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01 February 2008, Volume 29 Issue 1 Previous Issue    Next Issue

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Analysis on Gravity-Magnetic Anomalies in Basement Geotectonic Divisions in Junggar Basin ZHAO Jun-meng, MA Zong-jin, YAO Chang-li, LI Yi-shi, LIU Zhan-po 2008, 29 (1):  7-11.  Abstract ( 92 )   PDF (962KB) ( 267 )   Save Based on the 1:200 000 gravitational and magnetic anomalies, the 48 faults in Junggar basin including 7 of first class, 6 of second class and 35 of third class have been determined, by means of multi-processing and analyses. In particular, the fault F6 in EW orientation and the fault F1 in SN orientation have been determined by detailed data processing and combining with crystalline basement deposition feature of the basin. The study shows that Junggar basin can be classified into such three first tectonic regions as Region Ⅰ (southern part), Region Ⅱ (middle part) and Region Ⅲ (northern part). The Region Ⅱ can be further divided into 4 sub-regions, forming a four-phase pattern. The each phase can be also divided into several further secondary geotectonic units. The structure, density and magnetic intensity are different in each phase, composing some differences in time and space. References | Related Articles | Metrics

Numerical Simulation of Seismic Wave Propagation in Complex Structures LIU Yang, WEI Xiu-cheng 2008, 29 (1):  12-14.  Abstract ( 94 )   PDF (195KB) ( 380 )   Save Numerical simulation from wave equations is a valid means of studying seismic wave propagation. In this paper, the pseudospectral method by the wave equations of inhomogeneous elastic isotropic media is developed and the stable conditions for it are given. This method is used to simulate a real complex structure, the shot records are precisely gained, with abundant wave field features. The case study shows that this method is more suitable for simulation of seismic wave propagation in complex geologic structures. References | Related Articles | Metrics

Carbonate Reservoir Characteristics and Control Factors in Yuqi Area, Tarim Basin KUANG Li-xiong, GUO Jian-hua, HUANG Tai-zhu, HUANG Zong-he 2008, 29 (1):  15-18.  Abstract ( 85 )   PDF (257KB) ( 235 )   Save The lithologic feature, spatial type and reservoir quality in Yingshan carbonate reservoir of Middle-Lower Ordovician in Yuqi area of Tarim basin are analyzed comprehensively by using core observation, cast thin section, cathodology, SEM, porosity and permeability analysis and mercury injection method, etc., and the reservoir is synthetically evaluated then. The results show that the main rock types in Yingshan formation are micritics, calcarenite and dolomite, of which, micritics and calcarenite have the best development and the widest distribution. The carbonate reservoirs belong to cave, fracture-pore and fracture types with intermediate physical property. The cave reservoir develops widely in the west slope of Yuqi area, but cave filling is very compact. Fracture-pore reservoir is relatively a better kind of reservoir. The key factors influencing the reservoir quality are structure, karst and diagenesis. The favorable reservoirs are distributed along Wellblock YQ2 -YQ3 -YQ4 -LN13 in western Yuqi area. This conclusion provides an important theoretical basis for the next exploration in Yuqi area and its vicinities where carbonate rocks are partially eroded. References | Related Articles | Metrics

Control Effects of Spreading Structure and Reversal Structure on Hydrocarbon Distribution—An example from Dongnan uplift in Songliao basin LI Jun, HUANG Zhi-long, LIU Bao-zhu, LIU Bo 2008, 29 (1):  19-21.  Abstract ( 105 )   PDF (176KB) ( 242 )   Save Songliao basin is a large-scale complex sedimentary basin of Mesozoic and Cenozoic with fault depressions and depressions. It features three structural evolution stages, showing fault depression at early stage, depression at middle stage, reversal structure at late one. Dongnan uplift is the Class-I tectonic unit in Songliao basin, in which there are lots of spreading structures and reversal structures. They play good control parts to the hydrocarbon accumulation and distribution here. But different stages of formation and different horizons of development for the spreading structures and reversal structures result in different control effects of them on hydrocarbon accumulation in it. The spreading structures mainly control the primary hydrocarbon reservoirs, while the reversal structures mainly control the secondary reservoirs in deep sag and the primary ones in slope area. References | Related Articles | Metrics

Genetic Types of Crude Oil and Analysis of Oil Sources in Gas Hure Oilfield WANG Li, JIN Qiang, PENG De-hua 2008, 29 (1):  22-25.  Abstract ( 181 )   PDF (263KB) ( 193 )   Save Gas Hure oilfield is the largest on in Qaidam basin. There are many opinions about the oil sources in this oilfield. This paper presents its geochemical characteristics and genetic types of crude oil in the deep and shallow reservoirs by abundant biomarker parameters through concentrated sample collection and systematic analysis. It is suggested that the characteristics of crude oil within the two reservoirs are very similar, belonging to typical salt-lake facies and immature crude oil, but differences between them indicate that the oils originate from different oil sources. According to analysis of oil-source correlation and research results of source kitchen, hydrocarbon sources in Gas Hure oilfield are found out. That is, the deep crude oil is from Oligocene source kitchen in Mang'ai sag and the shallow crude oil is from mixed source kitchens of Oligocene and Miocene in Mang'ai sag. References | Related Articles | Metrics

Exploration Potential of Pre-Jurassic in Southern Margin of Kumu Swell in Tuha Basin LI Hua-ming, LI Xin-ning, HUANG Wei-dong, LI Bin, DENG Shen-hong 2008, 29 (1):  26-28.  Abstract ( 84 )   PDF (212KB) ( 207 )   Save The pre-Jurassic is the important sequence for replacement of petroleum resources in Tuha basin. There are three sets of source rocks developed in Kumu swell. They are the Upper Carboniferous, the Taodonggou group of Permian and the Aydingkol Lake formation of Lower Permian, in which faults and traps are well developed with good types of traps and abundant resources. Three major oil-bearing systems such as Jurassic, Permian-Triassic and Carboniferous exist at this area, becoming a favorable target area for oil migration and a giant and multi-sequence oil-bearing zone. The oil-gas field has been found in northern margin of Kumu swell. The structural belts of the southern margin have the same conditions for oil and gas accumulation. They could be the major exploration regions in the near future. References | Related Articles | Metrics

A Study on Seismic Vertical Resolution by Forward Model ZHANG Ya-min, ZHANG Shu-fa 2008, 29 (1):  29-32.  Abstract ( 99 )   PDF (218KB) ( 241 )   Save In order to investigate the relation of vertical resolution of seismic reflection with stratum structure and frequency of incidence wavelet, and the relation between the percentage of sandstone and the amplitude and wave impedance of seismic reflection in sand layers, two geological models are developed. One is the stratum association model with different thickness of sand-mudstone; the other is the association of stratum models with different percentages of sand-mudstone. The study shows that there exist linear proportional relations between the seismic reflection amplitude and wave impedance and the sand-mudstone percentage. The vertical resolution of seismic reflection is related not only to the incidence wavelet frequency into target zone, but also to the stratum sedimentary rhythm and structure. References | Related Articles | Metrics

Oil Resource Prediction and Exploration Potential in Zhanhua Sag WANG Xue-jun 2008, 29 (1):  33-36.  Abstract ( 96 )   PDF (211KB) ( 370 )   Save According to the exploration degree in Zhanhua sag, the oil resource is predicted and the exploration potential is analyzed by means of reservoir size sequence in terms of law of Pareto. Study shows that about 333 reservoirs are to be discovered at present. The OOIP to be proved is expected about 9.7×108t, suggesting that this area is of huge petroleum resources and potentials for exploration. The evaluated units such as Bonan-Gudao, Zhuangxi-Changdi-Gudong and Chengdong blocks could be the main areas of incremental reserves for further exploration. References | Related Articles | Metrics

The Paleo-Karst Feature of Ordovician Carbonate Rocks in Lunnan Area PANG Wen, SHI Hong-xiang 2008, 29 (1):  37-40.  Abstract ( 84 )   PDF (191KB) ( 354 )   Save Lunnan area in Tarim basin was ever been risen and denudated under the effects of early Hercynian movement in Late Devonian and late Hercynian movement in Late Permian. Its Ordovician carbonate strata underwent leaching and solution by meteoric water, and formed buried hill. Karst system very developed in Lunnan area, most of wells met strata with fissure-cavity system like Yijianfang formation and Yingshan formation. Therefore, the karstification and the tectonic movement are the key factors controlling the distribution of Ordovician reservoirs. The study shows that the reservoir bed is mainly distributed within 300 meters apart from weathering crust in vertical direction. The karstification mainly occurs in central and west part of Lunnan area, and the reservoir space is dominated by fracture/fissure, solution pore and solution cavity in lateral direction; in the east part, the reservoir space is dominated by fracture or fissure because of the effects of tectonic movements. References | Related Articles | Metrics

Characteristics of Shallow Oil Reservoir in Youquanzi Field in Western Qaidam Basin LIANG Chang-guo, LIN Cheng-yan, WANG Guo-min, LIU Jian, ZHANG Yong-mei 2008, 29 (1):  41-44.  Abstract ( 63 )   PDF (297KB) ( 187 )   Save The main oil-bearing series in Youquanzi shallow oil reservoir in western Qaidam basin is Shangyoushashan formation of Neocene (N2 2), being a lithologic-structural reservoir. Based on core analysis, imaging log, mercury injection, cast thin section, etc., this paper analyzes the main control factors to the structure, petrophysical property and reservoir quality in this studied area. It is pointed out that the lithology in this reservoir mainly includes sandy micrite limestone, (silty) algal limestone and limy (muddy) siltstone; reservoir spaces include intergranular pore and solution pore; the best lithology is (silty) algal limestone, and the second are silty micrite limestone and limy (muddy) siltstone. The main controlling factors for reservoir quality include sedimentary microfacies, fault/fracture action, atmospheric water solution along fault zones and organic acid solution. References | Related Articles | Metrics

Main Factors Controlling Hydrocarbon Accumulation in Neogene Shawan Formation in Chepaizi Swell of Junggar Basin LUO Jin, ZHUANG Xin-ming, HAN Xiang-lei 2008, 29 (1):  45-47.  Abstract ( 82 )   PDF (232KB) ( 225 )   Save Chepaizi swell in western margin of Junggar basin is a favorable area with composite hydrocarbon accumulation. In recent years, a number of prolific lithologic reservoirs have been discovered in the Sha-II member of Neogene Shawan formation, representing an important breakthrough in shallow-depth exploration. This paper analyzes the hydrocarbon distribution and typical reservoir characteristics of the Sha-II member, discusses its main factors controlling hydrocarbon accumulation and reservoir pattern, and proposes four main elements to control hydrocarbon accumulation such as lake-enlarged beach bar sands, hydrocarbon conduit system, lateral barrier conditions and paleostructural crest, and the reservoir pattern controlled by multi-factors of distal source and late accumulation. The beach bar sands parallel to the paleo-lake strandline could be the key target for further exploration. References | Related Articles | Metrics

Diagenetic Facies and Reservoir Quality of Paleogene-Cretaceous in Northern Tarim Basin XUE Hong-bing, ZHU Ru-kai, GUO Hong-li, GAO Zhi-yong, ZHANG Li-juan, SUN Yu-shan 2008, 29 (1):  48-52.  Abstract ( 79 )   PDF (311KB) ( 211 )   Save The Paleogene-Cretaceous reservoirs with lithic sandstone and greywacke lithic sandstone in northern Tarim basin is mainly in stage of medium diagenesis, and have obvious differentces among them in different areas, different intervals, rock composition, diagenetic evolution, diagentic mineral assemblage and pore type. This paper presents the diagenesis classification in terms of authigenic mineral type, distribution and genetic order as well as the effect of pore type assemblage, pore characteristic and tectonic action on the reservoirs, including the intense cementation and compaction diagenetic facies, the medium cementation and dissolution diagenetic facies and weak cementation diagenetic facies, among which the reservoirs with analcite-dolomite cementation are the best ones. Also, the reservoir quality is divided into four types of reservoirs base on the lithologic and pethophysical parameters of Paleogene and Cretaceous in different areas and different structural belts. TypeⅠ and Type II reservoirs could be as the main targets for oil and gas exploration, Type III low permeability reservoir is as the target for gas exploration, and Type IV reservoir with super low porosity-permeability and compaction even belongs to non-reservoir. References | Related Articles | Metrics

Hydrocarbon Expulsion History of Middle-Upper Ordovician Source Rocks in Tarim Basin LIANG Ze-liang, GANG Wen-zhe, YE Zhi-xu 2008, 29 (1):  53-56.  Abstract ( 94 )   PDF (384KB) ( 196 )   Save The Middle-Upper Ordovician source rocks are one of the main marine source rocks in Tarim basin. This paper studies the spatial distribution and the geological and geochemical characteristics in the Middle-Upper Ordovician source rocks, estimates the hydrocarbon expulsion efficiency of them by adsorption model and develops the model for simulating the hydrocarbon expulsion history of such source rocks, obtaining the intensity and the quantity of hydrocarbon expulsion of them in each geological history time. The oilexpelled quantity and gas-expelled quantity are estimated by 325.10×108t and 610.25×1011m3, respectively, totaling about 811.35×108t in hydrocarbon expulsion quantity. The main hydrocarbon expulsion time for calcareous source rocks is in the Middle-Late Ordovician and the Silurian-Triassic, centering in uplift of north sag, Tazhong (central Tarim) uplift, southern Bachu uplift and partial area of Maigaiti slope; the hydrocarbon expulsion center for muddy source rocks is mainly in Manjiaer sag and Awati sag. References | Related Articles | Metrics

Palaeontologic Assemblage and Sedimentary Environment of Quaternary in Chaerhan Area of Qaidam Basin DONG Ning, YANG Ping, YUAN Xiu-jun, ZHANG Hai-quan, WANG Hai-ling 2008, 29 (1):  57-60.  Abstract ( 97 )   PDF (282KB) ( 227 )   Save Huge thickness of lake facies deposit of Quaternary is developed in eastern Qaidam basin, in which the abundant microfossils such as ostracods, charophytes and gastropods are important evidences for analysis of stratigraphy and sedimentary environment. According to the abundant stratigraphic and palaeontologic information of Quaternary in Well Cha-7, Ilyocypris assemblage zonation, Gastropods assemblage zonation and Charophytes assemblage zonation from up to down can be divided into of this well, and can be well correlated with the ones of Well Chadi-2, Chadi-3, Chadi-4, Chadi-5 and Chadi-6 around it, hence they take an important part in stratigraphic division and correlation in this area. Moreover, the paleoecologic significance of these zonations is consistent with the environmental significance in petrology and geochemistry, for example, the content of Cl-is fall rapidly but the value of TOC is relatively high in interval with Ilyocypris assemblage zonation, indicating a sort of sedimentary environment symbol adjacent to bayou where freshwater organism is developed. In background of drying palaeoclimate in Quaternary, a short-term development of freshwater biota such as ostracods and charophytes is resulted from the effects of local tectonic movement on the sedimentary environment. References | Related Articles | Metrics

Induction Log Response and Environment Impact of Filtrate-Invaded Zone CHEN Qi-yan, FAN Xiao-min, WANG Bin 2008, 29 (1):  61-64.  Abstract ( 79 )   PDF (207KB) ( 277 )   Save Because of the co-effect of formation heterogeneity and mud invasion, there exits varied radius of filtrate-invaded zone with depth. In this paper, the analytical model of mid-induction log in 2D axis symmetrical heterogeneous media is developed. Based on the skin effect geometrical factor theory and formation resistivity log method, the theory of the forward modeling of gradual change of filtrateinvaded zone front are discussed. The main features of induction log response in different angles of inclination area are described and the effect of environmental factors such as well bore, filtrate-invaded zone and layer thickness on inductologs is estimated. The results show that the deep-and mid-induction logs have similar shape but different amplitudes in the same stratum condition. The mid-induction log is more influenced by the filtrate-invaded zone. Few influences on the logging response occur in only change of well bore size, mud resistivity, filtrate-invaded zone resistivity along with its invaded depth or the layer thickness, except for changing shape of the invaded zone. The results not only provide a general explanation for the invaded environment, but also make a reasonable interpretation on some anomaly in induction log. This consideration will be helpful to get proper well log interpretation. References | Related Articles | Metrics

Sequence Stratigr aphy of Neogene Shawan Formation in Chepaizi Area, Junggar Basin CHEN Xuan, ZHANG Shang-feng, ZHANG Chang-min, NING Liang, SHANG Chun 2008, 29 (1):  65-67.  Abstract ( 106 )   PDF (226KB) ( 328 )   Save According to synthetic core, logging and seismic data from Shawan formation of Neocene in Chepaizi area of Junggar basin, the Shawan formation could be divided into two sequences of Class III. Its unconformity surface as the sequence boundary of Shawan formation can be identified from the seismic profile and well section. The determination of maximum lake flooding surface is based on the changing of stratigraphic superposition pattern, lithology and logging curves, which is the key of the division of systems tract. The study shows that the structure of this area assumes a large-scale slope without distinct slope break, so the sequence stratigraphic model for a basin with gentle slope without continental slope break can be developed. In control of unitary structural framework, the development of Shawan formation should be controlled by the sediment supply rate, the climate and the change of lake level. Also, the favorable reservoir-cap rock assemblages are predicted using sequence stratigraphic theory integrated with oil entry features of Well Che-89 and Che-95. References | Related Articles | Metrics

Derivation and Correlation of Production Rate Formula for Horizontal Well CHEN Yuan-qian 2008, 29 (1):  68-71.  Abstract ( 204 )   PDF (214KB) ( 347 )   Save Horizontal well is an important tool for enhancing productivity of oil wells. At present, the formulae that are frequently used to calculate horizontal well production rate include Borisov's formula, Joshi's formula, Giger et al formula and Renard-Dupuy's formula. Based on the studies on horizontal well given by Joshi and Giger, this paper makes use of the physical conceptions of areal equivalent pseudo-circular drainage radius and production rate equivalent pseudo-circular production channel. The former transforms the elliptic drainage boundary into pseudo-circular drainage boundary; the latter transforms the length of horizontal well interval into pseudo-circular production channel. Moreover, using equivalent flow resistance method of water electric analogy principle, a new formula for calculating horizontal well production rate is obtained in this paper. The actual application and correlation of these five formulae indicate that the new formula proposed here is practical and effective. References | Related Articles | Metrics

Stress Sensitivity and Productivity of Fractured Reservoirs LI Chuan-liang 2008, 29 (1):  72-75.  Abstract ( 68 )   PDF (199KB) ( 528 )   Save Closure or openness of fractures in reservoirs depends on the stresses on and the roughness of fractures. Fractured reservoirs are middle-week sensitive to pore pressure. Rapid decline of production from fractured reservoirs is not due to the closure of fractures resulted by stress sensitivity, but the natural performance of periodical production behaviors of fractured reservoirs. References | Related Articles | Metrics

Technical and Economic Limits for Horizontal Well Development of Heavy Oil Reservoir in Shengli Oil Field ZHOU Ying-jie 2008, 29 (1):  76-78.  Abstract ( 87 )   PDF (190KB) ( 264 )   Save The result of horizontal well development of heavy oil reservoir is not only influenced by the conditions of reservoir and the design parameters of horizontal well, but also restricted by present oil price. This paper presents the statistical analysis of the field data from Shengli oil field, numerical simulation and economic evaluation, and then proposes the technical and economic limits for the horizontal well design in such a reservoir in condition of present oil price and technological level: the buried depth of reservoir is less than 1 500 meters; the degassed crude viscosity at 50℃ is lower than 30 000 mPa·s; the pay zone thickness is greater than 3 meters; the length of horizontal section is less than 300 meters; the vertical position apart from the top of pay zone is determined by 2/3. References | Related Articles | Metrics

Determination of Technical and Economic Limits for Horizontal Well in Water flooding Reservoir HAN Ling-chun, HAN De-jin, ZHANG Xue-ling 2008, 29 (1):  79-81.  Abstract ( 81 )   PDF (103KB) ( 192 )   Save Based on real situation of horizontal well development at home and abroad, the variation of horizontal well production is analyzed. And the deduced equations of economic limitation for both well production and OOIP controlled by horizontal wells in early stage of such a development. These equations can be integrated and used to distinguish the economic benefit by horizontal drilling process and make an optimized design of it. References | Related Articles | Metrics

A Portfolio Decision-Making Optimization Model for Oil Production Plant WANG Yong-lan, SUN Lei, SUN Liang-tian, LI Jun 2008, 29 (1):  82-84.  Abstract ( 83 )   PDF (102KB) ( 173 )   Save This paper presents the modern portfolio theory and related math model, modifies the benefit and risk function from oil production plant portfolio model: the net present value instead of yield rate is as the measurement of yield function; the absolute deviation instead of variance is as the measurement of risk function. Based on the feature and requirement of oil production plant investment and management, the optimized portfolio model with mean semi-absolute deviation is developed and applied to a case study. Compared with traditional investment option methods, this model is proved to be more effective and feasible for application. References | Related Articles | Metrics

Performance Analysis of Transient Pressure in Low Permeability Reservoir XIU Nai-ling, XIONG Wei, GAO Shu-sheng, YU Zhong-liang, SUN Yu-ping, WANG Xue-wu, YANG Qian-xiong 2008, 29 (1):  85-87.  Abstract ( 85 )   PDF (134KB) ( 371 )   Save The unsteady flow in low permeability reservoir is a non-linear problem with dynamic boundary, so it is extremely complex to find exact solution. In order to simplify the calculation, an approximate equation for reservoir pressure distribution is used to study the transient pressure distribution characteristics followed by obtaining the movement rule of dynamic boundary using material balance principle. Finally, the varied bottom-hole pressure is calculated. References | Related Articles | Metrics

Simple Calculation of OGIP and Water Influx in Gas Pool by Water Drive Process LIU Shi-chang, LI Min, WU Yang, ZHAO Juan, XUE Guo-Qing 2008, 29 (1):  88-90.  Abstract ( 144 )   PDF (138KB) ( 388 )   Save Original gas in-place (OGIP) and water influx in gas pool by water drive process are the key parameters for determination of a gas pool development scale and production plan. Using apparent geologic reserves method, only production performance data are needed without water influx, the OGIP can be estimated from mapping apparent geologic reserve curves, and then the water influx can be backward calculated by putting the OGIP data into the equation for apparent geologic reserves. The case study and correlation indicate that the results given by this method are accurate and reliable. References | Related Articles | Metrics

Theory and Methodology for Reservoir Upscaling QI Da-sheng, PEI Bai-lin 2008, 29 (1):  91-93.  Abstract ( 120 )   PDF (86KB) ( 216 )   Save In the past two decades, various reservoir upscaling theories and methods have been proposed for reservoir characterization and reservoir simulation. They are classified into five categories such as power-law average method, renormalization technique, pressure-solver method, vector method and pseudo-function technique. The common problem of conventional reservoir upscaling methods tends to smear out the spatially continuous permeability extremum strips like shale intercalation and fracture. However, the simulation and the practice for heterogeneous reservoirs have shown that oil recovery, especially breakthrough recovery mainly depends on the spatial connectivity of the extreme permeability values. This paper discusses how to deal with the permeability extrimum strips in the upscaling process and how to make an upscaling for natural fractured reservoir and carbonate reservoir, which are the remained major challenging problems in this area. References | Related Articles | Metrics

Application of Fuzzy System to Reservoir Modeling SHEN Nan, ZHANG Chun-lei, QIN Xu-sheng 2008, 29 (1):  94-97.  Abstract ( 81 )   PDF (240KB) ( 193 )   Save Fuzzy system consisting of fuzzy rules, defuzzying and self-learning process is applied in reservoir modeling. A new reservoir modeling method by interpolation and stochastic simulation is proposed. Correlation analysis is made using measured data from famous GSLIB software. Study shows that using the fuzzy system can make a modeling of geologic parameters, effectively. Such a method is better than the traditional geostatistics methods (Kriging and sequential gaussian simulation) in modeling precision, histogram and characteristic parameter recovery. References | Related Articles | Metrics

Application of Resistivity Log and Transient Electromagnetic Method to Study of Surface Structure ZHAO Feng, LI Xian-min, PENG Yong, QIN Chao-an 2008, 29 (1):  102-105.  Abstract ( 104 )   PDF (307KB) ( 200 )   Save The study purpose of surface structure is to develop corresponding depth-velocity model of surface structure, based on the variation of velocity and depth of surface and near surface uncemented sediments in seismic survey area, and using the static correction data from each observation point to delete the interference (moveout statics) of the variation on adjacent channel. Although data acquired by nonseismic technology can not directly be used to develop such a model, but can used to describe the variation of surface or near surface geologic body, followed by developing the velocity-depth model using data from seismic micro log and refraction. This method for developing the velocity-depth model of surface and near surface according to the geological model is of uniqueness for getting static correction quantity. References | Related Articles | Metrics

Reservoir Geological Modeling with Multi-Seismic Attributes Collaboration CHEN Jian-yang, YU Xing-he, LI Sheng-li, WANG Yan-hui, YANG Yu, DAI Wei-ping 2008, 29 (1):  106-108.  Abstract ( 81 )   PDF (151KB) ( 233 )   Save The basic principles for multi-seismic attributes extraction and analysis are presented, including interwell attribute prediction algorithm, cluster analysis algorithm, regionalized variable analysis of structure and collaborative Krikin algorithm, etc. The procedure includes extracting the multi-seismic attributes for cluster analysis, selecting the seismic attribute combination, simulating correlation with sand thickness of well, predicting the lateral distribution of sand thickness, making spatial correlation analysis using variogram tool of the software for geological modeling, collaborating the predicted interwell sand thickness distribution results, and then developing 3D sand matrix and attribute parameter models for quantitative characterization of spatial distribution and heterogeneity of reservoir. Taking an example of Wellblock Xing-56 in Xingshugang oilfield of Daqing, it is suggested that the reservoir geological modeling collaborated with the multi-seismic attribute analysis results is favorable for combination of a variety of information such as seismic, geological and well log data in order to provide a good platform of fully effective and more comprehensive use of multi-scale information. References | Related Articles | Metrics

Application of SVM to Prediction of Incremental Well Production by Stimulation Treatments WANG Ji-qiang, HAN Da-kuang, JIN Zhi-Yong, FENG Ru-yong, YANG Zuo-ming, ZHANG Guang-qun 2008, 29 (1):  109-112.  Abstract ( 83 )   PDF (164KB) ( 266 )   Save Support Vector Machine (SVM) is a novel learning method with solid theoretical basis depending on small amount of samples. Instead of the traditional inference process from induction to deduction, it greatly simplifies classification and regression problems. The decision function of SVMis only determined by a few support vectors, so the complexity of computation depends on the number of support vectors rather than the dimension of the sample space, thus avoiding the "curse of dimension" to some degree. Using SVM to process the fracturing data from a block in Daqing oilfield, a model for prediction of additional well production by fracturing stimulation is developed. The applied results indicate that SVM is a simple, feasible and effective method with high accuracy for prediction of incremental well production by stimulation treatments. References | Related Articles | Metrics

Petroleum Origination from Source Bed and Formation in Reservoir Bed LI Shui-fu 2008, 29 (1):  113-116.  Abstract ( 137 )   PDF (175KB) ( 163 )   Save In view of the shortage of theory of petroleum genesis, this paper proposes a new theory of petroleum genesis, which considers that hydrocarbons originate from source bed and form within the reservoir bed. In the burial process of biological organic matter, at early period of diagenesis, some of the polarity organic matter was expelled from the source bed with pore water, and then gradually became hydrocarbons within reservoir by thermal action. This paper discusses the differences between this new theory and the early or late organic genesis theories. This new theory can be used to make a good explanation of genesis of immature oil, avoid the problem that late hydrocarbon expulsion is difficult, and explain that the source rocks below "depth without hydrocarbons" can still generate some hydrocarbons. Also, it is presumed that the source rocks could not generate large numbers of hydrocarbons with increase of its vitrinite reflectance (Ro). References | Related Articles | Metrics

Classification of Newly Found Oil-Bearing Layer of Well Hongnan 9-12 in Tuha Basin LUO Quan-sheng, YANG Jun-qi, LI Sen-ming 2008, 29 (1):  117-119.  Abstract ( 72 )   PDF (240KB) ( 182 )   Save A new set of oil-gas bearing layer between Sanshilidadun formation of Lower Cretaceous and Kalazha formation of Upper Jurassic has been found in Honglian oil field in Tuha basin. This paper presents the correlation and demonstration of several opinions on the new oil-gas bearing layer classification based on the integration of multi-disciplinary information such as core, logging and seismic features. It is concluded that the new oil-gas bearing layer is located above the unconformity between the Cretaceous and the Jurassic, and should be classified into Sanshilidadun formation of Lower Cretaceous. The new oil-gas layer could be as a favorable target for further exploration for it is of basic conditions of hydrocarbon accumulation in this area. References | Related Articles | Metrics

A Discussion on Tectonic Patterns Proposed by Paper Thrust Belt Structure and Significance for Petroleum Exploration in Hala' alat Mountain in Northwestern Margin of Junggar Basin ZHANG Yu-bin, ZHU Feng-yun, WANG Yu-xin 2008, 29 (1):  120-122.  Abstract ( 68 )   PDF (248KB) ( 217 )   Save In literature [1] Thrust Belt Structure and Significance for Petroleum Exploration in Hala'alat Mountain in Northwestern Margin of Junggar Basin, the Triassic and Permian strata in Heshituologai basin, which were used for supporting its proposed tectonic patterns, are in big differences compared with the actual geologic data. Also, it was concluded by above paper that the deformation of Hala'alat thrust belt originated from the Late Triassic, inherited at the Late Jurassic and ceased after the Cretaceous. The authors in this paper argue that the most intensive deformation of lower structural zone in that pattern should originate mainly from the Cenozoic, and it is the neotectonic movement that transforms intensively all previous tectonic movement evidences, resulting in the difficulties for recovery of previous tectonic/structural deformation in this area. References | Related Articles | Metrics

Mobilistic Ideas in Oil and Gas Geology V.P.Gavrilov 2008, 29 (1):  123-127.  Abstract ( 69 )   PDF (296KB) ( 211 )   Save The author presents the main results of mobilistic ideas recognition in up-to-date oil and gas geology. HC generation may occur by different ways: not only by scenario of classical sedimentary-migration theory. HC fluid may be generated indirectly in bottom sediments of water basins of riftogenic type under sufficiently high heat flow that do not require submersion of original oil and gas source mass at the depth of 3 km and more (riftogenic model). In global process of oil and gas generation it should not be excluded the mineral synthesis of HC which may occur by different schemes. However, nonorganic synthesis produces predominantly methane, while present oils in their formation require organic matter participation or the other effective catalyst. However, oil and gas genesis should be considered as mixed (mixed genetic, polygenic). As a global regularity of spatial distribution of oil and gas territories one can follow a tendency of outlining units of oil and gas geological zoning — oil and gas accumulation belts within which oil and gas provinces or basins are singled out. Forecasting of new (not discovered) poles of oil and gas accumulation gives explorers additional possibilities to increase HC reserves. Due to belted distribution of oil and gas fields in the lithosphere as well as geodynamic (plate-tectonic) approaches to their genesis understanding, the principles of oil and gas geological zoning of the subsurface are also modified. Adoption of mobilistic approach in oil and gas geology provides petroleum geologists with new guide lines in exploratory process. In particular, non-traditional exploration objects appear: underthrust zones, basement of platform areas, veined zones of oil and gas accumulation and etc. all the significantly widens horizons of exploration activity for oil and gas and gives a hope of possible prolongation of oil and gas epoch of human civilization. Related Articles | Metrics

Petroleum Geology and Exploration Strategy in Sudanese Red Sea Area WANG Guo-lin 2008, 29 (1):  128-130.  Abstract ( 109 )   PDF (170KB) ( 295 )   Save Sudanese Red Sea area is located in west of middle section of Red Sea basin.Only syn-rift stratum (Upper Oligocene-Pleistocene) occurs here, in which the Middle Miocene is a stably distributed salt layer, including two sets of source rocks of lower Rudeis formation and upper Zeit formation, forming the lower and the upper reservoir-cap rock assemblages. The former becomes the major target for petroleum exploration at present. With consideration of the challenges on the exploration in oversea offshore block, this paper proposes the exploration strategies of focusing on the lower section in shallow water area in first phase and stepping into deep water area in second phase. References | Related Articles | Metrics