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01 October 2008, Volume 29 Issue 5 Previous Issue    Next Issue

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Oil-Gas Reserves Increasing Trend in Sinopec-Controlled Exploration Areas HE Hong 2008, 29 (5):  545-547.  Abstract ( 107 )   PDF (253KB) ( 210 )   Save Based on the incremental proven oil-gas reserves every year and the relevant discovery history, along with the targets of "the Eleventh Five-Year Plan" and exploration deployment, the conventional oil-gas reserves increasing trend in 25 years to come is predicted using Logistic, Comperts and Hubbert methods. In the present conditions that Sinopec-controlled exploration areas do not change and exploration investment requirement remains the same on the whole, it is predicted that the newly incremental proven oil accumulative reserves will reach 11.28×108 t, newly incremental proven gas accumulative reserves will be 7 100×108 m3 during the period of 2006- 2010; 10.75×108 t to oil, 7 359×108 m3 to gas of 2011-2015; 10.70×108 t to oil, 7 792×108 m3 to gas of 2016-2020; 9.08×108 t to oil, 6 422× 108 m3 to gas of 2021-2025, and 6.81×108 t to oil, 4 495×108 m3 to gas of 2026-2030, all of which shows good potentials for oil-gas exploration in the future in Sinopec-controlled exploration areas. References | Related Articles | Metrics

3D Pressure Analysis in Wellblock Moshen-1 in Junggar Basin FAN Hong-hai, TONG Hui, LIN Hong 2008, 29 (5):  548-550.  Abstract ( 94 )   PDF (336KB) ( 327 )   Save Moshen-1 Well is a key well for scientific probe of CNPC, with completion depth of 7 500 m. This well is characterized by deep drilling horizon and varied formation lithology, so its successful drilling and completion played an important role to understand deep pressure distribution in Mosuowan area. This paper presents the characteristics of vertical and transverse formation pressure in Wellblock Moshen-1, and based on 3D seismic data constrained inversion by well logging, obtains 3D interval velocity. Finally, by taking advantage of Bowers method, 3D pressure in this area is gained. The correlation of seismic interval velocity from Moshen-1 Well and Pencan-2 Well with sonic logging velocity is made, and the more consistent results show that the 3D pressure can well reflect the pressure distribution in this area. References | Related Articles | Metrics

Volcanic Eruption Pattern and Distribution of Fengcheng Reservoir of Permian in Wellblock Xia-72, Northwestern Margin of Junggar Basin PAN Jian-guo, CHEN Yong-bo, XU Duo-nian, HUANG Lin-jun, WANG Bin, TAN Kai-jun, LIU Zhen-yu 2008, 29 (5):  551-552.  Abstract ( 119 )   PDF (297KB) ( 276 )   Save The Fengcheng formation of Permian in Wellblock Xia-72 in Northwestern margin of Junggar basin composes of rhyolitic clinkering breccia tuff with good petrophysical property and high productivity, and is a favorable area for deep oil-gas exploration. This paper analyzes the controlling factors for the volcanic eruption pattern and distribution of this reservoir. It is suggested that the fissure volcanic eruption is its main eruption pattern, and the distribution is mainly controlled by the crater and the paleogeomorphology. The result provides the basis for exploration of such a reservoir. References | Related Articles | Metrics

Geochemical Feature of Low-Mature Crude Oil in Sub-Sag of Guanzhen in Subei Basin YANG Bin, LIANG Xing, MA Xiao-xiang, ZHOU Songyuan, LOU Ji-sheng, CAI Ya-ping 2008, 29 (5):  553-556.  Abstract ( 93 )   PDF (310KB) ( 202 )   Save The sub-sag of Guanzhen is located in middle part of Hongze sag in Yanfu depression, Subei basin. Its low-mature crude oil is characterized by the "four highs and one low" physical properties: the middle-higher crude density, high viscosity, high solidification point, high paraffin content and low sulfur content. The oils in wells in this sub-sag are not subjected to biodegradation, with the typical low-mature oil feature of their group compositions, which are proved by low degree of the thermal evolution data of light hydrocarbons including sterane, low m(Pr)/m(Ph) and high m(Ph)/m(nC18) ratios. The m(Pr)/m(Ph) ratio indicates the crude is product from the reductingstrong reducting environment and dominated by sapropelic kerogen. The high paraffin content of crude oils is related to those that a part of humic kerogen formed oil in low-mature stage and botryococcane in saprogelic kerogen early formed oil. References | Related Articles | Metrics

Fine Interpretation of Logs from the Pluvial Glutenite Reservoirs—An example from Karamay field YAN Ze-jiang, TANG Fu-ping, YAO Ying, HU Xin-ping, HU Wan-qing, SHAN Jiang, LIU Ping 2008, 29 (5):  557-560.  Abstract ( 110 )   PDF (404KB) ( 262 )   Save The glutenite reservoir of T2xk in District No.3 in Karamay field is characterized by complicated structure of rocks, strong heterogeneity, clear difference between layers and being difficult to interpret old log data. This paper presents the new ideas about developing fine interpretation model for well logs by different logging suites and lithologies on the basis of logs normalization. By using this model to 846 wells in studied area for second interpretation, the results indicate that this model is of high interpretation accuracy and practical significance to improve the fine interpretation precise of logs from glutenite or conglomerate reservoir. References | Related Articles | Metrics

The Porosity Evolution of Volcanic Reservoir of Carboniferous in Luxi Area, Junggar Basin ZHANG Shun-cun, HUANG Zhi-jiu, KONG Yu-hua, SHI Ji-an, LEI Tian-zhu, FANG Lin-hao 2008, 29 (5):  561-564.  Abstract ( 106 )   PDF (388KB) ( 214 )   Save The volcanic reservoir of Luxi area in hinterland of Junggar basin is made up of primary pores, secondary pores and fractures with different combinations. The evolution of the volcanic reservoir spaces has five stages: the formation stage, the efflorescence and denudation stage, the embedding and tectonic movement stage, the dissolution and modification stage and the oil-gas accumulation stage. In addition, five diagenesis factors influencing the volcanic reservoir spaces are presented, including tectonic breaking, efflorescence and eluviation, corrolding, dissolution, fill and cementation. References | Related Articles | Metrics

The Porosity and Evolution of Volcanic Rocks in Northwestern Margin of Junggar Basin LIU Xi-shun, GUO Jian-hua, QU Jian-hua, ZHANG Yuan-zhi, LI Lu-ming 2008, 29 (5):  565-568.  Abstract ( 129 )   PDF (407KB) ( 273 )   Save In-depth analysis is made on lithology, storage space type, porosity evolution, pore-fissure combination of volcanic rocks and their influencing factors in northwestern margin of Junggar basin. For given six types of the lithologies and the storage spaces and their forming mechanisms, it is suggested that the volcanic rocks with poor connective primary porosity didn't become effective reservoir rocks until the post reconstruction that allowed it to greatly improve the volcanic reservoir quality such as dissolution and tectonic movement appeared. Also, the process and controlling factors for such main the volcanic reservoir porosity evolution as andesite, volcanic breccia and tuff are analyzed. Based on these analyses, the evolution process in this area could be divided into five stages as follows: formation stage, weathering-leaching stage, burying and structural process stage, solution-reconstruction stage and oil-gas accumulation stage. References | Related Articles | Metrics

Fracture Detection with 3D P-Wave Azimuthal AVO DU Hui-ping 2008, 29 (5):  569-571.  Abstract ( 81 )   PDF (336KB) ( 224 )   Save Theoretically, the anisotropy of subsurface medium resulted from fractures in approximately same strike can be characterized and predicted using the variation of reflection amplitude of P-wave seismic date with azimuth. The target stratum in studied area is carbonate reservoir of shallow-middle depth, which are characterized by the seismic data of wide-azimuth, high-fold and high S/N ratio. The technology of amplitude preservation is carefully used during seismic data processing for preserving amplitude variation from azimuth AVO and avoiding amplitude abnormity produced from acquirement and processing. The technologies of macro-binning and pre-stack time migration (PSTM) are used for improving the imaging quality of target stratum. Based on the PSTM data volumes of 5 different azimuthal angles, the strike and intensity of fractures in studied area are predicted. Along with the geologic data and the characteristic of P-wave azimuthal AVL, the prediction results are analyzed and discussed. References | Related Articles | Metrics

Conversion Characteristics of the Oil Controlled Reserves in Jiyang Depression ZHANG Jia-zhen, XU Bei, LI You-qiang, ZHANG Yan 2008, 29 (5):  572-574.  Abstract ( 101 )   PDF (216KB) ( 206 )   Save The oil controlled reserves conversion has become the main resource of the proven reserves in Jiyang depression. Increase of exploratory workload, reevaluation of the old wells and development of testing techniques are the main reasons of the oil controlled reserves conversion in Jiyang depression. Some factors such as reserves scale, reserves abundance, productivity and buried depth of the reservoirs are influencing the conversion of the controlled reserves blocks greatly. It is concluded that the oil controlled reserves block with reserves scale over 500×104 t, reserves abundance over 50×104 t/km2, buried depth less than 3 500 m, steady productivity per 1 000 m footage over 2.8 t/km·d (on land) or 202.8 t/km·d (in shallow sea) can be converted into oil proven reserves on the whole. References | Related Articles | Metrics

Marine Strata Oil-Gas Shows and Distribution Characteristics in Southern China PENG Jin-ning, LIU Guang-xiang, PAN Wen-lei 2008, 29 (5):  575-577.  Abstract ( 105 )   PDF (187KB) ( 260 )   Save The oil-gas shows in marine strata of southern China are systematically discussed from three aspects: the type and the lateral and vertical distribution as well as controlled factors. Study shows that in view of oil-gas shows types, horizons and distributed regions, the marine strata of southern China are characterized by the most of oil and gas in shallow strata and the most of asphalt in deep level; more oil and gas in north part, more asphalt in middle and northern margin; few oil-gas shows in south part of southern China. In view of controlled factors, the oil-gas shows and distribution are always controlled by the source rocks at the first, and secondly by the tectonic movements and the sedimentary assemblages in this area. References | Related Articles | Metrics

Approach to Oil-Gas Migration Patterns in Stratigraphic Unconformity—An example from Jiyang depression CHEN Tao, JIANG You-lu 2008, 29 (5):  578-580.  Abstract ( 82 )   PDF (323KB) ( 182 )   Save The pore and fracture are widely developed in sandstone, carbonate rock and magmatite under unconformity, which tend to forming high porosity and high permeability belts, while those in mudstone are filled by recrystallization due to deuterodiagenesis without permeability. These belts are possible to shape the main passageway of long-distance oil migration because crude remained in the fractures and pores can be seen by core and microscopic observation. This paper presents the process of stratigraphic reservoir's oil accumulation in south slope of Dongying sag, and sets up two types of oil-gas migration patterns under unconformity: one is lateral migration pattern, and the other is clearstory-like vertical migration pattern. References | Related Articles | Metrics

Lacustrine Tempestite Sediment Feature and Significance in Second and Fourth Members of Xujiahe Formation, Upper Triassic in Middle of Sichuan Basin CHEN Hui, TIAN Jing-chun, JIANG Yu-qiang, YOU Li-wei, ZHANG Xiang, KANG Jian-wei 2008, 29 (5):  581-584.  Abstract ( 106 )   PDF (320KB) ( 288 )   Save Based on the field section and the core observation, this paper presents the characteristics of lacustrine elastic tempestites in the second and fourth members of Xujiahe formation, Upper Triassic in the middle of Sichuan basin, sets up the storm deposition model in this area, including the conditions and significance of the tempestite formation. The tempestites are composed of unconsolidated arenaceous sediment and boulder clay, which were from the sediments of mere corcagh and shoreside swamp churned up by storm wave, and transported to delta and beach bar of shore shallow lake. A plenty of the sedimentary structures of typical tempestite appears with less of mono-layer storm sediment, and the superposed half-baked tempestites formed by polygenic storm wave are often observed. The existence of tempestites is helpful to in-depth understanding of sedimentary facies in this area, indicating that the Upper Triassic was subjected to influence of the paleopacific climate in this area, and the hydrodynamic force of lacustrine basin was correspondingly intensified. Parts of original sandy sediments were vulnerable to be reconstructed, shaping new beach bar of shore shallow lake. It is suggested that the tempesite sand body can be as a favorable reservoir rock and could form prospective lithologic or structural-lithologic hydrocarbon reservoir. References | Related Articles | Metrics

The Deep Abnormal Pressure and the Formation of Lithologic Reservoir in Dongying Sag BAO You-shu, ZHANG Lin-ye, ZHANG Shou-chun, LIU Qing, ZHANG Lei 2008, 29 (5):  585-587.  Abstract ( 72 )   PDF (248KB) ( 225 )   Save The relationship between the deep overpressure and the lithologic hydrocarbon accumulation in Dongying sag is presented. The study shows that the oil-gas containing degree in the deep sand body is positive correlation to the overpressure which could be the main dynamic force for lithologic trapping and filling, lowering the cutoff value of PVT in such a reservoir. Therefore, the petrophysical conditions could not be as the main factors to constrain hydrocarbon accumulation in the overpressure belt rather than the fractures formed by overpressure. With the overpressure fractures' intermittent opening and close, oil-gas fluid could fill intermittently into the lithologic trap in the form of mix phase, while the water within the trap could flow out continuously and slowly. It is concluded that the existence of strong dynamic force allows the deep lithologic reservoir in Dongying sag to be of bright exploration potentials. References | Related Articles | Metrics

The Faults in Huizhou Sag and Their Controls on the Petroleum Accumulation TIAN Peng, MEI Lian-fu, YU Hui-ling, YU Shui-ming 2008, 29 (5):  591-594.  Abstract ( 74 )   PDF (293KB) ( 342 )   Save The research on the development and distribution of the faults in Huizhou sag is conducted by changes of the slips, extensional length, horizons, dip angles of the faults, based on which three grades of the faults are given. The study shows that Grade-II faults have biggest controls on the petroleum accumulation, in which higher enrichment of it could be found along NW faults, but those with too big slips of faults couldn't help the accumulation. The late active faults have bigger controls on the petroleum accumulation in this area. References | Related Articles | Metrics

Control Factor and Reservoir-Forming Pattern of Lithologic-Stratigraphic Reservoirs in Raoyang Sag WANG Quan, JIN Feng-ming, WANG Su-qing, QIAO Xiao-xia, SI Ji-wei, LI Qing 2008, 29 (5):  595-598.  Abstract ( 83 )   PDF (328KB) ( 336 )   Save Raoyang sag is a typical continental rifted sag richest in hydrocarbons in Jizhong depression and has good geological conditions for forming lithologic-stratigraphic reservoirs. Researches indicate that the forming and distribution of lithologic-stratigraphic reservoirs in this sag are controlled by four control factors, among which the structural setting and paleogeomorphology control extension of sedimentary system and sand body; the basement of carbonate platform and strong tilted block movement in Cenozoic and the sedimentary-reservoir facies belt and trough rich-in oil control definitively the distribution and abundance of lithologic-stratigraphic reservoirs. The reservoirforming patterns of lithologic-stratigraphic reservoirs are established on the basis of reservoir-forming characters of steep belt, trough belt, central buried-hill structural belt and slope belt within the sag. References | Related Articles | Metrics

Discovery of Tumuxiuke Formation of Upper Ordovician in Tazhong-88 Well with Stratigraphic Division DONG Bao-qing, DU Pin-de, LIU Xing-li, HUANG Guang-jian, TAN Ze-jin, LUO You-cheng, DING Li-juan 2008, 29 (5):  599-602.  Abstract ( 97 )   PDF (491KB) ( 273 )   Save In Tazhong-88 Well, the conodont fossils in the late of Middle Ordovician and the early of Late Ordovician slope facies have been found for the first time. The seismic and logging data indicate that there exists Tumuxiuke formation of Upper Ordovician and Yijianfang formation of Middle Ordovician in Tazhong-88 Well. The existence of these strata in Tazhong low swell becomes possible for the stratigraphic correlation of Ordovician and the analyses of regional structure and sedimentary environment among Tazhong, Lunnan and Yingmaili areas. References | Related Articles | Metrics

The Method for Partitioning Sedimentary Architectural Elements in Nearshore Subaqueous Fan System—An example from Sangonghe formation in Cai-9 Wellblock CHEN Qing, ZHANG Ji-chun, ZHAO Bao-shun, QIN Xu-sheng, ZHANG Wu 2008, 29 (5):  603-606.  Abstract ( 74 )   PDF (415KB) ( 203 )   Save Based on the study of microfacies, in view of the lithology, bedding structure, grain size and rhythm feature, etc., the interface of sedimentary architectural element in Sangonghe reservoir of Cainan oilfield is determined. Throuth analysis of the correlation of lithological interface and electrical curves, the electrical rhythm standard for profile of sedimentary elements such as SP reversion, GR raise, R fall or step-rate curve, etc. are set up, which can be used for detailed description of continental sedimentary system and its architectural elements. References | Related Articles | Metrics

A Chemical Tracer Plug Interpretation Model for Well Residual Oil Saturation Test PEI Lian-jun, ZHANG Jun-jie, LI Xiao-shan 2008, 29 (5):  607-609.  Abstract ( 102 )   PDF (200KB) ( 285 )   Save This paper presents a chemical tracer plug interpretation model for well residual oil saturation. This model advantages over past pulse interpretation model in accordance with real injected conditions and wide tracer selections as well as much lower cost of used tracers. It can be used for interpretation of field test results from in-situ tracer zone without obvious drift in shut-in oil wells. The numerical simulation indicates that the hold-up volume ratio determined by recovery section between original tracer and secondary tracer is not sensitive to the tracer diffusion. Compared with past numerical simulation results, the difference of residual oil saturation given by these two methods could be less than 0.5%PV, and compared with well pulse interpretation model, 2% can be increased in interpreted precision using this model. References | Related Articles | Metrics

Horizontal Well Deployment Optimization in Badaowan Formation in Wellblock Hongqian-1 TAN Ji-qiang, ZHAO Hong-yan, GUAN Quan-sheng, GENG Mei, YANG Zhi-dong 2008, 29 (5):  610-612.  Abstract ( 89 )   PDF (182KB) ( 226 )   Save In view of the geological characteristics of the delineation and undeveloped reserves in Badaowan heavy oil reservoir in Wellblock Hongqian-1 in Junggar basin, research on the integral steam-stimulation horizontal well deployment optimization is made by means of numerical simulation and economic analysis. According to the economic production limits under different oil prices, the technical parameters have been optimized for horizontal well deployment. It is determined that the low limit of pay zone thickness for horizontal well development is 2 m, the lateral length is 200 ～300 m, the well spacing is 100 m. The study shows that using integral steam-stimulation horizontal well development in this well block can get satisfactory results, and the recovery factor can be up to 28.4%. References | Related Articles | Metrics

Application of Gas Well Production Decline Prediction Methods to CO2 Gas Reservoir LI Chun-qin, XUE Guo-qing, LI Min, XIAO Wen-lian 2008, 29 (5):  613-615.  Abstract ( 68 )   PDF (246KB) ( 251 )   Save This paper presents some formulas which are based on Fraim's chart matching model for gas reservoir, combined with the nonlinear regression analysis and the relationship of PVT in CO2 gas reservoir. They can be used to determine the OGIP and reservoir parameters according to CO2 gas well production history. Through calculation of OGIP of Gao-53 Well in Huagou gas field, the reserves producing degree in this field has been found out, which can be as an important basis for further exploitation decision. Also, this paper presents the criterion to validate the calculation results with the semi-log figure of normalized time vs. normalized pressure being straight line or not, and provide references for acquiring proper OGIP or reserves and reservoir parameters. References | Related Articles | Metrics

Ascertainment of Well Spacing Density in Production Tail by Water Drive Process LIU Chun-mei, LIU Gang, WANG Gao-wen 2008, 29 (5):  616-618.  Abstract ( 93 )   PDF (210KB) ( 221 )   Save Based on the previous studies available, a new method for calculation of rational well spacing density and ultimate well spacing density of a field or reservoir after development by water drive process for a number of years. This method not only takes account of the investment, overhead expenses per year and the interests of crude oil vendition income, but also considers the injection-to-production-well ratio, remained oil distribution and production decline rate, etc. This method can be used to demonstrate if the old field patterns are infilled or not for purposes of avoiding the risk of uncertain investment to the maximum. References | Related Articles | Metrics

Understandings of Low-Resistivity Reservoir in Huoerguosi Area, Southern Margin of Junggar Basin WEN Gang-feng, TIAN Shi-chen, HAN Jun, ZHAO Jiang-qing, LI Cui-ping 2008, 29 (5):  619-621.  Abstract ( 77 )   PDF (263KB) ( 224 )   Save The typical low-resistivity oil-gas layers reflected on well logs in Huoerguosi area in southern margin of Junggar basin resulted in difficult identification of oil/gas-bearing strata here. The drilling engineering conditions indicate that the low-resistivity property of the reservoir mainly resulted from the influence of drilling fluids. The rock resistivity with different salinities of drilling fluids saturated with 9 400 mg/L, 18 000 mg/L, 45 000 mg/L, 80 000 mg/L and 120 000 mg/L are measured, obtaining the corrective relationship between the rocks and the logs. By means of this relationship, the available well data are corrected in order to get real the reservoir resistivity and to well identify the oil and gas layers in this area. References | Related Articles | Metrics

A study of Dual Cresting of Horizontal Wells in Reservoirs with Gas Cap and Bottom Water WU Zeng-gui, SUN Xin-min 2008, 29 (5):  622-625.  Abstract ( 115 )   PDF (319KB) ( 318 )   Save A procedure is proposed to study dual cresting of horizontal wells in gas cap and bottom oil reservoir by water drive process. The seepage flow panel that is perpendicular to the lateral is divided into many bidirectional plane-parallel flow models in which gas displaces oil from above and water displaces oil from below. By dynamically allocating flow rate into each flow region, the advancing process of gas-oil contact and oil-water contact in each region is calculated in each time step. Using this method can get a whole picture of gas crest and water crest at any time before they arrive at bottomhole and calculate gas and water breakthrough time when horizontal well has different standoffs to oil-water contact. Both crest shapes and breakthrough times of gas and water are comparable with results from commercial simulator-Eclipse. It is indicated that this method can used to predict the performance of horizontal wells in reservoirs with gas cap and bottom water. References | Related Articles | Metrics

A New Method for Determination of Start-Up Pressure Gradient in Low Permeability Reservoir TAO Jun, YAO Jun, FAN Zi-fei, WU Xiang-hong, ZHAO Lun 2008, 29 (5):  626-628.  Abstract ( 87 )   PDF (256KB) ( 224 )   Save The adsorption of crude oil surfactant component in the wall of pores and throats forms a boundary layer which has more influence on low permeability reservoirs than that on high permeability reservoirs. It is this boundary layer that causes start-up pressure gradient in low permeability reservoirs to be much higher than that in middle-high permeability reservoirs. In this paper, the formation of boundary layer and its influence factors are analyzed, and then a pore scale network model is developed for percolation simulation, finding out a flow curve between pressure gradient and flow velocity, by which determining the start-up pressure gradient. This method studies the start-up pressure gradient by considering the effect of boundary layer directly for the first time. In addition, it extends the usage of pore scale network model to low permeability reservoirs. References | Related Articles | Metrics

A New Method for Ultimate Water Cut Determination HUANG Xiao-liang, TANG Hai, WANG Zhong-wu, LV Dong-liang, LV Jian-jiang, YU Bei-bei 2008, 29 (5):  629-630.  Abstract ( 123 )   PDF (155KB) ( 243 )   Save This paper presents the normalization processing of relative permeability curves from reservoirs, establishes the relationship between productivity index and water cut based on Darcy's law, and obtains the ultimate water cut from given well economic limit rate and reservoir limit producing pressure differential. The case study of low permeability reservoir demonstrates the validity and the practicability applied to determination of ultimate water cut in oilfield development. References | Related Articles | Metrics

The Practical Reservoir Engineering Methods for Determination of Porosity Volumes in Fractured Volcanic Reservoirs ZHENG Zhen-heng, CAO Wen-jiang, WANG Zhao-feng, KONG Chui-xian, CAO Fei 2008, 29 (5):  631-634.  Abstract ( 81 )   PDF (300KB) ( 157 )   Save The buildup test data and field flow pressure information during production test are used to ascertain the fracture and matrix porosity volume within single well drainage area in fractured volcanic reservoir by means of Pollard-Pirson and influence functions methods. The results show that these methods can be applied to effectively make up the theoretical and technical limitations appeared in existing methods for ascertaining fracture and matrix porosity volumes in fractured volcanic reservoirs. It is significant to further study the reservoir geology, reservoir engineering and productivity performance in fractured volcanic reservoirs. References | Related Articles | Metrics

Using Porosity and Permeability Parameters to Construct Capillary Pressure Curves XIAO Zhong-xiang, ZHANG Chong, XIAO Liang 2008, 29 (5):  635-637.  Abstract ( 94 )   PDF (247KB) ( 485 )   Save It is the most direct and effective method to evaluate reservoir pore structure using capillary pressure data. Acquiring capillary pressure curves consecutively is the seeking target by geologists. In view of the finiteness of quantity of reservoir capillary pressure data, based on the analyses of various core mercury injection data, a new method for constructing capillary pressure curves using conventional porosity and permeability parameters is proposed and the relevant structural model is developed. The continuous capillary pressure curves can be constructed using this method. Comparison with core mercury injection capillary pressure data indicates the reliability of this method. References | Related Articles | Metrics

Effect of Hydrophobic Associated Polymer (AP-P4) Concentration on Its Structural Images WANG Yu-bo, YE Zhong-bin, SHI Xue-zhi 2008, 29 (5):  638-640.  Abstract ( 125 )   PDF (288KB) ( 243 )   Save The structure images of hydrophobic associated polymer (AP-P4) solution with different concentrations on mica slice is studied using atomic fore microscopy (AFM). The effect of the concentration on the structural image is confirmed definitively. It means that the images are quite different in different concentrations. When AP-P4 solution concentration is at 200 mg/L, its structure mainly appears in form of aggregates; at 500 mg/L, it occurs in form of spatial reticular structures. This method is helpful to understand the molecular images and the gel structures of AP-P4 and to study the solution structure of the polymers. References | Related Articles | Metrics

The Method for Determination of Abandonment Pressure in Water-Bearing Gas Pool YU Bei-bei, TANG Hai, LI Dong-lin, LV Dong-liang, LV Jian-jiang, HUANG Xiao-liang 2008, 29 (5):  641-643.  Abstract ( 91 )   PDF (212KB) ( 266 )   Save The abandonment pressure of water-bearing gas pool is the key parameter to ascertain the recovery factor, directly influencing the recovery size. This paper takes account of the change of parameters that have big impact on water-bearing gas well productivity equation and derives a binomial coefficient equation for it under different damage degrees and harm radius at any moment. Under a definite collar production working, such an abandonment pressure can be ascertained using minimum liquid-carrying velocity at minimal bottomhole flowing pressure as constraint condition. References | Related Articles | Metrics

A Model for Prediction of Constant Volume Sealed Reservoir Performance and Recoverable Reserves TONG Kai-jun, SHAN Yu-ming, YANG Lu, LI Li-juan 2008, 29 (5):  644-647.  Abstract ( 80 )   PDF (251KB) ( 183 )   Save It is an important task for forecasting the economically recoverable reserves in oilfield development evaluation when oilfield goes into the middle and late development stage. This paper analyzes and explains the correlative curve distribution characteristic between accumulative oil production and reservoir pressure in sealed reservoirs and its statistical regularity. Based on the study of growth curvature in life system, it introduces a general Usher model and affords a new model suiting for depletion drive stage in sealed reservoirs to predict relevant dynamic targets. By using nonlinear least-squares method to solve the new model, all the fitting parameters and the recoverable reserves can be acquired. The case study shows that this model is effective for use, simple for calculation and precise for prediction. References | Related Articles | Metrics

Correction Method for Acquiring Smectite-Rich Sandstone Porosity and Permeability ZHANG Lixia, LI Pei-jun 2008, 29 (5):  648-649.  Abstract ( 82 )   PDF (126KB) ( 213 )   Save Smectite-rich sandstone is characterized by water swelling and high-temperature dehydration and contraction. Its porosity and permeability measured by core sampling, wash oil and dry sample tend to being higher than the real values. For this reason, this paper proposes a correction method for acquiring real porosity and permeability of smectite-rich sandstone. The corrected values can get rid of these situations above mentioned. References | Related Articles | Metrics

Magnetic Resonance Imaging Logging Technology and Application ZHAO Quan-sheng 2008, 29 (5):  650-653.  Abstract ( 125 )   PDF (390KB) ( 609 )   Save Magnetic resonance imaging logging (MRIL) is a fire-new logging method. Such unique information from it is regarded as the most progress in logging technology and an important breakthrough in well logging data interpretation and oil-gas evaluation of open hole. This paper illustrates the basic theory and principle of MRIL. By means of interpretation software for case study, the MRIL interpretation result is exactly the same as the logging show, which proves the advantage of this technology and its important function in oil and gas evaluation. References | Related Articles | Metrics

Application of Fullbore Formation MicroImager (FMI) to Study of Glutenite Sedimentary Structures in Jiyang Depression ZHOU Lun-xian 2008, 29 (5):  654-656.  Abstract ( 112 )   PDF (634KB) ( 335 )   Save Taking steep slope region of Jiyang depression as an example, the FMI logs of glutenite are analyzed, setting up the core vs. image relationship, based on which, the glutenite sedimentary structures and paleocurrent directions could be identified. The FMI map's colors and features are helpful to identification of the sedimentary structures by the fact that different kinds of beddings such as horizontal and parallel bedding, planar, trough and wavy cross bedding, graded bedding and massive bedding can be discerned on the images by fine changes of color within a stratum and dip azimuth between lamina surfaces picked up on them. Penecontemporaneous deformation structures such as load structure, sand ball or pillow and deformed bedding are easily recognized by similar characteristics on images from outcrops or cores. The paleocurrent direction can be deduced by dip direction of cross laminae of glutenite interpreted on images. References | Related Articles | Metrics

Study Progress in Limestone Classification with Perfection DUAN Kai-bo, DUAN Dong-sheng, WANG Jie, ZHANG Ju-hui 2008, 29 (5):  657-661.  Abstract ( 143 )   PDF (284KB) ( 477 )   Save The results of limestone classification gained by scholars at home and abroad are introduced. It is pointed out that Folk's division (1962) and Dunham's division are good in practicability, hence being milestone's significant in the history of limestone classification. And Embry's modification (1971) and Wright's further revision (1992) as well as Riding's division of microbolite (2000) can be regarded as three major progresses for it. It is "two milestones" and "three progresses" that allow the limestone classification to be more scientific, more reasonable and more perfect. In view of the importance and complexity of biotic (esp. microbial) processes in formation of limestone, together with Riding's division of microbolite into stromatolite, thrombolite, dendrolite and leiolite as well as recent-year studied progress, this paper suggests new complements and perfections for limestone classification. References | Related Articles | Metrics

The Method for Acquirement of Conventional Logging Response-Based Lithomechanical Parameters HE Shun-yi, SHI Yong-min, XIE Nan, ZHANG Zhi-xiang, LI Cui-ping 2008, 29 (5):  662-664.  Abstract ( 99 )   PDF (294KB) ( 816 )   Save Through the normalized processing of well logging responses in different years and different logging tools, this paper presents an effective method for getting lithomechnical parameters based on the conventional logs that are widely applied to oilfield and the rock mechanical features as well as their correlations, followed by error correction, coherent analysis and multivariate linear regression technique. Also, this paper provides the lithomechanical model which could be as a guide to field application for the studied area. References | Related Articles | Metrics

The Relationship Between Surface and Subsurface Rock Permeability LI Chuan-liang 2008, 29 (5):  665-667.  Abstract ( 177 )   PDF (215KB) ( 204 )   Save The permeability of rock is usually measured at common pressure and temperature on surface. However, the pressure and the temperature underground are much higher than that on surface condition. The permeability of rock decreases due to compression at higher pressure, and increases due to thermal expansion at higher temperature. A theoretical formula is proposed in this paper to calculate the permeability of rock underground from the permeability measured on surface condition. The formula takes account of the influences of pressure and temperature on the rock permeability. The calculations by the formula show that the permeability of rock underground is not much different from that measured on surface condition. References | Related Articles | Metrics