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01 December 2011, Volume 32 Issue 6 Previous Issue    Next Issue

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Depositional Model and Geological Significance of Wetland JIN Zhen-kui, YANG You-xing, SHANG Jian-lin, WANG Lin-sheng 2011, 32 (6):  577-578.  Abstract ( 141 )   PDF (249KB) ( 237 )   Save Wetland as a transitional area between land and water area (e.g. lake, ocean) is a significant type of sedimentary facies. In this paper, the wetland is redefined and reclassified, and divided into two types from the view point of sedimentology, and divided into two types, i.e. swamp wetland (swamp in brief) and wet plain wetland (wet plain in brief). The deposit of the former is coal, while that of the latter is mudstone with rich plant fossils. Many researchers always classified dark mudstone into underwater reduction environment (lake) sediment and regarded it as potential source rock. This is definitely incorrect. Because some dark mudstones can be wet plain sediments and can not become as source rocks. So, to know well the depositional model and recognition feature of wetland and exactly distinguish wet plain and lake deposits or sediments are of great significance for basin oil genetic potential evaluation and lake basin evolution history understandings. References | Related Articles | Metrics

Geochemical Characteristics of Carboniferous-Permian Volcanic Rocks in Zhongguai Area in Northwestern Margin of Junggar Basin SUN Guo-qiang, YAO Wei-jiang, ZHANG Shun-cun, XING Cheng-zhi, SHI Ji-an, LI Bing 2011, 32 (6):  580-582.  Abstract ( 102 )   PDF (319KB) ( 493 )   Save The analyses of the whole-rock elements of 25 samples from Carboniferous-Permian volcanic rocks in Zhongguai area in northwestern margin of Junggar basin reveal that the volcanic rocks are mainly composed of intermediate-acid andesite, dacite, rhyolite, volcanic breccia and tuff, of which SiO2 content averages 66.840%, and they are dominated by calcic series and calc-alkalic series (calcic series accounts for 64% and calc-alkalic series for 36%). According to the geochemical characteristics of the volcanic rocks in this area, the volcanic eruption should occur in the continental inner side of island arc system and undergo melting process of continental crust. References | Related Articles | Metrics

New Understanding of Sedimentary Facies of Baijiantan Formation in Baikouquan Area, Junggar Basin SHANG Jian-lin, JIN Zhen-kui, WANG Lin-sheng, SHI Xiao-zhang, DU Wei-xing, WANG Zhi-zhong, LIU Lin 2011, 32 (6):  583-585.  Abstract ( 114 )   PDF (476KB) ( 262 )   Save Previous studies regarded the glutenite of Baijiantan formation of the Upper Triassic in Baikouquan area in Junggar basin as deposits of the delta front, and the main basis was that the mudstone interbedded with glutenite was in reduction color which represents underwater reduction environment deposits. But the analyses of a large amount of core observation, well logs, logging data and seismic information indicate that the glutenite reservoir of Baijiantan formation is dominated by braided fluvial deposits, a few belong to delta front deposits. The colors of most mudstones interbeddedd with the glutenite are dark, because they contain a lot of fossils of many plant roots, rods, stems, leaves, and even have coal seam interbed. Also, the Baijiantan formation is a sedimentary cycle gradually becoming shallow from the top to the bottom, the lower part is lake deposit, the middle is delta deposit and the upper is braided fluvial one. The sands of braided fluvial deposits in the studied area are characterized by strip, coarse granularityand, low shale content and good reservoir quality, in which the main oil-bearing reservoirs have been formed and found; while sands of the delta front characterized by sheet, fine grain size, high shale content and poor reservoir quality, in which oil-bearing zone has not been found. References | Related Articles | Metrics

Distribution of Sand Body of Lower Sub-Formation of Karamay Formation (Kexia Sub-Formation) in West No.1 District in Karamay Oilfield XIN Yu-xia, WANG Zhi-zhan, PANG Xiong-qi, LIN Jun, Gulizhadan, LI Wen-feng 2011, 32 (6):  586-588.  Abstract ( 94 )   PDF (400KB) ( 211 )   Save The Kexia sub-formation in west No.1 distribution in Karamay oilfield is a well-developed fan delta depositional system whose sand body types consist of braided channels, channel bar, channel margin, interchannel mud, underwater distributary channel, underwater distributary channel margin, underwater distributary interchannel mud, distal bar, pre-fan delta mud. By using cross-hole simulation technique and well logs, four superposition patterns of complex channels are identified: isolate type, butt joint type, cut overlapping type and superimposed type. Meanwhile, according to the cross-hole simulation and the six principles of sand body lateral comparison (height difference, thickness difference, configuration difference, range difference, rhythm difference and quality (productivity) difference), the vertical and horizontal characteristics of the sand body of the Kexia sub-formation are obtained, which can support adjustments for further field development in this area. References | Related Articles | Metrics

Characteristics of Volcanic Reservoirs of Harjiawu Formation in Malang Sag in Santanghu Basin LIU Cheng-zhi, LIU Hong, WANG Xiang-fei, HE Ren-zhong, WANG Xin, YU Hai-shan 2011, 32 (6):  589-593.  Abstract ( 99 )   PDF (1031KB) ( 292 )   Save Based on the data of core, thin section, scanning electron microscopy and the petrophysical property, this paper presents the characteristics of Harjiawu volcanic reservoir of the Carboniferous in Malang sag, and obtains the following understandings. ①The lithology is dominated by basalt, andesite and transitional lithology; ②The main lithofacies is overflow facies, explosion and volcanosedimentary facies are secondary; ③The volcanic reservoir are of medium-low porosity and low-super low permeability; ④Primary porosity is not developed because of its underwater eruption, however, the pores, vugs and fractures often superimposed on the original storage space after the transformation of the post-magmatic diagenesis and woven together form the effective storage spaces; ⑤The phenomena such as albitization, arfvedsonitization and Sideritization prove existence of hydrocarbon alkali fluid in the Carboniferous volcanic rocks and the extensive development of alkali metasomatism; ⑥Devitrification, weathering, tectonism, metasomatism and dissolution have significant effects on the volcanic reservoir modification, which are the main diageneses for forming secondary pores and the key factors for forming effective reservoirs of the Harjiawu formation. References | Related Articles | Metrics

Forming Conditions and Explorative Targets of Chang-6 Reservoir in Panlong Oilfield in Eastern North Shaanxi Slope, Ordos Basin BAI Yu-bin, ZHAO Jing-zhou, LUO Jing-lan, CHEN Xiao-ping, ZHANG Ai-cheng 2011, 32 (6):  594-596.  Abstract ( 199 )   PDF (307KB) ( 214 )   Save Low-degree investigation on forming conditions of Chang-6 reservoir of Panlong oilfield in Ordos basin results in unsatisfied result of petroleum exploration. Except for finding out Chang-6 reservoir in Shazegou area in southern Panlong oilfield, this reservoir has not been found in the middle and north parts of this oilfield, showing that the potentials of petroleum exploration of Chang-6 reservoir are still very big. Studies show that the forming conditions of Chang-6 reservoir are advantageous. This paper comprehensively and systematically analyzes and summarizes the exploration experiences of Chang-6 reservoir in Shazegou area, and suggests that to further study its lows of petroleum migration and accumulation, and increase the exploration efforts, the exploration of Chang-6 reservoir in the middle part of this oilfield will make progress soon. References | Related Articles | Metrics

Effect of Quaternary Formation Water in Sanhu Depression on Biogas Migration and Accumulation CHENG Fu-qi, LIN Hui-xi 2011, 32 (6):  597-599.  Abstract ( 105 )   PDF (349KB) ( 230 )   Save The kinetics and geochemistry characteristics of formation water in Sanhu area are investigated in order to reveal the effect of Quaternary formation water in Sanhu depression on biogas migration and accumulation, and the effect of formation water on biogas migration and accumulation is determined clearly by the features of biogas migration and accumulation. The study shows that the potential energy of the formation water in Sanhu depression in south is greater than that in north. Laterally, the salinity of formation water is lower in depression margin than in center, and 3 high-salinity districts appear. These high-salinity districts should be the favorable places for biogas precipitation and accumulation, for instance, the formation of Tainan and Sebei gas fields. Vertically, the salinity of formation water is increasing from the top down, with up and down multi-cycle variation. Such a "south-high and north-low" potential energy of formation water allows the biogas dissolved in water to migrate from the south to the north and accumulate toward slope zone in the north. And the multi-cycle variation results in the biogas precipitation at high-salinity section and dissolution at low-salinity segment, shaping multi-group superposed gas reservoirs. Also, the amplitude of multi-cycle variation of the formation water salinity is proportional to the biogas enriched extent. References | Related Articles | Metrics

Genesis and Distribution of the Cambro-Ordovician Dolomite in Tarim Basin ZHENG Jian-feng, SHEN An-jiang, LIU Yong-fu, CHEN Yong-quan 2011, 32 (6):  600-604.  Abstract ( 201 )   PDF (578KB) ( 503 )   Save The dolomites of Cambro-Ordovician in Tarim basin are of four geneses, corresponding with four kinds of dolomitization ones such as sabakha dolomite, seepage reflux dolomite, buried dolomite and hydrothermal dolomite, which can be properly identified from the lithologic characteristics and geochemical characteristics. This paper comprehensively analyzes the paleogeographic and paleoclimate data, concludes the vertical and lateral distributions of dolomites with different geneses in Tarim basin: the development of sabakha dolomite and seepage reflux dolomite are controlled by sedimentary facies and mainly developed in Lower-Middle Cambrian; the development of burial dolomite are controlled by diagenetic facies, but the reef and shoal with high porosity as well as open system connected with fracture passage are easy to dolomitize; hydrothermal dolomite mainly develops below unconformity and near the discordogenic fault. References | Related Articles | Metrics

Shajingzi Fault Belt and Its Controlling Effect on Hydrocarbons in Awati Sag in Tarim Basin ZHOU Yuan-yuan, LV Xiu-xiang, QI Ying-min, BAI Zhong-kai, ZHU Hai-yan, LI Yu-feng 2011, 32 (6):  605-608.  Abstract ( 124 )   PDF (436KB) ( 446 )   Save Shajingzi fault is boundary fault in northern Awati sag in Tarim basin, with trend of NE-SW and length of 180 km. The study of such a large-sized fault belt is now relatively not in-depth. Based on the analysis of the fault belt in plane distribution, profile characteristic, development and evolution, and its controlling effect on hydrocarbon accumulation, it is suggested that Shajingzi fault belt can be divided into western part, middle part and eastern part. It begins development since the early period of Hercynian, and its major fault has been active up to the present, which controls the structural framework, sedimentation, trap formation, oil-gas migration and accumulation of northern Awati sag. References | Related Articles | Metrics

Detection of Oil and Gas in Turbidite Fan System by Low-Frequency Shadows Method LIU Wei, HE Zhen-hua, CHEN Xue-hua, WENG Bin, JIANG Xiu-di 2011, 32 (6):  609-612.  Abstract ( 73 )   PDF (600KB) ( 229 )   Save In recent years, low-frequency shadows technique hase been applied effectively to detection of glutenite and reef-flat reservoirs, but seldom to turbidite fan system. The key for detection of low-frequency shadows is to make a good time-frequency analysis. In order to study the feasibility of low-frequency shadows for oil and gas detection in turbidite fan system, the generalized S transform (GST) is applied to transient spectral decomposition, creating a series of common frequency data volumes. Through detection of the amplitude energy variances of different frequencies, it is shown that the amplitude energy beneath turbidite fan reservoir is gradually weakened and disappeared with the frequency increasing, which is regarded as low-frequency shadows. The case study indicates that the seismic low-frequency shadows can directly indicate existence of oil and gas, thus in turbidite fan system, they are also taken as an effective method for reservoir prediction and oil-gas detection. References | Related Articles | Metrics

Mode for Hydrocarbon Accumulation of Jurassic in Bohu Depression in Xinjiang Yanqi Basin ZHANG Hui, WANG Run-chao, JIN Bei-bei, JIN Yun-yun, HUANG Shuai-bo 2011, 32 (6):  613-615.  Abstract ( 112 )   PDF (238KB) ( 293 )   Save The migration of oil and gas generated from Jurassic source rocks in Bohu depression of Yanqi basin mainly depends on two modes of layered migration and reticulated migration. The hydrocarbon accumulation process follows the "differential accumulation" principle, and the oil-gas adjustment modes appear in "vertical adjustment" and "horizontal adjustment". Also, the accumulated oil and gas are lost by "exposure condition" and "buried condition". This paper suggests that the key area for further petroleum exploration in Bohu depressions should turn to the lithological reservoirs with "less tectonic movement effects and better oil-gas preservation conditions in the late stage". References | Related Articles | Metrics

The Optimizing Method for On-Ground Retorting Targets in Oil Shale Mining Areas WU Min-jie, ZHANG Jing-ping, LI Zhong-cheng, TANG Shu-heng, XIE Hui, LV Jian-wei 2011, 32 (6):  616-620.  Abstract ( 95 )   PDF (288KB) ( 215 )   Save There are two primary ways to mine oil shale, i.e. on-ground retorting and in-situ exploitation, the former is the traditional way for development of oil shale resources. Different ways should have their own parameter evaluation systems during optimizing the development target of them. In order to more rationally and orderly develop the oil shale resources, a new system for on-ground retorting was built by analytical hierarchy process (AHP). The parameters related to oil shale evaluation are selected and weight values assigned by AHP, then a scoring software which can mark the actual parameters is developed. The scores of each mine are obtained through multiplying the score values of the actual parameters and their weight values. According to the scores, all the oil shale mines across the country are evaluated at last. The results show that there are twenty-eight the best potential areas for on-ground retorting exploitation. They are North Bogda mountain oil shale mine, Fushun oil shale mine and the Danzhou oil shale potential mine, etc. References | Related Articles | Metrics

The Coal-Accumulating Environment and Coal-Forming Model of Yacheng Formation in Qiongdongnan Basin REN Gui-yuan, XIAO Jun, LI Yan-li, LIAO Ji-hua, LI Guo-liang, XIA Cun-yin 2011, 32 (6):  621-623.  Abstract ( 98 )   PDF (306KB) ( 415 )   Save Based on the drilling data, core data and seismic information, this paper discusses about features of coal-accumulating environment and coal-forming of Yacheng formation in Qiongdongnan basin with application of methods and theories of sequence stratigraphy and sedimentology. Coal seams of the Yacheng formation are mainly found in peat flat of supralittoral zone and intertidal zone of tidal flat, peat swamps of the braided river delta plain and fan-delta plain. Focusing on the coal-accumulating environment and considering the influence of paleostructure, the coal-accumulating model for Qiongdongnan basin is developed as following: the supralittoral zone and intertidal zone in tidal flat are of the largest area, being the main coal-accumulating environment; the distribution of coal-forming sedimentary system in gentle slope zones is broader than that in steep slope zones controlled by faults; the second member of Yacheng formation is of greater potentiality of coal-accumulating. References | Related Articles | Metrics

EOR Study in Beibu Gulf Oilfield by Associated CO2 Injection Process XU Huai-yin, ZHANG Bao-sheng 2011, 32 (6):  627-628.  Abstract ( 132 )   PDF (218KB) ( 912 )   Save By screening and assessment, the C oil field located in Beibu Gulf is chosen as the place for EOR to inject the CO2 discharged from the terminal of gas field in Hainan Island. According to the oilfield conditions, when the rate of injected CO2 reaches 1 000 t/d, it is just accordant with the requirement of stable CO2 injection for 20 years. Although paving 180 km pipeline is expensive, the benefit from EOR by CO2 injection process will be greater, not only offsetting the cost invested at the early stage, but also gaining a lot of profit. If carbon tax and carbon trade are implemented in China, the CO2 injection process for EOR will be more promising. References | Related Articles | Metrics

Variation of Critical Producing Pressure Differential of Horizontal Well in Gas Reservoir with Bottom Water WU Ke-liu, LI Xiang-fang, HAN Yi-long, ZHAO Jing-jing 2011, 32 (6):  630-633.  Abstract ( 98 )   PDF (409KB) ( 317 )   Save Using material balance principle, gas-bearing height and water-bearing height variations in bottom-water reservoir with time are deduced, and the sweep efficiency is approximately determined. Then, based on the equivalent flowing resistance method and vertical critical velocity of bottom water drive, the computational model for critical producing pressure differential for development of gas reservoir with bottom water is derived. Therefore, the variation of decline trend when quantitatively expressing the increase of critical producing pressure differential of horizontal well with time is clarified. Moreover, this paper analyzes the influences of ratio between vertical permeability and horizontal permeability, the difference between water and gas density, the ratio of water to gas viscosity and height of bottom water coning on the critical producing pressure differential. The results could provide theoretical basis for determination of reasonable producing pressure differential and producing rate by horizontal well development of gas reservoir with bottom water. References | Related Articles | Metrics

Fractal Feature of Viscosity-Temperature Curves to In-Place Oil TANG Hong-ying 2011, 32 (6):  634-636.  Abstract ( 89 )   PDF (212KB) ( 188 )   Save The comprehensive analysis of in-place oil viscosity-temperature curves and oil analysis data aims at deepening the understanding of crude physical property. The study shows that the crude oil viscosity-temperature curves from different oil fields, different horizons and different well depths have good fractal feature. Under the fractal conditions that we regard viscosity as scale and temperature as object, the fractal dimension D is decimal, and the numerical value ranges from 0.1 to 0.3. With increase of the fractal dimension, the effect of temperature on viscosity becomes smaller. The fractal dimension and the parameters such as density, viscosity and initial boiling point of crude oil have good correlativity. So the fractal dimension D can be taken as a new characteristic parameter reflecting crude oil physical properties. It is only related with asphaltene content, rather than wax content and gel content, showing that the asphaltene and its content is the main factor influencing fractal dimension value of crude property and viscosity-temperature curve. This conclusion is accordant with the viewpoint that asphaltene fraction takes principal part in changing wettability of rocks, compared with other fractions. References | Related Articles | Metrics

The Protist of Crude Oils in Karamay Oilfield: Features and Application YU Juan, CHEN Ai-hua, CHEN Yong-li 2011, 32 (6):  637-639.  Abstract ( 104 )   PDF (155KB) ( 200 )   Save Based on the lab experiments and field tests of in-situ original microbes drive in light oil blocks and the lab feasibility studies of such a drive in heavy oil blocks in Karamay oilfield, the features and applied values of the protist in light and heavy oil reservoirs in this oilfield are presented. It is suggested that in light oil blocks the content of in-situ original microbes is relatively low, with poor activity, for this reason, the screening, culturing and re-injection of the microbes can notably enhance the oil recovery (EOR) of these reservoirs, while in heavy oil blocks the content of in-situ original microbes is relatively high, with good activity, using direct injection of culture medium to activate such microbes is more ideal for EOR, at the same time, the viscosity-reducing process by emulsification for high-viscosity and high-calcium heavy oil can be realized, with viscosity-reducing rate of over 50% and de-calcium rate of over 90%. References | Related Articles | Metrics

Chaos Identification of Time Series of Acidized Well Oil Production Rate TANG Gang, LIU Cheng-jie, ZHANG Guang-zheng, LIU Jun 2011, 32 (6):  640-642.  Abstract ( 101 )   PDF (249KB) ( 235 )   Save Well production rate is commonly predicted based on the permanence principle of traditional technical economy prediction. However, such a prediction principle has been challenged by the emergence and development of chaos theory. Unfortunately, there is little work has been done on the chaos identification and prediction of acidized well production rate. This paper presents techniques of phase space reconstruction and correlation dimension extraction, by which the 60-day time series of oil production rate from an acidized well in one oil filed in west China is investigated. It is discovered that the correlation dimension of the time series of oil production rate is 11, and the attracter's dimension is 2.64. Thus, the attracter is a strange one and the production rate varied chaotically. Furthermore, it indicates that the number of essential variables of the production variation ranges from 3 to 11. The results present quantitative reference to presenting accurate dynamic model of the production system, especially to defining the correct number of input layer nodes in ANN (artificial neural network) models. References | Related Articles | Metrics

Mechanism and Adaptability of Removing Block by Enzyme-Aqueous Preparation ZHAO Jin-cheng, ZHANG Shu-huan 2011, 32 (6):  643-645.  Abstract ( 102 )   PDF (145KB) ( 206 )   Save Using enzyme-aqueous preparation to remove blocks in porous media during production is a new high-tech. On the basis of latest research results in enzymology and enzyme engineering principles, combined with new understandings in contemporary reservoir engineering theory, in-depth discussion of such a blocking mechanism is made to lay a solid foundation for the practical application of the enzyme-aqueous preparation. According to the technical requirements for oilfield development, the adaptability of blocking operation is analyzed, which provides scientific basis and technical support for engineering design and field operation. References | Related Articles | Metrics

Well Performance Analysis Method for Volcanic Gas Reservoir Based on Flowing Material Balance LIU Ping, SHI Xin-pu, LI Zhi, DING Xue-zhi, YANG Dan, LI Bo, HE Lu-jun 2011, 32 (6):  646-649.  Abstract ( 91 )   PDF (327KB) ( 250 )   Save Volcanic gas reservoir is generally characterized by serious heterogeneity, great permeability difference, complicated distribution of gas and water, complex productivity distribution and big differences of well-controlled reserves by exploitation. Therefore, the well performance of volcanic gas reservoir is hard to analyze using the conventional gas reservoir decline analyses such as exponent, hyperbolic and harmonic decline methods. This paper presents single well performance analysis method for the volcanic gas reservoir based on flowing material balance. Furthermore, Blasingame curve is introduced to diagnose the gas flow characteristic section in such a well and enhance the reliability for parameter estimation. The reservoir permeability, wellbore skin factor and dynamic reserves can be obtained with the new well performance analysis method, which are of significance for the volcanic gas reservoir development. References | Related Articles | Metrics

2-D Acoustic Wave Numerical Simulation and It's Application in Frequency Space Domain LIAO Jian-ping, WANG Hua-zhong, YANG Tian-chun, WANG Qi-ren, LIU Xin-hua 2011, 32 (6):  650-652.  Abstract ( 81 )   PDF (321KB) ( 225 )   Save Adopting the nested-dissection method to store the acoustic wave equations for finite difference dispersion frequency space domain can shape large scale sparse coefficient matrix, which can decrease the requirement of computer capacity and reduce the computing amount greatly. Using the fast computational procedure of multi-shot acoustic wave simulation in 2-D frequency space domain can also increase the computing velocity of numerical simulation. In this paper, the hypocenter singularity problem from the frequency domain forward modeling is analyzed and discussed in detail, and corresponding solved measures are proposed, clarifying the principle for correct selection of parameters during such a numerical simulation. The results of numerical simulation experiments on the velocity model of representative complex geologic structures in Shengli oilfield demonstrate that the nested-dissection method has many advantages compared to compressed storage format, such as saving huge storage and computing time and high computing efficiency, etc., and it can be definitely used to simulate real data. References | Related Articles | Metrics

Forecast Model for Oil Migration and Accumulation Coefficient Based on BP Neural Network LV Yi-bing, ZHANG Tao, LV Xiu-xiang 2011, 32 (6):  653-655.  Abstract ( 87 )   PDF (226KB) ( 300 )   Save Based on the data from a series of petroleum migration and accumulation units, the major geologic factors for controlling oil migration and accumulation coefficient are selected. The forecast model for oil migration and accumulation coefficient based on BP neural network is developed by taking the major geologic factors as the input vectors and the oil migration and accumulation coefficients as output vectors. It is indicated that the applied result of this model is in good agreement with the observed data with average relative error of 10.89% and the corresponding agreement index is about 92.51%. Moreover, the prediction precision by using this model is much higher than that by using multi-element nonlinear regression model. References | Related Articles | Metrics

Application of PSO-GA Hybrid Algorithm to Residual Statics Correction HE Chao-qun, WANG Yan-chun, ZHANG Pin 2011, 32 (6):  656-659.  Abstract ( 93 )   PDF (653KB) ( 255 )   Save The residual statics correction is a global optimization problem with multi-parameter and multi- extreme values. The ordinary genetic algorithm (GA) is almost impossible to avoid the premature phenomenon because of the large number of unknown parameters, so it is difficult to convergence to a global optimum. This paper presents a PSO (particle swarm optimization)-GA hybrid algorithm (PGHA) based on the advantage of PSO and GA. PGHA combines the rules of updating the velocity and situation of PSO with the idea of crossover and mutation of GA. Using PGHA and GA to experimentally deal with these two theoretical models shows that PGHA is better than GA in performance and adaptability and it is a practical method for calculating residual statics correction in complicated topographic conditions. References | Related Articles | Metrics

Static Correction Technique for 3D Converted Wave SONG Yu-mei 2011, 32 (6):  660-663.  Abstract ( 95 )   PDF (415KB) ( 163 )   Save The static correction of converted wave is far complicated than that of P-wave, and it directly influences the imaging quality of the converted wave. On the basis of 3D3C seismic data in Lamadian studied area, the statics are corrected via step-by-step solution from large to small of statics. The model method is firstly adopted to solve the problem of the static component of the long wave length related with the datum level, and then by using the reflection information of P-wave and converted wave on common receiver stack profile, the medium-long wave length can be dealt with. Finally, the same task for the short wave length can be also completed through surfaceconsistent residual static correction. The practical results show that the 3D converted wave imaging profile in Lamadian studied area is accordant with the P-wave profile in styles of structure and fault, furthermore, the wave group sustains the individual characteristics of Pwave and S-wave, thus the above achievements have laid the foundation of the petrophysical property analysis of the reservoirs using Pwave and S-wave combination. References | Related Articles | Metrics

3D High Resolution Reservoir Characterization Technique Based on CT Imaging and Application SHE Min, SHOU Jian-feng, ZHENG Xing-ping, ZHANG Tian-fu, DONG Hu 2011, 32 (6):  664-666.  Abstract ( 121 )   PDF (346KB) ( 273 )   Save Applying 3D high resolution reservoir characterization technique based on CT imaging, the sandstone core plug, dolomite core plug and basalt outcrop sample have been analyzed for researching their micro-pore textures. The work includes the sample preparing, CT scanned imaging, image processing, and attributes calculating. According to the CT scanning data, the 3D visualization images of solid phase and pore phase of the samples have been also built. For sand core plug, relative statistics of pores is conducted and the petrophysical properties (porosity and permeability) are obtained by computing. The data of porosity and permeability are compared to conventional laboratory measurement on the same cores with good agreement. The study shows that the research of micro-pore texture using 3D high resolution reservoir characterization technique based on CT imaging has many advantages, including low requirement for sample, more visual result, more abundant data and higher efficiency. References | Related Articles | Metrics

New Method for Prediction of Well Productivity in Low Permeability Reservoir LI Ai-jun 2011, 32 (6):  667-668.  Abstract ( 89 )   PDF (147KB) ( 250 )   Save Accurately predicting the well productivity in low permeability reservoir is crucial to reasonably develop it with efficiency. According to the porosity and permeability characteristics of low permeability reservoir in Changqing oil field, the sensitive analysis on reservoir factors which might affect well productivity by applying numerical simulation is conducted, determine the relationship between the single well productivity and oil layer thickness, permeability and oil saturation with the orthogonal analysis is determined, giving the regression formulae of single well productivity prediction with multi-factors. The method has been proved to be simple, convenient and reliable. References | Related Articles | Metrics

Logging Methods Under Air Drilling Conditions in Junggar Basin LI Bin, SHEN Wen-xing, ZHOU Yuan-fu, ZHOU Xian-song 2011, 32 (6):  669-671.  Abstract ( 99 )   PDF (182KB) ( 255 )   Save Air drilling is the drilling process by taking air as medium to replace drilling mud for carrying cuttings back to the surface. Its use brings challenges to the collection, processing and application of downhole information or data. Because the bit of this process is air hammer which makes the rocks underground breaken into cuttings or powders, then the air can carry the cuttings back to the wellhead. Such a process may affect the authenticity of cuttings and cause the difficulties for lithologic discrimination or identification, including the lithologic naming, the stratigraphic classification, the engineering forecast and oil-gas-water layer discovery, etc. This paper proposes the improved measures for logging methods under the air drilling conditions performed in Junggar basin, which could be used for reference for further logging technological improvement under air drilling conditions in the future. References | Related Articles | Metrics

Application of New Mini-Frac Friction Pressure Testing Technique to Gas Wells WANG Da, LIU Gang-zhi, FENG Pu-yong, LIN Tao 2011, 32 (6):  672-674.  Abstract ( 104 )   PDF (219KB) ( 264 )   Save Because the near wellbore friction pressures were very high in pre-frac mini fracturing tests in two gas wells in an oilfield, reperforations were then conducted to reduce the high friction pressure. The well jobs were successful, but the operation costs were high. The post-frac analysis showed that the amounts of the fracturing fluid pumped in such pre-frac mini fracturing tests were too small to effectively displace gas and thus causing gas-liquid two phase flow in the near wellbore pore spaces, which accounted for the high friction pressures. This paper presents the theoretical analysis of the fracturing friction pressures and proposed a new mini-frac method. Application of it to many wells indicate that such two-phase flow interference can be removed by over 85%, hence, the operation time and costs have been reduced greatly. References | Related Articles | Metrics

Experiment of Degassing Efficiency for Different Viscosity Drilling Fluids YANG Ming-qing 2011, 32 (6):  675-677.  Abstract ( 104 )   PDF (253KB) ( 256 )   Save Accurate detection of gaseous hydrocarbon content of drilling fluid is one of means for discovering and evaluating the shows of oil and gas. However, the viscosity of drilling fluid greatly affects the detection result. With the help of high-temperature and highpressure rotary simulator for drilling fluid, the degassing experiments of different viscosity drilling fluid are conducted, regressing the degassing efficiency chart and equations of the different viscosity drilling fluid, including establishing the coefficient-corrected chart and equations. By them, the real-time calibration of the volume fraction of the gaseous hydrocarbon in drilling fluid can be made at the well site, being good for timely discovery and exact evaluation of the shows of oil and gas. References | Related Articles | Metrics

Laboratory Study on Viscosity Reducer for Paraffin Removal in Oil Well LAI Yan-ling, ZHENG Yan-cheng 2011, 32 (6):  678-680.  Abstract ( 108 )   PDF (154KB) ( 291 )   Save To develop the viscosity reducer characterized by environmental protection, efficiency, multiple functions for paraffin removal in oil well is the direction for meeting the needs for oil production with different contents of paraffin in the future. Based on the evaluations of the effects of different surfactants and additives on paraffin dispersion, paraffin removal and viscosity reducing efficiency of Dagang heavy oils, the alkylbenzene sulfonates (ABL), amide nonionic surfactant (XE) and lignosulfonate (EM) were screened out to optimize the formulations and composite performance of the viscosity reducer by orthogonal test. The results show that the solution of formulation F6 (ABL and XE) is of stability, good for the dispersion of wax sediments and better for paraffin removal and viscosity reduction. The lab study indicates that the viscosity reduction rate and paraffin removal rate are 98% and 99%, respectively. References | Related Articles | Metrics

Research on Petroleum Seismogeology with System Theory YANG Jie, WEI Ping-sheng, LI Xiang-bo 2011, 32 (6):  681-685.  Abstract ( 113 )   PDF (212KB) ( 277 )   Save System theory or systematology provides brand new vision and new method for people to recognize and rebuild the world and it also plays a powerful role in guiding the research of petroleum geology. By using viewpoint of systematoloty, this paper reinvestigates the petroleum seismogeology, a emerging interdiscipline, from all aspects, including its history, research object, scale, content, method, applied prospect and development trends in petroleum exploration and development, and suggests that only introducing the system theory to petroleum seismogeology, can the research level of it be really improved, promoting its development and perfection, and gaining much better results in the actual application. References | Related Articles | Metrics

A Review of Studies on Organic Matter Preservation in Muddy Source Rocks FAN Fu, CAI Jin-gong, ZHANG Yong-sheng, CUI Hai-na 2011, 32 (6):  686-689.  Abstract ( 94 )   PDF (198KB) ( 298 )   Save Many preservation ways of organic matter exist in the muddy source rocks. Besides the oxygen-deficient environment, the organic matter is stably preserved by the degradation and condensation, selectivity preservation, vulcanization and clay protection. The organic matters with different preservation mechanisms form the multiple organic micro-components, such as the sponge amorphism organic matter, configuration organic matter, sporomorph, and particle amorphism organic matter, etc. It is different evidently in the generating hydrocarbon time and the capacity of generating hydrocarbon, which is possible to lead to the wide interval of generating hydrocarbon in the muddy source rocks. In-depth understanding of the preservation mechanisms of organic matter, discussion of the relations of the different preservation mechanisms with each other and the relation between external sedimentary circumstance and organic matter preservation mechanisms, especially the interaction between minerals and organic matter, which are the essential and important problems to study on the organic matter in the future petroleum geology. It is of great significance for deepening the theory of oil and gas genesis, evaluating the oil and gas resources, exploring the new areas for petroleum exploration. References | Related Articles | Metrics

The Industry Standard for 《Determination of Wax Appearance Temperature of Crude Oil: Test Method by Rotational Viscometer》: Problems and Suggestion JIANG Qi-guang 2011, 32 (6):  690-691.  Abstract ( 107 )   PDF (135KB) ( 202 )   Save The irrationality of continuous cooling method in industry standard for "Determination of wax appearance temperature of crude oil-test method by rotational viscometer" is analyzed through investigation on temperature controlling principle of rheometer, and the suggestion by staged cooling process is put forward. In the matter of the program of calculating wax appearance temperature, if calculating by software recommended in the standard, low or high wax appearance temperature will appear when the curves of low temperature section become nonlinearity. The improvement suggestion is given that the wax appearance temperature of crude oil should be determined based on the deviating degree of low temperature section curve and simulated straight line of high temperature section. References | Related Articles | Metrics

Hydrocarbon Accumulation Features and Main Controlling Factors in Typical Foreland Basins in Pediment of the Andes TIAN Na-xin, CHEN Wen-xue, YIN Jin-yin, MA Ya-song 2011, 32 (6):  692-695.  Abstract ( 133 )   PDF (275KB) ( 330 )   Save A series of sedimentary basins were formed between eastern Andes folded belt and Guyana shield. The history of tectonic evolution can be divided into three stages: the Palaeozoic craton margin stage, the Mesozoic back-arc rifting or continental marginal rifting stage and the Cenozoic back-arc foreland stage. The main hydrocarbon source rocks are the Cretaceous marine shale and carbonate rocks. The Cretaceous and Tertiary reservoirs dominated by sandstone are developed. The Cretaceous dark mud formed in rifting stage and the Paleogene mud can be the good cap rocks, which constitute two sets of reservoir-cap assemblages vertically: passive continental margin and foreland sequence. The structural traps are developed in pediment folded belt and the discovered reservoirs are large in size. The fluids in them are mainly oil, light oil and gas. Various trap types, such as structural trap and stratigraphic trap, are developed in the slope belt where the discovered reservoirs are small and the fluids are mainly heavy oil and super-heavy oil. High quality and mature hydrocarbon source rocks are the main controlling factors for oil and gas accumulation. The traps formed in the main orogenic episodes are the most advantageous to capture oil and gas. The high quality reservoirs and faults consist of hydrocarbon migration passage systems. The destruction of tectonism and washing effect cause the formation of the heavy oil reservoirs in the slope belt. References | Related Articles | Metrics

Evolution and Petroleum Geologic Characteristics of Neuquen Basin in Argentina QIN Yan-qun, DENG Hong-wen, LI Xiao 2011, 32 (6):  696-698.  Abstract ( 187 )   PDF (317KB) ( 453 )   Save Sedimentary and tectonic evolution of the Neuquen basin is divided into three stages: the syn-rift stage (Late Triassic-Early Jurassic), depositional systems of fluvial, lacustrine and pyroclastics are developed; the post-rift stage (Early Jurassic-Early Cretaceous), two large transgression and regression cycles are developed, marine and lacustrine sediments occur in bottom cycle, while fluvial delta sediment in upper cycle; and foreland one (Late Cretaceous-Cenozoic), dominated by compressional mechanism, marine and continental sediments are developed. There are abundant petroleum resources in the Neuquen basin, in which the major source rocks are found in Vaca Muerta formation, the main productive reservoirs are sandstone and limestone of the Upper Jurassic-Lower Cretaceous. The cap rocks in the Jurassic or below it are distributed regionally, those above it are semi-regional. Petroleum in this basin is mainly found in surrounding parts, but gas is in the center. They are dominated by structural-stratigraphic traps. Thrust belt in western basin and surrounding heavy oil belt in eastern basin could be favorable areas for petroleum exploration. References | Related Articles | Metrics