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01 October 2010, Volume 31 Issue 5 Previous Issue    Next Issue

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Petroleum Prospect and Exploration Targets of Paleozoic in Junggar Basin KANG Yu-zhu 2010, 31 (5):  449-453.  Abstract ( 133 )   PDF (466KB) ( 313 )   Save Junggar basin is located in northern Xinjiang and has an area of 13×104 km2. More than 30 oil and gas fields have been found up to now. The study shows that this basin has crystalline and metamorphic basement of pre-Sinian, and develops broad Paleozoic sediments under control of latitudinal Xiyu system and NE-trending tectonic system. The prototype of the basin is composed of the riftedcratonic basin of Sinian-Ordovician, the compressional rifted-cratonic basin of Silurian-Devonian and the craton-like depression basin of Carboniferous-Permian. There exist three sets of source rocks of the Cambrian-Ordonican, the Lower Silurian and the Carboniferous- Permian, which contain very abundant hydrocarbon resources and play important roles in petroleum exploration at present and for the future. It is suggested that the northwestern Junggar basin, the northern Junggar basin and Luliang area are the favorable domains for exploration of oil and gas fields of Paleozoic. References | Related Articles | Metrics

The Deep Crust Structure Features and Petroleum Exploration Potential in Hailar-Tamtsag Basin ZHANG Jing-lian, LEI Ming, WEI Ping-sheng, CAO Zheng-lin, YAN Cun-feng 2010, 31 (5):  454-459.  Abstract ( 77 )   PDF (444KB) ( 315 )   Save Petroleum exploration of Hailar-Tamtsag basin is closely paid attention to recently. But the origin of non typical sedimentary rocks and the origin and genesis of Budate group crude oil are still not clear. The study on the mantle fluids, isotopic geochemical provinces, the distribution of low-velocity and high-conductive layers in mid-crust shows that ① the non typical sedimentary rocks as special reservoirs are products of metasomatism among mantle fluids enriched with alkali metals K, Na and alkaline earth metal Mg; ② Sino-Mongolia block as the Pacific-type block has the giant petroleum resource potential; ③ the low velocity-high conductive layer of mid-crust in this basin controls the distribution of oil-gas fields. Therefore, some of the oil and gas in Hailar-Tamtsag basin might belong to the deep inorganic origin. According to this hypothesis, some large oil and gas fields may be found in Budate group buried hill belt. References | Related Articles | Metrics

The Idea and Method for Exploration of Lithologic Reservoir in South Area in Western Qaidam Basin ZONG Yi-ping, FU Suo-tang, ZHANG Dao-wei, ZHANG Yong-shu 2010, 31 (5):  460-462.  Abstract ( 90 )   PDF (292KB) ( 235 )   Save The south area in western Qaidam basin is a main area for petroleum exploration in Qaidam basin, with petroleum resources of 15.35×108 t and proved OOIP of 3.53×108 t, which shows that it is in low identified rate and great potential for prospecting. The reservoirs discovered up to now are still dominated by structural reservoirs. With the increase of the explorative extent and the advancement of explorative technology, lithological reservoir exploration is becoming the major domain for petroleum exploration in this area. The petroleum geologic evaluation suggests that the south area in western Qaidam basin develops clastic lithologic reservoir of Tertiary controlled by fluvial delta system, being of broad domain and bright prospect for petroleum exploration. In recent years, the lithologic exploration achievements in such areas as Hongliuquan $E^1_3$ reservoir, Wunan $N^1_2$ reservoir and Kunbei $E_{1+2}$ reservoir support this mature idea and method for further petroleum exploration here. References | Related Articles | Metrics

Analysis of Structural Genesis in Raoyang Sag ZOU Wei-hong, DAI Jun-sheng, WANG Yu-quan, SONG Yong-dong, REN Wen-bo, WANG Peng 2010, 31 (5):  463-466.  Abstract ( 148 )   PDF (409KB) ( 302 )   Save Raoyang sag is a Cenozoic halfgraben-like fault depression with faulting in the eastern part and overlapping in the western part, in which a series of extensional and strike-slip structures are developed, dominated by extensional structure. The statistics of 4th-grade faults strikes in each horizon show that they trend from near EW to NW-SE and to near SN in the Early to Late Paleogene by turn clockwise. Dextral strike-slip structure assumes such main fault plane steep-tilting styles as enechelon, brush, flower structures and main fault tail structures, etc., which are primarily formed in the third segment of Shahejie period and Dongying period. The ramp-flat patterns and extensional activities of master faults like Maxi, Hejian and Liulu faults result in regular distribution of the fault belt, major hollow groove belt, central buried hill belt, sub-swamp groove belt and slope from east to west direction. The main detachment plane with big depth in the north is basement-tilted area, the central part with medium depth is basement fault-bend area, and the southern part with small depth is cap rock-slip fault-fold area. References | Related Articles | Metrics

Tectonic Controlling Factors of Ordovician Reef and Bank Reservoir in Tazhong Uplift in Tarim Basin WU Guang-hui, JU Yan, YANG Cang, ZHAO Kuan-zhi 2010, 31 (5):  467-470.  Abstract ( 92 )   PDF (339KB) ( 230 )   Save The analysis of structure and reservoir along Tazhong No.1 belt in the northern Tazhong uplift of Tarim basin shows that in the Ordovician reef and bank without reconstruction there only exists low-porosity and low-permeability reservoir, and the tectonic action controls the development of high-productivity reservoirs. In the end of the reef and bank deposition of the Lianglitage formation in Tazhong No.1 zone, intensive exposed karstification with large caverns was formed due to the uplift of the eastern structure, the reservoir quality in the eastern area is better than that in the western one. The faulted belts are the main locations where large fractures and caverns with anomaly "beaded" seismic response developed. The fracture-cavern bodies formed by dissolution in multistage burials are mainly controlled by the faults. So, the fractures have constructive effects on post dissolution and reservoir permeability, also, it is significant factor for high oil-gas production. The structural differentiation in Tazhong No.1 zone allows the distribution of reef and bank body and the development of reservoirs to be of subsection property. The eastern platform margin is in high, steep, long and narrow location, in which the fracture-cavern reservoirs well developed due to weathering crust karstification and structural action, being favorable for high and stable petroleum production. The western area with underdeveloped faults has broad but ramp platform margin dominated by low porous reservoirs. References | Related Articles | Metrics

Characteristic of Volcanic Reservoir in Malang Sag in Santanghu Basin CHEN Jian-qi, JI Yan-hong 2010, 31 (5):  471-473.  Abstract ( 87 )   PDF (217KB) ( 230 )   Save The volcanic reservoir body in Santanghu basin is dominated by neutral-basic volcanic rocks. The main reservoir rocks are composed of vesicular and almond-shaped basalt and andesite in the top of block lava. The key of improvement of such a reservoir quality is the epigenetic reconstruction, mainly including weathering and leaching, dissolution, faulting and micro-fracture, by which form secondary solution pore-vugs and secondary fractures, and become good reservoir body with pore spaces such as solution pore, fissure and structural fracture, constricted fissure, etc., belonging to porous-fractured reservoir with strong heterogeneity. Controlled by lithology and lithofacies, this reservoir is characterized by short-range vertical migration and accumulation, oil-gas rich belt distribution adjacent to hydrocarbon generation. The top vesicular, almond-belt remained thickness, weathering, leaching and dissolution extent as well as fractural communication are the key factors for its hydrocarbon accumulation. Near the denudation line of Permian and the volcanic erupting and intermittent zone are favorable zones for forming the volcanic reservoir. In the Permian and Carboniferous volcanic reservoirs in Niudong, Mazhong, Tiaozhong and Nanyuan blocks, a hundred million ton-grade potentials for petroleum exploration have been discovered at present. References | Related Articles | Metrics

Characteristics of Sedimentary Evolution of Paleogene and Neogene in Altun Slope in Western Qaidam Basin YI Ding-hong, CAO Zheng-lin, PEI Ming-li, YUAN Jian-ying, WU Wu-jun, ZHENG Xi-min 2010, 31 (5):  474-476.  Abstract ( 108 )   PDF (229KB) ( 282 )   Save The multi-well crossing section's sedimentary system evolvement of Paleogene Xiaganchaigou formation ($E_3 xg^1$) to Neogene Shizigou formation ($N_2 s$) in Altun slope from Qigequan structure in the west to Niubiziliang structure in the east in western Qaidam basin indicates that ①Altun slope area develops fan delta, turbidite fan and shore lake bar deposit system from $E_3 xg^1$ to $N_2 s$; ② it develops an integral sedimentary cycle as a whole, in the early, $E_3 xg^1$ is a retrograding cycle and in the middle and late it is a progradational cycle; ③ the time that the each sedimentary system appears progradational cycle is different, of which Yue-3 well area develops the progradational cycle in the middle of the E3xg2, while Xichagou structure develops the cycle in the early of the $N_2 s$, in Yue-1 well area the cycle does not appear, and ④Niucan-1 well area develops retrograding cycle from the early of the $N_2$sy to the $N_2 s$. The development and evolution characteristics of sedimentary system in Altun slop area fully reflect that the Altun fault activity is of multistage, phase and local properties as well as out-of-step property to the full. References | Related Articles | Metrics

The Sequence Characteristic of Triassic and Its Significance in Petroleum Exploration in Tabei Area, Tarim Basin SHI Xiao-zhang, WANG Jian-xin, JIN Zhen-kui, WANG Zhe, LIU An, LI Peng, GUAN Quan-sheng, YANG You-xing 2010, 31 (5):  477-481.  Abstract ( 95 )   PDF (1037KB) ( 295 )   Save By means of sequence stratigraphy, seismic sedimentology and modern sedimentology theory, the comprehensive analysis of the logging and well logging data from 128 wells, 25 000 km 2-D seismic profile and a part of 3-D seismic data in Tabei area is conducted, and five 3rd-order sequences (Tsq1-Tsq5) bounded by unconformities are identified in the Triassic. Tsq1 and Tsq2 belong to the Lower Triassic, Tsq3 and Tsq4 belong to the Middle Triassic and Tsq5 belongs to the Upper Triassic. All the five sequences are composed of the low-stand system tract dominated by braided river, meandering river and delta and the transgressive system tract dominated by littoralshallow lake, semi-deep lake and deep lake. The tectonic movement, lake level change and sediment supply are the main controlling factors of the Triassic sequences. According to the analysis of sequence evolution and petroleum geology conditions, the complex channel and delta distributary channel developed in low-stand system tract are favorable explorative targets for lithological trap's reservoirs. References | Related Articles | Metrics

Petroleum Geologic Characteristics and Hydrocarbon Exploration Objectives of Sinian in Tarim Basin HE Jin-you, WU Guang-hui, LI Qi-ming, MA Feng, LI Hong-hui 2010, 31 (5):  482-484.  Abstract ( 145 )   PDF (198KB) ( 254 )   Save This paper analyzes the petroleum geologic characteristics of the outcrop sections around Tarim basin and the Sinian in wells in this basin. It is recognized that dolomite in top of Sinian develops solution pores, vugs and fractures caused by karstification, and the reservoir pore space also contains inter-rubble pores. The effective source rocks of Sinian are argiloid of Nanhua-Sinian, mudstone and muddy limestone of Lower Cambrian which directly overlaps the Sinian dolomite reservoir as a good cap rock, forming a good reservoircap rock assemblage. The analysis of the Sinian petroleum accumulation history indicates that its top dolomite is of multistage oil-gas charging conditions, and the primary paleo-reservoir could be preserved in the paleo-uplift slope area. On this basis, integrated with regional tectonic zone evaluation, it is proposed that the Sinian strata of north slope in Tadong low swell, north side in Tazhong low swell and Keping-Bachu uplift will be favorable objectives for hydrocarbon exploration. References | Related Articles | Metrics

Geophysical Anomaly Characteristics of Gas Hydrate Zone in Northern South China Sea SU Pi-bo, LEI Huai-yan, LIANG Jin-qiang, SHA Zhi-bin, LIANG Jin 2010, 31 (5):  485-488.  Abstract ( 64 )   PDF (627KB) ( 383 )   Save Based on the geophysical data of gas hydrate prospecting area in northern South China Sea, the correlation analysis of the seismic reflectance and attribute profiles, geophysical logging curves and geothermal data in this area is conducted, and the anomaly characteristics of these and their relations are discussed. The result shows that the conventional seismic profile integrated with post-stack seismic attribute profile interpretation can be used to effectively identify the gas hydrate zone in northern South China Sea; the combination of acoustic velocity logs, resistivity logs and density logs is the effective way to judge the occurrence of the gas hydrate zone in this area; the comprehensive analysis and combination of these geophysical characteristics can optimize and integrate effectual geophysical technologies, enhance the validity of identifying gas hydrate and develop a set of reliable prediction means. References | Related Articles | Metrics

Characteristics of Geothermal-Geopressure System and Its Relationship with Oil and Gas Distribution in Banghu-Zhouji Syncline Belt in Qianjiang Sag KANG Jian-yun, YE Jia-ren, GUO Fei-fei, TANG Wen-xu 2010, 31 (5):  489-491.  Abstract ( 108 )   PDF (378KB) ( 211 )   Save Banghu-Zhouji syncline belt is the best source belt in Qianjiang sag with abundant hydrocarbon resources. Based on the theory of geothermal-geopressure system and observed temperature-pressure data from more than 90 wells, this paper analyzes the plane and section characteristics of the geothermal field, geopressure field and geothermal-geopressure system in Banghu-Zhouji syncline belt as well as the relationship between these characteristics and hydrocarbon distribution. The research shows that the high geothermal gradient in Banghu-Zhouji syncline belt is propitious to the maturity of source rocks and generation of hydrocarbons; the deep low overpressure could be as the important motivating force for petroleum migration; vertically, it has the characteristic of overpressure complex geothermalgeopressure system, but the vertical migration capacity of hydrocarbons is weaker, being dominated by short-range lateral migration; laterally, various oil-bearing reservoirs are mainly distributed in the areas with relatively low fluid energy, which is surrounding or adjacent to the areas with relatively high fluid energy. References | Related Articles | Metrics

Bioturbation of Donghe Sandstone Member in Tarim Basin YANG Wei-fang, WANG Bo, ZHANG Hui-liang 2010, 31 (5):  493-495.  Abstract ( 81 )   PDF (486KB) ( 270 )   Save The effect of bioturbation to deposition process is complex. It is generally recognized that bioturbation exists in surface granular mud sediments, such as the deep sea beds, estuary bays, tidal flats and other conditions. Donghe sandstone member in Tarim basin was deposited in high-energy shore clastic sedimentary environment. The numerous trace fossils and a large number of bioturbation structures may state the fact that there exists bioturbation in high-energy environment. The intensity of bioturbation has further become the evidence of identifying the sedimentary microfacies and the crypto-bioturbation can always reflect the original sedimentary structure. References | Related Articles | Metrics

Application of Sidetracking Horizontal Well to Adjustment for Luliang Oilfield Development CHEN Lun-jun, JI CHENG-wei, MA Ji, LI Bin-wen, YANG Zhi-qiang, LEI Ying 2010, 31 (5):  497-499.  Abstract ( 70 )   PDF (263KB) ( 271 )   Save The Hutubihe reservoir of Lower Cretaceous in Wellblock Lu-9 in Luliang oil field in Junggar basin is a typical sandstone reservoir with thin oil layers and active edge and bottom water. Affected by the edge and bottom water coning and injected water breakthrough, some wells have entered into high water cut stage with low recovery factor and difficult incremental production. For this reason, several measures have been applied to in-depth study of watered-out oil layers' status and water drive regularity and determination of remained oil-enriched area. This paper optimizes the main technical parameters of sidetracking horizontal well by means of reservoir engineering and numerical simulation. In 2008-2009, 14 sidetracking horizontal wells were drilled, with incremental production per well of 8.1 t/d in average, water cut drawdown by percentage of 47.2 and productivity increase of 2.69×104 t. References | Related Articles | Metrics

The Foundation of Modern Well Test Interpretation CHEN Yuan-qian 2010, 31 (5):  500-505.  Abstract ( 147 )   PDF (505KB) ( 251 )   Save The modern well test interpretation technique is an automatic fitting and solution method by computer operating system integrated with exclusive software, by which the velocity and quality of well test interpretation can be greatly increased and improved. However, it is also closely related with the work ability of interpretation engineer. At present, many interpretation engineers can only finish the interpretation task by means of computer, they just know a little or basic theory and methods referred to the technique. This may not only directly influence the quality of well test interpretation made by them, but also influence their skill development. This paper elaborates the basic knowledge and methods of the modern well test interpretation technique, including dimensionless processing and unit conversion, definition and variation of differential of pressure, deduction of differential of pressure calculation method, dimensionless rate and typical curve, etc. Finally, two examples are cited to explain how to use modern well test interpretation technique for solution of various parameters required for homogeneous and dual porosity reservoir. References | Related Articles | Metrics

Optimized Conceptual Design of Deep Heavy Oil Reservoir Development by Cyclic Natural Gas Injection Process ZHANG Yan-yu, SUN Wen-jing, SUN Xiao-fei 2010, 31 (5):  506-508.  Abstract ( 79 )   PDF (218KB) ( 210 )   Save With the discovery of a mass of natural gas resources and the continuous improvement of EOR technology by natural gas injection process, the heavy oil reservoir developed by natural gas injection process has become significant technical means for EOR. In view of the geology and exploitation of deep heavy oil reservoir in an oil field, based on the lab experiment and phase behavior simulation, this paper builds up the numerical simulation model for such a reservoir, and optimizes the parameters of the EOR program by cyclic natural gas injection process using the compositional model after history match and modification. According to the parameter optimization program of deep heavy oil reservoir by cyclic natural gas injection process, good effects of incremental oil production and reducing water cut have been gained. References | Related Articles | Metrics

Experimental Study of Dehydration Temperature Optimization of Super-Heavy Oil in Liaohe Oil Field OUYANG Chuan-xiang, ZUO Chen-xiao 2010, 31 (5):  509-511.  Abstract ( 108 )   PDF (266KB) ( 340 )   Save Taking oil sample from DU229+84 super-heavy oil block in Liaohe oil field as the experimental object, this paper studies the relationship of super-heavy oil density and viscosity, mixed crude emulsion density and viscosity, emulsion interfacial film pressure and mixed crude dehydrated droplet fall velocity etc. vs. temperature, and analyzes the effect of temperature on the rate of super-heavy oil dehydration. Experimental results show that the density and viscosity of mixed crude oil and emulsion decrease; the density difference between crude and dehydrated water increases followed by decreasing; the droplet fall velocity in medium (crude oil) increases and the interfacial film pressure decreases with increasing of the temperature. The temperature increase is favorable to speed up the rate of superheavy oil dehydration. At the temperature of 70~95℃, the density difference goes to the highest, and the viscosity reduction of the crude oil and emulsion achieves the maximum. Taking economic factors into comprehensive consideration, the best temperature of super-heavy oil breaking dehydration is 80~95℃. References | Related Articles | Metrics

Simple Method for Parameter Optimization by Wang-Li Model for Production Forecast LI Fa-yin 2010, 31 (5):  512-513.  Abstract ( 94 )   PDF (115KB) ( 169 )   Save With the greatest inheritance for 1stOpt software, the parameters of Wang-Li model can be fast, easily and accurately obtained. It is shown by application that this method has better applicability to oil layer, oil reservoir, gas pool, oil field, gas field, pure oil zone and transition zone, general well pattern and infilled well pattern. References | Related Articles | Metrics

New Method of Coupling Numerical Simulation and Application to Fracture-Cavern Carbonate Reservoir KANG Zhi-jiang 2010, 31 (5):  514-516.  Abstract ( 108 )   PDF (244KB) ( 456 )   Save This paper firstly proposes the calculation method for inner cavern two-phase flow dynamics, develops the interfacial processing method between cavern and solution pore and builds up the cavern-solution pore coupling two-phase mathematics model for fracturecavern reservoirs, including related finite volume numerical solution and PC-applied program. In successful application to study of water injection oil displacement mechanism of Tahe fracture-cavern reservoir in Tarim basin, the waterflooding process of multi-well fracturecavern element is also proposed firstly, and the oil incremental effect is obvious after field implementation. References | Related Articles | Metrics

Production Performance of In-Situ Combustion in Heavy Oil Reservoir after Steam Injection HUANG Ji-hong, GUAN Wen-long, XI Chang-feng, CHENG Hong-jie, LI Xiao-ling, WANG Yu-xin 2010, 31 (5):  517-519.  Abstract ( 99 )   PDF (428KB) ( 272 )   Save As a succeeding development process following steam injection (huff and puff, steam drive) in heavy oil reservoir, in-situ combustion has been used in WellBlock HQ-1 of Karamay oil field in order to further enhance oil recovery. This paper studies the effect of ground secondary water on in-situ combustion process, presents five production stages and their production performances of producers by means of reservoir numerical simulation and physical modeling methods, and analyzes the three different occurrences and their formation mechanisms in early responses. These will be of significance of grasping the fire-flooding performance under similar reservoir conditions. References | Related Articles | Metrics

Variation of Oil or Liquid Productivity Index in Low-Pressure and Super-Low Permeability Reservoir WANG Li-qiang, SUN Yu-kai, LIU Yue-qiang, CUI Ying-huai, LUO Yang-jun, YANG Dan 2010, 31 (5):  521-522.  Abstract ( 110 )   PDF (262KB) ( 295 )   Save Low pressure and super-low permeability reservoir is of more rock pressure sensitivity than conventional permeability reservoir. In this paper, the formula for calculation of non-dimensional oil or liquid productivity index by considering changes of starting-up pressure and permeability pressure sensitivity is deduced. Taking Niujuanhu reservoir with low pressure and super-low permeability in Tuha oil field as an example, the variation between non-dimensional oil or liquid productivity index and water cut is discussed when oil-water viscosity ratio, starting-up pressure and permeability deformation factor are changed dynamically. The studied result shows that the dynamic change of starting-up pressure of such a reservoir has obvious effect on the non-dimensional oil or liquid productivity index. Moreover, this index is much more affected by the starting-up pressure and permeability deformation factor than that of conventional low permeability reservoir. References | Related Articles | Metrics

New Model for Calculation of H2S-Rich Natural Gas Deviation Factor BIAN Xiao-qiang, DU Zhi-min, TANG Yong 2010, 31 (5):  524-526.  Abstract ( 80 )   PDF (195KB) ( 212 )   Save The development of new model for calculation of H2S-rich natural gas deviation factor is based on the deviation factor Z value measured by Li Qun, et al. and non-integral power polynomial fitting method. The measured deviation factor is calculated by simulation using this new model and Dranchuk-Abu-Kassem-Wichert-Aziz model. The comparison results with tested data show that the new model is in good accordance with experimental Z value, with average relative error of 0.276% and maximal relative error of 2.734%, obviously higher than that of Dranchuk-Abu-Kassem-Wichert-Aziz model in accuracy. In addition, the new model is characterized by quick calculation and convenient differential-integral calculation. References | Related Articles | Metrics

Prediction of Oilfield Production with Variable Coefficient Modified GM(1,1) Model WANG Bo, SONG Xin-min, YANG Zhao-ping, TANG Hou-jun 2010, 31 (5):  527-529.  Abstract ( 82 )   PDF (185KB) ( 187 )   Save Prediction model for production decline is an important method for oil-gas reservoir engineering research. In this paper, a variable coefficient GM (1,1) model and parameter estimation method are developed on the basis of gray forecast model theory. The variable coefficient GM (1,1) model and original data transformation modify the gray model. Case study indicates that the improved gray forecast model is of higher accuracy for prediction of oilfield production. References | Related Articles | Metrics

A Feasibility Study on Exploitation of Heavy Oil Reservoirs by High Temperature Compound Gas Drive FAN Yao, LIU Yi-fei, RU Ting, LI Bin-gang, HUANG Hai 2010, 31 (5):  530-532.  Abstract ( 92 )   PDF (258KB) ( 446 )   Save Aimed at the benefits decline and production shortfall of the heavy oil reservoirs, the research of the gas injection methods for heavy oil reservoirs is conducted. From the analysis of the viscosity-temperature and rheological characteristics of heavy oil, the oil displacement mechanism and problems by steam drive process for heavy oil reservoirs are investigated. According to the theoretical analysis and the experimental results, the feasibility on exploitation of heavy oil reservoirs by high temperature compound gas drive utilizing N2, CO2 and steam properties is studied in detail. The results indicate that the high temperature compound gas drive with N2 and CO2 is better than steam drive, showing much higher crude oil recovery. References | Related Articles | Metrics

Mechanical Analysis of Stress Acted on Residual Oil Film by Polymer Solution LIU Li-li, WANG Li-hui, ZHANG Ying, LIU Shu-qi 2010, 31 (5):  533-535.  Abstract ( 97 )   PDF (433KB) ( 309 )   Save By means of continuity equation, momentum equation, constitutive equation and Polyflow (a software for calculation of fluid dynamics), the stress acted on residual oil film by polymer solution at oil-wet rock surface is calculated. The results show that the bigger the viscoelasticity of polymer solution, the greater the stress acted on the residual oil-film, and the more favorable to the oil-film deformation; the bigger the flow channel width, the greater the deviatoric stress acting on the oil-film, the more favorable to the oil displacement efficiency enhancement. References | Related Articles | Metrics

A New Method for Development of Bottom-Water Reservoir Without Natural Barrier LIU Yan-CHENG, WANG Jian, MENG Jian-xun, LIU Pei-pei, FAN Wei, LU Guang-liang 2010, 31 (5):  536-538.  Abstract ( 59 )   PDF (265KB) ( 257 )   Save During development of bottom-water reservoir without natural barrier, many oil wells are faced with difficulties such as fast bottom-water coning, low critical yield and short water-free oil production period, etc. Based on previous researches, partition theory and the dual completion bottom-water coning control technology, the development model for the bottom-water reservoir without natural barrier is discussed. And a method for effective development of such a reservoir by plugging agent injection (artificial partition) and drainage bottom-water coning control is proposed for the purpose of scientific, efficient and rational development of such a reservoir. References | Related Articles | Metrics

Analysis of Transient Deliverability of Multi-Branch Horizontal Gas Wells JIANG Kai, LI Min, LIU Zhong-qun, HE Zhi-xiong 2010, 31 (5):  539-542.  Abstract ( 101 )   PDF (397KB) ( 201 )   Save Using multi-branch horizontal wells can greatly increase the drainage area of reservoirs and effectively raise gas production. Based on gas transient flow theory, the pressure drop analytical solution of the horizontal gas well in parallel with x-axis is concluded according to Newman's product principle and Green function. Combined with rotation of axes, the transient deliverability equation for horizontal gas well is derived with α angle to the x-axis. And then the transient deliverability forecasting model for multi-branch horizontal gas wells is presented based on the principle of pressure drop superposition. The analysis result shows that: (1) the production of multibranch horizontal wells in gas reservoirs increases with the increasing of number of the branches, but interference effect strengthens, production growth range decreases when the number increases, indicating that there is an optimal value of the number of branches; (2) according to the optimal number of branches, the production is declining with time, followed by tending to a certain value, and the flow reaches pseudo-steady state. References | Related Articles | Metrics

Application of Sidetracking Horizontal Well to Adjustment for Luliang Oilfield Development CHEN Lun-jun, JI CHENG-wei, MA Ji, LI Bin-wen, YANG Zhi-qiang, LEI Ying 2010, 31 (5):  543-545.  Abstract ( 98 )   PDF (346KB) ( 224 )   Save The Hutubihe reservoir of Lower Cretaceous in Wellblock Lu-9 in Luliang oil field in Junggar basin is a typical sandstone reservoir with thin oil layers and active edge and bottom water. Affected by the edge and bottom water coning and injected water breakthrough, some wells have entered into high water cut stage with low recovery factor and difficult incremental production. For this reason, several measures have been applied to in-depth study of watered-out oil layers' status and water drive regularity and determination of remained oil-enriched area. This paper optimizes the main technical parameters of sidetracking horizontal well by means of reservoir engineering and numerical simulation. In 2008-2009, 14 sidetracking horizontal wells were drilled, with incremental production per well of 8.1 t/d in average, water cut drawdown by percentage of 47.2 and productivity increase of 2.69×104 t. References | Related Articles | Metrics

Application of Trend-Surface Analysis to Fault Recognition in Yingmai-2 Well Area in Tabei Area, Tarim Basin MENG Xiang-xia, YAO Qing-zhou, LIU Jian-xin, WANG Jin-xi, YUAN Wen-fang 2010, 31 (5):  546-547.  Abstract ( 87 )   PDF (447KB) ( 241 )   Save Yingmai-2 structure of Tabei area in Tarim basin is a dome anticline, characterized by complex structure, multistage and multigrade faults. The identification and explanation of the faults are difficult due to high dip of strata. In this paper, the trend-surface analysis technique is firstly applied to the identification of the faults, and the faults distribution in this area is described effectively. References | Related Articles | Metrics

Application of Complex Fault-Block Reservoir Modeling Technology in Qiuling Oil Field LIU Bin, SHI Xiao-yan, HE Bo-bin, LIU Ying, LUO Yang-jun 2010, 31 (5):  548-550.  Abstract ( 79 )   PDF (388KB) ( 276 )   Save Taking well spacing density, seismic interpretation and fault data, reservoir prediction and sedimentary microfacies research result as controlling modeling factors, integrated with some technical means such as probability statistics, variogram analysis and sequential Gaussian association Kriging method, the fine 3D geologic model for complex fault-block reservoir in Qiuling oil field in Tuha basin is developed, by which the digitization and visualization of comprehensively researched results of geology of Qiuling oil field are realized. Also, it will play an important role in making further development modification and study of the field. References | Related Articles | Metrics

Evaluation Method for Economic Benefit of Secondary Development in Karamay Oil Field ZHANG Yu, WANG Jian-feng, XIANG Qian, ZHOU Chun-xia, LIU Bin, ZHANG Jun, QIU Yang 2010, 31 (5):  551-553.  Abstract ( 75 )   PDF (211KB) ( 257 )   Save This paper elaborates the targets, project contents, necessity and features of secondary development in Karamay oil field, analyzes the significant distinctions of economic benefit evaluation between the secondary development projects and the ordinary projects and draws up the case history of specific evaluations. This research has been applied to the secondary development work in this field and has important significances on research of development adjustment in old oil fields, stabilization of production in existing blocks, enhancement of oil recovery in the reservoirs and proper understanding of economic benefit of the secondary development. References | Related Articles | Metrics

Prediction of Thin Reservoir Thickness Less Than Seismic Resolution Limitation ZHOU Jia-xiong, LIU Wei-wei, SUN Yue-CHENG, SUI Bo 2010, 31 (5):  554-556.  Abstract ( 92 )   PDF (561KB) ( 432 )   Save Most scholars accept that resolution of seismic data is λ/4, but the thickness of most reservoirs that have been found at present is less than λ/4. This paper presents several available methods for prediction of thickness of thin reservoirs and gives definitions of the suitability and boundary conditions of each method, and good results are obtained by applications of these methods to various oil-gas fields. References | Related Articles | Metrics

The Evolution of Celestial Body and the Inorganic Hydrocarbons of the Earth—An inspiration from the Cassini Mission CAO Zheng-lin, ZHANG Jing-lian, YAN Cun-feng 2010, 31 (5):  557-561.  Abstract ( 111 )   PDF (251KB) ( 273 )   Save The hydrocarbons are universally distributed in meteorite, comet, moon, major planets of solar system and their satellites and the universe. The existence of plentiful methane, liquid hydrocarbon and black organic compounds in the Sature's Satellite Six is a typical example. Based on the planetary geology and the evolution history of the Earth, the possibility of inorganic hydrocarbon in the Earth is discussed. Some models for the inorganic hydrocarbon generation of the Earth at home and abroad are introduced, which include the earth outgassing model proposed by Gold and Du Letian; the Earth absorption-accumulation model by Ouyang Ziyuan; Fischer-Tropsch model by Volivofski, Sarkisuv and Szatmari; multi-origin model by Zhang Jinglian. According to Pb, Sr and Nd isotopic data, the origin of some oilfields in China can be distinguished. By means of the inorganic origin theory of hydrocarbon, China's oil fields distribution regularity can be explained and the future exploration targets can be predicted. The inspiration from the Cassini Mission is that there are huge petroleum reserves to be explored in the deep Earth, and based on the inorganic origin theory of hydrocarbon, it is possible to find out some giant oil-gas fields. References | Related Articles | Metrics