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01 April 2006, Volume 27 Issue 2 Previous Issue    Next Issue

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Mechanisms of Micro Hydrocarbon Gener ation and Macro Hydrocarbon Accumulation from Organic Matter ZHOU Yan-ru 2006, 27 (2):  135-141.  Abstract ( 111 )   PDF (429KB) ( 246 )   Save In this paper, that organic matter-generated hydrocarbon is a chaos domain is presented as viewed from modern physics; the scientific intension of concept of micro and macro applied to hydrocarbon generation and accumulation from organic matter is enucleated in terms of Lagrange function; the sequence and the mode in which the proton bundles impact the kerogen cracking in terms of valence bond theory of quantum mechanics are explained; an expression for energy release from kerogen cracking on the basis of binding energy of chemical bonds and thermodynamics energy that is the total of all energy in the system is derived; the primary migration of hydrocarbon in forms of creeping flow under expansion and compression is discussed by using the work-heat transformation theory of Carnot's circular thermodynamics; the abnormal temperature and pressure generated and accumulated in deep sag during the work-heat transformation are described, which provide the heat sources for seal zones and the pressure gradient for secondary hydrocarbon migration, respectively. Finally, the properties and characteristics of the micro hydrocarbon generation and the macro hydrocarbon accumulation are analyzed in detail. References | Related Articles | Metrics

Geochemical Char acter istics of Fluid Inclusions in Qungkurqack Structur al Belt, Tarim Basin LIU Shao-bo, SONG Yan 2006, 27 (2):  142-145.  Abstract ( 115 )   PDF (549KB) ( 177 )   Save Oil and gas shows are enriched in Qungkurqack structural belt on Mageti slope in southwest depression of Tarim basin, but multi-resource rocks, multi-stage hydrocarbon generation and tectonic activities allow its hydrocarbon accumulation period still difficult to study. This paper reveals its hydrocarbon accumulation stages and hydrothermal fluid flowing history based on the geochemical characteristics of fluid inclusions integrated with the numerical simulation of deposit-buried history, paleo-geothermal history. Microscope observation shows that the zone with hydrocarbon fluid inclusion from Well Qun-4 in this structural belt is corresponding to oil-bearing layers; hydrocarbon fluid inclusions are found in limestone of Xiaohaizi formation and sandstone of Silurian formation in Well Jia-1, with relatively low abundance of oil, indicating hydrocarbon migration happened here, but not forming petroleum accumulation. These fluid inclusions can be classified into two types: one is of low homogeneous temperature characterized by light blue fluorescence, the other is of high homogeneous temperature by yellow fluorescence in terms of homogeneous temperature and fluorescence features. It is concluded that two hydrocarbon accumulation stages occurred in this belt, one in Late Permian, with possible Cambrian-Ordovician source rocks and high maturity; the other in Neogene, with possible Carboniferous source rock and low maturity. Also, the homogeneous temperature of aqueous inclusion displays that Well Jia-1 and Well Ba-4 in Selibuya fault belt are higher than the geothermal value at the same depth in this area, showing that normal abnormity of geothermal fluid exists in this fault belt, which could be formed by deep high geothermal fluid migrating to shallow strata along the fault belt. References | Related Articles | Metrics

An Analysis of Ordovician Dolomitisation Origin in Northwestern Tazhong Area QIAN Yi-xiong, YOU Dong-hua 2006, 27 (2):  146-149.  Abstract ( 136 )   PDF (498KB) ( 244 )   Save The study of mineralogical-petrologic and geochemical characteristics of Ordovician dolomite in Wellblock Zhong-1 in northwestern Tazhong area shows that it is composed of dolosiltite, dolomicritein, spotty dolomite, replacement dolomite related with stylolite, baroque dolomite and sugar granular dolomite (dolorudite), characterized by mosaic, mist-core with bright rim, metasomatic and zonal diagenetic textures, reflecting buried diagenetic environment under these different media, with relatively low Sr of 161 ×10-6, relatively high Na of 0.09%; δ13C of -2.0‰ and δ18O of -6.8‰ in average, which indicate its nature of both buried dolomite and quasicogenetic diagenesis. The fluid inclusion study shows that the buried and dolomitized fluid is bittern with mid-high temperature of 115~130℃ and 170~210℃ and high salinity of 5%~7%, 8%~9% and 12%~13%. It is concluded that such a dolomite belongs to diagenetic dolomite and associated quasi-cogenetic dolomite in supratidal and intertidal zones. References | Related Articles | Metrics

Geologic Featur e and Study Progr ess of Silur ian Asphaltic Sandstone in Tazhong Area, Tarim Basin GUO Jian-jun, CHEN Jian-fa 2006, 27 (2):  151-155.  Abstract ( 100 )   PDF (465KB) ( 213 )   Save The Silurian asphalt sandstone is widespread in Tazhong area of Tarim basin and mainly found in the upper slope of paleouplift and oil-generating basin of Lower Paleozoic, which shows that the widespread asphalt sandstone could be the outcrop of paleo-oil pools in this area. The distribution of asphalt sandstone is mostly controlled by oil source, paleo-uplift, sedimentary system and petrophysical property. Microscopically, the asphalt characteristic also reflects the multi-stage filling and destructive accumulation history of Silurian hydrocarbons, with ebb and flow of oily bitumen content and colloid-asphltenes content. The strata with high asphltenes content appear relatively low volume of movable oil, and the bituminous reflectance is low and scattered, averaging 0.15%~0.50%. It is concluded that the source supply of Silurian asphalt sandstone is mainly from Middle and Lower Cambrian. References | Related Articles | Metrics

Gas Chimney Effect and Formation of Quaternary Gas Pool in Sanhu Ar ea, Qaidam Basin LIANG Quan-sheng, LIU Zhen, CHANG Mai, LI He-yong 2006, 27 (2):  156-159.  Abstract ( 89 )   PDF (625KB) ( 272 )   Save The high resolution seismic data show that gas chimneys exist around Quaternary gas reservoirs in Sanhu area of Qaidam basin.The Quaternary system is characterized by high geothermal gradient, with low scope of overpressure in its deep and shale caprock saturated with formation water of high salinity. The Gansenquan-Xiaochaidan basement faults affect the integrality of gas reservoir structures. These interacted factors result in the formation of gas chimney. The existence of gas chimney can explain the mixed source characters of Quaternary gas composition and ethane carbon isotope, thus resolving the contradictions between source rock hydrocarbongenerating potentials and gas reserves of each sequence. In conclusion, the gas chimney as a vertical path of natural gas migration plays an important role in Quaternary gas accumulation in this area. References | Related Articles | Metrics

The Evolution and Reservoir -Controlled Pattern in Chepaizi-Mosuowan Paleo-Uplift in Junggar Basin ZHAO Hong-liang 2006, 27 (2):  160-162.  Abstract ( 88 )   PDF (515KB) ( 230 )   Save The Chepaizi-Mosuowan (Chemo) paleo-uplift of N-E extending was shaped with the uplifting of hinterland of Junggar basin during the Mid-Late Jurassic, which changed the structural framework of monoclinal hinterland of the basin, forming quite a few lithostratigraphic traps of Mid-Upper Jurassic distributed along both sides of Chemo uplift. These traps provided favorable places for oil-gas accumulation. While Himalayan tectonic movement made the north-side continuously rise and the south-side extremely sink, causing secondary adjustment of pre-formed reservoirs that underwent destruction in the north side, the south side structures were still preserved up to now. These structures should be as favorable domains for deep hydrocarbon exploration in hinterland of Junggar basin. References | Related Articles | Metrics

Discovery of Str ike-Slip Fault Belt and Its Significance for Hydrocarbon Accumulation in Baikouquan Oilfield YANG Xue-wen, SHAO Hong-liang, SHANG Jian-lin, WANG Yong, FENG Xu-jun, NIE Jian-jiang, WANG Chang-yong, XING Feng-cun, GAO Zhen-zhong 2006, 27 (2):  163-165.  Abstract ( 138 )   PDF (833KB) ( 236 )   Save A set of NNW strike-slip fault belts has been found in Baikouquan oilfield, Karamay area. The Karamay-Wuerhe great fault of NE trend was truncated into ten more pieces by this fault. Its 3D seismic horizontal slices clearly display that each wave group appears such event ends as directional linear extension, the event image is dragged, the same event waveforms are apparently dislocated and suddenly changed, and a suit of waves is abruptly bended in a same direction. Its seismic profile shows that the Mesozoic waves disappear suddenly and joint with messy reflection of Carboniferous basement, the waves appear interrupted points with high-angle extending down deep, the waves vary in undulance or the reflections become obscuring suddenly, etc. It is concluded that this strike-slip fault is in tensoshear property and should be lagging products associated with reverse fault of NE trend. The oil-enriched blocks accord generally with this developed fault belt, indicating its contribution is mostly constructive to hydrocarbon accumulation in Baikouquan oilfield. References | Related Articles | Metrics

Genetic Character is tics of Vesicular Volcanic Clastic Reservoir of Fengcheng Formation in Wellblock Xia-72 and Its Significance for Hydrocarbon Exploration WU Yun-qiang, CHANG Qiu-sheng, JIANG Yi-qin, SUN Zi-jin, WANG Gui-jun, YANG Hong-xia 2006, 27 (2):  166-168.  Abstract ( 89 )   PDF (1061KB) ( 168 )   Save The vesicular volcanic clasitic reservoir of Fengcheng formation in Wellblock Xia-72 is a rare reservoir rock with great potential for hydrocarbon exploration. Microscopic analysis has been conducted with microscope by using large cast thin section manufacturing technology to make a systematic research on the component feature, textural structure and porous type and to examine the genetic mechanism and exploration significance. This paper suggests that the extremely hot erupted ash flow of such types of reservoirs is influenced by vaporized water steam on the surface, and asymmetric diatexis process take place during deposition, forming vesicular diatexis rhyolitic and vitric tuff with volcanic gravels. The lower part of rock mass is good reservoir and percolation rock characterized by developed constricted fissures and dissolved pores; the mid-upper part is good reservoir rock with developed vesicular and matrix micropore textures. Such a volcanic clastic reservoir is believed to be of great potential for petroleum exploration. References | Related Articles | Metrics

Sequence Stratigraphy and Lithofacies Paleogeography in Ziniquanzi Formation in Piedmont Fault-fold Belt, Southern Margin of Junggar Basin SHEN Yu-lin, GUO Ying-hai, LI Zhuang-fu, RAN Qi-gui, BEN Xu-dong 2006, 27 (2):  169-172.  Abstract ( 100 )   PDF (473KB) ( 349 )   Save The correlation study of outcrop and drilling-well logging data shows that Ziniquanzi formation of Paleogene in piedmont faultfold belt in southern margin of Junggar basin can be divided into two 3-order sequences with which sequence stratigraphy framework of the studied area is set up, based on existing two sets of mudstones in regional and steady development of Ziniquanzi formation, regional unconformity and erosion surface or sedimentary system interface. The lithofacies paleogeography map is drawn in terms of sequence. The feature and evolution of lithofacies paleogeography during Ziniquanzi deposition period within this framework are discussed. The early period of it (Sequence I) is characterized by co-existing alluvial fan, braided river-braided channel delta and lake facies; the late period (Sequence II) by the expanding lake and the assemblage of braided river-braided channel delta-lake facies dominated by lake deposit. References | Related Articles | Metrics

Edge Detection Optimum Partitioning Method for Automatic Division of Log Strata XIE Zhong-huai, LI Bao-li 2006, 27 (2):  173-175.  Abstract ( 81 )   PDF (352KB) ( 214 )   Save Log strata automatic division method as an optimum partitioning one available now is still insufficient to utilize well log patterns and distinguished point information, along with big amount of calculated data and low efficiency, affecting its own reliability. This paper presents a new method for log strata automatic division of optimum partitioning integrated with edge detection. Using this method to find and select log distinguished point and then make an optimum partitioning at the aggregate points could greatly improve the velocity of calculation; meanwhile, the flexibly designing edge detection index means not only to get the maximum interlayer deviation quadratic sum, but also to differentiate the logs style at both sides of dividing point, thus improving the reliability of log strata division. The case of Mesozoic strata division in Jiyang depression shows that this method has a good applied effectiveness. References | Related Articles | Metrics

Experimental Study on Physical Modeling of Hydrodynamic Condition in Low-Rank Coalbed Methane Reservoir WANG Bo, JIANG Bo, WANG Hong-yan, LIU Hong-lin, CHEN Zhen-hong, LI Gui-zhong 2006, 27 (2):  176-177.  Abstract ( 78 )   PDF (172KB) ( 330 )   Save Hydrodynamic condition is one of the critical factors that affect low-rank coalbed methane (CBM) accumulation. The CBM accumulation model is used to simulate the hydrodynamic condition of low-rank coalbed methane reservoir. Study shows that H2S and methane concentration will be reduced, δ13C1 be lightened, N2 and CO2 contents be increased under the strong hydrodynamic alternation, which have unfavorable impact on CBM accumulation. Also, this paper analyzes the hydrodynamic condition in eastern margin of Ordos basin and discusses the difference among conservation conditions in CBMreservoirs. References | Related Articles | Metrics

Detailed Study of Structural Transposition Zone and Exploration of Non-Structural Reservoir WANG Feng-hua, LI Rong-quan 2006, 27 (2):  178-180.  Abstract ( 79 )   PDF (545KB) ( 174 )   Save Depositional structural transposition zone is the most important discharge area of clastic sediments and the main zone for distribution of various sand-conglomerate bodies and favorable reservoirs. In post-depositional structural transposition zone, central distribution of a variety of non-structural reservoirs takes place due to variation of reservoir characteristics. Therefore, to study the favorable zone characteristics of reservoir distribution within depositional structural transposition zone, to search for the areas of favorable hydrocarbon accumulation within post-depositional structural transposition zone and to carry out the evaluation of matched relations between reservoir distribution and favorable structural zone are the key method for such a detailed study and reservoir exploration. Shengtuo area in Dongying sag has obtained great discovery for petroleum exploration by using this method. References | Related Articles | Metrics

Genetic Type of Ordovician Condensate Gas Pool in Eastern Lunnan Bur ied Hill, Tarim Basin LIU Jing-jiang, LI Mei, LIU Hui-rong, GU Qiao-yuan 2006, 27 (2):  181-183.  Abstract ( 72 )   PDF (594KB) ( 214 )   Save This paper suggests from the fluid property analysis that the Ordovician condensate gas pool in Lunnan buried hill reservoirs is a hybrid type of reservoir re-shaped from the ancient oil reservoirs. It possesses the features of them, but is mainly characterized by condensate gas pool. It is not an isolated reservoir, but is a part of the Ordovician buried hill reservoirs in this area. References | Related Articles | Metrics

3D Seismic Inversion and Reservoir Prediction in Complex Fault-Block Areas in Eastern China NIAN Jing-bo, ZHANG Er-hua, LIU Xi-wu, LIU Yong-sheng 2006, 27 (2):  184-187.  Abstract ( 83 )   PDF (562KB) ( 185 )   Save The seismic inversion and reservoir prediction in complex fault-block areas are hard to make due to complicated geologic conditions and poor quality of seismic data. This paper presents the case of 3D seismic inversion and reservoir prediction of a complex fault-block area in eastern China and reviews the inversion experiences. The practical strategy and technical scheme are elaborated, including data analysis and processing (e.g. judgment of seismic event polarity, regularization of well logs and sensitivity analysis, etc.), wavelet extraction, reconstruction of pseudo-sonic logs, constrained impedance inversion, velocity field establishment and stochastic simulation of geo-statistics, etc. as a model of multi-discipline integration. The study results can be as an important basis for well deployment in the working area. Other similar areas may take them as an example for reference. References | Related Articles | Metrics

A New Generalized Water Drive Curve REN Yu-lin 2006, 27 (2):  188-190.  Abstract ( 81 )   PDF (425KB) ( 180 )   Save Water drive type curve is a key method for prediction of oilfield water flooding performance. There are more than 50 types of the curves proposed by domestic and foreign scholars. However, these methods have been restricted for application due to different objects, thoughts and applied fields of studies. This paper presents a novel method, a generalized water drive curve, that just one equation is applied to describe the variety types of water drive curves. References | Related Articles | Metrics

Variation Laws of Compressibility, Porosity and Permeability of Rocks during Injection-Production Process of Reservoir WANG Zhou-hua, GUO Ping, ZHOU Dao-yong, GAO Hui-jun 2006, 27 (2):  191-193.  Abstract ( 201 )   PDF (471KB) ( 515 )   Save The keep-up pressure recovery of most oil-gas reservoirs and the gas storage measurement on some depletion reservoirs have been made in China, which have endlessly caused variation of pressure difference between inside-pore and outside-pore, followed by always changes of compressibility, porosity and permeability of rocks due to injection and production time and again of reservoir fluids. The variation of petrophysical parameters with pressure drawdown is better known, but the changing law of them with cycling, rising and declining of formation pressure is seldom researched. This paper presents the experiment of compressibility, porosity and permeability by using artificial cores on which different confining pressures are put. Study shows that these petrophysical parameters will change with pressures, of which rock porosity will affect other parameters' variations, and permeability has lag-effect during cycling, rising and declining of the pressure. References | Related Articles | Metrics

The Influence of Capillary Number Effect on Inflow Performance in Condensate Gas Well TONG Min, HU Yong-le, LI Xiang-fang, WANG Zhi-wei 2006, 27 (2):  194-196.  Abstract ( 76 )   PDF (360KB) ( 427 )   Save Condensate dropout is widely existent in development of condensate gas pool, usually different from gas inflow performance. The theoretical study and field application indicate that big error will occur when predicting condensate gas performance by just using dry natural gas or converting method for the reason that the influence of retrograde condensed liquid on relative permeability of condensate oil and gas is normally ignored. This paper establishes the prediction method for inflow performance of condensate gas well under condition of pseudosteady state by using the theory of condensate gas phase state and flashing method, with consideration of changes of fluid phase behavior and composition as well as skin factor of condensate gas well, along with consideration of the influence of capillary number effect on relative permeability of condensate oil and gas system by using steady state theory and two phase pseudo-pressure functions. The case study shows that the equation for two phase pseudosteady state inflow performance with consideration of capillary number effect can be helpful to properly estimate the productivity of a condensate gas well and correctly recognize the behavior of a condensate gas pool through weakening the effect of retrograde condensation. References | Related Articles | Metrics

The Experimental Study on Rheological Behavior of Polymer ZHANG Xing, LI Zhao-min, SUN Ren-yuan, SU Cheng-xiang 2006, 27 (2):  197-199.  Abstract ( 92 )   PDF (364KB) ( 260 )   Save As theoretical foundation of polymer flooding design, the polymer rheological behavior is systematically studied by using DVIII rotational viscometer. The result shows that polymer solution appears shear-thinning behavior and apparent viscosity is the function of shear rate, temperature and concentration of polymer, and at the same temperature, the consistency coefficient is increasing with the concentration increase, the power-law index is decreasing with the concentration increase. Through development of rheological model and introduction of support vector machine method, the prediction of the rheological behavior of polymer is conducted, showing consistent results between prediction and measurement. This provides base for polymer flooding numerical simulation, reservoir performance prediction and field engineering design. References | Related Articles | Metrics

Theory and Mathematical Modeling of Nano-Silica Gel System for Oil Displacement JU Bin-shan, FAN Tai-liang, QIU Xiao-feng, SUN Ren-yuan, WANG Xiao-dong 2006, 27 (2):  200-203.  Abstract ( 86 )   PDF (331KB) ( 299 )   Save The theoretical analysis of nano-silica gel for oil displacement is conducted to quantitatively study the oil displacement effect of SiO2 gel system in nanometer scale. Based on the theories of continuous flow of porous media, rheology of silica gel solution and adsorption and migration of silica gel in porous media, a two-phase multicomponent mathematical model for oil displacement is developed with a numerical simulator, by which effects of the silica gel mass concentration, injection volume and flooding style on porosity, permeability and production response. The results show that the nano-silica gel solution can be applied to decrease values of reservoir porosity and permeability and obviously increase oil recovery, indicating that the plug injection process of silica gel solution is better than its alternative or continuous injection process for oil displacement. References | Related Articles | Metrics

Research on Streamline Distribution of Flow through Anisotropic Porous Media with Complex Boundary HE Ying-fu, YIN Hong-jun 2006, 27 (2):  204-207.  Abstract ( 91 )   PDF (506KB) ( 264 )   Save The steady-state flow mathematical model for anisotropic reservoir with impermeable barrier is developed. The pressure equation of arbitrary point of formation is obtained by using boundary element method (BEM) to the model solution, and streamline field generating technique is then proposed, including the streamline distribution diagram with anisotropic flow field, complex boundary and impermeable area effects as well as streamline feature analysis. The study shows that the streamline distribution is sensitive to the existing anisotropic flow field and impermeable area. Hence, the plotted diagram could more visually reflect the flowing tracks of reservoir fluid between injector and producer, providing an important basis for optimization of well pattern and injection strategy. References | Related Articles | Metrics

The Optimal Choice of IPR Equation for Deviated and Horizontal Wells LIU Cheng, GAO Wen-jun, SONG Wen-li, TANG Xi-ming 2006, 27 (2):  208-209.  Abstract ( 114 )   PDF (178KB) ( 187 )   Save The Vogel parameter values of different inclinations in different IPR equations are given by using six types of IPR equations and re-matching the generated data from the reservoir simulator of Literature [1]. The values analysis shows that Winggins-Russell-Jennings equation is the best, Klins-Majcher equation is good, Vogel equation is poor, and Fetkovich, Harrison and Bendakhlia-Aziz equations are the worst in matching accuracy, indicating Winggins-Russell-Jennings equation and Klins-Majcher equation are better used for describing the IPR equation of different inclinations than Vogel equation, while Fetkovich, Harrison and Bendakhlia-Aziz equations are of poor applicability. References | Related Articles | Metrics

Analysis of Abnormal Binomial Coefficient (B<0) for Binomial Deliver ability Equation GOU Hong-gang, ZHAO Ji-cheng, QING Zhi-bao, CHANG Yong-feng 2006, 27 (2):  210-212.  Abstract ( 105 )   PDF (279KB) ( 227 )   Save Theoretically, the binomial coefficient B does not allow being negative value. But the abnormal situation (B<0) still occurs in practice without consideration of influence of bottom hole liquid loading, causing unable to make in-situ deliverability interpretation and evaluation. The study suggests that for a gas pool with low pressure and low permeability, if ignoring the influence of pre-working system on post-performance, especially under the pressure build-up insufficiency after each working-system operation, productivity curve style of a gas well will be reversed. This theoretical deduction presents recommended equation that not only accords with deliverability regularity, but also represents real productivity of a gas well after correcting curves. The case study with the recommended equation indicates its reliability and applicability to similar gas pools. References | Related Articles | Metrics

Effect of Surfactant on Natural Gas Hydrate WU You, YE Zhong-bin, ZHANG Zhi, SHI Xue-zhi, WU Xiao-ni 2006, 27 (2):  213-215.  Abstract ( 87 )   PDF (344KB) ( 216 )   Save Surfactant can be used not only to increase generated velocity of natural gas hydrate, but also to inhibit from its generation. The former effect will bring itself to broad prospect for commercial application due to its huge gas capacity and safe and convenient storage feature. The latter one could result in plugging of equipment and pipe, affecting normal production and transportation and even more cause off production, owing to forming the hydrate in the gas flowing process. Hence, adding some surfactant can effectively avoid such a generation of natural gas hydrate. References | Related Articles | Metrics

The Calculating Method for Effectively Producing Injection-Production Well Spacing of Low Permeability Reservoirs HE Xian-ke, CHEN Cheng 2006, 27 (2):  216-218.  Abstract ( 90 )   PDF (285KB) ( 199 )   Save Determination of rational injection-production well spacing is significant for economic and effective exploitation of low permeability oilfield or reservoir due to existence of starting pressure gradient and recovery difficulty. Based on theory of fluid flow mechanics, the pressure gradient distribution equation between injector and producer under unequal production rate is deducted, by which the change of driving pressure gradient with well spacing under available injector-producer conditions can be determined. Study shows that such a relationship between injector and producer is not established until the driving pressure gradient completely overcomes the starting pressure gradient of reservoirs. Hence, the injection-production well spacing corresponding to the minimum driving pressure gradient in overcoming the maximum starting pressure gradient should be a proper maximum injection-production well spacing that the pay zone can be effectively produced. Well block Shu-322 in Yushulin oilfield is taken as an example integrated with starting pressure gradient and permeability, the relationship between the maximum injection-production well spacing and reservoir permeability is set up, showing that the effective producing maximum well spacing should be 242 m compared with 300 m available now. This is more reliable basis to be used for next-step modification of the oilfield development. References | Related Articles | Metrics

Application of Log-Constraint Seismic Inversion to Dolomite Fractured-Vuggy Reservoirs ZHANG Yong-hua, ZHAO Yu-qing, YANG Dao-qing, SUN Yao-hua, YAN Fu-wang, TIAN Xiao-min 2006, 27 (2):  219-222.  Abstract ( 72 )   PDF (850KB) ( 212 )   Save Technique for prediction of dolomite fractured reservoir has been quite urgent for petroleum exploration and development in Biyang sag. Taking the dolomite fractured-vuggy reservoir in Biyang central deep sag area as an example, the key problem of low constraint inversion application to fractured-vuggy reservoir description is analyzed, and corresponding solutions are suggested. Starting with single well reservoir classification and correlation, the deposition model is firstly developed, and then detailed reservoir calibration, multiwell constraint seismic inversion and porosity constraint inversion are conducted, based on the well logs correction and the wavelet analysis. Finally, through detailed interpretation and composite analysis, such a reservoir's distribution scope is predicted, the porosity distribution features are delineated, by which the newly incremental control reserves of 991×104 t have been obtained in this area. References | Related Articles | Metrics

Application of Higher -Order Traveltime Correction to Anisotropic Media DUAN Wen-sheng, LIU Wen-ge, HUANG Lu-zhong 2006, 27 (2):  223-224.  Abstract ( 68 )   PDF (533KB) ( 160 )   Save Velocity anisotropy can be widely seen in low-relief structures and carbonate fractures of Tarim basin. It is difficult for both conventional normal moveout (NMO) and multi-term Taylor series expansion to eliminate nonhyperbolic traveltime caused by anisotropy, which will affect following stack imaging and research of reservoir rocks. Compared with NMO based on assumption of isotropy, the technique of higher-order traveltime correction based on theory of anisotropy is more approximate to the real formation media. By using this technique, a methos for velocity analysis in anisotropic media is proposed, and a typical seismic procession flow for anisotropic parameter ηis given. The study shows that the technique of higher-order traveltime correction combined with NMO can solve efficiently the problem of velocity anisotropy and meet the need of accurate imaging in low-relief structures. References | Related Articles | Metrics

A New Method for Calculating Dimensionless Water Influx Rate ZHAO Ji-yong, HU Jian-guo, FAN Zhe-yuan 2006, 27 (2):  225-228.  Abstract ( 132 )   PDF (194KB) ( 312 )   Save The calculation of dimensionless water influx rate has to be made for both reserves estimation and performance prediction in process of development of natural water drive reservoirs. However, it is not practical and not precise to calculate the dimensionless water influx rate by available table-lookup method. Based on the theory of mathematical statistics, the widely applied empirical equation method of van Everdingen-Hurst dimensionless water influx rate calculation for infinite radial water drive and finite natural water domain is evaluated. And a new method for calculation of finite confining natural waters' dimensionless water influx rate is then proposed in this paper. References | Related Articles | Metrics

The Establishment and Application of 3D Model for Hydraulically Created Single Fracture LI Hong-xi, LIU Quang-wen, WANG Xue-hua 2006, 27 (2):  229-231.  Abstract ( 92 )   PDF (186KB) ( 188 )   Save 2D fractured model is generally used for field single fracture created by hydraulic fracturing process. The varied length, height and width of the fracture may affect the accuracy of the fracturing design, causing big difference between designed result and real fracturing effect. This paper deducts and establishes related 3D mathematic model in terms of extending and non-extending upper and lower layers, including presentation of equations of controlling 3D extending of fracture, fracturing fluid flowing pressure drawdown, fractured width and model interpretation. Also, this paper presents the effect of length and orientation of fracture on the reservoir development effectiveness by hydraulic fracturing process and simulation calculation of fracture extending for a multilayer fracturing well. The validity of the model has been proved. References | Related Articles | Metrics

A Simple Method for Prediction of Reservoir Fluid Saturation with Production Data AO Ke, HUANG Bing-guang, LUO Xing-wang, JIANG Jun, ZHANG Yan-mei 2006, 27 (2):  232-233.  Abstract ( 77 )   PDF (65KB) ( 127 )   Save The model of average water saturation changes with time in water flood reservoir or block is developed by using material balance method combined with Logistic model, by which few production data are required and the procedure for solution is very simplified. The case study shows that this method is practical as an effective way for prediction of average fluid saturation of reservoir or block in the period of production decline for mid-tail development phase. References | Related Articles | Metrics

Discussion of Single Well Productivity Allocation by Commingling Production with Geochemical Monitoring Method WANG Qiang, XU Zhi-ming, FU Xiao-wen, ZHU Zhao-jun, LIN Feng 2006, 27 (2):  234-235.  Abstract ( 69 )   PDF (113KB) ( 213 )   Save Two oil samples with different maturities from a basin in western China are selected, mixed and separated by group composition in order to properly estimate the allocation of single well productivity with geochemical method. The saturated hydrocarbons are analyzed by gas chromatography. The result shows that both linear and nonlinear changes occur in fingerprint indicator ratio and mixed ratio of the mixed sample. The reason is that the process of mixture is not pure physical one, but a physicochemical one. Through linear match, the error can be greatly reduced by recalculation of it after removing those imperfect fingerprints in linear correlation. Also, the error could be decreased by using presumed the single layer fingerprint ratio rather than the initial single layer value. The study could be as a guide for selection of peak fingerprint and optimization of related calculation method for productivity monitoring. References | Related Articles | Metrics

Application of ECS Logging Data to Well block Cai-31 in Cainan Oilfield LV Fu-su, HAN Jun, MIAO Hong-sheng, YANG Lei 2006, 27 (2):  236-238.  Abstract ( 143 )   PDF (702KB) ( 157 )   Save Element capture service (ECS) can be applied to quantitative determination of the contents of Si, Ca, Fe, S, Ti, Gd in stratum. The correlation of these elements and lithology and given rock mineral contents can be used for distinct lithology and strata correlation as well as porosity and oil saturation corrections. This technique has been applied to Well block Cai-31 for lithology identification, and a good accordance between ECS's lithology and core-describe lithology is gained. The study shows that using ECS lithological profile and element content integrated with conventional well log data, the strata correlation, sedimentary environment recognition and deposition analysis could be conducted in more detail. References | Related Articles | Metrics

Unconformity Type and Its Significance in Petroleum Geology YIN Wei, CHEN Zhao-nian, XU Hao, SI Yu-mei 2006, 27 (2):  239-241.  Abstract ( 161 )   PDF (346KB) ( 213 )   Save Various unconformities can be classified into such seven types of unconformities by conformation and mechanism as parallel, truncation, overlap, fold, faulted-fold, extensional and growth ones. Vertically, rocks near the unconformity appear layers which are in turn semi-weathering rock, weathering clay bed and basal conglomerate. The unconformity plays important roles on the migration and accumulation of hydrocarbons in nature as a pathway for long-distance petroleum migration. And paleo-weathering crust or palaeokarst belt take the part of improvement of reservoir quality of rocks, forming unconformity reservoirs. However, the unconformity may cause caprock damage and affect the maturity of hydrocarbon source rocks. References | Related Articles | Metrics

Response of Structural Elements to Hydrocarbon Accumulation in For eland Basin TANG Ji-guang, MEI Lian-fu, SHEN Chuan-bo, ZHOU Feng 2006, 27 (2):  242-246.  Abstract ( 79 )   PDF (355KB) ( 179 )   Save A foreland basin system may be divided into four structural elements such as piedmont fold-thrust belt, fore deep depression belt, slope belt and frontal uplift belt. This paper discusses hydrocarbon distribution regularity and hydrocarbon accumulation pattern of each structural element in foreland basin system by analysis of key factors of source rock, reservoir rock, source-reservoir-caprock assemblage and petroleum migration in order to post the differences of hydrocarbon accumulation among different structural elements and basinal petroleum distribution regularities. The study shows that the petroleum distribution in foreland basin is controlled by the basinal structure, and a hydrocarbon accumulation is responsible to the basinal structural element. Based on this proper classification, to comprehensively understand the hydrocarbon accumulation characteristics of sedimentary systems of pre-basin-forming and basin-forming period for different structural elements is the crucial way for foreland basin hydrocarbon accumulation study. Moreover, the post-reformations must be paid more attention to for petroleum exploration of foreland basins in central-western China. References | Related Articles | Metrics

A Study on the Model of Primary Migration of Oil and Gas LI Chuan-liang 2006, 27 (2):  247-250.  Abstract ( 107 )   PDF (769KB) ( 224 )   Save A study was conducted on the model of primary migration of oil and gas. It is believed that source rocks still have certain permeability. The higher the permeability, the stronger the ability of primary migration of oil and gas out of source rocks is. And the lower the permeability, the stronger the ability to seal the reservoir pressure of source rocks. The heterogeneity and micro-fissures in source rocks are unfavorable to primary migration of oil and gas, which retained some oil gas within the source rocks forever as micro-reservoirs. Thinner source rocks have a lower a potential capacity of hydrocarbon generation, a higher capacity of hydrocarbon drainage and a lower capacity of hydrocarbon accumulation. However thicker source rocks have a higher potential capacity of hydrocarbon generation, a lower capacity of hydrocarbon drainage and a higher capacity of hydrocarbon accumulation. References | Related Articles | Metrics

Destructive Factor s of Mesozoic Organic Matter in Giant Petroliferous Basins in West Siber ian Province A. N. Fomin, V. O. Krasavqikov, A. V. Estomin, O. N. Pogorelova, S. U. Beliaev 2006, 27 (2):  251-259.  Abstract ( 79 )   PDF (296KB) ( 181 )   Save The maturity of Jurassic organic matter in giant petroliferous basin of West Siberian province depends on the depth and the maximum temperature. The temperature distribution in sedimentary cap rock and local fault block-folded time in Paleozoic basement as well as deep fault formation are related to the magmatic rock composition and intrusion time. These factors controlling temperature field and cap rock's organic matter maturity are found globally. The fault blocks are classified into three types that accord with geotectonic style in terms of the basement- consolidated time. The first type of fault blocks accords with blocks in Baikalides; the second one with those in Hercynian and Himalayan fold belts; the third one belongs to Triassic rift in the basement, which accords with large scale granitic mass and fluid-transporting faults. Related Articles | Metrics

Hydrocarbon Geology in Amu-Daria Basin and Prediction of Its Favor able Areas GUO Yong-qiang, LIU Luo-fu, ZHU Sheng-li, ZHU Yi-xiu 2006, 27 (2):  260-264.  Abstract ( 95 )   PDF (526KB) ( 224 )   Save An integrated study on stratigraphy, tectonics, sedmentology and petroleum geology in Amu-Daria basin is conducted. Four factors that control its hydrocarbon distribution such as thermodynamics, structure, lithology and hydrogeology are determined. Four rules of distribution of big gas fields in this basin are reviewed. It is predicted that the most favorable prospecting areas are the marginal zones adjacent to the basin in northern Bewuerjashik-Xiwen depression, Wuqaderen uplift and Mali-Xielahe uplift; the favorable prospecting areas are Charzhu bench, Buhala bench, Badehezi-Kalabili bench, Zhaungbuzi placanticline and marginal zones adjacent to the depression. References | Related Articles | Metrics