock is favorable for hydrocarbon enrichment and for exploration and development in northern margin of Qaidam basin. References | Related Articles | Metrics

System Tract and Depositional F acies of Lower Ganchaigou Formation in Qigequan Area,Qaidam Basin LI Jun, WU Yin-ye, CUI Hua-juan, LIU Zhong, JIANG Bo, WU Wei-an, GUO Bin-cheng 2005, 26 (4):  370-372.  Abstract ( 70 )   PDF (523KB) ( 206 )   Save Transgressive system tract and regressive system tract in lower member of Lower Ganchaihou formation are recognized from the analysis of geological logging and well logs in Qigequan area. The reservoir rock type is dominated by fan-delta sand body and deep-hemideep lake turbidite sand body. The log sequence analysis is integrated with seismic reservoir prediction technique. The system tract is applied to the analysis of seismic atribute and the map compilation of sedimentary facies. It is predicted that lithologic oil- gas reservoir may be shaped in the delta front of the southeastern Qigequan area and the sublacustrine fan's sand body of the northern Qigequan area. References | Related Articles | Metrics

Sedimentary] Facies of Y oushashan Oilfield in Qaidam Basin WANG Lin, JIA Ying-lan, JIANG Yi-quan, HUANG Zhen-lian, JIA NG Ming-zhong 2005, 26 (4):  373-376.  Abstract ( 105 )   PDF (906KB) ( 443 )   Save The west part of Qaidam basin underwent the lacustrine transgression during E1+2-N11, followed by entering the regression in N21, with large-scale uplfting of Kunlun mountains situated in the southwestern margin of Qaidam basin. Hence the depocenter of lacustrine basin commenced moving from southwest to northeast. Under such a background, Youshashan area was subjected to the deposits of braided stream delta-saucer lake in N1-N12. The XII-I oil measures in Y oushashan oilfield normally assume anticycle deposits shoaling upward. Below VII oil measure (N1) is dominated by braided stream delta front-shore saucer lake deposits; over this oil measure (N12) by braided stream delta plain-front deposits. Laterally, II-V blocks are contolled by the structures in reservoir distribution, with stable sedimentation, while I and VI blocks are mostly influenced by lithogical factors. References | Related Articles | Metrics

Restudy of Evolution of Qiketai- W enjisang-Qiudong Decollement Structural System LI Cheng-ming, NI Lian-bin, SONG Xue-liang, JIANG Bing, WANG Wen-xia 2005, 26 (4):  377-379.  Abstract ( 109 )   PDF (812KB) ( 152 )   Save Taibei sag controlled by Mount Bogda is the major depressed area in Tuha basin. It has been in foreland sub-depression area since Jurassic, and formned decollement structural system with vast cap compression, including Qiudong and W enjisang structures in center of the sag and Qiketai thrust belt in the southern slope margin. The Qiudong and W enjisang structures behind the system belong to sliding folds, with special stratigraphic configuration after multi-stage movement since Late Jurassic. This paper determines the stages and thrusting scale of Qiketai thrust belt formation in front of the decollement structural system, which helps to impersonal analysis of the hydrocarbon accumulation within the system. References | Related Articles | Metrics

Non-Structural Reservoir Explora tion in Jiergalangtu Sag, Erlian Basin SUN Jing-min, PANG Xiong-qi, SHENG Jun-shan, LIANG Feng, LANG Jing 2005, 26 (4):  380-382.  Abstract ( 80 )   PDF (268KB) ( 233 )   Save With high exploratory extent in Erlian basin, Jiergalangtu sag is believed to have high remained resources and great prospecting potentials. Comprehensive assessment indicates that huge exploratory potential exists along Baoraonei belt which is a main source subsag and major target for finding out non-structural reservoirs in it. By means of sequence stratigraphic theory, this paper presents detailed evaluation and well site locations by deepening geological understandings and intensifying efforts of sedimentary study and reservoir prediction, and could be of active significance for guiding such a non-structural reservoir exploration. References | Related Articles | Metrics

Analysis of Reservoir in W eimark-2 Gas- Bearing Structure of Kongquehe A rea ZHANG Ke-yin 2005, 26 (4):  383-385.  Abstract ( 104 )   PDF (520KB) ( 204 )   Save The in-depth analysis of W eimark-2 gas-bearing structure shows that the main targets for exploration should be the reservoir with low porosity-low permeability and extremely low porosity-extremely low permeability, and gas enriches in lower sand section of Silurian, dominated by wet gas. The gas supply is both from late kerogen pyrolysis gas and crude cracked gas, with mixture feature of the same source and different stages. There exist two stages of petroleum accumulation principally formed in period of Himalayan movement. The efctive reservoir- cap assemblage, relatively homogeneous reservoir rocks, developed fractures and locations as well as faults in two sides of the anticline are the main controlling factors for forming reservoirs. References | Related Articles | Metrics

Approach to Hydrocarbon Source Condition in Buried Hill, Jianghan Basin LU Ming-guo, TONG Xiao-lan, WANG Bi-jin, ZHANG Jian-hua 2005, 26 (4):  386-388.  Abstract ( 81 )   PDF (438KB) ( 202 )   Save The hydrocarbon source of buried hill in Jianghan basin is discussed by using drilling, logging, seismic and experimental data in aspects of the source feature and conducting system. The study shows that there exists multi-supply of hydrocarbon sources to the buried hill, where the buried hill belts of Qianbei and Tonghaikou are of the best for the source supply, the belts of W ancheng and Xingou take the second place, and the Tianmen buried hill is poor for it. These provide solid bases for the buried hill's hydrocarbon accumulation in this area. References | Related Articles | Metrics

Sedimentary Facies of No.3 Section of Hetaoyuan Formation and Hydrocarbon Distribution in Anpeng Oilfield MING Hai-hui, YIN Zhen-kui, ZHOU Xin-ke, FENG You-kui 2005, 26 (4):  389-392.  Abstract ( 65 )   PDF (474KB) ( 334 )   Save The lower No.3 section of Hetaoyuan formation of Paleogene in Anpeng oilfield is a major horizon for exploration, its sedimentary facies study is of significant guidances for exploration and development of this field. Based on core lab, well log and geological logging data and analysis of the depositional characteristics, it is believed that the No.3 section of Hetaoyuan formation belongs to a near-source fan deltaic deposit with fan delta front and pro-fan delta subfacies, except for fan delta plain. The fan delta front is furthermore divided into the near-source and the far-source underwater distri butary channels, the mouth bar, the far bar sand, frontal sheet sand and inter-tributary channel. The sedimentary microfacies study reveals its effect on the reservoir quality, confirming the relationship between the microfacies and petroleum distribution. The results show that there exist apparent differences of reservoir quality and petroliferous feature in different sedimenrary facies. The far-source underwater distributary channel and mouth bar are good in reservoir quality, being the main facies for petroleum accumulation; the frontal sheet sand and far bar sand are relatively poor. References | Related Articles | Metrics

Himalayan Movement and Petroleum A ccumulation in Jiuxi Basin ZHOU Xiao-feng,ZHAO Ying-cheng ,ZHANG Ya-jun 2005, 26 (4):  393-396.  Abstract ( 128 )   PDF (459KB) ( 528 )   Save Jiuxi basin is located in the northeastern margin of Qinghai-Tibet plateau with active natural earthquake. Himalayan movement in this basin can be divided into eleven stages in terms of weak-strong intensity of structural compression. The Middle Pliocene is its main deformation/formation stage and petroleum accumulation stage in this area. The structural deformation originates in Oligocene. With cont inuous north-shifting of sedimentary center, the development periods of each structural belts tend to postponing from the south to the north, thus controlling the fault- related fold, structural trap and zonal distribution pattern of oil-gas reservoirs in this area. It is indicated that the natural earthquake is an important role in petroleum migration and accumulation. References | Related Articles | Metrics

Differential Hydrocarbon Accumulation of Triassic in Taibei and Tainan Sags, Tuha Basin YANG Zhen-xiang, KANG Yong-shang, JIAO Li-xin, HE Zhi-ping, YANG Song-ling 2005, 26 (4):  397-400.  Abstract ( 75 )   PDF (465KB) ( 227 )   Save The reservoir characteristics of Triassic between Shanshen structure belt in Taibei sag and Lukeqin structural belt in Tainan sag as well as their controlling factors are analyzed. The differential mechanism in hydrocarbon accumulation is due to their different structural settings in late Indosinian movement, late Y anshan movement till Late Himalayan movement. The paleo-uplift structural belt (i.e. Shanshan arcuate zone) in Taibei sag is adjacent to the source rocks, but for diagenesis and tectonic variation, the differential reservoir quality and trap shape timing behind hydrocarbon generation and expulsion periods occur; while the relatively shallow deposits of Early Jurassic in Tainan sag have better reservoir quality for its weak diagenesis and compaction. A lso, since Late Indosinian movement, the structures in the southeastern Tainan sag commence stable and continuous tilting, thus being the long- term directional domain. Therefore, the petroleum exploration of Triassic in Tuha basin should pay more attention to the southern area with relatively stable structures,hydrocarbon supply and better reservoir quality. References | Related Articles | Metrics

Structural Characteritics and Hydrocarbon A ccumulation in Dongwan A nticline WANG Chang-cheng, SHI Ze-jin, TIAN Ya-ming, LI He 2005, 26 (4):  401-403.  Abstract ( 91 )   PDF (509KB) ( 154 )   Save Dongwan anticline is located in the southern margin of Junggar basin with better source, reservoir and cap rocks. Is structures were proved by multi-demonstration with many geophysical and geological methods. However, there was no oil-gas indication from Dongwan-1 Well that was completed in 2003. In-depth understanding of the southern margin regional setting is made, the structural evolution, shape mechanism and hydrocarbon accumulation conditions are discussed, and the oil-gas accumulation pattern is summarized. Finally, two types of petroleum accumulation/reservoir models possibly existed in Dongwan area is presented in this paper. References | Related Articles | Metrics

Discovery and Significance of Paleodictyon of Paleogene in Dongying Sag WANG Hai-fang, HU Bin, ZHANG Guan-long, CHEN Shi-yue, YAN Ji-hua 2005, 26 (4):  404-407.  Abstract ( 115 )   PDF (1381KB) ( 354 )   Save The trace fossil Paleodictyon characterized by high abundance and low distinctness was discovered in Shahejie formation of Paleogene in Chunliang area of Dongying sag. Observation indicates that Paleodictyon in lacustrine environment has much smaller the string width and the mesh diameter than that in marine environment, and tends to being irregular in mesh pattem. The fabric analysis suggests that the Paleodictyon should be formned in deeplake -hemilake environment concerning with the turbidity current. This conclusion enriches and perfects the environmental significance of Paleodictyon. References | Related Articles | Metrics

Reasons for Diversity of Reservoir Water Types in Keshen 120 Well, Kekeya Field DENG Xing-liang, GAN Gong-zhou, CHENG Rong-hong, LIU Xin-hui 2005, 26 (4):  408-410.  Abstract ( 94 )   PDF (240KB) ( 266 )   Save The condensate gas reservoir of Paleogene in Kekeya field, Tarim basin, is a carbonate gas pool with super-depth of 6400m,superhigh pressure of 128 MPa and pressure cofficient of 2.0. At the present, only Keshen Well 102 is producing. This well was brought into poduction on Aug. 7, 2003, and began to yield reservoir water on Dec. 28, 2003. The eservoir water analysis provided CaCl2 and NaSO4 types of water. This paper presents the former (CaCl2) is formed due to declining of the reservoir pressure and squeezing: -out of residual water in shale of the supethigh pressure gas eservoir; the ltter (Na2SO4) is due to intrusion of local lenticular water or edge water. References | Related Articles | Metrics

Optimum of Horizontal Well Section Position for Heavy Oil Reservoir with Bottom Water NI Xue-feng, CHENG Lin-song 2005, 26 (4):  411-413.  Abstract ( 56 )   PDF (259KB) ( 207 )   Save The optimum position of horizontal section for heavy oil reservoir with bottom water of Leng-41 block in Liaohe oilfield by horizontal driling process is studied by using the reservoir numerical simulation technique. The ratio between horizontal, vertical permeability and horizontal permeability, the viscosity-temperature relationship of the crude, the fraction multiple of the botom water and the effect of varied pay- zone thickness on the horizontal section position are analyzed. The numerical simulation results from different cases show the dimensionless distance of the horizontal section position to the bottom water, obtaining the chart changing with other parameters and matching formulas. This method can be as a guide for the similar heavy oil field development. References | Related Articles | Metrics

Development and Solution of Sand Inflow Erosion Model for Cold Heavy Oil Production REN Yong, SUN Ai-ying, LU Shu-zhi 2005, 26 (4):  414-417.  Abstract ( 83 )   PDF (325KB) ( 184 )   Save The developed sand inflow erosion model for cold heavy oil production is based on the mass conservation law and Darcy's law, considering the effect of fluid flowing on sand inflow/production, and the solution in uncompressible condition of single phase is obtained. The result shows that continuous sand inflow greatly improves the porosity near the well and the performance of fluid flowing, thus increasing the heavy oil production with tendency of sand inflow increasing drastically in the early period, then declining, and finally reaching stability. Such a feature is accordant with the field data. It is demonstrated that the valid model of one dimension can be applied to guide the experiment of sand inflow and cold production, and make validation as well. Hence this model is of bright future for application to the sand inflow erosion model's study under radial flow, two-phase flow, and coupling with rock matrix plastic deformation. References | Related Articles | Metrics

Application of Fractal Model to Quantitative Characterization of Reservoir Heterogeneity ZHENG Hong-jun, LIU Xiang-jun, GOU Ying-chun, CAO Zheng-lin, YAN Yao-zu 2005, 26 (4):  418-420.  Abstract ( 76 )   PDF (271KB) ( 172 )   Save The fractal dimension calculated from mercury injection curves is used for quantitative characterization of heterogeneity in micro-porosity structure of reservoir. A method of the grid refinement of case dimension-based log calibration is presented. The fractal dimension given from single sand body logs is applied for quantitative characterization of macroscopic heterogeneity in inner- and inter-layer. These two fractal dimensions are combined to develop a reservoir fractal model by which the microscopic heterogeneity's quantitative characterization can be expanded into the macroscopic heterogeneity's quantitative characterization of single sand body. An example of fluvial facies sandstone reservoir in a water flood oilfield at stage of moderate-high water cuts is taken for this study, and perfect effectiveness for application is obtained. References | Related Articles | Metrics

Numerical Simulation of Gas Reservoir with Low Permeability Deformation Media ZHANG Ju-zeng, ZHANG Lie-hui, WEI Li-xin, LI Jian 2005, 26 (4):  421-423.  Abstract ( 69 )   PDF (321KB) ( 210 )   Save Gas field development and indoor experiment indicate that start-up pressure gradient exists in low permeability gas reservoirs owing to influence of narrow pore throats, poor connectivity, extremely low permeability, and the effect of interfacial tension among gas, liquid and solid, etc. The impact of rock deformation on permeability is significantly obvious. Conventional gas reservoir simulation technique is based on Darcy's Law, and cannot accurately describe the percolation with start-up pressure gradient and rock deformation. On the basis of the predecessors' research work, a mathematical model of non-linear percolation in gas reservoir is developed, and a case is given in this paper. The results show that the star-up pressure gradient and rock media deformation have serious effect on the performance for gas reservoir development. References | Related Articles | Metrics

Approach to In-Situ Stress of Carbonate Reservoir in Eastern LunGu of Tarim Basin with Well Logs FU Hai-cheng, QIN Wei-qiang, ZHANG Li 2005, 26 (4):  424-425.  Abstract ( 68 )   PDF (320KB) ( 225 )   Save The eastern Lungu area in Tarim basin is of the stress with significant effect on the fractural development in its carbonate reservoir, with obvious differences of fractural development in different local stress fields. This stress is studied by using various well log data, particularly using dipole shear -wave acoustic log, including the present orientation, distribution and relative size of the stress. The multi-well processing results show that the stress direction/ orientation in carbonate reservoir obtained from well log data is an effective method. It is indicated that the present stress size in eastern Lungu area is closely related to its fractural development, thus controlling the local hydrocarbon accumulation to a certain extent. References | Related Articles | Metrics

Application of Well Log Activity Curve to Parasequence Classification ZHU Jian-bing, ZHAO Pei-kun 2005, 26 (4):  426-427.  Abstract ( 95 )   PDF (404KB) ( 313 )   Save The characteristic and significance of well log activity curves that can be used to identify the interface of parasequence unit are analyzed. Example is taken from the regression system tract of No.2 sequence in the third middle member of Shahejie formation in T-715 Well of Sheng li oilfield. Integrating with the field core analysis, three parasequence units are classified and can be well identified by using three kinds of activity curves (SP, RT and GR), of which SP logs can be used to identify high-resolution sequence. The study shows that the method of weighting several activity curves for identification of parasequence units is of feasibility, applicability and good efficiency. References | Related Articles | Metrics

Pyrrolic Compounds and Application in Hydrocarbon Migration NI Chun-hua, BAO Jian-ping, ZHANG Bao, SONG Huan-xin 2005, 26 (4):  428-431.  Abstract ( 102 )   PDF (782KB) ( 223 )   Save The basic geochemical property, the separation and ana lysis techniques, distribution pattern and geochemical significance (i.e.,maturity, sedimentary environment and original source material, etc.) of pyrrolic compounds in petroliferous geologic bodies and the effect on hydrocarbon migration are presented. The recent research state and the applying cases at home and abroad are reviewed. It is pointed out that the research and application of pyrrolic compounds to petroleum migration greatly promote the development of non-hydrocarbon geochemistry. Also, some limitations of the compounds application to the petroleum migration are given, such as that the crude sample should be obtained from the same kitchen; and how the maturity influences on its distribution is unknown yet. References | Related Articles | Metrics

On Boreal-Style Petroliferous Domain AN Zuo-xiang, MA Ji, PANG Qi-wei 2005, 26 (4):  432-436.  Abstract ( 114 )   PDF (711KB) ( 213 )   Save The boreal-style petroliferous domain can be divided into three domains of Asia, Europe and America, each of which there exist one nuclear land with large area named Anabal , Baltic and Canada, respectively. The Paleozoic, Mesozoic and Cenozoic girdles surround these lands. The configuration of the girdles assumes half annularity with seldom superposition among these girdles, except for the piedmont of western Rocky mountain. The oil-gas bearing rock layers in the petroliferous basins of individual domain are relatively not complex. Several basin types occur such as intracraton, foreland, fold belt, active continental margin, divergent continental margin and inner rift basins. The deposition velocity of Paleozoic, Mesozoic and Cenozoic assumes uninodal pattern. During formation of oil-gas field (reservoir), remigration of petroleum, or multiple petroleum system, is seldom found. References | Related Articles | Metrics

Exploration Courses and Reserves State of Quaternary Biogas in Qaidam Basin XU Zi-yuan, XIE li, ZHANG Dao-wei, JIANG Gui-feng, HAN Feng-xiang 2005, 26 (4):  437-440.  Abstract ( 86 )   PDF (1254KB) ( 263 )   Save This paper highlights the reserves study and the geological understanding of Qaidam basin, reviews the consideration and thought way for petroleum exploration in different periods, displaying the development courses from the simple to the complex targets for exploration, from the outcrop to the buried geological structures, from the superficial (phenomenon) to the deep (essence) in understanding, from imprecise to precise in reserves study, from qualitative to quantitative assessment, from small to large amount of reserves, and from small-sized gas pool toward large sized gas province. The study has an active and significant value for reference and guidance to the petroleum exploration and reserves study of other similar sedimentary basins. References | Related Articles | Metrics

Abnormal High Pressure Versus Hydrocarbon Generation GAO Xiang-cheng, ZHONG Jian-hua, ZHA Ming, ZHANG W ei-hai, CHEN Zhong-hong 2005, 26 (4):  441-444.  Abstract ( 91 )   PDF (946KB) ( 223 )   Save Over 180 super pressured basins in the world have been found today, of which more than 160 are rich in hydrocarbons. The oil-gas fields with abnormal high pressure account for about 30 percent of the total fields. Compared with the normal pressure condition, the abnormal high pressure source rock tends to having lower gas production rate and organic matter maturity, but higher oil production rate, in the same conditions. The incremental pressure may postpone and restrain the organic matter maturity and hydrocarbon generation. The relationship between the pressure and the maturity in the abnormal high pressure system is analyzed. The effect of the abnormal high pressure on the hydrocarbon generation is discussed with some cases. Also, the types, origins of abnormal high pressure as well as their guiding roles to future References | Related Articles | Metrics

Deep Crust Structure and Petroleum Potential in Yixian-Beipiao Basin, Liaoning Province一And concurrently produced the mystery with large-area species death in terms of rare animal ZHANG Jing-lian 2005, 26 (4):  445-449.  Abstract ( 516 )   PDF (922KB) ( 304 )   Save It causes domestic geoscientists' great concern that the abundant biological fossil group of Rehe in western Liaoning was found, especially the dinosaur with feather and rare birds were discovered, with various animals' large-area death but keeping remains intact. The comprehensive study of Dongwuzhumuqinqi- Haicheng-Donggou cross-section indicates that there exists a low-velocity layer (vp=5.8-6.0km/s) in deep middle-crust of Yixian-Beipiao basin. According to the distribution of Pb isotope discontinuity zone, it is considered that large-sized oil-gas field exists in the deep of this basin. Also, this paper reveals the mystery of concurrent formation of the rare bio-fossils and large- area death of the species. References | Related Articles | Metrics

Discussion of Undercompaction of Rocks一一And impossibility of hydrocarbon expulsion during rock compression LI Chuan-liang 2005, 26 (4):  450-452.  Abstract ( 117 )   PDF (467KB) ( 397 )   Save Based on the mechanism of deformation of rocks, porosity-depth curves of rocks can be divided into tow periods as compaction and compression. The porosity of the former decreased exponentially, while that of the latter maintains a constant which is conventionally mistaken as under compaction period. According to the theory of mechanics of solids and fluids, the volume variation during rock compression is studied, and It is concluded that fluid or hydrocarbon expulsion in rocks is impossible during the period of rock compression. References | Related Articles | Metrics

Re-Discussion of Coal-Formed Oil Mechanism in Turpan-Hami Basin SU Chuan-guo, ZHU Jian-guo, M ENG Wang-cai, JIANG Bing, W ANG Tian-peng, WANG Wen-xia 2005, 26 (4):  453-458.  Abstract ( 125 )   PDF (376KB) ( 251 )   Save Tupan-Hami (Tuha) basin is deemed to be a typical coal-formed oil basin. This paper presents the analysis of the hydrogen-enriched coal maceral, simulated hydrocarbon generating characteristic, special hydrocarbon accumulation pattern, and the correlation of predicted and proved resources in different areas. The results indicate that the Jurassic coal measure in Tuha basin does not possess large-scale hydrocarbon generating and expulsing capability for forming a commercial oilfield. According to the evidences in geology and geochemistry, it is considered that the crude oil from the Middle Jurassic in Taibei sag is strictly not "coal-formed oil", but "source-mixed oil" formed by deep lacustrine facies and coal measure source rocks. References | Related Articles | Metrics

Stratigraphic Correlation of Paleogene in Lengke-1 Well, Qaidam Basin YUAN Xiu-jun, DONG Ning, ZHANG Hai-quan 2005, 26 (4):  459-461.  Abstract ( 98 )   PDF (321KB) ( 239 )   Save Lengke-1 Well is a scientific investigation well with depth of 5 200 m. With the multidisciplinary research and correlation, the classification problem about in-situ strata in this well is solved, thus unifying or determining the borderline between eastern and western Qaidam basin. The well depth with Hemicyprinotus valvaetumidus and Australocypris in the northern margin of Qaidam basin is calibrated on the seismic line of 1182-1 179-1199 in Saishiteng sag. Prowiding a significant evidence for mapping the regional strati graphic framework in this area. References | Related Articles | Metrics

Syprideis Breaking-Out Point and Determination of Upper Youshashan Formation Bottom Boundary in Qaidam Basin LU Yan-li, ZHANG Hai-quan, QIAO Zi-zhen 2005, 26 (4):  462-464.  Abstract ( 95 )   PDF (403KB) ( 259 )   Save Based on the principle of biogenetic isochronism, new boundary between Upper and Lower Y oushashan formations in Fengxi structure of Qaidam basin is presented. Using this principle for correlation of G-5 Well in Honggouzi structure, the Lower Ganchaigou formation at depth of about 4 000 m in this well should be classified into the Upper Ganchaigou formation. By strata correlation of microfossils from cutting logging, Cyprideis abundance curve is plotted and new method for strata correlation through identification of Cyprideis breaking-out point is proposed. References | Related Articles | Metrics