Table of Content

01 April 2007, Volume 28 Issue 2 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Reference Manager ProCite BibTeX RefWorks

Toggle Thumbnails

Petroleum Geology and Exploratory Targets in Marginal Basins, Northern South China Sea HE Jia-xiong, SHI Xiao-bin, YAN Pin, HUANG An-min, ZHANG Shu-lin, LIU Hai-ling 2007, 28 (2):  129-135.  Abstract ( 107 )   PDF (262KB) ( 199 )   Save This paper presents the petroleum exploration history and geologic research results in marginal basins of northern South China Sea, and based on the abundant geologic, geophysical and geochemical data, analyzes and summarizes the different basinal geologic features, the regional structural background for oil-gas migration and accumulation and the exploratory potentials or targets in this area. In light of low degree of prospecting and research as well as complex geologic condition for hydrocarbon accumulation, the research of hydrocarbon migration and accumulation and the exploratory direction in this area will be in further exploration. References | Related Articles | Metrics

Characteristic of Hydrocarbon Accumulation of Chepaizi Swell in Junggar Basin SONG Chuan-chun, HE Lun-jun, MA Li-gun, REN Hai-ning, ZHU Guang 2007, 28 (2):  136-138.  Abstract ( 94 )   PDF (260KB) ( 294 )   Save It is indicated from drilling that Chepaizi swell is characterized by multiple oil-bearing zones, multiple reservoir types and multiple oleaginous grades. The "tri-multiple" characteristics are related to the cutting of structural framework, the control of sedimentary cycle and hydrocarbon-accumulating stage and the charging of multi-directional oil sources in terms of correlation and analysis of sedimentary strata, structural evolution and source rocks. The existence of paleo-ridge in SE direction of southern Chepaizi swell and the development of paleo-ridge in ES direction of northern Chepaizi swell allow the feature to be different, that is, in southern part the shallow Tertiary reservoir is dominated by late stage light oil accumulation and in northern part the Carboniferous-Jurassic reservoirs are characterized by heavy oil distribution and late reconstruction. References | Related Articles | Metrics

The Buried Hill Paleogeomorphology and Reservoir Characteristics in Slope Belt of Eastern Damintun Sag WU Dong-sheng, XU Zhen-mei, CHEN Gong-yang, DENG Li-fa 2007, 28 (2):  139-142.  Abstract ( 83 )   PDF (377KB) ( 197 )   Save The buried hill paleogeoomorphology in Damintun sag is resulted from both basement fault block differential lift and weathering erosion. It controls the distribution of remained buried hill strata and affects the distribution of overlying Fangshenpao formation and Sha-4 member. This paper analyzes in detail the contact relationship among the buried hill strata and predicts from the thickness and seismic data of Fangshenpao formation and Sha-4 member that there exist four combinations of lithologic parameters: Type I represents the Archaeozoic metamorphic rocks, reflecting the uplift area of buried hill paleogeomorphology; Type II the Mesozoic sandstone and conglomerate, reflecting the depressed area; Type III and Type IV reflect its slope belt with lithology of Proterozoic carbonate rocks. In plane, Type I, III and IV combinations are favorable areas of reservoir development. References | Related Articles | Metrics

Distribution of Residual Pressure and Oil-Gas Migration and Accumulation Conditions of Yanchang Formation in Ordos Basin LIU Xiao-qi, DENG Hong-wen, LI Qing-bin, REN Guo-xuan 2007, 28 (2):  143-145.  Abstract ( 81 )   PDF (268KB) ( 204 )   Save The distribution of fluid residual pressure of Mesozoic strata in Ordos basin is studied based on the equilibrium depth method. The residual pressure presented in each well of the studied area is mostly distributed in Chang-7, followed by Chang-6, Chang-4+5 and Chang-8 in turn. The study shows that most oil fields are found in plane in the low-value belt of residual pressure of the corresponding oil layers, and vertically in the relative low-value belt of abnormal pressure segments as well as the normal pressure ones, by which the oilgas migration and accumulation conditions of Chang-7 layer are analyzed. It is pointed out that Ansai and Yanchi are the oil accumulated areas of Chang-2, the east of Longdong-Baibao-Jingbian is the target area of Chang-6 oil migration and enrichment, while Longdong, Baibao and Jingbian are the target areas of Chang-8 oil migration and enrichment. References | Related Articles | Metrics

Classification of Crude Group in Ying'er Sag and Its Exploratory Significance HAN Yong-ke, ZHANG Li, HAN Xiao-song, YANG Zhi-ming 2007, 28 (2):  146-149.  Abstract ( 107 )   PDF (161KB) ( 182 )   Save The crude oil from Ying'er sag in Jiuquan basin features similar nature in geochemistry, but it can be divided into three groups based on given oil group, light hydrocarbons and biomarker data integrated with geologic productive reservoir of the crude oil. The oil source correlation shows that these groups are related to the source rocks in Zhonggou formation, Lower Xiagou formation and Chijinbu formation. The three sets of self-existent hydrocarbon accumulation systems in Ying'er sag should be paid more attention to during further exploration in this area. References | Related Articles | Metrics

The Fractural Distribution of Carboniferous Reservoir in Wubaiti Area in Eastern Sichuan Province WEI Qin-lian, ZHAO Ping-hai, FU Shun 2007, 28 (2):  150-153.  Abstract ( 98 )   PDF (270KB) ( 266 )   Save Based on the field geologic survey, core observation and well logging fractural identification, it is shown that in the tight reservoir in Wubaiti gas pool of eastern Sichuan developed structural fractures controlled by local structure. Experimental analysis indicates that petrophysical property, dynamic nature of rocks and stress field intensity of structural deformation are the main geologic factors controlling the fractural development in this area. The fracture in studied area can be divided into diagenetic micro-facture, weathering fracture and structural fracture. According to real geologic situation, the preliminary evaluation of the structural fracture development in the studied area is conducted by means of structural stress simulation method in this paper. References | Related Articles | Metrics

The Drilling Efforts and Significance of Ordovician in Guchengxu Uplift of Tazhong Area WU Guang-hong, LI Bing, ZHOU Xin-ke, FENG Yong-hong, WANG Wei, HUANG Hua, HU Yong 2007, 28 (2):  154-157.  Abstract ( 88 )   PDF (376KB) ( 223 )   Save Guchengxu uplift located in the east side of central uplift in Tarim basin indicates that the Ordovician strata are complete, and the grain limestone and porous-type reservoirs in Yijianfang formation of Middle Ordovician-Yingshan formation of Lower Ordovician are newly discovered in this area. The reservoirs rocks are characterized by intergranular pores, intercrystal pores and pinpoint-like solution pores, with micro-fissures and sutures as channels, shaping 2~50 m thick and wide spreading layered porous-type reservoirs with 4 percent of porosity given by the interpretation of imaging logging data. The study shows that such reservoirs were mainly controlled by distribution of tableland marginal sand-bank facies, and post-solution was advantageous to improvement of their storage performances; the good reservoir-cap rock assemblage was formed by the grain limestone reservoirs and overlying shale of Upper Ordovician as the regional cap rocks; the good sealing nature allowed to shape multilayer and potential reservoirs under multistage fillings of highly matured hydrocarbons in the source area. Gas flow from a well drilled and completed in this area by drillstem test has fully revealed its tremendous potentials for petroleum exploration here. References | Related Articles | Metrics

The Miocene Ostracoda and Paleoenvironment in Jianshishan Area of Qaidam Basin JI Li-ming, JIANG Gui-feng, ZHU You-hua 2007, 28 (2):  158-162.  Abstract ( 87 )   PDF (369KB) ( 239 )   Save Based on analysis of micropaleontology on the cuttings and core samples from Jianshi Well 1 in Jianshishan area of middle Qaidam basin, a few ostracoda fossils dominated by Eucypris obtus and some others like Eucypris stenoformi, Cyprideis and Cyprinotus (Heterocypris) have been found in the Upper and Lower Youshashan formations. The era distribution of these fossils indicates that the strata with ostracoda in this well belongs to Miocene, abundant Cyprideis-bearing strata should be the top boundary of Lower Youshashan formation. The ecological distribution of the ostracoda shows that the sedimentary environment of Upper Youshashan formation and Lower Youshashan formation belongs to seldom-real brine lake, and the former is more salty than the latter. From Miocene to Pliocene, the lake was transported eastward and underwent the evolution from shallow to deep, then to shallow with brine being gradually salty in this area. References | Related Articles | Metrics

The Organic Maceral Characteristic of Yanchang Source Rock in Ordos Basin KONG Qing-fen 2007, 28 (2):  163-166.  Abstract ( 114 )   PDF (480KB) ( 298 )   Save From the viewpoint of organic petrology, combining kerogen method with bulk rock, this paper classified the organic macerals of Yanchang formation high-quality source rock in Ordos basin into 4 groups as follows: sapropelinite, exinite, vitrinite and inertinite. The classification is based on petroleum industry standard and takes account of the characteristic that the optical variance of the hydrogen-rich macerals is obvious during the thermal evolution at the same time. As the most primary maceral of Yanchang formation, the sapropelinite indicates that lake alga is predominant parent material. In addition, it is confirmed that the existence of sapropel particulate vitrinite means deoxidized depositional environment and intense micro-degradation, as well as that high-quality source rock has entered remarkable hydrocarbon-generating stage, which offers evidence for classification of thermal evolution stage of organic matter. References | Related Articles | Metrics

Application of Absorption Coefficient to Oil-Gas Prediction in Southeastern Sichuan Area NING Song-hua 2007, 28 (2):  167-169.  Abstract ( 83 )   PDF (312KB) ( 300 )   Save The absorption coefficient of strata is controlled by elastic property of rock matrix, also by the properties of porosity and pore fluid. In addition, it is an important parameter reflecting oil-gas bearing property of reservoir rocks. The variation of the absorption coefficient can be used to trace oil-gas bearing reservoir rocks, especially gas pools. This paper presents the processing results of poststack seismic data in an area of southeastern Sichuan province, obtaining the 3D absorption coefficient database. And the analysis indicates that the coefficient of gas zone is bigger than that of non-gas zone. It is concluded that the comprehensive analysis from these results, combining with geologic, drilling and well logging data, could better delineate the distribution scope of oil-gas bearing zone for the purpose of prediction of oil and gas reservoirs. References | Related Articles | Metrics

Applying Frequency Spectral Analysis to Identify Milankovitch Cycle and Calculate Sedimentation Rate of Cretaceous in Wushi Sag ZHENG Min, PENG Gengxin, LEI Gang-lin, HUANG Shao-ying, WU Chao, GUO Hua-qing, LI Yue-jun 2007, 28 (2):  170-174.  Abstract ( 112 )   PDF (245KB) ( 277 )   Save Based on abundant information of gamma-ray curves, combining wavelet analysis with fast Fourier transform, the Milankovitch cycle and its thickness of Cretaceous in Wushi sag is identified using frequency spectral analysis, then the sedimentation rates of each layer of Cretaceous in studied area are precisely calculated. The results show that the thickness of sedimentary cycle caused by eccentricity cycle ranges from 8.70 m to 13.89 m; the thickness of it caused by obliquity cycle from 3.01 m to 5.88 m; the one of it by precession cycle from1.28 mto 2.44 m, and the average sedimentation rate of Cretaceous strata fromfour sampling wells is 0.093 78 mm/a. References | Related Articles | Metrics

Migration Directions of Silurian Crude Oil in Tazhong Area HUO Hong, LIU Luo-fu, XIE Qi-lai, CHEN Yuan-zhuang 2007, 28 (2):  175-178.  Abstract ( 67 )   PDF (254KB) ( 193 )   Save Carbazole non-hydrocarbon compounds are used as tracers for investigation of Silurian oil migration direction in Tazhong area, Tarim basin. The results from their abundances, parameter variations indicate that the movable oil has unremarkable distillation efficiency of lateral migration and proximal feature similar to the Cambrian-Ordovician source rocks in Manxi area and slope of northern Tazhong area, with lateral migration directions towards Tazhong 47 from SE to S, and then Tazhong 11, Tazhong 12-50 and Tazhong 16 structures. Vertically, the movable oil migration of Silurian has a tendency from lower to upper sections. The process of the oil migration is controlled by regional structures and the direction of the oil migration is consistent with the strike of major faults of Silurian. References | Related Articles | Metrics

Study of 3D Variation Function in Reservoir Stochastic Modeling GUO Kai, SHI Jing, YANG Yong 2007, 28 (2):  179-181.  Abstract ( 87 )   PDF (124KB) ( 205 )   Save 3D variation function is the most important parameter showing reservoir heterogeneity. But, this basic factor in today's reservoir stochastic modeling tends to being ignored. In light of vertical distribution characteristic of reservoir petrophysical property, the geologic factors affecting the 3D variation function such as singular value, hybrid distribution and drifting are systematically analyzed. The corresponding measures and methods for eliminating these factors are outlined, and the work flow for solving the 3D variation function is proposed in this paper. References | Related Articles | Metrics

Prestack Time Migration Applied to Seismic Data Processing in Complex Fault Blocks, Biyang Sag ZENG Qing-cai, DU Yao-bin, WANG De-fa, DUAN Hong-you, LI Chen 2007, 28 (2):  182-184.  Abstract ( 96 )   PDF (406KB) ( 179 )   Save The slope zone in northern Biyang sag is characterized by complex structure, developed minor fault blocks, varied seismic vertical and horizontal velocities and difficult to get imaging, which result in that conventional imaging approaches are hard to meet the needs for exploration and development of this area. This paper presents the prestack time migration to curved rays for minor fault blocks, which is of more accurate migration, allowing the travel-time equation to be more close to the real pathway of layered media seismic wave propagation, the focused imaging to be more precise, the migrated results to be of good preserved amplitude processing property and the output trace gathers to be used for the lithologic analysis and inversion study. Case study shows that by this approach the imaging profiles with higher quality can be obtained, hence new recognitions of faults are gained, new traps are discovered and good oil shows in slope belt of northern Biyang sag have been encountered by drilling. References | Related Articles | Metrics

Stratigraphic Division, Correlation and Geologic Significance of Silurian in Tarim Basin WANG Cheng-lin, ZHANG Hui-liang, LI Yu-wen, SHEN Yang 2007, 28 (2):  185-188.  Abstract ( 181 )   PDF (290KB) ( 251 )   Save Through survey of Silurian outcrop section in Keping area in western Tarim basin, the Silurian can be divided into Kepingtag, Tataaiertag formations of Lower Silurian, Yimugantawu formation of Middle-Upper Silurian. The Kepingtag can be sub-divided into lower, middle and upper parts, while the Tataaiertag into lower and upper parts. Also, six horizon markers for strata correlation have been identified. The study shows that Tazhong (central Tarim) uplift lacks of the lower and the middle parts of Kepingtag formation, Tabei (northern Tarim) uplift lacks of the lower part in Yingmaili area; the whole Kepingtag formation is found in Manjiaer sag and Tadong (eastern Tarim) area, and Yimugantawu formation is partly found in Tazhong and Tabei areas. Keping and Tabei areas are dominated by shore-neritic facies' clastic deposits, Tazhong area by estuarine-tidal flat deposits and Tadong area by continental river-braided stream delta's coarse fragment deposits. The integrated analysis indicates that before Silurian, Tazhong and Tabei areas were inherited uplifts showing paleo-relief of the higher in east and the lower in west; the transgressive direction was from WN towards ES; the strata were overlapped from WN towards ES. The top stratum denudation of Silurian was caused by the post tectonic uplifting. The unique characteristics of Silurian deposit reveal the paleo-relief feature, source and transgressive directions in Tarim basin. References | Related Articles | Metrics

Production Decline Rules and Recoverable Reserve Prediction WANG Jun-kui 2007, 28 (2):  189-193.  Abstract ( 104 )   PDF (226KB) ( 218 )   Save A differential equation for production decline rate is set up based on the study of variation of production decline curve, by which the dimensionless decline equation for describing the production decline rule is deduced. This equation shows that after oil production decline of any reservoir occurs, the dimensionless cumulative production rate and dimensionless time in rectangular system are all straight lines which pass through origin of coordinates with slope of 1, hence the cumulative production rate and annual oil production rate of the reservoir could be extrapolated and predicted. The equation for variation of production rate with cumulative production rate is then derived. By this equation, the residual recoverable reserves and abandoned annual production rate could be predicted. In addition, the reasonable limit of reserve-production ratio when production decline occurs is researched. Case studies indicate the correctness and practicability of these equations which can be used in reservoir engineering study and prediction. References | Related Articles | Metrics

Characteristic Correlation of Two Water Displacement Curves XU Jun, GAO Wen-jun, LIU Ying, WAN Yong-hong 2007, 28 (2):  194-196.  Abstract ( 114 )   PDF (134KB) ( 202 )   Save Water displacement curve is the most common method for water cut rule study, productive index prediction and recoverable reserve calibration. There are more than 50 methods of such a kind nowadays. However, selecting the curves that may describe the relationship between different water cut styles and recovery percent are the permanent topics to oilfield development operators. This paper presents the characteristic correlation between Zhong Dekang and Gao-I water displacement curves. The analysis shows that these two water displacement curves are of the characteristic of describing different water cut styles vs. recovery percent, the former has no corresponding water displacement curve, but the latter has. So the latter is the most perfect water displacement curve with wider application than the former. References | Related Articles | Metrics

Study on Reasonable Sand Producing Process for Unconsolidated Sandstone Heavy Oil Reservoir TIAN Gang, TANG Hong-ming, WANG Chun-hua 2007, 28 (2):  197-199.  Abstract ( 94 )   PDF (104KB) ( 200 )   Save This paper proposes the reasonable sand producing process for unconsolidated sandstone heavy oil reservoir, based on conventional sand control and cold flow production process, including its principle for stimulation and reservoir conditions suitable for this process. Through some cases abroad for its field application, it is proved that this process is of advantage of obviously improving oil production. Finally, this paper discusses several critical problems that should be paid attention to in application of this process. References | Related Articles | Metrics

Production Decline Analysis for Gas Well with Abnormal Pressure XUE Guo-qing, LI Min, YU Chun-sheng, LIU Shi-chang 2007, 28 (2):  200-202.  Abstract ( 71 )   PDF (136KB) ( 156 )   Save Shut-in pressure survey is the conventional method for determination of gas reservoir parameters. For extra-low permeability gas reservoir, the time for pressure buildup is normally long, sometimes lasts several months. So it is necessary to do it based on the gas well production history so as to avoid economic loss caused by the shut-in. For wells with production history, the modern production decline analysis can be applied to yielding the formation parameters, and the semi-log figure of normalized time vs. normalized pressure is taken as the criterion to validate the calculated results. Case correlation study shows that for gas wells without shut-in pressure survey, this method can be used to resolve the reservoir parameters. References | Related Articles | Metrics

Method for Production Prediction of Horizontal Well LI Fan-hua, JIA Li-ping, SUN Hong-an, SHAN Dong-bo, WANG Jin-fang, YAN Zeng-min 2007, 28 (2):  203-206.  Abstract ( 85 )   PDF (207KB) ( 246 )   Save In recent years, the technology for horizontal drilling is developing rapidly. Featured by large drainage area, low production pressure, high productivity and broad applicability, the horizontal well has much more unique superiority than vertical well. One of reasons for horizontal well not being popularized extensively is the lag in its production prediction. According to near 200 horizontal well's production data at home, the production decline laws for 8 kinds of reservoirs by horizontal well, such as bottom water, super heavy oil, low permeability and thin bed reservoirs, are presented, with corresponding production formulas and the cumulative production formulas. By using the initial productivity equation and the production decline empirical equation, the future production of a horizontal well could be exactly predicted at designing step of horizontal drilling. References | Related Articles | Metrics

Mechanism of Eliminating Retrograde Condensate Damage in Gas Condensate Well by Methanol Injection Process SHI De-pei, LI Xiang-fang, LIU Hua, SUN Lei 2007, 28 (2):  207-209.  Abstract ( 101 )   PDF (147KB) ( 366 )   Save By using PR state equation, the gas compositional fugacity is calculated, and the gas-liquid equilibrium model for hydrocarbonmethanol system is developed to simulate the phase behavior of this system in order to reveal the mechanism of eliminating retrograde condensate damage near wellbore in gas condensate well by methanol injection process. The study shows that the dew point pressure of this system can be reduced with increase of injected methanol amount in gas condensate well under the real initial temperature and pressure; the condensate saturation in constant composition expanding process will be cut down and the retrograde condensate amount and condensate viscosity are obviously decreased in constant volume depletion process. It is concluded that methanol as an effective solvent for eliminating the retrograde condensate damage is of re-vaporizing effect on condensate oil. References | Related Articles | Metrics

The Hor izontal Principal-Stress Orientation and Its Effect on Development of Low Permeability Reservoir of Paleogene in Anpeng Oilfield CHEN Cheng, SUN Yi-mei, JING Guo-chao, BI Sheng, QIU Kun-tai, SU Jian-dong 2007, 28 (2):  210-213.  Abstract ( 62 )   PDF (239KB) ( 322 )   Save The maximum horizontal principal-stress orientation of Paleogene low permeability reservoir of Anpeng oilfield in Biyang sag is in dispute. The available core observation and orientational coring data indicate that there exist crossed two-group natural fractures in this reservoir, one trend ranges from 20°to 40°, the other trend from 80°to100°, with shear or extension-shear mechanical property. It is inferred that the maximum horizontal principal-stress orientation of the fractures when formed was about N60°E. But affected by the idea of being EW trend of the orientation, the present maximum principal-stress orientation has become the direction of injected water breakthrough, causing quickly raising of water cut in production wells. This paper presents the measures for improving the waterflood sweep efficiency as follows: converting production well to injection well or adding new wells allow the original EW array of water injection wells to become NE one. References | Related Articles | Metrics

Production Decline Analysis by Matched Curves LAI Feng-peng, LI Zhi-ping, CEN Fang 2007, 28 (2):  214-215.  Abstract ( 101 )   PDF (71KB) ( 190 )   Save The production declines have appeared in most domestic oilfields. And the production decline analysis is more and more important for traditional models for it are more complicated in calculation and prediction. This paper presents five history-match models for production decline/variation by means of mathematic statistics of the production history data. Case study indicates that these models are well used to run the history match and improve the accuracy of production prediction. References | Related Articles | Metrics

A Method for Productivity Appraisal of Supper-High Pressure and Rock Stress-Sensitive Gas Reservoirs WANG Jian-guang, LIAO Xin-wei, YANG yong-zhi 2007, 28 (2):  216-218.  Abstract ( 69 )   PDF (125KB) ( 183 )   Save The effects of high pressure and reservoir rock stress sensitivity on super-high gas reservoir productivity are considered, the new productivity equations are deduced and the method for determination of the coefficient and the absolute open flow potential or deliverability are presented. Field application and appraisal result show that the deliverability given by this new method is 10%~25% lower than that by the conventional method, but comparable with that by pressure-squared method without regard to the stress sensitivity. This paper suggests that when making productivity appraisal of super-high pressure and stress sensitivity gas reservoir during early phase of exploration or development, the pressure-squared method can be used to approximately determine the absolute open flow potentials of gas reservoirs. References | Related Articles | Metrics

A Novel Method for Division of Petrophysical Facies with Application DUAN Lin-ti, ZHANG Yi-wei, ZHANG Chun-lei 2007, 28 (2):  219-221.  Abstract ( 81 )   PDF (161KB) ( 228 )   Save A method for division of reservoir petrophysical facies by fuzzy clustering is proposed. Taking Dagang Zaonan oilfield as an example and selecting the parameters of sedimentation and diagenesis, the five types of petrophysical facies featuring the reservoir rocks in this studied area are given by this method. And the relationship between the petrophysical facies and the production indices of the oilfield is analyzed. The study shows that with upgrade of the petrophysical facies level, both of the reservoir genetic parameters and the statistical petrophysical properties gradually change better, so does related reservoir productivity. The conclusion does help to searching for the favorable oil/gas-enriched horizons and remained oil-gas abundant areas. Also, this is as a guide for further regulation and additional potentials in this oilfield. References | Related Articles | Metrics

Application of Transient Electromagnetic Method to Static Correction Processing in Southern Margin of Junggar Basin ZHAO Feng, LI Xian-min, SONG Yang, Qiqige 2007, 28 (2):  222-225.  Abstract ( 84 )   PDF (368KB) ( 232 )   Save The vertical or horizontal lithologic variation of geologic body in surface and near surface is one of the key factors for static correction of different wave lengths. By using conventional static correction, it is difficult to develop the surface or near-surface velocitydepth model in seismic exploration of complex surface, causing inaccurate static correction value, due to big difference of such a depth vs. velocity resulted from limitation of numbers of up-hole shooting or weathering-refraction shooting point, along with lithologic changes between adjacent control points. By using transient electromagnetic method and by continuous survey, the electric seismic profile of the surface or near-surface texture in target area can be obtained, and the velocity-depth model can be developed by the relationship between the lithology and the electric feature. Furthermore, the accurate static correction value could be gained by arranging the up-hole shooting or weathering-refraction shooting points, getting relevant depth and velocity data and then developing relevant model. Such a surface geologic model-based geophysical velocity-depth model is of uniqueness for gaining the accurate static correction value. References | Related Articles | Metrics

Application of Swell Noise Attenuation and Spatial Continuous Velocity Analysis Technology in Omega Processing System DUAN Wen-sheng, DENG Jian-feng, HUANG Lu-zhong, XIANG Dong, YANG Shi-ming, ZHANG Hong-xia, CUI Yong-fu 2007, 28 (2):  226-228.  Abstract ( 90 )   PDF (375KB) ( 255 )   Save The noodle hang-like noise often presented in the seismic data of mountain area in Tarim basin greatly affects the validity of following deconvolution processing. It is difficult to effectively eliminate this kind of noise using conventional methods. A new approach named swell noise attenuation, which is based on spatial median filter arithmetic, can be adopted to suppress such a noise with some limitations. This paper presents spatial continuous velocity analysis technique, an effective solution to overcome these limitations. This technique depends on conventional NMO and mute as well as CMP velocity analysis, self-creates suitable velocity functions in order to resolve the deficiency existed in conventional velocity analysis. The case study shows that using this technique can be able to further improve the precision of stacking velocity and imaging in complex structural areas or with big variation of lateral velocity. References | Related Articles | Metrics

New Method for Geologic Risk Evaluation of Structural Traps and Application MA Zhong-zhen, PANG Xiong-qi, LI Bin, WEI Jian-she 2007, 28 (2):  229-231.  Abstract ( 92 )   PDF (162KB) ( 301 )   Save The advantage of the traditional geologic risk evaluation of hydrocarbon traps is that various geologic factors could be taken into full account and favorable for bringing person's experiences into play, and the shortcoming of it is that the evaluated results could be largely affected by the artificial factor and the data integrality of studied area. Trinity is new software for prediction of geologic risk in hydrocarbon traps and can be used to simulate the hydrocarbon generation and expulsion of source rocks from available geologic data, thus making an evaluation through accumulated hydrocarbon amount in the trap. This method is hardly affected by the data integrality and the artificial factor as reparation of the traditional method. So these two methods should be used together in a low-extent exploration area in order to get more reliable results. For trap evaluation of Binbei area in Songliao basin, these two methods are respectively applied and six favorable traps are selected in this paper, which can be as a guide for further exploration in this area. References | Related Articles | Metrics

Application of Wave Analysis to Identifying Minor Fault and Nip-Out Line LI Hai-liang, CHEN Qi-lin, ZHU Yun-hui, WANG Hong-bo, ZHANG Li-ping, YU Jian-ping 2007, 28 (2):  232-234.  Abstract ( 109 )   PDF (291KB) ( 233 )   Save The present petroleum exploration has trended from structural reservoirs to lithologic and stratigraphic reservoirs. One of the latter exploration focuses on exactly identifying mini-faults and nip-out line in stratigraphic reservoirs. Conventional coherent wave analysis can hardly be used for identifying the mini-faults with fault throw less than half of event. This paper studies such mini-fault identification, and develops a wave analysis-based identifying approach with up to date technologies, by which the stratigraphic nip-out line and the mini-faults can be precisely identified, thus, the interpretation accuracy and velocity as well as analytical cycle could be all improved. References | Related Articles | Metrics

Pressure-Sensitive Dual Porosity Medium Well Test Interpretation and Its Application in Tahe Oilfield WANG Zi-sheng, YAO Jun, DIAO Xian-wei 2007, 28 (2):  235-237.  Abstract ( 79 )   PDF (174KB) ( 232 )   Save A well test interpretation model for reservoirs with dual porosity pressure-sensitive medium is developed, which takes fractural permeability decreasing exponentially with drawdown into consideration. The wellbore storage and skin factor effects are calculated using fully implicit finite-difference form. The influences of dimensionless permeability modulus and skin factor on pressure response are discussed. The results show that the dimensionless permeability modulus will cause the increases of pressure and pressure derivative rather than the skin factor. The theory is applied to Tahe oilfield and an oil well tested twice is interpreted by it. The case study indicates that the theory has a good practicability and a consistency with field conditions. References | Related Articles | Metrics

A Simple Method for Identification of Injected Water Flow Direction ZENG Yu-qiang, LI Xiao-ping, LI Bin, WANG Qin, WANG Hui-qiang 2007, 28 (2):  238-241.  Abstract ( 124 )   PDF (207KB) ( 270 )   Save In the late stage of waterflooding, the key efforts of reservoir operation or management focus on the understanding of remained oil distribution, the rational arrangement of producer-injector spacing and the measures making for development modification, of which to grasp the interwell communication and the injected water flow direction is the chief task. Spearman's order correlation coefficient is applied to study of them by taking the production performance data from producers and injectors in Sangonghe reservoir of Shinan-4 Wellblock in Shinan oilfield as analytical parameters. The case study indicates that this method is simple, save-time and suitable for field application. References | Related Articles | Metrics

Application of New Theories and Technologies in Geosciences to Oil-Gas Exploration YAO Ya-ming, CUI Shu-jun, CHEN Jian-jun, YANG Bin-yi 2007, 28 (2):  242-247.  Abstract ( 73 )   PDF (178KB) ( 187 )   Save As an irreplaceable source of energy at present, petroleum plays more and more important role in global economic development and the civilized course of human society. But, with ceaseless efforts for petroleum exploration and adding in exploration degree year by year, the difficulty of the oil-gas exploration will be definitely more and more increasing. Under the guidance of "anticline theory", the most anticline-type reservoirs that are easily found have already been discovered. Today, what we face are the more and more complicated targets for petroleum exploration. However, the naissance and development of such new theories of geosciences as sedimentary basin dynamics, petroleum system, gas geology of deep basin and hydrocarbon accumulation dynamics establish scientific theory basis for stable development in petroleum exploration at home and abroad. The presence and application of such novel technologies as basin analysis and simulation, reservoir description/characterization and imaging logging, etc. provide technical guarantees for further hydrocarbon prospecting. References | Related Articles | Metrics

Discovery of Rectorite and Its Geologic Significance in Tarim Basin ZHAO Xing-yuan, ZHANG Bao-shou 2007, 28 (2):  248-251.  Abstract ( 139 )   PDF (389KB) ( 259 )   Save Rectorite, a clay mineral, was discovered in Silurian sandstone strata in Tarim basin by means of XRD, SEM, DTA, etc. Because the rectorite is not composed of 1:1 alternate arrangement of illite-montmorillonite layers, it could be named "pararectorite". The study indicates that the pararetorite belongs to K-rectorite transformed by Ca-rectorite, and sedimentation-diagenesis origin in weak acidic aqueous media with pH value ranging from 4 to 5 and under 120℃ or more. The results from the pararectorite research will be of great significance to the stratigraphic classification or comparison, the reservoir rock feature and the formation of the hydrocarbon reservoirs in Tarim basin. References | Related Articles | Metrics

Unification of Flow Equations in Tubes and in Porous Media LI Chuan-liang, ZHANG Xue-lei 2007, 28 (2):  252-253.  Abstract ( 249 )   PDF (69KB) ( 275 )   Save Flow can take place in tubes or in porous media. The porous media consist of bundles of tubes, so the flow in porous media is also finished through flows in tubes, namely, flow in tubes should be the same as flow in porous media. The equations for these two flows can be derived from each other. Tubular flow theory can be used for the situation of a certain number of tubes, in which the tube diameter can be easily measured. The theory of flow in porous media can be used for the situation of enormous tubes, or the situation of a certain number of tubes but the tube diameter being immeasurable. In practice, one of two kinds of flow theories can be chosen for a specific situation. References | Related Articles | Metrics

A Genetic Model of Normal Fault Under Compressive Tectonic Setting CUI Ze-hong, TANG Liang-jie 2007, 28 (2):  254-256.  Abstract ( 101 )   PDF (214KB) ( 199 )   Save This paper presents a genetic model of normal fault in the interior of basin under regional compressive tectonic setting. The normal fault is often superimposed underlying paleo-uplift and basement faults. This study suggests that the basement uplift, warpage and basement fault block activity caused by basement compression and contraction under regional compressive setting are primary dynamic mechanism induced extensional deformation of overlying cap rocks, while the paleo-structural framework is the premise condition for the normal fault origin and development. It is indicated from the origin of normal fault that the control effect of basin basement on the structural deformation of cap rocks is the product of inharmonic deformation between basement and cap rocks during evolution of basin. This kind of normal fault has been found in northern uplift of Tarim basin and hinterland of Junggar basin. References | Related Articles | Metrics

Petroleum Geology of South Tajikistan Basin in Central Asia ZHU Yi-xiu, LIU Luo-fu 2007, 28 (2):  257-261.  Abstract ( 135 )   PDF (231KB) ( 250 )   Save An integrated study on lithology, sedimentology, structural feature and petroleum geology in South Tajikistan basin is carried out. The source rocks of this basin are characterized by marine and lagoon and limnic mudstone, shale and limestone of Eogene, Cretaceous and Jurassic, with multiple petroliferous strata. The main oil reservoir features marine carbonate rocks and sandstone of Eogene and the main gas reservoir is offshore carbonate rock and sandstone of Cretaceous and Upper Jurassic in which gypsolyte becomes the regional cap rock of gas reservoir, while the muddy gypsolyte and marl of Cretaceous and Eogene are the regional or local cap rocks of oil-gas reservoir. The major stages of petroleum migration and accumulation occur in the Late Cretaceous and Early Pliocene. There exist three types of petroleum traps and reservoirs such as structural, structural-stratigraphic and stratigraphic ones in this basin. References | Related Articles | Metrics