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01 August 2004, Volume 25 Issue 4 Previous Issue    Next Issue

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Composition of Coal Structure and Its Effect on Hydrocarbon Generation CHENG Ke-ming, XIONG Ying, SUN Wan-gao, YANG Zhi-ming 2004, 25 (4):  351-354.  Abstract ( 120 )   PDF (771KB) ( 187 )   Save On the basis of described covalent bond cross.linked slructure and non-covalent bond associated struc:ture in coal leasures, this pa-per fiurther presents the water invasion phase coal-forning environmnent is favorable for preservation of coal lipids, development of non-covalent bond associated structure of coal measures and formation of coal-derived hydrocarbons. Solid 13C muclear magnetic resonance spectrometer and natural evolution combining with thernocompression simulator are used for analysis of variation of carbon matrix and functional group in the course of kerogen thermal evolution, showing that lipid carbons mainly contrbnte to the hydrocarbon generation. lhis paper also makes a corre-lation of carbon matrix and functional group composition attributes in different parent materials like lacustrine facies shale, coal and coal mea-sure shale kerogen. as well as their tendencies of oil or gas generation during the period of thermal evolution of liquid window. indicating that methylene[(-CH2-)n] is a dominant funetion of hydroearbou generation from kerogen and the key factor for coal-derived crudc oil is hat a cer-Lain number of methylene functional groups existing in coal-formed kerogen. This knowledge is appicable for rescarch of lacustrine and/ or ma-rine hydrocarbon generation. References | Related Articles | Metrics

Carbon Isotopic Composition of Alkylnaphthalenes and Alkylphenanthrenes in Crude Oils XIONG Yong-qiang, GENG An-song, LIAO Yu-hong, PAN Chang-chun, LIU De-yong, LI Chao, PENG Ping-an 2004, 25 (4):  355-356.  Abstract ( 67 )   PDF (581KB) ( 250 )   Save Phenanthrene and methyphenanthrenes, further separated and enriched from aromatic hydrocarbon fraction with adding the polarity of eluant step by step, can meet the requirernent of individua] carbon isotope analysis. The carbon isotopic cormpositions of alkylnaphthalenes and alkylphenanthrenes in the crude oils of Turpan-Hami basin are detennined by using the above method of enrichment and gas chrormatogra-phy-isotope ratio mass spectrometry (CC-IRMS) technique. The result shows that the alkylnaphthalenes and alkylphenanthrenes frorn coal measures obviously enriched in PC, ranging from-20%o~-28%o, comared with tbe same compounds from marine source, and the 83C value of individual polycyclie aromatic hydrocarbons can be considered as a potential marker for the origin of organic matter and oil correlation. References | Related Articles | Metrics

Characterization of Depositional System Tract for Exploration of Lithologic Pools-An example. of Qaidam basin WU Yin-ye, JIANG Bo, GUO Bin-cheng, ZHANG Qi quan, LI Jun 2004, 25 (4):  358-361.  Abstract ( 86 )   PDF (958KB) ( 201 )   Save Systern tract, a basic unit of I-grade sequence, is a combination of the same-terml depositional systems controlled by water level changes (lacustrine level or sea level). Petroleurm tends to being accumulated in the depositional sand bodies of different system1 tracts. The type. and distribution of lithologic pools could be predicted by characterization of system tracts and analysis of depositional systems. In southwestern Qaidam basin, the characterization of system tracts shows that there exist developed transgressive system tract (TST) and various types of reser-voirs such as sand body of deltaic front, lacustrine beach and dam as well as local turbidite of semideep Jake. Based on synthetically geologic and seismic analyses, using digital seismic processing techniques (Jason's reservoir inversion, etc.), the sand body distribation could be de-scribed, hence predicting that in southwestern Qaidam basin mainly developed the lithologic pools of SB, TU, DT and SS types. References | Related Articles | Metrics

Origin of Adnormal High Pressure in Kuqa Depression WANG Ya-xing, LIU Guang-di 2004, 25 (4):  362-364.  Abstract ( 73 )   PDF (556KB) ( 178 )   Save Dynamics and thermodyrnamics analyses show that the incremental pore fluid pressure caused by tectonic compressive stress is real-ized by bulk strain of reservoir indirectly,both of which assune relations of direct ralio. The statistic analysis showed more intensive posilive correlation between the tightness or conpressive ratio and overpressures in Mesozoic lraps in 1ortherm Kuqa depression. The analysis of dynan-ics and lectonic geology proved that the tightness and compressive ratio of lraps could be used for description of the bulk strain. lt is suggesled that the Lectonic conipression is one of the main factors resulted in the incremental pore fluid pressure of Mesozoic reservoirs in ltorthern Kuqa depression. References | Related Articles | Metrics

Inversion of Rare Earth Element (REE) in the Lithosphere in Jiyang Depression ZHANG Da-gang, SHI Bu-qing, ZHOU Yao-qi 2004, 25 (4):  365-367.  Abstract ( 71 )   PDF (969KB) ( 150 )   Save This paper presents a discusion of t.he dynamic process of Mz-Cz lithosphere in Jiyang depression of Bohai Bay basin by llsing REE inversion method based on classical theory of water-free melting mantle rock. The result shows abnormal high temperature of mantle is closely related to activity of continental mantle thermal plume that ascends since late Mz till Cz (Ek) and descends since N. Also, it is proved by calcu-lated magma original depth representing the depth of Lop of asthenosphere tlhat the upwelling of asthenosphere takes place with the thinning of lithosphere, hence, tbe thickness of lithosphere in Mz-Cz interface and before Jiyang movement (Es3) assumes thinning trend, So do the litho-sphere thickness during Es3 to Dongying movement (ES3) and the overall lithosphere thickness since Eg to present. References | Related Articles | Metrics

The Paleotemperature and Paleopressure Forming Inclusions in Yinan No.2 Well, Kuqa Depression LIU Zhong-yun, WANG Dong-feng, XIAO Xian-ming, LIU De-han 2004, 25 (4):  369-371.  Abstract ( 94 )   PDF (696KB) ( 235 )   Save Abundant fluid inclusions are found in Jurassic sandstone reservoir of Yinan No.2 W ell in Kuqa depression, Tarim basin, in which oil inclusion, brine inclusion and gaseous hydrocarbon inclusion are mainly developed, with their nniform temperature of 85~110℃, 90~ 120℃ and 128~168℃. The typical oil inclusion and gaseous hydrocarbon inclusion possess their own trapped temperatare and pressure of 115℃, 35.9MPa and 162℃, 54.8MPa, respectively by mnodeling estimation. Considering geologic setting of the reservoir, the time of shaping the inclusions is (12~ 10)×106a for oil inclusion and (7~6)×106a for gaseous inclusion, and the former came from Jurassic coal measure source rocks in Yangxia sag, while the latter from Jnrassic coal measure source rocks in Yinan No.2 W ell Block. References | Related Articles | Metrics

Petroleum Migration of South Trough in W uliyastai Sag, Erlian Basin XIAO Wei, LIU Zhen, DANG Hu-qiang, DU Jin-hu, YI Shi-wei 2004, 25 (4):  372-375.  Abstract ( 87 )   PDF (909KB) ( 380 )   Save Hydrocarbon migration always plays an important role in process of oil-gas accumulation. The south trough in Wuliyastai sag is char-acterized by small-sized and short-extending faults, poor plane connectivity of sandbodies under the control of sedimentary environrnent of subla-custrine fan, So lnconformity could be its dominant channel for hydrocarbon migration, and the hydrocarbons probably migrate along the conduct-ing systern composed of high porosity permeability sand body-secondary fanlt-unconformity. The sag has been found to possess static pressure system, vertically unified pressure system with formation pressure factor of about 1.0, horizontally more intensive pore fluid dynamic field to con-trol oil-gas migration directions. The study suggests that the oil gas reservoirs are mainly formed in low pressure areas with relative low energy. References | Related Articles | Metrics

The Formation/Evolution and Petroliferous Property of Chegu-20 Buried Hill Reservoir ZHAO Rong, FU Xiao-fei, YUN Jin-biao 2004, 25 (4):  376-378.  Abstract ( 100 )   PDF (598KB) ( 277 )   Save Clegu-20 buried hill is am anticline-like structure with NNE axial trend, Chengnan and Eraijie faults at both sides and developed secondary fauls which cut it into several blocks. It consists of Archaeozoic and Paleozoic strata in which Cambrian and Ordovician arc dominal-ed by limestone. The tectonism and weathering make it become a good reservoir. Chegu-20 buried hill was formed in early Kongdian fornation of Pauleogene. Sha 3 meuber of Choxi sag adjacent to Chegu-20 buried hill is a favorable source-migration-trap system for hydtocarbon accumula-tion with developed source rocks, abundant vil sources and source sag-faulting-buried hill configuration. It is suggested that Chegu-20 buricd hill might be an advantageous area for oil-gas prospecting. References | Related Articles | Metrics

The Reservoir Characteristics and Controlled Factors of Deep Series of Strata in Anpeng Oifield,Biyang Depression MING Hai-hui, JIN Zhen-kui, YANG Yu-ping, CHEN Xiang, YIN Wei 2004, 25 (4):  379-381.  Abstract ( 78 )   PDF (626KB) ( 173 )   Save The deep series of strata in Anpeng oilfield of Biyang depression is as the major explorative horizon at present by Henan Petroleum Exploration Bureau. Study of its reservoir characteristics and controlled factors is of great significance for exploration and development of this oilfield. The lower sub-member of No.3 member, Hetaoyuan formation of Paleogene belongs to fan delta deposits with buried depth of over 2 800m. The reservoir pore space mainly consists of intergranular pore, solution pore and fracture, dominated by residual intergralar pores and solution pores. Slim throat, micro-throat, poor throat connectivity and serious heterogeneity make it become a typical reservoir with low porosity, low permeability to extra low permeability. The variation of reservoir petrophysical property is primarily controlled by sedimentary facies, diage-nesis and structure in it. The best facies of reservoir capacity is the fan delta, lhose of others like distal sandbar, frontal sand sheet and proximal underwater distributary channel are poor. Secondary solution pores are generally found in B epoch of late diagenesis; fractures occurs on axis of the anticline, seldom on sides. References | Related Articles | Metrics

Characteristics of Mesozoic V olcanic Reservoir in Dawa Qilfield YANG Shen-gu 2004, 25 (4):  382-384.  Abstract ( 95 )   PDF (590KB) ( 294 )   Save Volcanics in Dawa oilfield. mainly distributed in Cenozoic Fangshengpao formation and Mesozoic, ure of layered distribution. com-posed of such lithologies as basalt, andesite, volcanic breccia aurd tuffs, of which volcanic breccia is a key reservoir of Mesozoic. The analysis of volcanic petrology indicates that he volcanie lithofacies can be divided into volcanic breccia, lava, ash and sedimentary oncs. The epidiagenesis types of volcanics and their effects on petrophysical properlies of the volcanic reservoir ure revcaled. On the basis of analyses of valcanic lith(-facics, epidiagenetic variation and petrophysical property. the evaluation of volcanic reservoir is rmade. dividing il into I. I and III types. predict-ing the plane distribution of il, and providing basic information and data for studying the volcanic reservoir in Dawa oilfield in this paper. References | Related Articles | Metrics

TheForming Mechanism and Identification Method of Shawodi Lithologic Traps in Junggar Basin CHEN Zhong-wei, ZHU Yun-hui, CHEN Zhong-yun, CUI Yong-fu 2004, 25 (4):  385-386.  Abstract ( 85 )   PDF (742KB) ( 360 )   Save Lithologic trap is the most important type of traps in Shawodi area of Junggar basin. This paper presents the model of Shawodi litho-logic-trap reservoir. In light of the factors of petroleum accumulation, it is a reservoir probably accumulated together with palaeohigh and sedi-mentary sand bodies with characteristics of unobvious late reconstruction and primary accumulatiou. Synthetic seismogram is used for calibra-tion of the stratigraphic units. Available lithologic reservoir models and suchr techuiques as conventional seismic facies recognition, seismic at-tribute pickup and well log-constrained seismic inversion are applied for prediction of the sand bodies. The results show that in studied area the second menber of Sangonghe formation is the potential reservoir, demonstrating the existence of the channel sand body in delta frontal facies; in western sag of Peng-1 Well develop several palaeohighs, which are the favorable areas for long term hydrocarbon migration; in slope facies belt occur Jurassic delta sand bodies, which may help to shape litho-structaral oil-gas reservoir; and the low-amplitude structure and lithologic trap in hinterland of Junggar basin should be as major targets for hydrocarbon prospecting. References | Related Articles | Metrics

Origin of Cretaceous Low-Resistivity Reservoirs in Junggar Basin ZHANG Li-xia, ZHU Guo-hna, LI Min 2004, 25 (4):  388-389.  Abstract ( 85 )   PDF (540KB) ( 187 )   Save The oil zone, oil-water transition zone and aqueous layer of Cretaceous Tugulu group in Junggar basin occur obvious resistivity lower than that found in reservoirs of Jurassic Toutunhe formation and Xishanyao formation. The study shows the reason or origin is due to the fact that the water cul in Tugulu reservoirs is higher than that of Jurassic; water bearing clay film developed in Cretaceous could greatly enlarge the cro8s-sectional area of electric conductive network, so the clay film is mainly responsible for existing low resistivity of Cretaceous reservoirs. In addi-tion, the difference of clay minerals has effect on the low resistivity reservoirs. References | Related Articles | Metrics

Effect of Static Correction on Stack Velocity in Seismic Data Processing ZHAO Feng, ZHENG Hong-ming, LOU bing, YANG Xiao-hai, CHANG Yu-rong 2004, 25 (4):  390-393.  Abstract ( 93 )   PDF (989KB) ( 340 )   Save The conventional static correction method is characterized by vertical timne migration and following static correction processing the re-flection tine for all of seismic traces could give rise to the same time-migration responses from the shallow to deep strata. Such a variation at t0 occurred in static correction that could not change the patterns of reflection events might allow the relevant dynamic correction velocity (normal-ly called stack velocity) to be changed. This variation of stack velocity generally depends on variation of the static corection on reflected t0 that tends to being related to selection of datum level available for static correction and base level for seismic data processing. In the relatively ordi-nary area of subsurface structure, it is closer between the derived stack velocity and observed apparent velocity of seismic reflection event; but in the complicated area of subsurface structure and relief region, there exist very obvious influences of the static correction velocity on the dynamie correction velocity following datum static correction and particularly regional static correction, hence, if the latter (stack velocity) is applied for structural and geologic interpretations,greater ertors will take place in this case. This paper makes a quantitative analysis of the influence of static correction on seismic velocity field based on above results fror theoretical model study,and provides sound theoretical bases for the da-tum determination and application of the datum static correction in futnre. References | Related Articles | Metrics

Comprehensive Evaluation of Trap Petroliferous Nature Using Geochemical-Seismic Prospecting Method-An example of South Songliao basin ZHU Huai-ping, XIA Xiang-hua, SUN Li-chun, LI Wu 2004, 25 (4):  394-395.  Abstract ( 75 )   PDF (438KB) ( 206 )   Save Geochemical-seismic trap evaluation is a comprehensive method of applying 2D and 3D seismic observation systems to get geophysi-cal infornation, through seismic dala processing to properly describe in-situ structural trap 's spatial morphology and related faulting distribution in order to define the reliability of structural traps. It can directly detect hydrocarbons within traps, pick-up oil gas leakage informalion near sur-face soil from traps under process of stress field, delineating the location of oil-gas accumulation in traps, help recognition of fhuid attribute in traps and conduct classification, evaluation and selection of explorative targets. Applying this method to Songnan oil-gas field, several structural traps have been evaluated and selected, which also passed an verification from drilling. achieving good results. References | Related Articles | Metrics

Correlation and Classification of Upper Ordovician Sangtamu Formation in Lunnan Area, Tarim Basin XU Lun-xun, XIAO Chuan-tao, ZHU Zhong-de, HU Ming-yi, LI Xiang ming 2004, 25 (4):  397-399.  Abstract ( 100 )   PDF (305KB) ( 180 )   Save There have not been an unified classification and correlation of Late Ordovician strata in Lunnan area of Tarim basin. This paper pre-sents original meaning and evolution of Sangtamu formation, based on which and principles about formation definition and its classification giv-en by A Guide Book of China's Geologic Positions, redefined the meaning of Sangtamu formation, and makes clasification and correlation of Late Ordovician biostrata in Lunnan area, including Sangtamu formation of Upper Ordovician. Study indicates that the era of Sangtamu forma-tion should be proper in Late Baota epoch to W ufeng epoch, which will be as a new guide for in-depth study of Lunnan 's stratigraphic classfica-tion and correlation. References | Related Articles | Metrics

Discovery and Significance of Botryococcus in Duwa Area of Hetian, Xinjiang HE Zhen-jian, JIA Feng-hua, JIANG Guang-xiu, BIAN Xue mei, LUO Hua-yi 2004, 25 (4):  400-402.  Abstract ( 124 )   PDF (627KB) ( 246 )   Save The Upper Permian-Lower Triassic outcrops in Duwa area of Helian, Xinjiang are dominated by thick dark shale. The sedirnenlary center is at north areal coverage, the source area is at the outcrop area in south o[ Duwa faulting. The former has decper sedimentary environl-ment than the lalter, so ils dark shale is thickened and distributed range is enlarged. The geochemical indicators for hydrocarbon generation from outerop samples are nol high. but there exist Botryvococcus fossils in marry intervals and sections. which are rich in somc horizons, with relative slable and exlensive distribution in plane. It means that the dark shale should be of higher capability or potential for hydrocurbon generalion. and will be as important strata for hydrocarbon source rock evalualiorl in Hetian region, Xinjiang. References | Related Articles | Metrics

Oil-Gas Occurrence and Flowing Features of Near wellbore Formation in Condensate Gas Reservoir SUN Lei, HUANG Quan-hua, LI Shi-lun, WU Yi-ming, DU Jian-fen 2004, 25 (4):  403-406.  Abstract ( 79 )   PDF (563KB) ( 159 )   Save A phase equilibrium simulation method for prediction o[ gas condensale phase behavior in porous nedia is presented, in which iler-facial effects of udsurplion and capillary coacervalion are considered. The nlethod is applied to sludy of Yaha condensate gas reservoir's dew point (dp). retrograde condensale suluration in porous inedia and compare with conventional lab analysis o[ PVT. The results show such coiunrci-dent outcome similar to previous studies as upper dp inereasing, down dp declining and retrograde condensate saturation ascending,thus indi-cating the application of this method with porous media effeets is feasible. Introducing it into theory of gas condcnsate percolation, a physico-chemical percolation model of gas condensate system with adsorption and capillary coacervation effects can be developed, including mathemat-ical models for descriplion o[ relrograde condensale saturation distribution, relative permeability distribution to gas and pressure drop funnel dis-tribution in near wellbore formation of condensate gas reservoirs as well as gas condensate well productivity equation considering different inter-facial phenomena. All the above prediction and estination prove that the porous media interfacial effect could intensify such retrograde conden-sate phenomenon, give rise to additional formation damages of retrograde condensale behavior and result in the decrease of relative pernleabilily to gas and produclivity of gas condensate wells in Y aha condensate gas rcscrvoir. References | Related Articles | Metrics

3D and 4-Phase Multi-Compositional Mathematic and Numerical Models ZHANG Mao-lin, MEI Hai-yan, GUO Ping, XIONG Zhong-hui, WU Shu-qiang, LI Lian-wen 2004, 25 (4):  407-410.  Abstract ( 64 )   PDF (356KB) ( 130 )   Save Cas injection aimns at reducing interfacial lension between oil and injected gas, forming miscible or partial misciblc, and producing in-situ remained crude oil. However, such a gas injection process tends to changing thermody namic conditions in the petroleum system. incInd-ing the systemn' s conuposilion. temperature and pressure, possibly giving rise lo precipitation of organie solid materials. This paper begins with assumptious of conventional multi composition model, supplemenls hypotheses required inn precipitation of organic solid materials, finally. de-velops a multi-conposition mathematic model with 3D and 4 Phase (oil, gas, waler and organic solids) by using Darey 's law and moles conscrva-lion theorem and a numerical model with explicit compnsition and saluration as well as implicit pressure by using finite difference metlhod. References | Related Articles | Metrics

Horizontal Drilling Study and Application to High-Pressure Area in Laojunmiao Oilfield ZHANG Hu-jun, WANG Qi-nian, LIU Ya-jun 2004, 25 (4):  411-413.  Abstract ( 86 )   PDF (295KB) ( 155 )   Save Laojunmiao oilfield is the first field exploited by water flooding process. For 51 years since its waterflooding, it has been characterized by highly dispersed remaining oils, complicated oil-water relations, regional high pressure, shale swelling and squirming, greater difficnlty for drilling and low rermaining oil potentials. In 2003, according to composite geologic analyses and horizontal drilling study, Well LH-1, the first horizontal well in Yumen field, was designed and drilled successfully. The good effect could be as a brand-new way for late-period regulation and finding out potential recoverable reserves in the old oilfield. Related Articles | Metrics

On Evaluation Method of Miscible Gas-Flooding Mechanism TANG Yong, SUN Lei, LI Shi-lun, GUO Ping, LI Yu-guan 2004, 25 (4):  414-417.  Abstract ( 84 )   PDF (906KB) ( 278 )   Save Indoor lab study and corresponding modeling are the bases of researching miscible gas-flooding mechanisms and evaluating gas in-jection projects. This paper presents a theoretical model of phase equilibrium estimation for pressure-composition and multi-contact miscible. experiments of gas injection, creates a systematic evaluation method of gas-flooding miscibility and displacing mechanism by simulating PVT data and matching the pressare-composition experiment and miscible-immiscible flood slim-tube experiment by means of Equation of State and available tools. Taking a real reservoir as an evaluating case, such a method established from lab study has been validated, hence can be used to provide reliable lab and theoretical bases for evaluation of design of miscible gas-flooding project of oilfields. References | Related Articles | Metrics

On Log Normal Distribution of Pore Structures by Using Fractal Theory MA Xin-fang, ZHANG Shi-cheng, LANG Zhao-xin 2004, 25 (4):  418-419.  Abstract ( 98 )   PDF (284KB) ( 251 )   Save Pore structures in reservoir rocks possess good fractal characters. The fractal dimension of pore structure can be used to qnantitatively describe its complexity and variation. Its distribution accords with its log normal distribution. This paper establishes a fractal characterization method of probability density function of pore size distribution by applying fractal geometry principle, according to the fractal geometry model of pore distribution and capillary pressure curves,which allows the conventional qualitative description to tnrn into quantitative estimation of the pore sized distribution. The estimation shows that this method is easier for use and higher in accuracy. References | Related Articles | Metrics

Analysis of Correlation among Proved, Probable and Possible Reserves in SPE Reserves Classification BI Hai-bin, WANG Yong xiang, HU Yun-dong 2004, 25 (4):  420-422.  Abstract ( 170 )   PDF (437KB) ( 602 )   Save The proved reserve definition given by Securities and Exchange Commission (SEC) is an essential basis for reservcs appraisals of all joinl-stock oil companies. but it can be rcgarded as a special case of the reserves classification defined by SPE. ln-depth understanding of SPE's definition, particularly, of relationship among proved, probable and possible reserves (PPPR) is favorable for right understanding of SEC's proved reserve definition. The correlation of SPE reserves is generally divided into three types; PPPR occurs 1) only in different blocks or reser-voirs; 2) in the sarne oil-gas reservoir, and 3) in accordance with original oil in-place (O0IP). References | Related Articles | Metrics

Production Performance of Condensate Gas Wells Considering Two-Phase Fluid of Gas and Liquid TAN Bin, LI Xiang-fang, Cheng Shi-qing 2004, 25 (4):  423-426.  Abstract ( 82 )   PDF (888KB) ( 196 )   Save Retrograde condensed liquid tends to being dropped oul during development of condensate gas reservoirs, thus showing different Alowing characteristics between reservoir percolation and dry gas drive or depletion gas drive. Up to now. most predictions of in-flow performance of a condensate gas well are based on singlc phase gas reduccd me:lhod. However, heoretical and field application indicatc that such a method muy give rise to greater errors owing to ignoring the effect of retrograde condensed liquid precipitation on relative permeability to gas. Although subslautial theoretical sludies have been made,its application still is restrained by ils complcxity and/ or absence o[ strict/ overall theoretical description. 'This paper, on the basis of oil-gas two phase percolation theoty, presents equation of psendo-steady state in-flow perfomance and striet verificalion of calculalions of reservoir distribution parameters. Applied cases show that adopting this equation of IW)-phase in-flow perfor-mance could help more proper estimation of condensate gas productivity and recognition of the reservoir performance. References | Related Articles | Metrics

Analysis of Suitability for Two Types of Reservoirs by MEOR WANG Hui, LU Yuan, YI Xiang-yi, ZHANG Hui 2004, 25 (4):  427-428.  Abstract ( 53 )   PDF (306KB) ( 165 )   Save The microbial treatment and pilot test of two different types of low permeability reservoirs were conducted by cooperation of No.3 Production Plant of Xinjiang Oilield Company with NPC Mictobial Company. USA. The results showed that the glutenite reservoir of Middle Triassic in District No, 1 west had mueb more responses than that of the fractured basement reservoir of Carboniferous in District No.1. This pa-per analyzes the effect of diferences among permeability, porosity, salinity and percolation mechanism for low permeabilily reservoirs on micro-bial recovery process, proposes some proper regulation measures for special reservoirs, and makes suggestions for optinmum processing progrurn and introducing real-time monitoring techniques. References | Related Articles | Metrics

Application of Physical Modeling to Natural Gas Accumulation Analysis ZHANG Hong, PANG Xiong qi, JIANG Zhen-xue, WANG Fang 2004, 25 (4):  429-430.  Abstract ( 66 )   PDF (601KB) ( 180 )   Save Hydrocarbon accumulation nodeling is to simulate the condition and result of oil gas accumulation under the given lab condilions, re-construct in-situ process o[ petroleum generation, migration and accumulation, by which a lab sinulation is nlade for Pingluoba gas accumula-tion pattemn in westerm Sichuan area. The effects of overthrust nappe faulting on gas pool fornation, petroleum accumulation in ranp structure and the ways for shaping primary and secondary gas pools are studied in this paper. Jt is concluded ihat the ramp sLructure plays an importanl part in the course of Pingluoba primary gas pool,and Pingluobas overthrust fault has the key effect for Jurassic secondary gas aceumulation. Above understandings could be as a guide for furtber exploration of natural gas pool in foreland basin of western Sicluan arca. References | Related Articles | Metrics

Application of W avelet Transform to Prediction of Gas Zone LIU Jing, YANG Xiu-wen, ZENG Shun-peng 2004, 25 (4):  431-432.  Abstract ( 75 )   PDF (481KB) ( 168 )   Save There exist noise signals independent of strata properties in most well logs in field oil production. The wavelet transform technique applied for removal treatment of the noise signals is presented based on the feature. Using his techmique mainly including noise-removal meth-ods of dimensional wavelet and wavelet package. a part of noise signal values could be reslored to in-situ origina! ones by density-porosity logs and neutron porosity logs processing. The results show hat the noise curves have been inhibited aler the processing of wavelet lransform. With higher qualily of logs,it allows lo make comprehensive inlerpretation together with rest of well logs, provide more proper prediction of related numbers and locations of gas layers, and grasp reliable bases for natural gas exploitation. References | Related Articles | Metrics

Application of Well Test Data to Evaluation of Hydraulic Fracturing Performance DU Jun-she, WANG Guo xian, YIN Wei-cai, WAN Wen-sheng, LIU Jin-jun 2004, 25 (4):  433-435.  Abstract ( 77 )   PDF (476KB) ( 219 )   Save Buildup test is now recognized to be the most effective method for evaluation of hydraulic fracturing performance. Formation pressure and effetive permeability can be estimated by pre fracturing buildup test data, then applied to make a proper interpretation for hydraalic frac-tures together with the post-fracturing buildup test data in order to avoid that different results of interpretation take place and provide correct e-valuation of the frac-performance. In this paper, 20 fractured wells in Zhundong low-permeability reservoir and their hydraulic fracture featnres have been explained by the buildup test method, with which comparison of calculated results from a 3D hydraulic fracturing model is conducted, followed by overall evaluation of frac-performance in Zhundong oilfield by nsing these buildup test data. References | Related Articles | Metrics

Application of Shear Wave Anisotropy to Evaluation of Fractured Carbonate Reservoir ZHANG Yong-zhong 2004, 25 (4):  436-437.  Abstract ( 67 )   PDF (619KB) ( 241 )   Save Shear wave anisotropy of formation assumes normal correlation with fractures and fracture openings, so there exist intensive shear wave anisotropies in the fractures flled with shale or calcite. To apply this character may recognize qualitatively crack flling extent and evalu-ate carbonate reservoirs. Successful application of this method to Sangtamu horst faulting zones in Tarim basin shows that the high-angle frac-tures flled with shale or calcite appear slight anisotropy, while horizontal fracture, network fracture and conjugated fracture have few the anisotropies. In addition, this study can provide basis for seeking favorable fracture systems in Tarim's carbonate reservoirs. References | Related Articles | Metrics

Field Application of the Modular Formation Dy namics Tester Tool (MDT) LI Jun, HUANG Zhi-jiu, XU A-li, YANG Jian-ping 2004, 25 (4):  438-439.  Abstract ( 91 )   PDF (453KB) ( 254 )   Save MDT log, compared with conventional log tools, has played a much more important part in petroleum exploration due to its technical advantages except for its higher testing cost. It is undoubted that for different objects and purposes of evaluation, to perform well field operation, minimize ineffective test spots and enhance the successful rate to test are necessary for realizing minimum well log costs and maximum geologic effectiveness, in other words, using a part of high investrnent to get high efficiency of whole explorative project in return. Therefore, for application of this approach, the suitable geologic condition,designing nethods prior to test and relevant notices for testing are studied systematically, developing a set of feasible field operations and interpretation methods in this paper. References | Related Articles | Metrics

Synthetic Temperature-Resistant Brine Swelling System and Its Application to Shengtuo Oilfield ZHANG Gui-yi, LI Guo-yong, LI Jian-shu 2004, 25 (4):  440-442.  Abstract ( 73 )   PDF (417KB) ( 165 )   Save Shengtuo oifield is characterized by complex geology with high temperature and high salinity, This paper works oul polymer molecule, selects proper polymer. croSs-linking agent, cross-linking acelaranl and inorganic proppant, synthesizes a new teniperature-resistant brine-tolerant pre-.ross linking swelling system, finally, optimizes the formulation of pre-cross linking swelling syslem by using orthogonalizing process. Results show that the synthetic sweling system has the characteristics of temperature resistance (120C). brine tolerancc (1.8x10+mg/ L), high intensity, intensive adsorption, good thermal and chemical stabilities. Field pilot test indicates that the slimulation response using this swelling system for profile control is positive. References | Related Articles | Metrics

Analysis of A bnormal Reservoir Pressure LI Chuan-liang 2004, 25 (4):  443-445.  Abstract ( 382 )   PDF (310KB) ( 467 )   Save Reservoir pressure can be divided into normal pressure, abnormal high pressure and abnormal low pressure in terms of the ratio between formation pressure and hydrostatic pressure. These pressure phenomena are analyzed in this paper. Study shows that the pressure in non-confining beds normally belongs to the range of normal pressure; confining zones with invasion of external fluids could give rise to abnormal high pressure; provided that induced fractures occur in confining zones where are affeted by tectonic movement, leading to growth of pore volume, it tends to appear abnormal low pressure herein. References | Related Articles | Metrics

New Understandings of Cretaceous Oil Generation Zone in Foreland Basin in Southern Margin of Junggar Abulimiti, TANG Yong, LI Chen, LI Shi-hong, MIAO Gang 2004, 25 (4):  446-448.  Abstract ( 88 )   PDF (973KB) ( 230 )   Save The comparison of structural conditions in western and eastem basins of China and geochemical analysis of Lower Cretaceous source rocks ill Junggar basin are nade. It is considered thal in tlre easten basins there exist vast distributions of Cretaceous source rocks, better reservoir qualty and thickness than those of the western basins 01 the whole,but the structural and depositional conditions in foothill sag in North Tianshan Mountain of Junggar basin are of a certain similarity with those in the eastern basins. ie, its Lower Cretaceous strata possesses a capability of lhydrocarhol generation, being significant and really existing source rocks for petroleum exploration of southern margin of Junggar basin. The oil-source rock correlation indicales that the crude biomarker features from Tugului and Horgos areas arc similar to thosc from surtacc crude and asphalt in Qingshuihe arca, and these bromarkers were all coming from the source rock of Lower Crelaceous. Therefore. the Cretaceous source rock can be determined reliably. In this paper, the distributiol extension of reservoir with oil source of Cretaceous is delineated. 'The contribntion of the Cretaceous source rock to hydrocarbon accumulation in foothill thrust zone is pointed out, and the mnajor target areas and drilling horizons for oil exploration are suggested in this paper. It is expected that lhte domain of petroleum prospecting in southern Junggar 's foreland basin will be wider and wider. References | Related Articles | Metrics

The Demand of Sustainable Development in Sino-Petrochemical Industry: Petroleum Metallurgy GUO Zhan-qian 2004, 25 (4):  449-452.  Abstract ( 70 )   PDF (408KB) ( 157 )   Save It is China's special continental Crusl that decides the unique of petroleunl in China. Because of small area of lhe conlinentaI crust. being compressed o11 all sides and volcanic movenent and new tectonic activities, there exist abundaurt dcep materials from the carlh in domestic crude oils. Particularly, the elements from the core and mantle sn1ch as various metal ones should be rnorc paid atlention to. To focus on theoreti-cal and technical studies in peLrolcuni metallurgical industry will greatly inerease the eronomic values of the crude (ils, thus allowing the short-age of domnestic mineral resources to Le flleld up and China's petrochemical industry to be further developed rontinually. References | Related Articles | Metrics

On Global Petroleum System AN Zuo-xiang, MA Ji, PANG Qi-wei 2004, 25 (4):  453-455.  Abstract ( 97 )   PDF (842KB) ( 272 )   Save Since commeneing the study of the world's oil-gas distribution launched by Dr. Weng Wen-bo for the purpose of proving the fact that there should exist abundant oil-gas resources within mainland of China, half century has past, and W eng's judgement has been proved and real-ized nowadays. On the basis of global plate tectonics, the petroleum system concept and its studying methods proposed by L. B. Magoon are ap-plied to deal with the data from bydrocarbon-bearing basins around the world. And study shows that the global petroleum or reserves distribution could be searched for in terms of Paleozoic, Mesozoic and Cenozoic hydrocarbon-bearing system distribution status, distribution relations arong them, including their relations to seven nucleuses on continental crust. It is concluded that the global petroleum system could be divided into such three types or seven domains as China Type, North Global Type (including Asia, Europe and North America) and South Global Type (in-cluding Australia-India, Africa-Arabia and South America) with diversity of features. When approaching their evolutions, the maximum time-rock unit, Era (Erathemn), and other Period and Epoch can be adopted for systernatic studies. References | Related Articles | Metrics

Characterization of Depositional System Tract for Exploration of Lithologic Pools——An example of Qaidam basin WU Yin ye, JIANG Bo, GUO Bin-cheng, ZHANG Qi-quan, LI Jun 2004, 25 (4):  456-460.  Abstract ( 90 )   PDF (987KB) ( 135 )   Save System tracl, a basic unit of T-gradc sequence, is a combinalion of the sarme-termm depositional systems controlled by water level changes (lacustrine level or sea level). Petroleum tends to being accumulated in the depositional sand bodies of differ-ent syslem tracts. The lype and distribution of lithologic pools could be predicted by characlerization of systeni tracts and analysis of depositional systems. In southwestern Qaidam basin, the characterization of system tracls shows that there exist developed transgressive system tract (TST) and various types of reservoirs 8uch as sand body of deltaic front, lacustrine beach and dam as. well as local turbidite of semideep lake. Based on synthetically geologic and seismic analyses, using digital seismic processing techniques (Jason's reservoir inversion, etc.), the sand body dislribution could be described, hence predicting that in southwest-ern Qaidam basin mainly developed the lithologic pools of SB, TU, DT and SS types. References | Related Articles | Metrics