Table of Content

01 August 2003, Volume 24 Issue 4 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Reference Manager ProCite BibTeX RefWorks

Toggle Thumbnails

Carbon and Hydrogen Existing Forms and Their Isotopic Compositions in Mantle Fluids WU Mao-bing, LIU Chun-yan 2003, 24 (4):  273-276.  Abstract ( 150 )   PDF (247KB) ( 199 )   Save Much progress has been made on studies of isotopic compositions and existing forms of carbon and hydrogen in mantle fluid during the last two decades by researchers at home and abroad using various analytical techniques. It is commonly recognized that carbon exists in the forms of diamond in kimberlite, liquid inclusions in carbonates and xenoliths, graphite and the CO2 erupted from mid-ridge of oceans. δ13C values are mainly around -5‰ with ranges of -2‰~-10‰ and -14‰~24‰. Hydrogen often exists in the forms of 0H-, H°, liquid inclusions, super-micro inclusions, magma cells and fractures in minerals from the mantle. Its isotopic composition accounts for -30‰~-90‰. This study is helpful for well interpreting carbon and hydrogen isotopic compositions of organic, inorganic and mixed origins of hydrocarbons. References | Related Articles | Metrics

The "Thick Top" Structure and Its Formation Mechanism in Chaidam Basin WANG Ming-ru 2003, 24 (4):  277-280.  Abstract ( 177 )   PDF (1235KB) ( 214 )   Save The "thick top" structure is typical and extensive occurrence in Chaidam basin. It can be divided into several types such as 1)tip roof back; 2)two-layer texture; 3)round top tent; 4)fault coincidence; 5)low mound, and 6)straw hat. In vertical direction, these types of struc-tures are mainly distributed in Oligocene (E3), Miocene (N1) and Pliocene (N21) of the basin; in lateral direction, they are mostly in the north-ern, western and central areas of it. The mechanism of this structural formation is due to plastic argillaceous strata under the environment of intense compaction and wrench deformation. For petroleum exploration in it, the "thick top" structure is in favorable source-cap conditions, and the reservoirs formed are dominated bu fractured ones. References | Related Articles | Metrics

Fault Systems and Their Control Effects on Hydrocarbon Migration/Accumulation in Luliang Uplift, Junggar Basin ZHANG Nian-fu, ZHANG Yue-qian, XU Chang-sheng, WANG Bin, ZHA Ming 2003, 24 (4):  281-283.  Abstract ( 91 )   PDF (842KB) ( 162 )   Save There exist two major fault systems in Luliang uplift of Junggar basin, i.e. deep fault system and middle-shallow fault system. The main faults such as Lunan, Jidong and Jinan are connected to the hydrocarbon sources. Among them, Lunan fault and 'idong fault possess structure of normal fault in the upper part and reverse one in the lower part; Iinan fault is a reverse fault without normal one in the shallow part; the upper part of Jidong fault appears normal fault with good lateral block-off property, favorable to form reservoir laterally blocked off by the fault; while in the upper part of Lunan fault occurs poor lateral block-off nature of normal fault and open in the vertical. It is indicated that Jinan fault activity stage well matches to the primary oil-generating or oil accumulation period in Fengcheng source rocks, till Triassic the fault plays a part of passage of oil-gas migration. For reverse faults of 'idong and Lunan, their matching relations to hydrocarbon accumu-lation are similar with that of Jinan fault, but their upper normal fault movement periods are right to fit the primary oil-generating period of Wuerhe formation which is called the second period of hydrocarbon accumulation. In Middle Jurassic to Early Cretaceous, these faults could be as good passages for oil-gas migration. It is concluded that the faults developed in Yanshan movement epoch play a significant role in the primary reservoirs’ preservation, reconstruction and destruction and the secondary reservoirs’ formation, preservation and reconstruction in this area. References | Related Articles | Metrics

Restudy on the 40Ar-39Ar Age of Wajilitag Basic-Ultrabasic Complex in Western Tarim Basin SONG Wen-jie, LI Yue-jun, HU Shi-ling, GUO Hong, HUANG Zhi-bing, ZHENG Duo-ming 2003, 24 (4):  284-285.  Abstract ( 98 )   PDF (156KB) ( 135 )   Save Wajilitag structure, about 40km southeast to Bachu county, is located at western Tazhong uplift, Tarim basin. There exists a set of slightly metamorphic unfossiliferous clastic rocks at Wajilitag where a developed basic-ultrabasic complex is outcropped. Although the gab-bro 40Ar-39Ar age of 821~837Ma was obtained from this complex in 1999, which was the first dating of Precambrian isotopic age in hinterland of Tarim basin, ages of this complex and its surroundings are still questionable. In order to validate the prev ious results, re-collected gabbro samples are used for 40Ar-39Ar dating from it, obtaining its plateau age of 879. 12+1.47Ma, corresponding isochronal age of 881.34t 18.82Ma and reverse isochronal age of 880.351 1.22Ma. These measurements indicate that Wajilitag basic-ultrabasic complex was formed in Precam-brian, belonging to a part of Precambian basement in Tarim basin. This conclusion is also supported by related petrochemical analysis, that is, Tarim basin possesses ancient continental crust basement.The magnetic rocks and Palaeozoic strata in Buchu area (including Wajilitag structure) are possibly basement outcrops. This study could be as a guide for hydrocarbon prospecting in Wajilitag structure. References | Related Articles | Metrics

Application of Spontaneous Potential in Interpretation of Pore Pressure WANG Lian-sheng, MA Zhi-hong, GUO Zhan-jian, YAN Shou-bin 2003, 24 (4):  286-288.  Abstract ( 104 )   PDF (990KB) ( 157 )   Save The sonic velocity approach used to be applied for estimation of reservoir pore pressure. However, it doesn’t operate to Daqing oil-field with diversified current interlayer pressures. Following long-term waterflooding, the sandstone reservoir has variable spontaneous potential (SP) resulted from variable electrofiltration potential which is closed with the pressure drawdown. The SP approach is introduced from it. Taking the sandstone reservoir in Daqing oilfield as an example, this paper presents a SP approach applicable to interpret the sand pore pres-sure variations during the field development, based on SP log principle and capillary flow potential theory. It is indicated that as a new thought using this approach may improve the accuracy in the pressure interpretation, hence save a great amount of testing fees. References | Related Articles | Metrics

Integrated Approach of Sealing Properties of Fault in Complex Fault Block Oil-Gas Field—An example of the lower member of Sha-2 reservoir in YongDan oilfield LIU Wei, DOU Qi-feng, WANG Shao-hua 2003, 24 (4):  289-291.  Abstract ( 81 )   PDF (654KB) ( 123 )   Save It is significant effect of studying the fault sealing properties, (i.e. lateral sealing factors such as filling compounds, allocated lithol-ogy of fault walls and syngenetic fault feature; and vertical sealing factors including the fault mechanics, geometry, stress field, faulted overly-ing strata) on determination of the distribution of reservoirs in complex fault block. The block sealing is not simply dependent on the lithology of fault walls, but on the property of fault zones. This paper presents an integrated approach of block sealing analysis with applicability and practicability. From the studies of oil-water contact in reservoir on two sides of the fault, acoustic logging data from over-fault wells and shale smear factor (Fss), the sealing status of fault is comprehensively estimated. A case is used to demonstrate the good effectiveness for ascertain-ing the lateral and vertical sealing properties of the faults by applying this approach. References | Related Articles | Metrics

Diagenesis of Chang-6 Reservoir of Upper Triassic in Jing'an Oilfield of Ordos Basin LI Bin, ZHU Yong-ming, TONG Xiao-hua, ZHAO Iing-zhe, LIU Li-li 2003, 24 (4):  292-295.  Abstract ( 99 )   PDF (908KB) ( 166 )   Save The composite study of five sections and 11 exploratory wells shows that Chang-6 reservoir of Yanchang formation of Upper Trias-sic in Jing'an oilfield underwent a series of complex diageneses with compaction, cementation and dissolution with various and distinctive features. The study shows that the early diagenetic compaction and multi-mineral cementation are major effective factors that lead to its poor petrophysical property and low porosity; while dissolution, in particular, dissolution of laumontite is one of significant factors controlling the quality of reservoir. References | Related Articles | Metrics

Hydrocarbon Accumulation of Section Ⅱ of Shahejie Formation in Liangjialou Oilfield SU Yong-jin, FANG Xin-na, CHEN Bing-shen 2003, 24 (4):  296-298.  Abstract ( 63 )   PDF (1751KB) ( 141 )   Save The main target zone in Liangjialou oilfield is the third section of Shahejie formation. During the exploration and development, it is found that oil reservoir of the second section is scattered in different regions. This paper studies the oil-gas geology and reservoir characteristics of the second section, according to regional exploration data available in this area, and indicates that the second section is typical minisubtle reservoir with primary reverse ridge block screened type and fault-lithology compound one. It is concluded that the oil-gas accumulation is characterized by small structures and faults that control oil-gas migration and petroleum distribution with the more and shallower in the south than in the north. This understanding will be of positive significance for petroleum exploration of the second sections in this area and adjacent regions. References | Related Articles | Metrics

Reservoir Characteristics and Favorable Sedimentary Facies of Lucaogou Formation in Malang Sag, Santanghu Basin TANG Yong, GUO Xiao-yan, PU Shi-zhao, Abuli Miti 2003, 24 (4):  299-301.  Abstract ( 75 )   PDF (888KB) ( 161 )   Save Lucaogou formation of Malang sag in Santanghu basin is of variety and complexity of rock types, which were mainly resulted from multiple sources of sediments supply. The reservoir rocks are dominated by carbonate and tuff developed in the middle section of Lucaogou formation, and possess characteristics of zoned development of different lithology. Heidun zone is dominated by limestone and clastic rock; Mazhong zone by tuffite; Niuquanhu zone by sandy dolomite. The petrophysical property assumes low porosity and extra-low permeability. The reservoir space can be classified into three types, i.e., fracture, fracture-denudation pore and siliceous pore-crack. The porosity structure assumes medium-poor sorting, moderate flexure mini-pore and micro throat with poor pore-throat connectivity and micro fractures that play parts of connection, storage and percolation in the reservoir. The reservoir quality depends on how fracture developed in it. The diageneses such as buried denudation, fractured process and dolomitization are the major positive processes. The vertical fracture development and dis-tribution are related to in-situ lithology and bed thickness directly. It is shown that the most developed fractures are in the micrite and tufffite. The transversal fracture devlopment and distribution are controlled by in-situ structural location and fold amplitude or intension. References | Related Articles | Metrics

Geochemical Characteristics of Lucaogou Source Rock in Malang Sag, Santanghu Basin DU Hong-yu, WANG Hong-yan, XU Zong-qian 2003, 24 (4):  302-305.  Abstract ( 148 )   PDF (1512KB) ( 148 )   Save A study of Lucaogou source rock in Malang sag,Santanghu basin is made. The result shows that 1) primary origin of asphaltene as-sumes predominant distribution in which organic matter could mainly come from bio-degradation of thallophyte; 2) the biomarker composition in soluble organic matter appears to be of general feature of mixed sources from both terrigenous higher plant and microorganism (thallo-phyte),with abundant hydrogen composition; 3) the sample of source rock reflects the characters of macroscopic pyrolysis with higher oil threshold temperature and narrower major hydrocarbon generation zone, similar to the hydrocarbon generation pattern of Type I kerogen. In addition,this source rock organic matter contains considerable amount of primary lipids,with a certain of low maturation hydrocarbon-gener-ated potentials. References | Related Articles | Metrics

Discussion of Some Problems in Seismic Data Processing DI Gui-sheng, SHI Xing 2003, 24 (4):  306-307+315.  Abstract ( 93 )   PDF (806KB) ( 168 )   Save Polarity of seismic wave is well concerned by geophysicists for its effect on accuracy of geologic calibration of horizons on a seismic profile. When composite traces or YSP information is inconsistent with events of some seismic data, this is not something the matter for the seismic data but the polarity. With correct estimation of the polarity, the reliability of seismic interpretation results can be improved. For the static correction of low-velocity layer, and with complicated topography and fairly big thickness of low-velocity layer, using vertical depth to estimate the amount of static correction will appear a certain of errors that are not allowed, and the normal depth of dip plane should be considered for it. In low signal-to-noise ratio and low dip angle (or complex folded zone), velocity information like retrograde phenomenon should be paid more attention to. For retrograde point of seismic velocity tends to be breaking point of fault in velocity spectrum of corresponding seismic profile, hence, systematic processing of these breaking points could obtain real fault localization. References | Related Articles | Metrics

Elevation Signification of CMP Reference Surface WU Jian-hua, JIA Ming-chen, LEI De-wen 2003, 24 (4):  308-309.  Abstract ( 180 )   PDF (623KB) ( 164 )   Save CMP reference surface, i.e. a RG line of two dimensional seismic profile, is a time domain reference surface induced by two-step correction of seismic data processing. This paper presented theoretically the formulae for calculating corresponding elevation to common midpoint (CMP) reference surface from the procedure of static correction computation of seismic data processing. It is concluded that CMP refer-ence surface corresponds to a flattened plane of static correction starting-point elevation in RG calculation, that is, CMP surface is of a cer-tain elevation signification. References | Related Articles | Metrics

Application of Seismic Attribute Information in Glutenite Reservoir Development—An example of Wuerhe reservoir of Upper Permian in Karamay oilfield LY Fu-su, HUANG Xiao-ping, REN Tao 2003, 24 (4):  310-312.  Abstract ( 71 )   PDF (1438KB) ( 190 )   Save Seismic attribute information is the useful information involved in seismic reflection wave. As increasing intensity of exploration and development and performing detailed reservoir characterization, the seismic attribute information is paid greatly attention to by geophysi-cists and geologists at home and broad. Despite the rapid development of modern seismic technology and improvement of signal-to-noise ra-tio and resolution, the seismic attribute information reflecting special in-situ geological phenomenon, sedimentary feature and fluid behavior, etc., should not be ignored. Taking Upper Wuerhe formation in District No.5 as an example, this paper presents the concepts of various com-mon seismic attribute information and their applicable effects in oil/gas field exploration and development. References | Related Articles | Metrics

Geophysical Method for Prediction of Carbonate Reservoir—An example of No.l Block in Tahe oilfield LY Iing-ying 2003, 24 (4):  313-315.  Abstract ( 73 )   PDF (835KB) ( 166 )   Save The carbonate reservoir of Ordovician in No.1 Block of Tahe oilfield is of big buried depth and serious heterogeneity, which bring about great difficulty to reservoir prediction and exploration arrangement. Based on correct understanding of basic feature of the reservoir, the variations of amplitude, frequency and waveform of seismic wave are used to recognize the reservoir; many techniques such as coherent events calculation, seismic well log inversion, velocity analysis and main curvature analysis are applied for study of fractural and vuggy development in the reservoir; and 3-D visualized technique is utilized to research karst development. Practice shows that such a method like these is feasi-ble and can be used for prediction of the favorable exploratory areas in developed carbonate reservoirs to some extent. References | Related Articles | Metrics

Surface Structure in Desert Area of Junggar Basin and Its Static Correction Method ZHAO Feng, ZHENG Hong-ming, FAN Xu 2003, 24 (4):  316-318.  Abstract ( 110 )   PDF (1287KB) ( 158 )   Save The hinterland of Junggar basin is mostly covered with desert. It brings about difficulty for seismic prospecting due to its fluctua-tion, inhomogeneous distribution of surface dune sand. It can not only absorb the signals with medium and high frequency in propagation of reflection event, but also allows reflection event from the same layer in a seismic record to produce static correction time lag with different wavelength in the close recorded trace. And such a high frequency part of the time lag directly impacts the stacking and imaging effects of seismic reflection event, while low frequency part of it can severely distort the configuration of underground geological structures. To remove the impact of static correction interval transit time in desert, it is necessary to study the near-surface structure and its depth-velocity relation, followed by developing the corresponding depth—velocity model, based on which calculating the static correction values of shot point and ac-ceptance point. References | Related Articles | Metrics

Systematic Management for Hydrate Prevention in Condensate Gas Well GUAN Wen-long, LI Xiang-fang, LI Jing-song 2003, 24 (4):  319-321.  Abstract ( 65 )   PDF (1730KB) ( 146 )   Save While a condensate gas well produces, hydrate prediction or prevention is a complicated work relating to reservoir engineering, drilling and completion engineering, production engineering and surface construction engineering, among which large numbers of equations and variables must be considered simultaneously and normally attended one thing and lost another. The systematic decision-making method for hydrate prevention in condensate gas well is proposed in the light of reservoir management. And the hydrate management system model is developed by considering the coupling relationships within these aspects and displayed by the system state chart. In addition, examples of hydrate prevention in three different condensate gas well are presented for application, showing that this method can be used effectively for condensate gas reservoir management. References | Related Articles | Metrics

Study on Technical Parameters for Reasonable Exploitation of Wellblock Hu-2 Gas Reservoir in Hutubi Gas Field QIAN Gen-bao, ZHANG Mao-lin, DU Zhi-min, LIU Ming-gao, WANG Bin, SUN Bao-zong 2003, 24 (4):  322-324.  Abstract ( 65 )   PDF (1916KB) ( 147 )   Save The high pressure PVT experiment data of Wellblock Hu-2 condensate gas reservoir in Hutubi gas field are calculated. The fluid compositional characteristic parameters used for describing the phase behavior of this reservoir are determined. According to the petrophysical parameters from individual well and layer integrating with structure geometry and well location, a 3D geologic model is developed. Following its reserves matching, study of the gas production history matching is made, obtaining satisfactorily matched results. For demonstrating the technical parameters for reasonable exploitation of Wellblock Hu-2 gas reservoir, the numerical simulation research in nine aspects is conducted. The main conclusions are that seven gas wells can meet the production requirement, and productivity plan of 150x104m3/d is reasonable, with stable production period of eight years ranging from Ian., 2003 to Dec., 2020. It is estimated that recovery percent of natural gas and condensate will reach 70.7558% and 44.1564%, respectively, by the end of 2020. References | Related Articles | Metrics

Feasibility Study on EOR by Nitrogen Injection Process in Ren 11 Well Buried Hill Reservoir, North China HE En-jie, JIANG Ming, XU Ai-yun, SONG Fu-xia, YAN Ai-hua, ZHU Hong-li 2003, 24 (4):  325-328.  Abstract ( 120 )   PDF (648KB) ( 152 )   Save As a major reservoir type in North China^s oil domain, buried hill reservoirs accounting for about 60% of the total producing OOIP have been into high water-cut development stage. How to dig the remaining oil potential and enhancing oil recovery further is dominant work target now. The EOR mechanism by nitrogen injection process and geologic condition are analyzed in the light of geology and production characteristic of massive carbonate reservoir with bottom aquifer in Ren 11 Well buried hill. Based on the numerical simulation, feasibility of EOR by nitrogen injection process is discussed, providing studies on optimization of well number of nitrogen injection, equilibrium time of oil, gas and water, fluid production rate, process of gas-injection recovery, gas injection rate and timing, well pattern, etc. Results show that EOR by nitrogen injection process in Ren 11 Well buried hill reservoir is feasible under the support of technology available, with estimated oil-enriched zone thickness formed by nitrogen injection about 200m and incremental recovery about 4%. References | Related Articles | Metrics

Simulation of Condensate Recovery and Natural Gas Liquefied Performance XIONG Yu, ZHAO Ming, ZHANG Jian 2003, 24 (4):  329-331.  Abstract ( 102 )   PDF (689KB) ( 160 )   Save loule-Thomson (J-T) thermal insulation/throttle expanding device and turboexpander are main equipments for gas condensate recovery and LPG production. This paper presents a new model for this light hydrocarbon recovery and gas liquefied performance simulation with thermal insulation efficiency. By applying PR equation-of-state, the procedures of thermal insulation expansion, turbine expansion and separation by deep refrigeration are simulated for surface engineering of gas condensate reservoir. Results show that this method can be well used for description of procedures of J-T thermal insulation/throttle expansion and turbo-expansion. References | Related Articles | Metrics

Technique for Biopolymer Plugging Adjustment DI Sheng-jie, LY Zhen-shan, WANG Li-feng, ZHANG Wei-guo 2003, 24 (4):  332-334.  Abstract ( 120 )   PDF (193KB) ( 156 )   Save In the light of high water-cut oilfield, technical study of the biopolymer plugging adjustment is made. Based on the biopolymer property, core flooding ability and biopolymer plug adjustment capacity are discussed. Following lab experiment of physical model oil displacement with enhancing recovery of 9% and incremental oil production of 647t by oil-well water block-off, the field tests of biopolymer plugging adjustment in two water producers are made, lowering water-cut of 7.7~64.5% in adjacent oil wells with more than one year effec-tiveness. Through test monitoring and performance analysis, that the main factors influencing the effect of biopolymer plugging adjustment are confirmed, being as a guide for in-depth research and large-scale application of this technique. References | Related Articles | Metrics

Application of Grey Correlation Analysis to Optimization of Oilfield Stimulation YANG Xiao-ping, CHENG Lin-song, SUN Fu-jie, ZHANG Xiong-jun 2003, 24 (4):  335-337.  Abstract ( 95 )   PDF (202KB) ( 202 )   Save The optimization of oil-gas field stimulation is a complex engineering project with multi-targets, which allows to use a series of technical and economic indexes for complete and systematical evaluation of available stimulation processes. According to correlation analysis principle of grey system theory, a grey correlation analysis approach used in oil-gas stimulation optimization is developed, with specifically applied cases. It is concluded that this approach can be not affected by mathematical statistics ones which limit data; when economic index of each program is given, the analytical result gained by applying this approach is given without changes for different analysts or decision-makers; possessing advantage over another methods in quantification of parameters. In addition, this approach is simple and reliable in calculations. References | Related Articles | Metrics

Production-Cost-Profit Analysis and Well Stimulation Decision Making CHEN Qing-han, ZHU Kal, ZHAO Yan 2003, 24 (4):  338-340.  Abstract ( 88 )   PDF (684KB) ( 171 )   Save By applying basic theory of production-cost-profit analysis and reservoir engineering method, the cost structure of well stimulation is analyzed, the critical IOR model, investment ceiling model and production critical sale price model are developed. Based on high investment of old well stimulation and greater risk in decision making, the concepts and analytical models of old well stimulation critical balance point operational efficiency and well stimulation safety marginal production rate are introduced for the first time. According to the practical experience, a general procedure for well stimulation decision making is presented, and some cases are given. The study shows that results from these models accord with the economical operational law for the well stimulation, hence they provide useful tools for evaluation/imple- mentation of old oilfield stimulation and integrated adjustment. References | Related Articles | Metrics

Pressure Behavior of Horizontal Well with Multiple Transversal Fractures LIU Zhen-yu, FANG Liang, AN Yan-ming, ZAI Yun-fang 2003, 24 (4):  341-343.  Abstract ( 78 )   PDF (388KB) ( 135 )   Save The flow mechanism of Horizontal well with multiple transversal fractures is studied. Under the assumption of variable flow rate between transversal fractures, theoretical curves of bottom hole pressure are given, which show flow characteristics of three periods: the first one represents the linear flow in fractures; the second one the instantaneous flow from strata to fractures and from fractures to the wellbore; and the third one the stable flow of the system equilibrium. They also indicate the effects of fracture length and fracture spacing on the wellbore pressure. In addition, study shows that at early stage, the bottom hole pressure behavior of horizontal well with multiple transversal fractures is similar with that of vertical well with vertical fractures. References | Related Articles | Metrics

Application of Correction Model for Abnormal Well Test Data Processing in Gas Well System XIA Xian-bai, WANG Wei-jun, HU Guang-jun, PENG Hai-jun 2003, 24 (4):  344-346.  Abstract ( 75 )   PDF (1108KB) ( 168 )   Save By influences of internal and external factors in the reservoir, different deviations of production and pressure data from stable well testing in gas well tend to resulting in abnormal shape of productivity curve, which is difficult to get open-flow capacity. In some cases, retesting has to be needed. The major factors for them include reservoir pollution, variable skin factor, interlayer interference and sand face flux, etc. And different factors have different effects on well test data in feature and extent. For this reason, SWT2000, a well-testing software, is applied for analysis of the abnormal phenomenon in well test data, and suitable correction model is selected for effective elimination of the falsification phenomenon of the curves, followed by obtaining the productivity parameters of the gas well. Practice shows that the reliable pro-ductivity parameters can be obtained if we make correct adjustment of abnormal factors of well test data, as well as selection of proper correction model. References | Related Articles | Metrics

Application of Benefit Evaluation in Oilfield Development YIN Yong-guang 2003, 24 (4):  347-348.  Abstract ( 74 )   PDF (378KB) ( 175 )   Save With PetroChina entering stock market,the maximization of enterprise business value and investment capital becomes its final goal and is also requested by its shareholders. Hence,it has to optimize resource allocation and reduce cost in order to obtain maximum profit and attract capital. Carrying out benefit evaluation is just to meet this requirement of the marketed company, providing scientific basis for correct working out an annual development plan of the oilfield. This paper presents the benefit evaluation process,including the principle,standard and discriminant of evaluation and its classification, etc. In addition, the chart of economic limit can be as a guide for old field stimulation and investment decision making,and apply ioi popularization to other fields. References | Related Articles | Metrics

Technique for Mapping Low-Amplitude Structure XU Wen-mei 2003, 24 (4):  349-350.  Abstract ( 85 )   PDF (155KB) ( 222 )   Save The study results of low-amplitude structure in Tuohula-Sandaoqiao area of Kuche depression in Tarim basin are summarized, based on which this paper presents the technique for mapping deep low-amplitude structures. The technique can be used to improve the mapping accuracy of low-amplitude structures, verify local structures, reduce risk for exploration. The key of the mapping technique is in un-derstanding of seismic velocity, in which the main procedures are described as following: 1) calculation of interval velocity from Dix formula and obtaining the average velocity by using the stack velocity; 2) calculation of pseudo average velocity from drilling geologic zonation data and seismic interpreted interval as well as its transversal variation gradient; 3) analysis and correlation of the average velocity and variation (i. e. velocity and gradient matching); 4) averaging the difference between steps 2) and 3), and making correction by Kriging interpolation tech-nique; 5) correlation of t0 interpretation and average velocity change; 6) consideration and remove of 3D boundary effect, and 7) making time- depth conversion. References | Related Articles | Metrics

Study of Stress and Strain State in Reservoir Rocks LI Chuan-liang, DU Wen-bo 2003, 24 (4):  351-352.  Abstract ( 75 )   PDF (158KB) ( 125 )   Save The strain state is assumed to be one dimension strain, while the stress state appears 3D one in process of rock sedimentation. However, during oil-gas production in reservoir rocks, it is shown that both the strain state and the stress one are of 3D features. Therefore, the rock compressibility coefficients measured in core labs represent the values under the 3D strain state, and can be directly applied to study of related reservoir engineering without necessary to be converted. It is invalid for traditional practice to convert rock compressibility coeffi-cient from 3-D strain state to a dimensional one, which may allow the elastic energy in an oil-gas reservoir rock to be underestimated badly. References | Related Articles | Metrics

A Discussion about Interpretation Method for DST Date in Low Permeability Formation MAO Wei, YU Bi-jun 2003, 24 (4):  353-355.  Abstract ( 73 )   PDF (1269KB) ( 147 )   Save Pressure derivative method at constant flow rate, Peres convolution and deconvolution methods are used to interpret pressure data in flow period. The result shows that reliable formation parameters can be obtained when flow period is long enough. Peres convolution and deconvolution methods are applicable to infinite acting radial flow, but can not be applied to analyze pressure data in early and late periods which are affected by wellbore storage and boundary. Pressure derivative method at constant flow rate has multi-solutions because the pres-sure derivative curve is not on the 0.5 horizontal line. Buildup period is longer than flow period, so the pressure derivative curve is more com-plete, reflecting flow regime of various models. A new method is proposed which use pseudo-steady time and pseudo-steady flow rate to sim-ulate flow period. According to these two parameters, typical curve match and non-linear regression methods are used to analyze the buildup period. Pressure buildup data from 10 wells are interpreted using the proposed method. The interpreted results are correlated with results of linear analysis methods (three kinds of pressure buildup methods) and average flow rate method. The results show that the new method is more accurate and reliable and makes identification of variable boundary conditions. References | Related Articles | Metrics

Analysis of the Change Characteristics and Development Trend of Proven Oil Reserves in China ZHOU Zong-ying, ZHANG Kang, TANG Yao-gang 2003, 24 (4):  356-359.  Abstract ( 134 )   PDF (509KB) ( 192 )   Save In recent years, China’s proven oil reserves show the varied characteristics which can be summarized as following: 1) growth with steadiness and high range, but there exist distinct differences; 2) reduction of both pool size and reserves abundance in the newly discovered oilfields, and 3) extremely slow growth of remained recoverable reserves. According to these characteristics, Logistic model, experience trend method and grey system model are selected, integrated with domestic various prediction results, comprehensive analysis of growth trend of proven oil reserves is made for the short-term and medium-term in China. It is estimated that new incremental proven reserves will reach 3.5~3.8 billion tons during the period from 2001 to 2005; 3.2~3.5 billion tons during the period from 2006 to 2010, showing a good exploration potential. References | Related Articles | Metrics

Heterogeneity of Karst-Vuggy Carbonate Reservoir Rocks LU Xin-bian 2003, 24 (4):  360-362.  Abstract ( 160 )   PDF (169KB) ( 314 )   Save A karst-vuggy reservoir is serious in reservoir heterogeneity, hence to fully understand or pay more attention to its developing situation is of significance for the reservoir development. The vertical and lateral heterogeneous structural characteristics specifically appeared in a karst-vuggy reservoir are analyzed, and the major factors affecting and controlling its heterogeneity are studied, considering its specific porosity-permeability structure and correlation. In addition, a number of techniques for describing this kind of reservoir heterogeneity are evaluated, such as random simulation, fractal geometry and cloudy transformation in reservoir modeling. It is shown that random simulation play an important part in reflecting reservoir heterogeneity such as space distribution estimation of porosity, simulation of permeability value connectivity and quantitative estimation of uncertainty of carbonate reservoir, etc.; the model developed with fractal geometry is higher coincidence to real conditions than the model developed with conventional methods; while cloudy transformation technique can be used for more clearly and truly reflecting permeability and its distribution in vuggy reservoir zone. References | Related Articles | Metrics

Rapidly Developing Xinjiang Petroleum Geology—Quotation analysis of Xinjiang Petroleum Geology CHEN Jian-jun, LIU Chi-yang, YAN Wei-hong, TANG Yong-huai 2003, 24 (4):  363-366.  Abstract ( 68 )   PDF (442KB) ( 141 )   Save The evaluation about the influence of a scientific-technical journal depends on the effective factor and the quoted frequency in domestic journal field, while these indices are mostly based on the average quoted rate (AQR) of a journal. On the other hand, only a journal with high AQR has high effective factor and/or quoted frequency. The authors analyze Xinjiang Petroleum Geology in average quoted rate, references, textures and authors available, and suggest that this journal will be of high potentials in AQR, quoted frequency and effective factor. If paying more attention to the quotation of the reference which is greatly effecting the quality of the journal and reducing time-delay period for manuscript publication, it is believed that the influence of Xinjiang Petroleum Geology will be more increased. References | Related Articles | Metrics

Geologic Technology for Heavy Oil Reserves Development Using Condensate Flooding E.M. Khalimov, N.V. Kolesnikova, I.S. Djapharov, A. Khirayama 2003, 24 (4):  367-368.  Abstract ( 86 )   PDF (530KB) ( 139 )   Save In frames of joint Russian-Japanese scientific-research project,the study of prospects of high-viscous oil reserves development in West Siberia using condensate flooding was carried out. Results of laboratory tests by mixing high-viscous oil with condensate allowed to recognize that at 25% adding of condensate,mix viscosity decreases almost 60 times in comparison with such of high-viscous oil. On the example of Russkoye field a possibility of tests on condensate injection is considered; necessary volumes of condensate and possible volumes of oil production are evaluated, veriants of production transpiortation shown. Related Articles | Metrics