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01 June 2006, Volume 27 Issue 3 Previous Issue    Next Issue

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Thrust Belt Structure and Significance for Petroleum Exploration in Hala'alat Mountain in Northwestern Margin of Junggar Basin HE Deng-fa, GUAN Shu-wei, ZHANG Nian-fu, WU Xiao-zhi, ZHANG Yue-qian 2006, 27 (3):  267-269.  Abstract ( 147 )   PDF (328KB) ( 535 )   Save The foreland thrust belt in northwestern margin of Junggar basin is a large-scale imbricated thrust system developed since Late Carboniferous. The Hala'alat mountain, the eastern segment of the leading thrust belt, is composed of four elements such as Xiemisitai monocline, the Heshituologai basin, the Hala'alat imbricated zone and the western slope of Mahu sag. The Hala'alat thrust system can be subdivided into the upper and lower units of distinct deformation styles bounded by slippage surface of Paleozoic strata. There exist three or four imbricated thrust zones in the upper unit, each of which pinches out the slippage surface. In the lower one, there could be ten more superimposed structures consisted of Paleozoic fault blocks. The Hala'alat thrust belt is about 61 km wide and shortened by 53 km with scalage of 46%.t. The structural deformation originated at the Late Triassic and ceased at the Early Cretaceous. In the paraautochthon of the lower block in the leading thrust occurred a series of fault-bend folds and superimposed structures, which are the most potential targets for oil-gas exploration in the near future in the northwestern margin of Junggar basin. It is concluded that the targets should be the major domains for discovering another "Karamay field" beneath existing Karamay oilfield. References | Related Articles | Metrics

Relationship between Hydrocarbon Accumulation Stage and Hydrocarbon Generation and Expulsion Stage in Futai Oilfield LU Shuang-fang, XU Li-heng, SHEN Jia-nian, ZHANG Bin 2006, 27 (3):  270-272.  Abstract ( 119 )   PDF (317KB) ( 236 )   Save A chemical kinetic model is developed for calibrating organic matter-generating oil and gas of Sha-3 member shale in Jiyang depression by using data from thermal simulation experiments. The profiles of hydrocarbon generation and expulsion in Chexi sub-sag are analyzed, and the concepts of threshold of oil generation, peak oil generation and threshold of hydrocarbon expulsion are discussed in detail. Based on these, the quantitative evaluation of the history of hydrocarbon generation and expulsion for three possible source rocks in Chexi sub-sag is conducted, indicating that the hydrocarbon expulsion time took place mainly in late or recent period since the deposition of Dongying formation in Chexi Sha-3 member that is the dominant oil sources in buried hill area. This is completely consistent with the period of fluid migration and accumulation determined by inclusion's uniform temperature. Thereby, the cognitions about the periods of hydrocarbon generation, expulsion and accumulation are validated one another. References | Related Articles | Metrics

Gas Transporting Conditions for Formation of Large-and Medium-Sized Gas Fields in Different Types of Basins of China FU Guang, YU Dan, LV Yan-fang 2006, 27 (3):  273-276.  Abstract ( 124 )   PDF (296KB) ( 283 )   Save The characteristics of gas migrating channels of large-and medium-sized gas fields in different types of basins of China are analyzed, it is believed that no matter what the basin types are, faults or fractures act as the main gas migrating channels. This paper presents the definition and the calculation of comprehensive evaluation parameters for gas transporting capability of gas pools and studies the capabilities of 46 large-and medium-sized gas fields in domestic three types of basins where the faults act mainly as gas migrating channels. The study shows that the large-and medium-sized gas fields in Cratonic basin possess the highest or strongest gas transporting capability, those in foreland basin have medium one and those in rift basin are the lowest. By definition, calculation and study, it is shown that the gas accumulation efficiency of foreland basin is the highest, that of rift basin is medium, that of Cratonic basin is the lowest. By study of relationship between the gas accumulation efficiencies and the comprehensive evaluation parameters, it is believed that the foreland basin is of the greatest effect of gas transporting capability on the gas accumulation efficiency, the rift basin is of medium one and Cratonic basin is of the smallest. This paper also presents that the minimum value of comprehensive evaluation parameters required for forming gas transporting capability of high efficiency of foreland basin is about 1.6×10-14 m/s, that of rift basin is about 2.0×10-14 m/s and that of Cratonic basin is about 5.2×10-14 m/s. References | Related Articles | Metrics

The Conditions and Prospects of the Heavy Oil and Coal-Formed Gas Accumulations in Southern Slope of Huimin YU Jun-feng, XIA Bin, YU Jian-guo 2006, 27 (3):  277-279.  Abstract ( 126 )   PDF (519KB) ( 323 )   Save The southern slope of Huimin is a new exploration area for replacement of oil and gas resources. Based on data from development wells and prospecting wells drilled in this area, the hydrocarbon generation condition of Linnan sub-sag, the slope structure and reservoir-cap rock features are analyzed. It is believed that this paleo-uplift zone is provided with matured condition for hydrocarbon accumulation. The target zones for prospecting include three reservoir-cap rock assemblages of Cenozoic dominated by exploring heavy oil-gas pool and secondary gas pool and three reservoir-cap rock assemblages of Mesozoic and Paleozoic dominated by exploring coalformed gas. Lithology traps and structural traps are mainly found in Mesozoic and Cenozoic strata, while fault block-buried hill traps are primarily in Paleozoic strata. References | Related Articles | Metrics

Paleoecology and Sedimentary Environment of Carboniferous in Qaidam Basin YANG Ping, HU Yong 2006, 27 (3):  280-284.  Abstract ( 191 )   PDF (284KB) ( 810 )   Save The Carboniferous outcrops is mainly distributed in two areas of Northeastern and Southwestern margins of Qaidam basin. On the basis of uniform stratigraphic framework and correlated biostratigraphic sequences, comprehensive analysis of paleoecology and sedimentary feature provides convincing evidences for division of the sedimentary facies. The Lower Carboniferous is rich in fossil coral and brachiopod in the northeastern margin of Qaidam Basin. The coral evolved from small size of monomer toward big one, and the number of fossil genus and species varied from few to more with their abundance increasing, indicating that the sedimentary environment went stable and the water went deep. Meanwhile, two lithologic cycles of glutenite or inter-bedded sandstone and shale graded to limestone are developed, and the sedimentary environment evolved gradually from shoreland toward carbonate terrace. The biota of Upper Carboniferous is dominated by fusulinid and secondly by brachiopod and coral with flourished fossil plants in the lower part. Fossil brachiopod evolved toward smaller size and the abundance of coral is reduced, these changes are connected with shallow water and cold climate. The lithologies are dominated by alternating sandstones, shales and limestone, and the sedimentary environment based on shoreland tidal flat with swamp developed in the lower. The biota of Lower Carboniferous is dominantly composed of coral and brachiopod in southwestern margin of Qaidam basin. The biota of Upper Carboniferous is composed of dominantly fusulinid and secondly brachiopod, and the lithologies are mainly bioclastic limestone and oolitic limestone. Sedimentary environment of Carboniferous in southwestern margin based on alternating carbonate shoal of higher-energy environment and carbonate terrace of lower-energy environment. The analysis indicates that there existed transgressions twice in Early Carboniferous and continuous transgression in Late Carboniferous; the carbonate shoal facies favorable for oil accumulation is well developed in the southwestern margin, and the alternating marine and continental facies that is in favor of forming assemblage of oil source bed, reservoir and cap rocks is developed in the northeastern margin. References | Related Articles | Metrics

The Fracture Patterns and Oil-Controlled Process in Piedmont Bruchfalten Zone, Southern Margin of Junggar Basin LI Xue-yi, WANG Bing, CHEN Yang 2006, 27 (3):  285-287.  Abstract ( 161 )   PDF (492KB) ( 430 )   Save The fault in southern margin of Junggar basin is divided into three fracture patterns based on theory of fault-fold correlation, the structural model and typical structural studies, such as piedmont thrust faulting pattern, shallow slippage-thrust faulting pattern and deep slippage-thrust faulting pattern, including analyses of their mechanisms and faulted styles. This paper suggests that the hydrocarbon source in southern margin of Junggar basin originates from deep Permian and Jurassic strata, and that good configuration of the faulted styles is the key factor for hydrocarbon accumulation. Also, the correlation of fault configuration and the mechanism for hydrocarbon accumulation are analyzed in detail by taking its typical structures as example here. References | Related Articles | Metrics

Gas Chimney and Hydrocarbon Exploration LIANG Quan-sheng, LIU Zhen, WANG De-jie, LI Wei-lian, CHANG Mai 2006, 27 (3):  288-290.  Abstract ( 233 )   PDF (813KB) ( 362 )   Save Gas chimney is one of seismic anomalies resulted from vertical fluid migration, which is the interactional outcome due to overpressure, low stress and shale barrier. Multi-layered nonlinear neural network is now an effective technology for gas chimney research. The gas chimney can be applied in hydrocarbon exploration in terms of ranking prospects, detecting migration pathways, distinguishing sealing or non-sealing faults, identifying potential over-pressured zone and drilling (shallow gas) hazards as well as assessing the sea floor stability for platform design and drilling. References | Related Articles | Metrics

Application of Soil Physical Properties to Seeking Crude Oils in Biyang Sag JIANG Chun-ming, LI Lian-sheng, CUI Xue-hui, MEN Wei-hua 2006, 27 (3):  291-293.  Abstract ( 128 )   PDF (776KB) ( 251 )   Save Synthetically applying abnormal values of magnetism, electric conductivity and high resolution gravity of soil, this paper presents an approach of predicting the prospective oil and gas areas in Biyang sag, and good effects have already been obtained. With values such as low cost, simple and fast for field operation and non-resource and non-devastation, this approach provides a novel thought and technique for directly exploring oil-gas pools. References | Related Articles | Metrics

A study on Petroleum Accumulation in Basement Reservoir, Biyang Sag CHENG Xue-feng 2006, 27 (3):  294-298.  Abstract ( 125 )   PDF (838KB) ( 753 )   Save Biyang sag is a small half-graben basin full of oil and gas of Cenozoic. With its formation controlled by Tanghe-Liyuan fault of N-W strike and Liyuan-Biyang fault of N-E strike, Biyang sag is a fan-shaped and halfgraben-like basin which is deep in southeastern part and shallow in northwestern part. It is found that a huge thickness of Hetaoyuan formation of Paleogene with good hydrocarbon-generating conditions is laterally contacted to the old metamorphic complex on the faulting arctic region in the southeastern margin of Biyang sag, which allows to forming basement reservoirs. This paper presents the sag's sequence stratigraphy, sedimentary system, marginal faulting style, source rock condition and oil shows investigation in the southern margin as well as basement lithology and reservoir quality. The petroleum accumulation models of basement reservoir on this arctic region are then development. The advantageous targets for petroleum exploration are given. References | Related Articles | Metrics

Geologic Conditions of Coalbed Methane and Favorable Exploration Areas in Lujiabao Sag LIU Hui-fang, YANG Zi-rong, TENG Yu-hong, ZHOU Sheng-peng 2006, 27 (3):  299-301.  Abstract ( 141 )   PDF (401KB) ( 266 )   Save In order to make full use of coalbed methane resources and highlight shallower horizons of Fuxin coalbed, this paper rechecks and explains the well log data of 29 wells in Baoriwendu and vicinity, confirming 14 wells with coalbeds in which 8 wells are newly explained, 6 wells are re-verified. These allow to determination of the coabed distribution, thermal evolution history and petrophysical property as well as seals conditions in Lujiabao sag. Meanwhile, this paper presents the evaluation of the favorable areas for coalbed methane exploration and point of view about how to explore it according to the composite geologic analyses. References | Related Articles | Metrics

The Sedimentary Sequence and Sand Body Distribution Controlled by Palaeogene Structures in Qikou Sag, Bohai Bay CHEN Ying, LIN Chang-song, ZHOU Xiao-jun, ZHANG Xue-wei, YANG Xiao-fa, LEI Yan-ping 2006, 27 (3):  302-304.  Abstract ( 116 )   PDF (332KB) ( 313 )   Save With control of the structural evolution stages, Qikou sag in Paleogene underwent such sedimentary evolution sequences as semi-arid saucer lake environment in chasmic stage, deep-water lacustrine environment in strongly chasmic environment and open saucer lake environment in late chasmic stage. With control of the basin's palaeotectonic framework, seven sub-structural units can be classified into in this study area for the special distribution of sedimentary facies. Three source systems exist in Qikou sag which controlled the distribution of four sand bodies located at the southwest slope-break zone, the center of southern margin of the sag, the joint of F1 fault and northeastern margin fault and the joint of low swell southern margin fault and northeastern margin fault. References | Related Articles | Metrics

Determination of Water Property in Carbonate Formation Testing LIU Jing-jiang, YU Zhi-nan, HUANG Qian, LIU Hui-rong 2006, 27 (3):  305-307.  Abstract ( 106 )   PDF (138KB) ( 185 )   Save Because of the special geological structures in Tarim basin, it is quite complicated that the case of formation water comes forth by carbonate formation testing. The water coming from carbonate rocks or reservoirs could be divided into seven aqueous types by its geochemistry characteristic and water status. The source of the water has been confirmed according to its geochemistry characteristics, reference formation water characteristic parameters and water classification by taking the carbonate buried hill reservoir of Ordovician in Lunnan area of Tarim basin as an example. The main factor that influences the water analysis is the sampling condition. It is concluded that the key to properly determine the real aqueous source is to rightly use the information from formation testing and comprehensively understand the geological characteristic and the water occurrence. This method for distinguishing formation water and searching for the real aqueous sources is of some significance to other similar strata for reference. References | Related Articles | Metrics

Distinguishing the Gas-Contained Carbonate Rocks by P-S Wave Quality Factor Ratio XIN Yi, LIU Rui-lin, ZHANG Xiao-ming 2006, 27 (3):  308-310.  Abstract ( 138 )   PDF (520KB) ( 285 )   Save Compressional (P)-and shear (S)-wave attenuation and quality factors (Qp and Qs) were calculated by using the dipole shear sonic imager (DSI) log data. The studies of the features of the P-S wave attenuation in the carbonate formation containing gas and noncontaining gas show that P-wave attenuation in the carbonate formation containing gas is higher than non-containing gas. However, S-wave attenuation and quality factor do not show such a strong dependence. According to the features, this paper presents a method to distinguish the carbonate formation containing gas and non-containing gas by P-S wave quality factor ratio of Qp/Qs. References | Related Articles | Metrics

Identification of Carboniferous Reservoir Types in Tahe Oilfield with Conductance YUAN Xiu-ting, ZHOU Hong-tao 2006, 27 (3):  311-312.  Abstract ( 133 )   PDF (214KB) ( 317 )   Save Pore structure in carbonate reservoir influence greatly conductance, distribution of pore fluid, productivity and reserves. To distinguish the type of carbonate reservoir is the first step in evaluation of this reservoir. Ordovician strata in Tahe oilfield belong to carbonate reservoir with well developed fractures and dissolution pores. Using conventional well log data to calculate the conductance can be able to well recognize the reservoir type. In light of Tahe oilfield, the method and standard to recognize the reservoir type by conductance are presented. Case study shows that this method is suitable to Tahe oilfield. References | Related Articles | Metrics

A Study on the Element Pattern Characteristics of Fish-Bone Well PENG Xian-qiang, WU Xiao-dong 2006, 27 (3):  313-315.  Abstract ( 194 )   PDF (390KB) ( 269 )   Save As a new well type, appearance of fish-bone well is now considerable concern for its high productivity nature. Its proper well placement is a crucial aspect in such a well application for oil-gas field development. With numerical simulation software, the uniform pattern of spacing for combination of fish-bone well with vertical well is numerically simulated. The influences of variety of fish-bone well types, branch angles, branch length, branch location on productivity, as well as the effects of different well patterns (five-spot, seven-spot and nine-spot patterns, etc.) on production performance are analyzed. This paper presents the selected principles for optimum branch orientation, angle and location of fish-bone well placement, and also, the selected method for injector placement orientation in these well patterns, which could be as a guide for design of such a well placement. References | Related Articles | Metrics

A Theoretical Model of Steady-State Flow for Naturally Fractured Low-Permeability Reservoir FENG Jin-de, CHENG Lin-song, LI Chun-lan 2006, 27 (3):  316-318.  Abstract ( 146 )   PDF (269KB) ( 454 )   Save Natural fractures that distribute randomly in the reservoir are different from the hydraulic fractures that connected with oil and water wells. Using the steady-state productivity equation, a conventional method, is difficult to theoretically deal with the randomly dispersed natural fractures. This paper presents the equivalent flowing resistance method, a theoretical model of steady-state flow for naturally fractured low-permeability reservoir, by which this issue can be solved through research of effects of natural fracture parameters on production rate and formation pressure as well as effects of hydraulic fracture parameters on fracturing well production rate. This model is characterized by simple and practical application with fully considering fracture parameters. The case study shows the reason that for low permeability reservoir, oil well and water injection well should be spaced where natural fractures are developed in order to reach better production response. References | Related Articles | Metrics

Combining Optimization Model for Prediction of Oil Production by Polymer Flooding Process YUAN Ai-wu, ZHENG Xiao-song, YANG Fu-lin 2006, 27 (3):  319-321.  Abstract ( 129 )   PDF (139KB) ( 259 )   Save Fourteen non-linear models are selected to establish a model base, and according to the prediction error analysis of these models during a period of time, the optimum non-linear model is selected. One-order smooth exponential model and neural network model are applied to predicting, correlating and analyzing oil production by polymer flooding process. Optimization arithmetic of objective function is introduced to determine the optimum combination of these prediction methods. The results show that the prediction value of network model and combining optimized model are well closed to the actual curves and better than non-linear optimized model and oneorder smooth exponential model. The reason is that the two models can comprehensively include many factors influencing oil production so that the prediction values are in more accordance with the actual production performance by polymer flooding. And the combining optimized model is established based on maximizing the information values, which comprises all the information of single model and has better prediction effect. References | Related Articles | Metrics

Relationship between WOC Dipping and Varied Petrophysical Properties SHI Dian-hai 2006, 27 (3):  322-323.  Abstract ( 149 )   PDF (138KB) ( 279 )   Save The water-oil contact of each reservoir is dipping to some extent in general, which is resulted from the variation of petrophysical properties in reservoir rocks. Based on the theories of reservoir engineering and physical chemistry, a study is conducted on the relationship between dipping angle of WOC and the variation of petrophysical properties, and a theoretical formula is proposed to calculate the relationship. A case study is presented. The creditable description of permeability variation of a reservoir supports the development scheme of this reservoir. References | Related Articles | Metrics

The Reservoir Performance Assessment Model Based on Dissipative Structure Theory WANG Ren-yi, XU Jun, ZHANG Yu-rong 2006, 27 (3):  324-327.  Abstract ( 131 )   PDF (192KB) ( 486 )   Save The oil field waterflooding system is a dissipative system and follows the law of dissipative structure. Based on the grey correlation entropy, the system development and evolvement can be analyzed and studied by the use of the dominate factors that control the system evolvement direction. The minus entropy flow is the prerequisite for unbalanced and orderly structure of dissipative structure. Under the circumstances of minus entropy flow system, the system is in course of benign development and evolvement with decreasing gradually overall entropy and good efficiency of system energy in use, and in good order tendency and with good cooperation and matching among elemental subsystems. The development technical policy must be continually readjusted in accordance with constantly diverse oil water motion law so that minus entropy can be introduced to harmoniously exploit the oil field. References | Related Articles | Metrics

Modification of Cold Heavy Oil Production Model: Establishment and Interpretation of Radial Flow Model REN Yong, QIAN Li-jun, SUN Ai-ying, LIU Shu-zhi 2006, 27 (3):  328-331.  Abstract ( 121 )   PDF (295KB) ( 308 )   Save In order to more properly understand the mechanism of cold heavy oil production (CHOP), the one dimensional CHOP model is applied to the radial flow conditions. Re-introducing dimensionless variables is made to simplify and solve the model, developing the radial flow model. The case calculation indicates that the radial flow model can reflect the behavior of cold production and sand inflow, be consistent with real situations quantitatively, and prove its reliable property. The study also shows that continuous sand inflow is indeed one of the most key mechanisms by CHOP for IOR, such as forming highly flowing channels, removing skin effect and improving fluid flowing performance in heavy oil reservoir. Finally, a brief discussion is conducted on the defects and the development in the future. References | Related Articles | Metrics

The Experimental Study of Critical Reynolds Number on Low-Velocity Non-Darcy Flow WANG Dao-cheng, LI Min, CHEN Hao, QIAO Guo-an, SUN Li-juan 2006, 27 (3):  332-334.  Abstract ( 150 )   PDF (158KB) ( 519 )   Save Lots of experiments are made based on oil-oil displacement under irreducible water saturation and on water-water displacement under residual oil saturation. With low-velocity non-Darcy flow method for low permeability reservoir, the corresponding critical Reynolds numbers under these two situations are obtained. The study shows the different Reynolds numbers mean that the different critical Reynolds numbers of low-velocity non-Darcy flow under these two situations are resulted from different media for displacing and being displaced. Furthermore, this paper presents the detail reasons for them and the case study for calculation of the critical flow velocity under low-velocity non-Darcy flow by using these critical Reynolds numbers. References | Related Articles | Metrics

The Effect of Relative Volume Percentage of Movable Fluid on Development Effects of Low Permeability Reservoir HAO Ming-qiang, LI Shu-tie, YANG Zheng-ming, LIU Xue-wei 2006, 27 (3):  335-337.  Abstract ( 122 )   PDF (217KB) ( 415 )   Save Relative volume percentage of movable fluid of more than one hundred of super-low permeability core samples is tested by using nuclear magnetic resonance technique. The results indicate that there exist good correlation between the percentage and permeability and oil displacement efficiency. The higher permeability, the bigger the percentage is, except for low permeability condition; the bigger the percentage, the higher the oil displacement efficiency is. Based on these, this paper suggests the classifying criterion of reserves by the relative volume percentage of movable fluid, by which the development effects of low permeability reservoirs between Daqing and Changqing fields are analyzed and correlated. References | Related Articles | Metrics

Influence Factors of Associated Polymer Solution Injectivity ZHOU Chang-jing, LI Hua-bin, CHEN Zhong-hua 2006, 27 (3):  338-341.  Abstract ( 134 )   PDF (474KB) ( 259 )   Save This paper presents the experimental study on rheological behavior for the associated polymer solution through screen cloth and the relationship between screen coefficient and mass concentration and viscosity. Through analysis of injectivity of the associated polymer in porous media, it is found that this polymer is of good flow and injection properties under high pressure difference near the bottom hole perforation, bringing bigger drag coefficient under low pressure difference of deep pay zone in favor of improving oil-displacement efficiency of it. Meanwhile, the experimental result shows that the existing methods for evaluation of polymer solution injectivity cannot be used to properly and/or objectively appraise the behavior of associated polymer solution injectivity, which can be as an important guide for development of this new assessment method. References | Related Articles | Metrics

An Analysis of Abnormal Formation Pressure in Yaha 2-3 Gas Condensate Field WANG Hong-feng, TANG Ming-long, XIAO Xiang-jiao, ZHANG Fen-e, QIAO Xia 2006, 27 (3):  342-344.  Abstract ( 130 )   PDF (320KB) ( 283 )   Save The partial pressure maintenance and cyclic gas injection processes were used for development of Yaha 2-3 gas condensate reservoir in Tarim oilfield. But in past years, the pressure monitoring data showed that the reservoir pressures of build-up test data from gas producer were higher than that of build-down test data from gas injector, allowing the related performance analysis to be difficult. This paper analyzes the field testing data, finds out the reasons for abnormal formation pressure and makes corrections to them in order to attain reliable formation pressure. Such a big problem appeared by formation pressure test in past years has been solved, being of more significance for scientific management of the gas fields. References | Related Articles | Metrics

The Stress Sensitivity Test for Dense Reservoir Rocks in Low Permeability Gas Pool ZHENG Rong-chen, WANG Xi-bin, LIU Chuan-xi 2006, 27 (3):  345-347.  Abstract ( 120 )   PDF (224KB) ( 410 )   Save There exist big differences in studied result with different test methods for dense reservoir rock in low permeability gas pool is sensitive to the stress. In this paper, three different test methods are applied to five core samples from Daniudi gas pool, respectively, and their stress changes between the test results and real production performances are analyzed in detail. Finally, two of three methods are selected, which are better reflecting the stress sensitivity variation rules. References | Related Articles | Metrics

A Study on the Stress Sensibility of Permeability of Reservoir Rocks LI Chuan-liang 2006, 27 (3):  348-350.  Abstract ( 244 )   PDF (168KB) ( 564 )   Save Permeability of reservoir rocks changes with stress applying on the rocks. The change of permeability is due to the change of primary effective stress of rocks, not the Terzaghi's effective stress. Study on the permeability sensitivity should adopt the primary effective stress instead of the conventional Terzaghi's effective stress. Adoption of Terzaghi's effective stress usually overestimates the loss of reservoir permeability due to the drawdown of reservoir pressure. References | Related Articles | Metrics

A Study on MicroDistribution of Residual Oil by Physical Simulation Process LI Hong-xi, LIU Quan-wen, HE Jia-xiong, ZHANG Xue-cai, LIU Jie 2006, 27 (3):  351-353.  Abstract ( 162 )   PDF (445KB) ( 451 )   Save The experiments on micromechanism of forming residual oil have been made by using microtransparent sand-packed model. The forming procedures, the micro distribution rule of residual oil and affected primary and second factors are researched by water flooding, polymer flooding and week gel flooding processes. This paper presents the classification of the residual oil into such three types as movable oil, movable oil due to some special conditions and non-movable oil. The study shows that the heterogeneity of reservoir rocks results in forming of the residual oil. The residual oil by water flooding process is mainly distributed in the un-swept area, the surface of oil-wet stone, sealed pore, micro pore, low permeability layer and partially blocked pore. The residual oil by polymer flooding process is mainly in sealed pores (non-movable oil), micropores and surface of oil-wet stone (condition movable oil). The residual oil by weak gel flooding process is in sealed pores and surface of oil-wet stone. References | Related Articles | Metrics

Application of Conformance Efficiency Modification Method to Determination of Theoretic Water Cut Curve of Reservoir ZENG Jian, TANG Hai, WU Yong, LV Dong-liang 2006, 27 (3):  354-356.  Abstract ( 154 )   PDF (215KB) ( 295 )   Save Water cut curve is the basic curve used to research the water-yielding rules of the water drive oilfield. This paper reviews the existing research methods for the water-yielding rules, presents the difference between the lab core and the real reservoir in macroscopic and microscopic geologic characteristics, integrated with the relative permeability curve and the methods for determination of the volumetric conformance efficiency of lab core and the real reservoir, and proposes a new method-conformance efficiency modification method that can be used to determine the theoretic water cut curve of the water drive oilfield. The case study indicates that the calculated theoretic water cut curve is more accordant with the actual performance than the existing methods. References | Related Articles | Metrics

Injection Allocation Rate Determination of Well Groups Using Multiple Regression Method LI Ling, HUANG Bing-guang, TAN Xing-ping, JIANG Jian-li, ZHU Yi-dong 2006, 27 (3):  357-358.  Abstract ( 110 )   PDF (144KB) ( 301 )   Save Waterflood development is one of crucial measures for high and stable productions. With definite water injection timing and pattern, water injection intensity and, especially, the injection allocation rate is very important. The proper injection allocation rate of well can effectively relieve the contradictions of plane, interlayer and inherent layers, and improve the effects of oilfield exploitation by waterflood or water drive process. After synthetically analyses and researches of the existing methods for injection allocation rate, this article takes the group of water-injecting wells in waterflood oilfield as the research unit, the multiple regression method to decide the injection allocation rate is applied, by which and its regression coefficient and partial correlation coefficient, the multivariate regression models of Model I and Model II are developed. The case study indicates that this method is characterized by simpleness and practicability for application. References | Related Articles | Metrics

Application of Pseudo-Azimuth Correction to 3D Seismic Data Processing DU Zeng-li, SHI Ze-jin, JIANG Wen-bo, ZHAO Fei 2006, 27 (3):  359-360.  Abstract ( 158 )   PDF (253KB) ( 238 )   Save F-K filtering is the most effective method of linear noise suppression. The linear noise in shot gather appears to be non-linear because of the non-uniformity of offsets between traces in 3D seismic data processing. So using the F-K method can not eliminate the linear noise efficiently. The seismic data processing of Wellblock Nanka-1 is made, by application of pseudo-azimuth correction, the signal to noise ratio is increased. The quality of seismic data is then improved, combined with other processing measures. Finally, Nanka-1 structure is recognized by elaborate interpretation and plotting of the seismic data. References | Related Articles | Metrics

Discussion on Status and Direction for Inorganic Theory in China AN Zuo-xiang, MA Ji, PANG Qi-wei 2006, 27 (3):  361-365.  Abstract ( 138 )   PDF (361KB) ( 592 )   Save The problems in study of inorganic theory at present are discussed. It is pointed out that the research on inorganic theory is still in stage of geological demonstration. It should deflower from continental oil source theory and source-controlled theory, dealing with the origin environment and lithology of source rocks and then studying the migration and accumulation of hydrocarbons. Of course, the physicochemical features of inorganic oil source should be distinguished absolutely. The geologic analysis shows that in Xia-38 oilfield of Jiyang depression in Bohai Bay basin, diabase is a possible source rock and crude from it could be inorganic oil. In other depressions near Jiyang depression might find out the similar oilfields to Xia-38. To discuss the origin environment of diabase should not only be paid attention to the mantle plume, but also to the transport faults occurred during magma activation. Also, the geochemistry of light oil of Neogene in Bohai Bay basin is particularly researched in order to attain the geochemical evidences of inorganic sources. References | Related Articles | Metrics

A Review on Cold Heavy Oil Production Technology ZENG Yu-qiang, REN Yong, ZHANG Jin-liang, WANG Qin, LUO Ji 2006, 27 (3):  366-369.  Abstract ( 231 )   PDF (172KB) ( 621 )   Save Heavy oil is the important resource of 21st century. Producing heavy oil resource will be the important means to lessen the pressure resulted from crude oil shortage in the future. To economically and efficiently exploit heavy oils is of realistic and strategic meanings to China. Nowadays, the domestic heavy oil reservoirs are mainly exploited by steam injection process, but serious challenges come from sand problem, steam breakthrough and high production cost. The cold heavy oil production (CHOP) technology can be applied to form in-situ high permeable channels by mass sand inflow and allow the heavy oil to be produced by means of foam-oil effects. Field practices abroad indicate that this technology is better than others in terms of decrease of production cost and utilization of crude resources. References | Related Articles | Metrics

Discussion on Some Problems about Measurement of Aqueous Sample Density by the Criterion of SY/T5523-2000 CHEN De-en, MA Dong-chen, LIU Yong 2006, 27 (3):  370-371.  Abstract ( 141 )   PDF (124KB) ( 310 )   Save This paper makes discussion on such problems about the density measurements in The Method for Oil-Gas-Water Analyses by the criterion of SY/T5523-2000 as testing method, symbol of quantum, formula of calculation and temperature coefficient, etc. Some of them should be corrected for their concepts that are even contradicted with the basic laws of physics and mathematics. References | Related Articles | Metrics

Discussion on Insufficient Oil and Gas Sources of Triassic Reservoirs in Jinan Area, Tarim Basin DI Hong-li, ZHAO Ying-jie, LI Jian-jun, ZHAO Fu-yuan 2006, 27 (3):  372-374.  Abstract ( 150 )   PDF (345KB) ( 201 )   Save The core samples, lab analysis and formation testing and well production data are used to analyze the reason why oil and water occur in the same zone of Triassic oil layer-I in Jinan area. The insufficient oil and gas sources found in the Triassic system are discussed in terms of petroleum accumulation feature, spatial distribution and degree of filling in oil-gas reservoirs. The results indicate that whether layer-I oil accumulation or layer-II gas accumulation of Triassic, both are lacking in enough oil and gas sources. Some advices on further exploration are also given in this paper. References | Related Articles | Metrics

On Heavy Oils in Eurasia E. G. Yashenko, U. M. Palishuk 2006, 27 (3):  375-382.  Abstract ( 145 )   PDF (2175KB) ( 162 )   Save The basic features of heavy oil in Eurasia are reviewed as major backup resources for oil production in recent years. The spatial distribution of heavy oil domain in Eurasia is studied. The most heavy oils are distributed in East Europe and the western China. The rule of change of crude oil viscosity with depth shows that the highest viscosity of crude oil ranges mainly from 1000 m to 2000 m in depth. The viscosity of crude oil is declined with decrease of the buried depth. Following the relationship between the viscosity and the geological period of oil-bearing strata, this paper suggests that the highest viscosity of crude oils is distributed in Mesozoic strata, while the lowest viscosity of crude oils is in Proterozoic strata. Generally speaking, it is concluded that heavy oils in Eurasia are heavy, sulfurbearing, highly colloidal and highly bituminous, with low paraffin content and initial boiling point of 20℃. References | Related Articles | Metrics

A Study on Fracture Feature and Hydrocarbon Accumulation in Gasab Block of Melut Basin, Sudan HU Xin-bo, ZHANG Hai-xia, HU Rong, FU Zhan-xiang, YU De-zhen, ZHOU Hong-ying 2006, 27 (3):  383-386.  Abstract ( 156 )   PDF (632KB) ( 291 )   Save Based on relationship among the sizes of faults, continuity and hydrocarbon accumulation in Gasab block, it is pointed out that the distribution of reservoirs is determined by two northwest dominant faults and their adjust faults created by strike slip motion.The arrangement relationship among sand body distribution direction, the strike of dominant faults and the active intensity of edge water control the hydrocarbon enrichment. Gasab block based on these understandings is another incremental reserves area after Moleeta oilfield of the hundred million tons level was found in Sudan. References | Related Articles | Metrics