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01 October 2006, Volume 27 Issue 5 Previous Issue    Next Issue

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A Microphysical Interpretation of Genetic Mechanism of Immature Oil ZHOU Yan-ru 2006, 27 (5):  515-521.  Abstract ( 133 )   PDF (639KB) ( 473 )   Save The genetic mechanism of immature-low mature oils is explained using theories of chaos and dissipative structure in microphysics. The theoretic basis for genetic mechanism of immature oil and the theoretic model for organic negentropy reaction in microscopic mechanism of hydrocarbon generation are presented. The organic matter and its property for forming the immature oil are applied to demonstrate the microscopic mechanism of the hydrocarbon-generating from acidic non-hydrocarbon and neutral nonhydrocarbon in immature-low mature source rocks. The typical examples, biomarker's maturity index and ZYR rearranged sterane isomeride are discussed. Finally, the accumulation characteristics of immature oil are described in this paper. References | Related Articles | Metrics

The Karst Palaeogeomorphology of Carbonate Reservoir in Tahe Oilfield KANG Zhi-hong 2006, 27 (5):  522-525.  Abstract ( 116 )   PDF (707KB) ( 334 )   Save The Ordovician reservoir in Tahe oilfield is a karst-type carbonate reservoir formed by multi-stage tectonics and karstification. Its crack-cavity system is controlled by the karstification which is restricted by the palaeogeomorphology. Because Tahe oilfield is of deepburied feature and few well data, it is insufficient to describe the karst palaeogeomorphology of it in detail. This paper adopts error simulation method combined with the seismic and the drilling data to reconstruct it and develop the karst palaeogeomorphology model of early Hercynian orogeny in Tahe oilfield, based on two isochronal boundaries and studies in sequence stratigraphy. Finally, the karst highland and the karst slope are recognized, and the secondary pores-developed blocks are predicted. References | Related Articles | Metrics

Oil and Source Rock Correlation in Mabei Area in Northern Margin of Qaidam Basin PENG Li-cai, PENG Xiao-qun, WANG Li-qun 2006, 27 (5):  526-529.  Abstract ( 124 )   PDF (598KB) ( 197 )   Save Two kinds of crude oils occur in the different structures in Mabei area in northern margin of Qaidam basin. One is the oil broadly distributed in this area, including Mabei-1 Well, Mabei-101 Well, Mabei-3 Well and late filled oil in Mabei-2 Well. Such oils mainly originated from the source rocks of Middle Jurassic with distinction of maturity. The oil from shallow layer in Mabei-1 Well and Mabei-3 Well originated from Gaqiu sag, belonging to matured oil; while the oil from deep layer in Mabei-1 Well and Mabei-101 Well originated from Saishiteng sag, being highly matured oil. The other, biodegraded oil, was found in Mabei-2 Well, originating from transitional facies source rocks of Carboniferous in this area. References | Related Articles | Metrics

Condition of Hydrocarbon Accumulation in Tuonamu Area in Qiangtang Basin, Nor thern Tibet JIN Wei, WANG Cheng-shan, WU Xin-he, LI Ya-lin 2006, 27 (5):  530-534.  Abstract ( 87 )   PDF (582KB) ( 245 )   Save Tuonamu area adjacent to Qiangbei depression and the central uplift belt is a relatively stable structure area in Qiangtang basin, where develops Suowa formation and Xueshan formation of Upper Jurassic. The oil and gas shows are fractured bitumen vein, oilimmersed limestone and shale, indicating that there exists process of large-scale hydrocarbon generation, migration and accumulation as basic geologic conditions for forming oil-gas field or reservoir. The characteristics of reservoir rock and cap rock in this area indicate that they belong to medium-quality reservoir rock and medium-advantageous cap rock. The source-reservoir-cap rocks could be classified into three Class-II assemblages of IV1, IV2 and IV3, of which IV2 is the most favorable for exploration, IV1 is the better and IV3 is relatively poor. It is concluded that Tuonamu area is of good conditions for hydrocarbon accumulation such as advantageous source rock, medium maturity, multi-type reservoirs, good reservoir quality and developed cap rock. References | Related Articles | Metrics

The Geologic Feature and Hydrocarbon Accumulation of Niujuanhu Oilfield in Santanghu Basin GAO Gang, LI Hua-ming, LI Chuan, WANG Zhi-yong, JIANG Qing-chun 2006, 27 (5):  535-538.  Abstract ( 122 )   PDF (777KB) ( 189 )   Save The basic characteristics of oil-gas reservoir are presented, the deposition, reservoir-cap rock assemblage and hydrocarbon accumulation stages are analyzed and the process of hydrocarbon accumulation is dynamically recovered in Niujuanhu oilfield. It is shown that it is in good assemblage and its crude oil originates from lacustrine source rocks of Lucaogou formation of Upper Permian, dominated by low-mature oil. The Xishanyao formation of Lower Jurassic is characterized by fan delta, fluvial and lacustrine deposits with sandstone and glutenite, etc. and primary intergranular pore and intergranular dissolved pore, belonging to porous-type reservoir of low porosity and low permeability. Lucaogou formation is characterized by coastal lake, hemi-deep lake, volcanic eruption and fluvial deposits with pore, fissure and cavity, being fracture-pore-type reservoir. Its crude oil originates from both source and reservoir in itself, and its hydrocarbon accumulation occurs in several stages and durative and starts from Late Triassic, but the main stages are Late-Jurassic to Cretaceous. Jurassic reservoir is principally formed at Late Cretaceous. Himalayan movement period is significant to the preservation of different horizons of reservoirs in this basin. References | Related Articles | Metrics

Classification of Sequence Boundary of Member 2 of Sangonghe Formation in Hinter land of Junggar Basin ZHANG Fu-shun 2006, 27 (5):  539-541.  Abstract ( 69 )   PDF (423KB) ( 206 )   Save In view of the complex water-oil relations of lithology reservoir in hinterland of Junggar basin, the sequence stratigraphic classification and correlation are conducted by comprehensive researches of core, logging, well logging and seismic profile. The result shows that a sequence boundary is identified inside member 2 of Sangonghe formation of Lower Jurassic, which is characterized by lithology of scour surface and conglomerate and gravel bearing gritstone over it, and by well logs of abrupt contact. The boundary can be identified and traced for correlation on the gamma inverse profile. In HST beneath the boundary have good interconnecting sand body, poor lateral sealing, and no oil shows; in LST and TST above it have delta distributary channel sand reservoir with serious heterogeneity and good lateral sealing, being oil layer. Hence, tracing this boundary and searching for the delta distributary channel sands in LST and TST will be the key for petroleum exploration in this area. References | Related Articles | Metrics

Approach to Liupanshan Arc Thrust System in Ordos Basin ZHANG Gui-song, ZHANG Jun, REN Jun-feng, WANG Xin 2006, 27 (5):  542-544.  Abstract ( 70 )   PDF (463KB) ( 236 )   Save Liupanshan arc thrust system in Ordos basin is located at the joint between Qinqi geosynclinal system and North China platform, featuring special tectonic location and complex geology. The comprehensive analyses from strata distribution, gravity, geomagnetism, seismic and CEMP data show that the thrust structural belt in western margin of Ordos basin is composed of Liupanshan arc thrust system and Zhuozishan-Helanshan thrust system, which are two independent nappe tectonic systems. Liupanshan arc thrust system is a nappe formed by Qilian terrain splicing to North China epicontinental terrain located in western Ordos block, with distinct dual-terrain superposed textures. It is suggested that west boundary of North China platform should be changed toward Zhongwei-Haiyuan-Baoji direction, and assumed that in deep Liupanshan basin may develop the basement of North China and the cap rocks of Paleozoic, which supports ideas for petroleum exploration beyond Ordos basin and finding out other natural gas-enriched strata of Paleozoic similar to Ordos basin. References | Related Articles | Metrics

Prospects for Deepwater Oil and Gas Exploration in Qiongdongnan Basin LIU Jun, WANG Hua, JIANG Hua, XIAO Jun, GAN Hua-jun 2006, 27 (5):  545-547.  Abstract ( 83 )   PDF (650KB) ( 377 )   Save In recent years, the hydrocarbon prospecting activities in deepwater areas in the world are endlessly ongoing, for abundant oilgas resources are found there. Nowadays, most large oilfields in such areas are found in passive margin basins in Atlantic Ocean. The central depression belt in Qiongdongnan basin is located in the marginal deepwater area in the South China Sea, which features the similar structures and deposit evolutions compared with the marginal deepwater areas abroad where oils have been discovered. Study shows that this belt is provided with fundamental geologic conditions shaping a large oil-gas field, in view of source rock, reservoir rock, trap, migration and accumulation, and hopeful to explore enriched hydrocarbon resources. References | Related Articles | Metrics

Hydrothermal History and Hydrocarbon Generation History in Northeastern Sichuan Basin LU Qing-zhi, GUO Tong-lou, HU Sheng-biao 2006, 27 (5):  549-551.  Abstract ( 62 )   PDF (243KB) ( 200 )   Save Based on the hydrothermal history reconstruction and the estimation of erosion thickness, the hydrocarbon generation history is investigated for Permian and Upper Triassic source rocks in northeastern Sichuan basin. The study shows that the paleo-heat flow value was reached to the top (62~70 mW/m2) at early stage of Late Permian, and then decreased to the present value (averaging 45 mW/m2, bottom-hole heat flow). The maximum erosion thickness occurred on Mesozoic-Cenozoic unconformity averaging 2 100 m. The hydrocarbon generation stage of Permian source rocks occurred during Early Triassic, Late Triassic and Early-Middle Jurassic; while that of Upper Triassic source rocks appeared during Middle-Late Jurassic and Late Cretaceous. References | Related Articles | Metrics

The Hydrocarbon Accumulation Conditions of Neogene in Yiliping Area of Qaidam Basin JIANG Gui-feng, KONG Hong-xi, XU Zi-yuan, HOU Ze-sheng, CAI Yun-lan, LI Yan-ping 2006, 27 (5):  552-555.  Abstract ( 67 )   PDF (422KB) ( 159 )   Save The dominating factors controlling hydrocarbon accumulation of Neogene are determined by analyses of the source-reservoircap rocks and traps in Yiliping area. The result shows that the source rock assumes dark mudstone in $N^{1}_{1}$ zone and $N^{2}_{1}$ zone, dominated by humic-type organic matter of relatively low abundance, maturity threshold depth of 2 800 m; the reservoir rock is characterized by siltstone; the traps are anticline and faulted anticline. The major hydrocarbon-generating stage of Neogene source rock well matches the period of trap formation, shaping the original hydrocarbon accumulation mode of internal storage, according to study of the structural evolution history, sedimentation history and hydrocarbon generation history. It is concluded that Jianshan and Jianshishan in this area could be regarded as exploration targets in the near future. References | Related Articles | Metrics

Compensation Method of Seismic Wave Absorption and Attenuation in Viscoelastic Media ZHENG Hong-ming, XUE Wei-ping, JIANG Lin, GU Li, PENG Yong, WANG Zhong-jun, DONG Liang-guo 2006, 27 (5):  556-558.  Abstract ( 79 )   PDF (533KB) ( 256 )   Save The high frequency part of seismic wave propagation in subsurface is easy to be absorbed or attenuated. The study of mechanism of the seismic wave absorption and attenuation is conducted in order to partly compensate the high frequency part that is absorbed and attenuated. In fact, this complex mechanism is hardly to be described or compensated using a simple mathematic model and seismic instrument. However, the compensation is still of significance in improving the inverse resolution of geological structure and lithologic distribution. The absorption and attenuation of seismic wave propagation is not only related to lithology, but also depended on the complicated propagation path with non-vertical self-transmitting and self-receiving. It is concluded that studying the compensation method of seismic wave absorption and attenuation along its propagation path is more precise and closed to the real conditions than available single-trace compensation technique as a conventional or fundamental method. References | Related Articles | Metrics

Correction of Well Logs in the Case of Severe Borehole Enlargement SUN Zhong-chun, GU Zhen-gang, LI Jun, YANG Bin 2006, 27 (5):  559-561.  Abstract ( 87 )   PDF (570KB) ( 199 )   Save In order to improve the quality of synthetic seismic records, this paper presents two correction methods for logs correlation calculation and logs forward calibration using sonic-density logging suite. The sonic logging is applied to the correction of density logs in condition of less distortion of compensated sonic logs; the density logging is used to the correction of logs in the case of severe distortion of sonic and density logs. The results applied to the quality improvement of synthetic seismic records in Junggar basin indicate the obvious effects of these methods. References | Related Articles | Metrics

Re-Processing of 3D Seismic Data—An example of District NO.4-(2) in Karamay oilfield LI Jia-ning, HU Xue-lei, SONG Yu-mei, LI Lu 2006, 27 (5):  562-563.  Abstract ( 69 )   PDF (571KB) ( 195 )   Save The 3D seismic data from District No.4-(2) in Karamay oilfield is mostly characterized by such poor quality as extremely low signal/noise ratio, serious surface wave and pulse interference, few effective reflection information, distinct pulse noise and undeveloped round trip echo in shallow, middle and deep strata, etc. All these bring great difficulties for the data processing. This paper adopts FOCUS and GRISYS for seismic data processing to prestack noise removal, DMO stack noise removal, prestack F-X field pre-filtering, deconvolution test, 3D RNA for improving signal/noise ratio and PR one-step migration technique, etc., and very good results have been gained. References | Related Articles | Metrics

Application of Weibull Model to Oilfield Development CHEN Gang-hua, GE Sheng-quan 2006, 27 (5):  564-566.  Abstract ( 83 )   PDF (260KB) ( 245 )   Save Prediction of production rate and reserves is a very important task during oil-gas field development. Weibull model for prediction of oil-gas field production rate is presented, including the basic correlations and its property. Dual linear simulation method for solving the model parameters is proposed. The practicability and validity of this model is verified by case study. Also, it is recognized that Weibull model is a generalized Wengcycle model in fact. This model not only adapts to the variation of oil-gas field production rate with single peak, but also to the declining case of oil-gas field production rate. References | Related Articles | Metrics

Productivity Behavior of Low Permeability Reservoirs LI Chuan-liang, YANG Xue-feng 2006, 27 (5):  567-568.  Abstract ( 75 )   PDF (113KB) ( 176 )   Save Natural productivity of low-permeability reservoirs is quite low. If wells produce at natural productivity, their flow rates decline with the same speed as the mid-and high-permeability reservoirs. It wells produce at higher rate than their natural productivity, the flow rates will certainly decline with higher speed, which is the inevitable result of earlier exploitation and late voidation of reservoirs. High speed declinationof flow rates of low-permeability reservoirs are not related to stress sensitivity in reservoir rocks. References | Related Articles | Metrics

A New Growth Curve for Forecasting Production of Oil-Gas Field HU Jian-guo 2006, 27 (5):  569-571.  Abstract ( 76 )   PDF (245KB) ( 210 )   Save This paper simplifies the existing growth curves based on their practical applications and develops a new growth curve model with more simplification of calculation procedure. It is used for forecasting the middle or long-term production and recoverable reserves of oil-gas reservoirs. The case study shows its high reliability and high accuracy. References | Related Articles | Metrics

New and Practical Waterdrive Characteristic Curves WANG Nu-tao, LUO Zhi-feng, HUANG Bing-guang, LUO Xing-wang, JIANG Jun 2006, 27 (5):  572-574.  Abstract ( 96 )   PDF (436KB) ( 280 )   Save Waterdrive characteristic curve is an important method for forecasting production rate and commercial reserves of waterflood field. There are many types of waterdrive characteristic curves presented by scholars at home and abroad. As the complexity of oilfield development, it is difficult to describe them quantitatively. Each type-curve is only suitable for particular water cut stage rather than the whole process of oilfield development. The curves widely applied in China are four types of A, B, C and D, based on which AB and CD type-curves are proposed in this paper. The case study demonstrates that these type-curves are good accordance with real data and possess simplicity, practicability and reliability. References | Related Articles | Metrics

A Study on Rheology Property of Emulsion of Crude Oil ZHANG Feng, QIN Ji-shun, ZHANG Xing, SUN Ren-yuan 2006, 27 (5):  575-577.  Abstract ( 108 )   PDF (235KB) ( 363 )   Save Viscosity of water-oil emulsion is an important parameter for oilfield development, which should be measured in condition of high temperature and high pressure using rheometer, when matching the formation conditions of an oilfield. The study shows that the point of reverse phase of water-oil emulsion occurs at water cut from 40% to 60%, by which the mathematical model for the emulsion viscosity prediction is developed. The viscosity variation is accordant with Gaussian and Lorentzian functions. That is, the viscosity of water-oil emulsion will be decreased with increase of gas-oil ratio, similar to the law of gas-free emulsion viscosity at normal temperature and pressure. These results provide the theoretical bases for oilfield development. References | Related Articles | Metrics

A Study on Automatic Matching of Gas-Well Production Decline in Abnormal Pressure Gas Reservoir LIANG Bin, ZHANG Lie-hui, LI Min 2006, 27 (5):  578-580.  Abstract ( 77 )   PDF (217KB) ( 199 )   Save The mathematic model of automatic matching of gas-well production decline for abnormally pressured gas reservoir is developed, based on LM's automatic matching of production decline, combined with the regression analysis. This model can be used to determine the permeability, porosity, net pay thickness and OGIP without chart matching. In order to improve the prediction precision, a way of acquiring the formation parameters is adopted by firstly removing the unsteady production data followed by the automatic matching technique. Also, the standard for verifying the calculated results is proposed for application of this model. References | Related Articles | Metrics

A Study of Asphaltene Deposition Caused by CO2 Injection in Reservoirs JIA Ying, SUN Lei, SUN Liang-tian, HUANG Lei 2006, 27 (5):  581-584.  Abstract ( 107 )   PDF (517KB) ( 236 )   Save Based on the investigation of comprehensive literatures about the asphaltene deposition caused by CO2 injection in reservoirs at home and abroad, the development of experiments and numerical models are summarized and their advantages and disadvantages are compared, and the properties of asphaltene deposition are analyzed. Finally, the suggestions of related directions of the researches are proposed in this paper. References | Related Articles | Metrics

A New Model for Production Decline Prediction of Oilfield ZHU Yi-dong, SUN Wei-quan, LIAO Jian-hua, RONG Ning 2006, 27 (5):  586-587.  Abstract ( 75 )   PDF (102KB) ( 171 )   Save Arps decline curve is a well-known reservoir engineering method for prediction of production decline low of oilfield. Also, there are many other predicting methods available in China, which allow such methods to be more perfect in technique, more widespread in applied field, and higher precision in prediction. Based on theory of simple harmonic oscillation in physics, this paper presents a novel model for production decline prediction given by deformation of critical damping oscillation equation which is predigested to Arps exponential decline form. The case study indicates that this model can be used for field production decline prediction as a guide for oilfield development and management. References | Related Articles | Metrics

Research on Water Production Law of Reservoir with Thin Thickness and Bottom Water Using Relative Permeability Curve JIANG Bing-jin, TANG Hai, LV Dong-liang, WANG Wei-dong 2006, 27 (5):  588-589.  Abstract ( 82 )   PDF (138KB) ( 212 )   Save The normalized processing of relative permeability data of cores is conducted to get the average relative permeability curves which have be regressed for the particular formula of Kro /Krw vs Swd of the reservoir. The waterflood characteristic curve equations of reservoir are then deduced theoretically. For thin layer reservoir with bottom water (water-free oil rate is close to zero), the linear equations between the logarithm of water/oil ratio and the recovery percent of OOIP are further deduced. The case study shows the theoretically calculated results are very close to the real water production of such a reservoir. So these deduced equations can be applied to predict the water production laws of thin layer reservoirs with bottom water. References | Related Articles | Metrics

Evaluation of Gas Pool with Closed and Restricted Water Energy DING Liang-cheng 2006, 27 (5):  591-592.  Abstract ( 99 )   Save The gas pools exploited in Shengli oilfield mainly belong to lithologic traps controlled by fractures and lithology, with closed and size-restricted water. Their performances in process of development are characterized by low water production and low water/gas ratio. This paper presents the dynamic evaluation method for calculation of water energy, based on the performances and material balance theory. The case study indicates that the calculated result by this method is reliable and practicable. References | Related Articles | Metrics

Application of Gompertz Model to Prediction of Solution Gas Development Index in Oilfield XU Yao-dong, DING Liang-cheng, DU Yu-shan, DONG Xiao-yan 2006, 27 (5):  593-594.  Abstract ( 103 )   Save The Gompertz model is derived based on differential equation of growth-type curve, in order to get a method for prediction of production rate, accumulative production rate, recoverable oil, peak annual production rate and corresponding time of solution gas in oilfield, and determine the valid applicable range in field. Taking Shengtuo field in Shengli oilfield as an example, the applied result of Gompertz model to prediction of solution gas production rate and reserve is analyzed. It is shown that this model can be used to predict development index of oil-gas field with some precision and reliability when the development characteristics of oilfield meet some conditions. References | Related Articles | Metrics

A New Method for Single-Point Well Test Data Processing XU Jin-jin, LI Zhi-ping, CEN Fang, LAI Feng-peng, HUANG Zhi-wen, WANG Shu-ping, ZOU Cun-you 2006, 27 (5):  595-596.  Abstract ( 113 )   Save When processing of data from single-point test, the value of αis generally taken by 0.25 for calculating the open flow potential of gas well, and the result is far from that from modified isochronal test. This paper deduced the relationship between α and other related parameters using data from single-point test in non-steady state, by which the accurate open flow potential of gas well is then gained for its proper value of α. The case study indicates that such a method is more reliable than before, and provides more precise bases for further open flow potential estimation and proration measures implementation. References | Related Articles | Metrics

Application of Virtual Reality Technique to Petroleum Exploration in Tahe Oilfield YANG Li-qiang, DONG Ning, WU Chang-wu, ZHAO Ting-shou 2006, 27 (5):  597-599.  Abstract ( 87 )   Save The basic concept of the theory of virtual reality technique and its software and hardware are presented. The feature and function of Petro-One of the virtual reality system in petroleum industry are discussed and introduced into the petroleum exploration study of carbonate reservoir in Tahe oilfield, which is characterized by large buried depth, weak seismic reflection signal and high heterogeneity. On the basis of multi-well spatial calibration, the fine structural interpretation in virtual environment and the multi-attribute analysis are adopted to horizon tracking and reservoir prediction, respectively. 3D visualization and description are conducted for large-scale fracturevug system of Ordovician in Tahe oilfield. The carbonate reservoir prediction is made using well data. Finally, the prospects of development and application of such a virtual reality system are discussed. References | Related Articles | Metrics

Application of Fluid Inclusion to Research of Oil-Gas Accumulations in Junggar Basin LI Wei, ZHANG Zhi-huan, YANG Yong-cai, MENG Fan-wei, HUANG Yu-ying, QIN Li-ming 2006, 27 (5):  600-603.  Abstract ( 90 )   PDF (498KB) ( 186 )   Save The saline inclusions in the authigenic minerals of sandstone reservoirs of Jurassic from two wells in Block-1 of center Junggar basin are measured by synchrotron radiation X-ray microprobe techniques. Some element contents, such as K, Ti, Mn, Fe, Ni, Cu and Sr, are calibrated by NIST SRM 612 typical sample. The results show that the microelement contents (except for Fe) of saline inclusions of Well Zhuang-1 and Well Zheng-1 are distinctly different. It is predicted that the reservoirs of Jurassic in Well Zhuang-1 and Well Zheng-1 are different in hydrocarbon accumulation and oil source, for their fluid properties are in big difference. The analysis of the homogenization temperature and the oil-bearing fluid inclusions of whole core confirm the conclusion above. References | Related Articles | Metrics

Application of CRS Stack to Seismic Imaging in Complex Area QIN Tian, JIA Ming-chen, LING Xun, ZHOU Zuo-ming, LIU Quan-yan 2006, 27 (5):  604-606.  Abstract ( 88 )   PDF (752KB) ( 234 )   Save Common Reflection Surface (CRS) stack, a new stacking technique compared with conventional common midpoint (CMP) stack, is a zero-offset profile imaging method independent of macro-model. CRS stack depends on determination of three wave-field attributes, makes a summation using reflections along the stack surface, and increases the stacking numbers from Fresnel zone, in order to boost up signal energy and improve the stack imaging quality. The real seismic data processing indicates that this method can increase both the ratio of signal to noise in profile and the continuity of reflective events. References | Related Articles | Metrics

Application of EMI Image Logging to Study of Sedimentary Facies—An example of Lower Wuerhe conglomerate reservoir of Upper Permian in Karamay oilfield XING Feng-cun, ZHU Shui-qiao, KUANG Hong-wei, AN Zhi-yuan, LIU Ya-ming 2006, 27 (5):  607-610.  Abstract ( 71 )   PDF (633KB) ( 226 )   Save EMI image logging technique is used for study of the sedimentary facies of Lower Wuerhe conglomerate reservoir in District No.8, Karamay oilfield, which deals with the loss and misplacement of some sedimentary information caused by the vertical discontinuity of core, short core, core break, leakage and misplacement as well as no direction of core. The characters of EMI image logging about lithology and sedimentary structure by comparison between the core data and EMI image logging data. The regressive sand wave crossbedding, which cannot be found in the core data, is identified in the studied area for the first time, based on which the features of the EMI image logging of microfacies of fluvial-dominated fan delta deposits in the target zone of District No.8 in Karamay oilfield are discussed. And the EMI image logging features of such microfacies as grain-flow deposit, channel deposit, natural levee deposit, interchannel deposit, mud-rock flow and debris flow are then presented in this paper. The grain-flow deposit is identified for the first time, which isn't found in the core data. Also, the application of EMI image logging data to the distribution and evolution of sedimentary facies and the source direction of the target zone is discussed. References | Related Articles | Metrics

The Earth Stress Calculation Using Well Logging Data in Dina Gas Field of Xinjiang YAN Ping, SUN Jian-meng, SU Yuan-da, LI Zhao-cheng, CHENG Rong-hong, WANG Huan-zeng 2006, 27 (5):  611-614.  Abstract ( 88 )   PDF (488KB) ( 182 )   Save The earth stress distribution and influenced factors in Dina gas field in Xinjiang are analyzed. The parameters required for earth stress calculation are determined, such as the rock mechanics and the inherent rock strength using well log data and available results. Using well log data to analyze earth stress is not only to quickly get the stress profile spreading along the depth, but also to save high cost for measurement. Furthermore, the horizontal stress direction of the target zone in the gas field is determined by means of borehole breakout data, drilling-induced fracture and DSI Fast shear azimuth. References | Related Articles | Metrics

Application of Ar tificial Earthquake Stimulation to Kar amay Oilfield XU Chun-mei 2006, 27 (5):  615-616.  Abstract ( 77 )   PDF (188KB) ( 169 )   Save As a new technique for tertiary oil recovery or EOR, artificial earthquake stimulation is increasingly valued for its quick response, high efficiency, non-pollution to well and influence-free on regular production of oilfield. Its principle is that the using vibroseis, the high frequency ray produced from seismic ray which acts on the strata may allow to produce cracks or fractures and to form some new channels for hydrocarbon migration, thus further improving the reservoir quality and physiochemical property of crude oil for the purpose of increasing production rate. This paper introduces the very obviously practical results using this stimulation to Karamay area for EOR performed by Xinjiang Oyasa Mineral Exploration Company Ltd. It is indicated that the artificial earthquake stimulation is worth popularizing in the future. References | Related Articles | Metrics

Frequency and Scope of Fluid Migration during Active Tectonic Movement WANG Peng-yan, XIONG Sheng-qiang 2006, 27 (5):  617-620.  Abstract ( 76 )   PDF (468KB) ( 172 )   Save An active tectonic movement changes the space shape of stratum and result in periodic stress concussion, which will influence hydrocarbon migration and accumulation as fluid deposit in stratum. Taking Kuqa depression as an example, the geologic analysis and earthquake phenomenon observation are made by means of modern earthquake theory, and the mechanism, frequency and scope of fluid migration promoted by a tectonic movement are discussed in this paper. The study shows that dynamic effect and static effect brought by tectonic movement play an important part in hydrocarbon migration and accumulation. Particularly, the earthquake pumping effects during active tectonic movement allow its single influence scope to outclass that by itself. Hence such high frequency and high intensity of periodic stress changes should promote the migration and accumulation of hydrocarbons in Kuqa depression. References | Related Articles | Metrics

Evaluation and Constraint Principle for Dominant Stochastic Modeling Technique JIANG Hui, YU Xing-he, ZHANG Xiang-xiang 2006, 27 (5):  621-625.  Abstract ( 90 )   PDF (174KB) ( 192 )   Save Stochastic modeling technique could be classified based on research target, stochastic model and constraint condition as well as its different applications and focuses into geologic, mathematic and logic concepts, respectively. This paper focuses on Boolean simulation, sequential indicator simulation, fractal simulation, annealing simulation and Markov random field simulation, which are quite popular domestically and internationally at present, and presents their advantages and disadvantages as well as corresponding evaluations. Four principles are summarized to improve precision of the stochastic modeling in terms of the constraint of equivalent time and classified levels, the constraint of depositional conditions, the constraint of statistical probability and the constraint of optimal stochastic models. References | Related Articles | Metrics

Positive Effect of Formation Water on Conservation of Natural Gas CHENG Fu-qi, JIN Qiang, JIANG Gui-feng, ZHANG Yong-mei, HOU Ze-sheng 2006, 27 (5):  626-628.  Abstract ( 114 )   PDF (132KB) ( 132 )   Save Based on the experimental and measured data, the positive effect of formation water on conservation of natural gas is discussed.The case study shows that first, the existence of pore water could change the pore structure of mud, increase its displacement pressure, decrease its diffusion coefficient, thus effectively prevent natural gas from leaking and diffusion out of reservoir; second, plentiful formation water provides good storage space for natural gas, and avoids escape of early generated gas, thus adding possibility of natural gas accumulation; third, the existence of formation water allows natural gas to be accumulated in forms of solution state and hydrate for shaping non-conventional gas pool. Therefore, formation water is favorable for extension of space of gas accumulation, hence enlarging the scope or area for natural gas exploration. References | Related Articles | Metrics

Origin Discrimination of CO2 Gas Pools in Jiyang Depression DU Ling-tong, LV Xin-biao, CHEN Hong-han 2006, 27 (5):  629-632.  Abstract ( 90 )   PDF (284KB) ( 216 )   Save The origin discrimination of CO2 gas pool is mainly based on CO2 volume ratio, δ13C, R/Ra and CO2/3He, etc. It is believed that six CO2 gas pools found in Jiyang depression are identified to be inorganic origin ones based on these indices, of which Pingfangwang gas pool originated from CO2 with nearly equal proportion of mantle and crust compositions; Pingnan gas pool has more crust composition; Huagou, Gaoqing and Yang-25 Well gas pools have more mantle compositions. References | Related Articles | Metrics

Evaluation on Probability of Oil-Gas Field Numbers in Petroliferous Basin with Low Degree of Prospecting V. R. Livshits 2006, 27 (5):  633-642.  Abstract ( 95 )   PDF (2690KB) ( 130 )   Save The total numbers of oil-gas fields in a petroliferous basin are calculated by means of Weibull method. The statistical characteristic reflecting oilfield number and the equations related to Paleto's truncated distribution parameters are adopted. Based on the reserves available in given giant oil-gas fields, the methods for calculating the numbers of oil-gas fields are presented, and their statistical characteristics are determined. References | Related Articles | Metrics

Analysis of Influencing Factorson CO2 Stimulation Response in Palogue Oilfield of Sudan MEI Shi-sheng, YANG Zheng-ming, LIU Xue-wei 2006, 27 (5):  643-645.  Abstract ( 110 )   PDF (365KB) ( 198 )   Save The experimental research is made on application of CO2 stimulation process to Samaa heavy oil reservoir with high porosity and high permeability in Block 3/7 in Palogue oilfield of The Republic of Sudan, which includes the effects of CO2 injection rate, soak time and flowing bottom hole pressure on this process. The study shows that soak time has a restricted effect, but flowing bottom hole pressure has a big effect on it; there exist optimum CO2 injection rate; multiple pressure drawdown and anterior three cycles of CO2 stimulation will get a good response. It is concluded that proper CO2 injection rate, reasonably controlled flowing bottom hole pressure and making multiple pressure drawdown will obtain better responses in a few cycles of CO2 stimulations. These results could be as a guide for field application and design of CO2 stimulation process in Samaa heavy oil reservoir. References | Related Articles | Metrics