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01 October 2005, Volume 26 Issue 5 Previous Issue    Next Issue

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Structural Division in Gansu-Qinghai-Tibet Petroliferous Sub-Province and Evaluation of Oil-Gas Potentials ZHANG Kai 2005, 26 (5):  467-471.  Abstract ( 119 )   PDF (643KB) ( 176 )   Save Gansu-Qinghai-Tibet petroliferous region is the largest sub- province of China with an area of about 269.5×104km2. In its nine subsiding belts, there are 32 petroliferous basins with an area of 159xI0* km2 in total. They are basins with long-term devolution and superimposed by petroliferous multi-formations of marine, continental-oceanic and continental facies of Mid-Upper Proterozoic, Paleozoic, Mesozoic and Cenozoic, shaping the geologic structural conditions of multistage non-biologic sources. Since the natural geographic conditions in this region are abnormal atrocious, the neo-tectonic movement is very active, its petroleum exploratory extent is still low and the effects for prospecting are unsatisfactory nowadays. This paper highlights the evaluation of hydrocarbon-bearning property from several aspects aiming at getting instructive dispute and thinking at home for further development of petroleum exploration cause in this region. References | Related Articles | Metrics

Palaeokarst of Cambro-Ordovician and Oil-Gas Distribution in Tarim Basin KANG Yu-zhu 2005, 26 (5):  472-480.  Abstract ( 104 )   PDF (1279KB) ( 507 )   Save The Cambro-Ordovician is very thick and widely distributed in Tarim basin. The well developed palaeokarst feature in it is due to multistage tectonic movement and its intrinsic sedimentary characteristics. It is the palaeokarst distributed vertically and laterally that controls the hydrocarbon distribution. More than ten large-and middle-scale such oil-gas fields have already been found up to now. This paper highlights the stage of palaeokarst development, the distribution, type and origin of palaeokarst and the characteristic and the oil-controlling effect of such a reservoir. It is concluded that the Cambro-0rdovician system(@) in Tarim basin is significant horizon(s) or zone (a) for finding out giant oil-gas field in future. References | Related Articles | Metrics

Main Factors of Petroleum Accumulations and Origin Types of Non-Structural Reservoirs in Junggar Basin YANG Wen-xiao 2005, 26 (5):  481-484.  Abstract ( 99 )   PDF (454KB) ( 272 )   Save Junggar basin is characterized by early discovery, multiple types, large scale, wide distribution and big differences of oil-gas reservoirs, accounting for 76.1% of proved 00IP. It has been playing a major target for petroleum exploration and development in Xinjiang region. For discovered non-structural reservoirs, their onigin types mainly inelude: the fractured-lithologic and lithologic stratigraphic reservoirs dominated by torrential fanglomerale and glutenite of steep slope in depositional fault bench in northwestem margin of Junggar basin, the structural-lithologic and lithologic-stratigraphic reservoirs by delta submarine fan, turbidite fan glutenite and sandstone in nearshore fault slope in Zhundong (east Junggar) area, the structural-lithologic and lithologic stratigraphic reservoirs by fluvial-delta sand-stone in Jurassic-Cretaceous gentle slope controlled by paleo-swell in hinterdand of Junggar basin, and the buried-hill-weathered-crust reservoirs of Hercynian episode in basement of Junggar basin. The basin-scale regional cap rocks of Baijiantan formation (Huangshanjie formation) of Upper Triassic are their boundaries, and upper and lower reservoir assemblages can be divided. The lower assemblage con-tains hydrocarbon from self source and adjacent source, and its main factors of fomming non-structural reservoir are lithofacies, petrophysi-cal property and transport system. The upper assemblage has hydrocarbon sources mainly from Permian remote source and Permian-Jurassic mixed source, its primary control factors of shaping non-structural reservoir are transport 8ystem, tectonic setting, lithofacies, trap and petrophysical property. References | Related Articles | Metrics

Seismic Attribute and Non-Structural Reservoir Exploration LIU Chuan-hu 2005, 26 (5):  485-488.  Abstract ( 94 )   PDF (622KB) ( 419 )   Save Seismic atribute from seismic data is a series of characteristic parameters reflecting reservoir body and oil-gas bearing proper-ties. Any change of geologic body and its nature will lead to change correspondingly in seismic response infornation. The study of dynamic feature of seismic wave by using various seismic attributes allows to obtaining the type of geologic body, rock physical property, reservoir quality and their variations. The non-structural reservoirs are the strata, lithology and complex traps being indistinct in shape and feature and unable to be recognized by conventional methods in seismic profile. In view of such a reservoir, integrating with its seismic facies and other information, the seismic prediction of non-structural reservoirs in Jiyang depression is made, and good effects have been laken in its field 's exploration and development. References | Related Articles | Metrics

Origin and Geochemistry of Natural Gas in Kuqa Depression,Tarim Basin LI Xian-qing, XIAO Zhong yao, HU Guo-yi, TTIAN Hui, ZHOU Qiang 2005, 26 (5):  489-492.  Abstract ( 82 )   PDF (693KB) ( 294 )   Save Geochemical characteristics of.natural gas in Kuqa depression of Tarim basin are studied.The maturity and source of gas in the depression is discussed by using the result of carbon isotope kinetics.The gas in Kuqa depression,containing wet gas,condensate and dry gas,appears the trends of both methane content and dryness cofficient decreases from west to east and from north to south.It belongs to coal-formed gas and originates from Mesozoic source rocks.Its maturity in different structural belts is differentiated with Ro ranging from 0.7% to over 2%.The Ro of gas from Kela-2 gas field ranges from 1.3% to 2.5%.It is considered from the comprehensive data analyses that the major source rocks in Kuqa depression should be Jurassic coal-bearing source rocks,while Triassic source rocks make the second contrbution to the gas pool in it. References | Related Articles | Metrics

Geochemical Characteristics of Crude Oil in Santai Area, Junggar Basin YANG Bin, LIAO Jian-de, HAN Jun, QIN Jun, REN Jiang-ling, KANG Su-fang 2005, 26 (5):  493-498.  Abstract ( 88 )   PDF (829KB) ( 424 )   Save Santai crude oil can be classified into three types based on light hydrocarbon stellar diagram, m(Pr)/m(Ph) of saturated hydro-carbon, content characteristics of β-cartane, composition of three types of regular steranes, content characteristics of pregnane and maturity index, composition characteristics of triterpene-tetracyclic terpane and gammacerane of crude oil in Santai area of Junggar basin, and based on rearanged drimanes/8B(H)-drimanes ratio, 4,4,8,8,9-PMDHN/4,4,8,9,9-PMDHN ratio of bicyclic sesquiterpenes and compoaition of C30-hopane, phenanthrene and metylic-phenanthrene in crude oil. The first-type crude oil, the major crude oil in Santai area, is original-ed from source rocks of Pingdiquan-Lucagou formnation of Middle Permian. The second -type crude oil is from source mocks of Jurassic. The third-type crude oil is from those of Carboniferous Batamayineishan formnation. The Permian crude oil comes from Jimusaer seg, Tianshan mountain front seg and Fukang seg. The Jurassic crude oil comes from Jurassic source rocks in Fukang seg, while Carboniferous crude oil is just from this studied area. References | Related Articles | Metrics

Hydrocarbon-Enriched Accumulation Belts in Junggar Basin LIN Long dong 2005, 26 (5):  499-501.  Abstract ( 110 )   PDF (523KB) ( 228 )   Save Three hydrocarbon- enriched belts to northeast-southwest have occured in northwesterm margin, binterland and eastem part of Junggar basin, and two belts to near est-west trend are probable to shape in hinterland and southem mangin of Julggar basin. Their for-mation and distibution are closely related to presence of fenestral and deep fauling (s) in the basinal basement. Particularly, the deep faulting to near-south-north trend is characterized by tensional and strike alip natures, being as “earthquake active zone” under the basin and ahaping a “highway” of the hydrocarbon and deep thermal material migration from south Io north. The cap rocks of the basin in these belts could be all as fracture- developed zones. These viewpoints have been supported in many aspects by analysis data from available crude oil and formation water. Based on such a viewpoint, the countermeasures and sugestions for petroleum exploration in the future are proposed in this paper. References | Related Articles | Metrics

Palaeohighs and Targets for Petroleum Exploration in Junggar Basin KUANG Jun 2005, 26 (5):  502-509.  Abstract ( 98 )   PDF (1364KB) ( 375 )   Save The palaeohigh in Junggar basin underwent multistage evolution from Neopaleozoic to Cenozoic, and four basic types 8uch as successional, discontinuous, tited and thrust ones were developed. This paper presents the tectonic and depositional evolutions and the hydrocarbon accumulations in this basin, and suggests the petroleum prospecting areas and targests in is Luliang uplift, Mosuowan swell and Che-Mo uplift. It is concluded that these places are all favorable for hydrocarhon accumulation such as swell area closely adjacent to the sag in Luliang uplift or inherited swell zone controlled by fault, Xiazijie formation of Upper Permian, top Xishanyao formation of Lower Jurssic and bottom Jiamuhe formation of Lower Permian as well as flank Che -Mo uplif. References | Related Articles | Metrics

Results and Technologies of Second-Time 3D Seismic Prospecting in Hinterland of Junggar Basin LEI De-wen, LV Huan-tong, HUANG Yong-ping, YANG Xiao-hai 2005, 26 (5):  510-512.  Abstract ( 93 )   PDF (573KB) ( 225 )   Save The first-time 3D seismic exploration activities have been made since 1990' B, which were dominated by regional 3D seismic with large bin size, aiming at fnding out large-to medium-sized structural traps and reservoirs, and lots of significant achievements were made. With the advent of new century, the insufficient precision of the first-time 3D seismic activities appeared gradually as the focus of prospecting loward lithologic-stratigraphic reservoirs. So it is necessary to perform the second-time 3D seismic activities in highly evalualed areas covered with 3D seismic survey before. And 5 different technologies are applied such as wide-azimuth geometry and swath coupling, acquisition with nommal or small bin size, seasonal or relatively wet surface acquisition, selection of source parameters by surface condition and application of medium-high frequency geophone and source-geophone array to receive seismic wave. In thick desert area,the main frequency of 45-50 Hz is used, about I5-20 Hz higher than the first-time 3D data, iand signal to noise ratio and fidelity are significantly improved. As a result, the seismic reflection image defnitions of small faults, unconformity surface, pinchout point and sandbody are also improved markedly and the recognition capability of the lithologic traps are intensified in terms of geologic effect. References | Related Articles | Metrics

Effect of F1 Fault on Formation and Preservation of Kela-2 Gas Field FU Guang, ZHU Yan-he, FU Xiao-fei 2005, 26 (5):  513-516.  Abstract ( 77 )   PDF (577KB) ( 185 )   Save The development and evolution of F1 fault is analyzed. The effect of F1 fault on forming Kela-2 gas field in Tarim basin is simulated by using the self-designed model. The pathway for gas migrating upward generated and discharged from Jurassic and Triassic source rocks in active F1 fault. The result shows its lttle contribution to the shape of Kela-2 gas field for the loaing velocity of gas through FI fault zone is bigger than the velocity of gas entering into Kela-2 gas field. The physical model experiment provides the plastic deformation limit of gypsum and mudstone and the minimum contents of gypsum and mudstone to seal gas in F1 fault zone. The fault plane pressure and the contents of gypsum and mudstone are used for evaluation of seal feature in static F1 fault zone, indicating its good vertical seal and favorable preservation for gas accumulation in Kela-2 gas field. References | Related Articles | Metrics

On Hydrodynamism in Petroleum Migration and Accumulation FU Yong, JIANG Zhen-quan, MA Li, GUO Yang 2005, 26 (5):  517-519.  Abstract ( 118 )   PDF (347KB) ( 174 )   Save It is an irreversible process and a dissipated structure with space-time match for petroleum migration and accumulation. The sedimentary water is the carrier and main driving force of petroleum migration and accumulation, which controls the fluid movement and appears centrifugal flow from the center to edge of basin, while penetrated water fommed by infiltration of atmospheric precipitation and surface water appears centripetal flow from the edge to center of basin by gravity process. The result is that press equilibrium zone is formed under the processes, where oil and gas can be accumulated. A big oilfeld could be formed by a lrap with the upper equilibrium structure preserving petroleum and the lower dissipated structure injected with oil and gas continuously. The hydrodynamism is also of significant effect on petroleum preservation and destruction. References | Related Articles | Metrics

Petroleum System of Upper Triassic in West Sichuan Depression CAO Lie, ZENG Yan 2005, 26 (5):  520-524.  Abstract ( 77 )   PDF (797KB) ( 180 )   Save The deposits of shallw marine-littoral, lacustrine and fluvial facies of Upper Tiassic in west Sichuan depression occur with abundant oil-gas resources, which form a petroleum system dominated by natural gas. By using basin modeling technology, the hydrocarbon-generating history of source rocks and the compacting history of reservoirs in this depression are studied quantitatively. The started geologic age and peak reached period of hydrocarbon generation are pointed out. The determination of critical timing of hydrocarbon accumulation, including petroleum migration and accumulation areas, is made. The gas-generating quantity coresponding to the peak period and the paleostructure prior to reservoir compaction are restudied. Finally, the quantitative characteristice of the petroleum system are elaborated in this paper. References | Related Articles | Metrics

Effect of Xiakou Fault on Field Distribution and Petroleum Migration in Linnan Slope Area DU Yu-min 2005, 26 (5):  525-528.  Abstract ( 86 )   PDF (637KB) ( 293 )   Save Xiakou fault is a Class-II fault with succession movement, by which Huimin 8ag can be divided into Linnan subsag and Linnan slope. Linnan oilfield and Qudi oilfield are distributed in sections near Xialou fault. The former is situated in footwall of west section of the fault, while the latter in upper wall of east section of it. Such a framework is related to the lateral differences of seal of the fault, especially to the fault occurrence. Since the west section has more seal capacity, the east section becomes the favorable pathway for petroleum migration from Linnan subsag toward Qudi area, where the steep part of the fault plays the role of preferred pathway. The steep and convex fault plane controls the petroleum migrating across the plane by the form of spreading or confluence flowing. The direction of confluence flowing is good for petroleum accumulation. References | Related Articles | Metrics

Characteristics of Fan Delta Microfacies and Its Hydrocarbon Distribution in Anpeng Field CHEN Chun-qiang, ZHANG Ya-zhong, WU Li-yan, JIANG Chun-ming, TAO Zong-pu 2005, 26 (5):  529-532.  Abstract ( 111 )   PDF (485KB) ( 214 )   Save The microfacies feature of tight sandstone reservoir in fan delta of Anpeng oilfeidl in Biyang 8ag is studied on the basis of sedimentology, reservoir geology, logging geology and core data, combined with the recognition of sedimentary facies signs like sediment granularity. The fan delta can be subdivided into two subfacies and three microfacie8. The characteristics of deposits, petrophysical property and distribution of these microfacies are elaborated. The relationship between the microfacies and oil-gas distribution is analyzed. lt is suggested that the mid-distal subaqueous distributary channel and channel mouth bar are the favorable microfacies for oil-gas accumulation. References | Related Articles | Metrics

Base Level Cycle and Reservoir Prediction of Lower Carboniferous in Hadexun Uplift, Tarim Basin TANG Zi-jun, LI Qi-rming, ZHAO Fu-yuan, DI Hong-li, YANG Shuan-rong, XIE Xu-zhao, ZHANG Chun-lian 2005, 26 (5):  533-535.  Abstract ( 93 )   PDF (517KB) ( 171 )   Save Based on prineiple and methods for base level cycle, the drilling. well logging, seismic and geochemical data from Hadexun area are analyzed. One I-type and three II-type sequence interfaces of Lower Carboniferous are recognized, and three medium-lerm base level eycles (SC1, SC2, SC3) corresponding to three trangressive-regressive cycles are classified. SC cyele is dominated by longshore bar deposit, while SC2, SC3 by tidal nat system. The study shows that SC1 sandstone and SC2 flagstone are favorable reservoir sand bodies and could be as key targets for exploration of stratigraphic and lihologic oil-gas pools. References | Related Articles | Metrics

Significance of Discovery of Chitinozoans from Late Ordovician to Early Silurian in Shun-1 Well, Tarim Basin CAI Xi-yao, MAO Shu-hua, CHEN Yue, ZOU Yuan-rong, CHEN Qiang-lu, YOU Dong-hua 2005, 26 (5):  536-539.  Abstract ( 85 )   PDF (562KB) ( 329 )   Save The Lower Silurian rocks are fully developed in Shun-IWell with classification of Llandoverian Kalpintag formation, Tataaiertag formation and Wenlokian Yimugantawu formation. The Kalpintag formation is subdivided into three members as upper and lower sand-stone members and middle mudstone member with grey and grey-greenish colors. Tataaiertag formation is subdivided into upper member with red-brownish and red mudstone intercalated with siltstone and lower member with purple-red mudstone. The Yimugantawu formation is composed of brown and dark brown mudstones intercalated with siltstone and fine grained sandstone. The Charchag formation of Upper Ordovician with lithology of grey and dark grey mudstone is only penetrated by 1 10m in thickness. The lithological and electrical properties of these formations are distinct. Prolifie Chitinozoan fossils were discovered from lower member of Kalpintag formation and Charchag formation, and five species of three genera and numerous others were identified. Furthermore, their ages and geographic distributions are discussed in detail. Based on the characteristics of the fossil assemblages, they are assigned to the Conochitina elaca and Conochitina sp.2 zones, respectively. According to the spatial distribution of Chitinozoans in global scope, the age of the Chitinozoan-bearing zones in Shun-1 Well is determined and the reclassification of its Lower Silurian is made by the litho stratigraphy, bio-stratigraphy and logging stratigraphy. It is the first time to provide important fossil evidences for the classification and the correlation of Lower Silurian in this area. References | Related Articles | Metrics

Sequence Stratigraphy and Source-Reservoir-Caprock Assemblages of Lower Cretaceous in Baorao Trough YI Ding-hong, JIU Y-rong, SHI Lan-ting 2005, 26 (5):  540-543.  Abstract ( 91 )   PDF (575KB) ( 251 )   Save One super-long term stratigraphic base level cycle (the second-class sequence) and coresponding 5 long temm stratigraphic base level cycles (the third class sequence) are recognized in Lower Creataceous of Jiergalangtu sag, Erlian basin by using the ways and principles of high resolution sequence stratigraphy. The long-term cycles could be described as ISC, LSC, LSC, LSC, LSC, and their developed characters are analyzed in this paper. Within the correlation framework of the sag, the development and distribution of the source-reservoir-caprock assemblages and their inner relationship to the base level eycle. [t is pointed out that four sets of the assemblages (LSCI, LSCz, LSC:+LSCs and LSCs) are developed, of which LSC3+LSCs assemblages are the most favorable for hydrorarbon accumulation. References | Related Articles | Metrics

Method for Quickly Forecasting Recoverable Reserves and Remaining Recoverable Reserves in Oil and Gas Fields CHEN Yuan-qian 2005, 26 (5):  544-548.  Abstract ( 137 )   PDF (924KB) ( 213 )   Save The recoverable reserves and the remaining recoverable reserves are important indices for oil-gas development. The remaining recoverable reserves should be as a material base for it in future. For waterflooding oilfields, the methods for prediction of recoverable reserves include water drive curve, production decline, forecast model and numerical simulation. However, when a oil-gas field gets into late stage, the production decline becomes lhe most forecast method, which is also one of generally applied methods for forecasting recoverable reserves in the world. Based on this method, this paper presents the methods for quickly forecasting the technologically recoverable reserves, economically recoverable reserves, remaining technologically recoverable reserves and remaining economically recoverable reserves. The practicability, effectiveness and reliability of these methods have been confimed by 12 oilfields in China. References | Related Articles | Metrics

Formulae for Minimum Allowed Production Rate of Condensate Gas Well and Application MA Xin-fang, LANG Zhao-xin, LI Xing min 2005, 26 (5):  549-551.  Abstract ( 134 )   PDF (304KB) ( 225 )   Save The calculation of minimum allowed production rate of condensate gas well is of great significance in optimization of production tubing size and estimation of bottom-hole liquid loading. According to the fuid flowing and the factors affecting flowing, this paper derivales the equation of minimum allowed production rate of condensate gas well, calculates the minimum allowed production rate in different tubing sizes and botom-hole pressures, analyzed the probability of bttom-hole liquid loading, provides the ltubing sizes of different pressures, varied production rates and the reasonable value of maximum tubing diameter. If bigger than this value, the btom-hole liquid loading will occur, resulting in abnormal production of condensate gas well. Finally, some probabilities of improving the liquid-discharged ability in condensate gas well are analyzed in this paper. References | Related Articles | Metrics

Application and A bnormal Data Processing from Systematic Well Test of Gas Well LI Xing-min, GAO Chun-guang, LANG Zhao-xin 2005, 26 (5):  552-553.  Abstract ( 76 )   PDF (270KB) ( 184 )   Save A method for simultaneous-solution of one-point binomial is established for using the abnormal data or curves from systematic well test of gas well to evaluate the productivity and inflow performance of multilayer gas pool and reasonably clasify the layer series of development. The uniquely indicative curve and unique curve of inflow performance curve from each layer in gas well are based on the processing of these abnormal well test data. Also, the productivity, interlayer interference and corresponding processes of selective zone production and full zone production are analyzed and applied to the case study. The results show that this method can be used for quantitatively evaluating the interference of mulilayer gas pool, thus determining the rational production or recovery process. References | Related Articles | Metrics

New Method for Absolute Open Flow of Gas Wells after Fracturing LUO Tian-yu, GUO Jian-chun, ZHAO Jin-zhou, CHEN Chao-gang, YU Xian-you 2005, 26 (5):  554-556.  Abstract ( 77 )   PDF (283KB) ( 207 )   Save Based on the percolation theory of gas reservoirs after fracturing, considering the meaning and its infuence factor of cofficient“a”, this paper suggests that taking ceofficient“a” as a conslant for gas well in some area with conventional radial flowing is reasonable.It mostly depends on the average terrestrial stress and permeability. However, for gas well after fracturing. the meaning of coeficient “x”is quite different for its tight relations to dimensionless conductivity of hydraulic fractures. W ithout considering this factor's influence, greater errors will occur. Taking Changqing gas field as an example, the corelation of value of“a” with the dimensionless conductivity is simulated. This method presents a new way for calculation of absolute open flow in gas wells after fracturing. References | Related Articles | Metrics

Artificial Neural Network-Based Combination Forecast Method for Oil-Gas Production WANG Lei, GU Hong-wei, YAO Heng-shen 2005, 26 (5):  557-558.  Abstract ( 107 )   PDF (325KB) ( 203 )   Save The numerous existing methods for prediction of oil and gas production are reviewed, and the principle of conventional combination forecast method is explicated. The method for determining optimal weights in combination forecast based on least square method is improved. A novel method based on BP artifcial neural networks is proposed, which is also applied to the case study in this paper. The results show that this novel method or model a8 a preferential technique can be used to effectively improve the accuracy for prediction of oil-gas production. References | Related Articles | Metrics

Application of Mass Conservation Principle to Porous Media Percolation REN Yong, SUN Ai-ying 2005, 26 (5):  559-561.  Abstract ( 114 )   PDF (229KB) ( 336 )   Save The universal principle of mass conservation is introduced into porous media fuid mechanics followed by obtaining the general form of the mass conservation equation which used for oil-gas or oil-water percolation and media-deformed rocks is verified. The result shows that the general form of mass conservation can be applied to describe the percolation features of the porous media fuids in single phase, multiphase and solid phase in deformation media. Introducing mass density allows the equation to be simple, understandable and applicable. In addition, the definition of flowing velocity are modified and perfected, testifying the relationship between real velocity and flowing velocity. References | Related Articles | Metrics

Determination of Reasonable Well Spacing Density and Injection-to-Production-Well Ratio in Waterflooding Field JIA Zi-li, GAO Wen-jun, ZHAO Xiao-ping, XU Jun-lin 2005, 26 (5):  562-564.  Abstract ( 163 )   PDF (299KB) ( 189 )   Save One of the crucial issues in reservoir engineering study is how to choose pattem well spacing in order to reach the highest recovery and optimal economic eficiency by waterooding process for field development project designing and well pattem infill or adjustment. Based on the relationship among recovery, well spacing density and injection-to-production-wel ratio given by Reference [1], integrated with other methods such as economic evaluation and injection-production balance analysis, etc., this paper proposes a new method for determination of .reasonable well spacing density and injection-to production-well ratio in waerlooding field. The case analysis and calculation from QL oilfield shows that there are additional potentials on the primary density and ratio under the rising of current oil price. References | Related Articles | Metrics

Paleo-Oil Leg Recognition and Its Application to Petroleum Exploration WANG Fi-yu, PANG Xiong-qi, ZENG Hua-sen, SHI Yu-lei, HU Jian-feng, LIU Ke-yu 2005, 26 (5):  565-569.  Abstract ( 97 )   PDF (722KB) ( 360 )   Save The technologies 10 detect paleo-oil leg include three parts: 1) recognition of zones with high porosity and high permeability, 2) analysis of residual hydrocarbons, and 3) history match for basinal fuids. The grain index and quantitalive nuorescence gain rely on the micro-petrography and laser scanning analysis to detemine the abundance of oil inclusion in reservoir, which characterizes paleo-oil saturation. The grain index of oil zone is generally over 5%, but higher than 10% for some samples at least. The grain index of aquifer is normally lower than 1%. Some samples from oil zone are lack of high value of grain index (higher than 5%), which indicates rapid petroleum accumulation or shallower accumulation. In pathways of petroleum migration, the grain index mainly ranges from 1% to 5%, but they are locally distributed vertically. It is coneluded that the grain index of oil inclusion and quantitative grain fluorescence technologies can be applied to recognize paleooil leg, delineate palevoil and water c'ontact, lrace re-migrated petroleum, confirm oil charge event before gas or condensate gas accumulation, find out secondary reservoir and underlying reservoir, and allow the charge history to be accurately constrained. References | Related Articles | Metrics

Application of Clay Mineral Study Results to Hydrocarbon Prospecting in Tarim Basin ZHAO Xing-yuan, LUO Jun-cheng, YANG Fan 2005, 26 (5):  570-576.  Abstract ( 206 )   PDF (1327KB) ( 289 )   Save Clay mineral research plays an important role in the oil and gas exploration in Tarim basin. Clay minerals can be applied to inferences of paleoclimate, sedimentary facies and diagenetic environment evolution, providing bases for stratigraphic correlation and depositional break. Reservoir petrophysics is not only related to clay mineral types, but also to their morphologic characteristic8 and occurrences. The results from clay mineral research can also help the well log interpretation. The abundant authigenic kaolinites dstributod in Eocene-Cretaceous (E-K) reservoirs can be as one of the sigmificant indications for tracing the gas source rocks in Kela-2 gas field. References | Related Articles | Metrics

Making Curves of Base Level Changes by Facies Series Shift Method——An example of Sulige gas field HU Guang-ming, JI You-liang, JIA Ai-lin 2005, 26 (5):  577-579.  Abstract ( 93 )   PDF (558KB) ( 122 )   Save The ascending descending base levels cause that facies series in ffectively allowed spaces shifts landward and basinward. The curves of base level changes can be made based on this principle. This method is elaborated by examples of the fluvial strata of Permian in Sulige gas field. The quasi-sequences in the target zones are divided into five types in terms of individual sedimentary facies and energy, and they form a facies series along the water flow. Hence, the studied area could be divided into three sections: upper reach, middle reach and lower reach. Stat and choose the best frequent quasi-sequence in each one, then link all the quasi-sequences in each section, and make curves of the base level changes. These curves are testifed quantitatively by the varied Iread of average thickness in sand body of over 1m. References | Related Articles | Metrics

Application of Homogeneous Temperature of Fluid Inclusions to Recovery of Denuded Strata Thickness ZHAO Li-bin, HUANG Zhi-long, LI Jun, XUE Wei 2005, 26 (5):  580-583.  Abstract ( 109 )   PDF (489KB) ( 326 )   Save The principle, methods and some problems for application of Homogeneous temperature of fluid inclusions in calculating denuded strata thickness are systematically elaborated in this paper. The detailed application is ilustrated by the examples of recovery of the denuded strata thickness in Well 4-1-1 of W enzhou depression in Donghai basin and Well Lunnan-1 in Tarim basin. The results show that the erosion thickness of E2 stratum in Well 4-1-1 is about 1 900-2 050m, while that of Ordovician unconformity in Well Lunnan-1 about 2 600m. The study reveals that the method for recovery of denuded strata thickness is valid and applicable. References | Related Articles | Metrics

Classification of Upper Yangtze River Basin and Its Significance AN Zuo-xiang, MA Ji, PANG Qi-wei 2005, 26 (5):  584-586.  Abstract ( 164 )   PDF (293KB) ( 222 )   Save The Upper Yangtze River Basin is classified firsly. It has an area of 50x10^ km?, located within Hubei, Chongqing, Sichuan, Guizhou and Hunan regions and characterized by its wide distribution in the Palcozoic in them. The basins such as Sichuan, Jianghan, Xichang etc, are superimposed above Upper Yangtze River Basin, which are favorable areas to explore for natural gas in the carbonate rocks of Palcozoic. Many gas fields or reservoirs have been found in Sinian, Carboniferous and Permian in Sichuan baain. This classified Upper Yangtre River Basin is of great significance for Paleoroic oil and gas prospecting in South China. References | Related Articles | Metrics

An Approach to Hydrocarbon Accumulation Period LI Ming cheng, SHAN Xiu-qin, MA Cheng-hua, HU Guo-yi 2005, 26 (5):  587-591.  Abstract ( 109 )   PDF (691KB) ( 412 )   Save Petroleum accumulation period is a section of time. The formation an oil/gas pool tends to being resuled from multiple charging The presence of hydrocarbon inclusion is the direct evidence for oil-gas migration and accumulation. The petroleum accumulation period can be determined based on the time corresponding to fuid inclusion homogenization lemperature which can be plotted by continuous and discontinuous distribution types of histograms. The continuous distribution type indicates continuous charging and just one-period accumulation. The discontinuous type means discontinuous changing and multi-period accumulations. In terms of accumulation history partly described by accumulation period, the Cenozoic petroleum accumulation history is relatively short, moet belong to one -period accumulation, while Palcozoic petroleum accumulation history is comparatively long, and there could be multi-period accumulations. This paper suggests that most of paleo oiVgas reservoirs is destroyed, only could those pools that are continuously charged with oil and gas or formed in late period preserve, but they may not necessarily be characterized by multi-period accumulations. Only by study of the accumulation or charging history can they be evaluated. References | Related Articles | Metrics

Discussion on Abnormally High Pressure in Kuqa Depression LI Chuan-liang, JIN Hai-hu 2005, 26 (5):  592-593.  Abstract ( 101 )   PDF (177KB) ( 221 )   Save Based on the analysis and calculation of rock mechanics, a study is conducted on the origin of abnormally high pressure in Kuqa depression. The study shows that the abnormally high pressure in Kuqa depression is not the result of compression of tectonic stress but resulted from its oil-gas migration and accumulation. References | Related Articles | Metrics

Crude Oil of Precambrian in Eurasia I. D. Timoshina, N. S. Kim 2005, 26 (5):  594-604.  Abstract ( 88 )   PDF (1499KB) ( 138 )   Save The physical and chemical properties and the hydrocarbon compositions of Epiproterozoic crude oils in Siberian, East European and Arabian plates are satudied. It is found that the Precambrian crude is of some special features besides natures of phanerobiotic crude, that is, it contains abundant C light isotope, and in its aliphatic composition dominates normal paralfn hydrocarbons. According to hydrocarbon biomarker composition of crude in Siberian platform, the crude can be divided into four groups, of which two groups are also found in East European and Arabian platforms. The study shows that the difference of crude properties among these platforms is relaled to the most primary prokaryole lipoid in local ecologic s8g of Precambrian ocean and the simplest eukaryote lipoid in biochemistry. Related Articles | Metrics