Petroleum Exploration and Development

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An assessment of tight oil resource potential in the Upper Cretaceous Cardium Formation, Western Canada Sedimentary Basin

Chen Zhuoheng and Kirk G Osadetz

, 2013, 40(3): 2044-0.

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The Cardium “halo oil” occurs either in the fringe of or between existing conventional discrete sandstone reservoirs and it is commonly associated with conventional oil and gas pools in stratigraphic traps in the Western Canadian Sedimentary Basin. This paper uses the geological model-based simulation approach to assess the “halo oil” resource potential in the Cardium Formation. This geological model-based approach, consisting of a geological model, a resource model and a stochastic modeling procedure, extracts essential information regarding the richness and spatial characteristics of oil resources from a variety of data sources using statistical methods and integrates this information with the geological and resource models respectively to estimate the resource potential. This approach predicts the resource potential, the spatial distribution of the resource and the exploration risk. These outputs provide critical information for exploration decision-making. The Cardium “halo-oil” assessment result indicates a mean total oil in-place (conventional and unconventional) of 46×108 m3 and a mean undiscovered “halo oil” in-place of 29×108 m3. Using current technology and economic constraints, the undiscovered recoverable “halo oil” in this tight reservoir is 1.1×108 m3, representing less than 4% of the remaining in-place oil resource, but accounting for 38% of total recoverable oil in the same formation. A comparison with resource estimates obtained using a well-performance approach based on the extrapolation of production data from stimulated horizontal wells suggests that the mean recoverable estimates obtained using the two different approaches are compatible, suggesting that the geological model-based approach provides a reliable estimate of oil resource potential.

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Weathered volcanic crust and its petroleum geologic significance: A case study of the Carboniferous volcanic crust in northern Xinjiang

Hou Lianhua; Luo Xia; Wang Jinghong; Yang Fan; Zhao Xia and Mao Zhiguo

, 2013, 40(3): 2135-0.

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The Carboniferous volcanic crust in northern Xinjiang was analyzed as an example to study the characteristics and distribution of volcanic crust and its petroleum significance using the analysis of outcrops, core samples, oil testing, and logging data, etc. A complete weathered volcanic crust has a six-layer structure, which includes soil layer, hydrolysis zone, leached zone, broken-down zone I, broken-down zone II, and underlying bedrock. The characteristics and indicators for the crust of different layers are different. Effective reservoirs are developed within the leached zone and broken-down zone I. Weathered thickness is controlled by leaching time. The maximum thickness of weathered volcanic crust is about 550 m corresponding to the leaching time of 46.3 Ma. The physical properties of weathered volcanic crust are controlled by litho-facies and weathered intensity. Faults and fractures are the main controlling factors of the percolation ability of weathered volcanic reservoirs. The closer the reservoir is to the fault zone, the better the percolation ability would be. The crust is mainly distributed at the paleo-topographic high place, slopes and low place with developed faults. The vertical span of reservoirs is bigger near the fault zones. According to the established evaluation method and model of weathered volcanic intensity and effective reservoirs, the weathered volcanic intensity and effective reservoirs of none-coring wells can be evaluated.

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Seismic prediction of sandstone diagenetic facies: Applied to Cretaceous Qingshankou Formation in Qijia Depression, Songliao Basin

Zeng Hongliu; Zhu Xiaomin; Zhu Rukai and Zhang Qingshi

, 2013, 40(3): 2136-0.

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Seismic diagenetic facies is an important control factor on reservoir quality. This study investigated the possibility and feasibility of predicting sandstone diagenetic facies with conventional 3D seismic data by seismic sedimentology, calibrated by lab core analysis data in the Qijia area of the Songliao Basin. There are three core issues related to seismic characterization of diagenetic facies, including how to correlate stratigraphic and diagenetic units from seismic data, how to evaluate relationship between core-based diagenetic facies and seismic attributes, and how to find an effective way to map seismic diagenetic facies. Well- and seismic-based high-resolution sequence analysis and seismic stratal slicing provided reservoir-scale (20 m) seismic representations of diagenetic units. Core-based analyses of sandstone diagenetic processes and diagenetic sequence revealed that the diagenesis has the most important influence on reservoir quality. An investigation of reservoir parameters and acoustic rock properties further disclosed link between diagenetic facies and impedance, leading to the recognition of calcite cementation as a process that can be detected by seismic data. Seismic-based lithology cube (e. g., 90°-phased seismic volume) provided amplitude (impedance) signal for detection of diagenetic facies. The stratal slices made from the seismic-based lithology cube were used to interpret depositional facies and systems. Eventually, a seismic diagenetic facies map was generated by analyzing relationships between depositional facies, impedance, and diagenetic facies. The case study of the clay-cemented sandstone and calcite-cemented sandstone in the Qijia area showed that although being in its infant stage with many difficulties, the seismic detection of sandstone diagenetic facies with conventional seismic data is not only possible, but also feasible.

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Evolutionary sequence of faults and the formation of inversion structural belts in the northern Songliao Basin

Sun Yonghe; Chen Yibo; Sun Jigang; Fu Xiaofei and Hu Ming

, 2013, 40(3): 2137-0.

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On the basis of regional seismic interpretation of the northern Songliao Basin and the analysis of fault geometry characteristics and the formation and evolution of faults, this paper analyses fault deformation mechanisms at different stages, which reveal the formation mechanism of inversion structures and their role for oil and gas migration and accumulation. Studies show that the faults in the northern Songliao Basin have experienced the following stages of evolution: a continued extensional deformation in the faulted phase, continuous transtensional deformation in the depression phase and continuous extrusion inversion tectonic deformation in the inversion phase. The late tectonic inversion and deformation evolved on the basis of huge rifts in the basement of the Songliao Basin, grabens formed in a NW-SE tensile stress field during the faulted period, and multi-orientation fault-dense zones formed in a nearly EW tension stress field during the depression period. The sinistral compresso-shear deformation field, half grabens and huge basal faults jointly control the formation of subprime anticlines and inversion structural belts during the reversal period. The Daqing placanticline area is controlled by both the NNE half grabens and NNE huge basal faults, so that it has a high reversal degree, which turns NE subprime anticlines into NNE structural inversion belts. Meanwhile, it turns fault dense zones from nearly SN into NW-NNW.

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Overpressure reservoirs in the mid-deep Huangliu Formation of the Dongfang area, Yinggehai Basin, South China Sea

Zhang Huolan; Pei Jianxiang; Zhang Yingzhao; Jiang Chunyan; Zhu Jiancheng; Ai Nengping; Hu Qianwei and Yu Junfeng

, 2013, 40(3): 2138-0.

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The relationship between reservoir property and such factors as sedimentary microfacies, clastic component, grain size, and special diagenetic environment of high temperature and overpressure were comprehensively analyzed to study reservoir characteristics and influencing factors in the first member of upper-Miocene Huangliu Formation of the DF13-1 structure in the Dongfang area, Central diapir zone of the Yinggehai Basin. The dominant reservoirs in the first member of the Huangliu Formation in the Dongfang area are composed of very fine to fine lithic quartz sandstones that are deposited in submarine fans sourced from the Kuntom uplift. The reservoirs are characterized by large thickness, broad distribution and good qualities. High-temperature thermal fluids activities and overpressure are two major diagenetic factors contributing to the good properties in the reservoirs. Thermal fluids activities of high tempreture accelerated the organic matter thermal evolution and clay mineral transformation, and in this process organic acids and CO2 were generated which dissolved the reservoirs and thus resulted in a secondary pore zone. Overpressure broadened oil generation window, increased corrosion time and strength, making secondary pores developed in deeper formations. Moreover, the overpressure was beneficial to preserve pores. The reservoir economic basement depths of siltstone, very fine sandstone and fine sandstone are about 3 100 m, 3 900 m and 5 000 m respectively. The fine sandstone and very fine sandstone in the first member of the Huangliu Formation could form excellent gas reservoirs in present depth of 2 600-3 500 m.

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New perspectives on deep-water sandstones: Implications

Shanmugam G

, 2013, 40(3): 2139-0.

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The emerging new concepts of sandy mass-transport deposits (SMTD) and bottom-current reworked sands (BCRS) have made a big impact on conventional turbidite concepts. Sediment failures near the shelf edge are the common cause of gravity-driven downslope processes. Mass-transport processes, which include slide, slump, and debris flow, exhibit elastic and plastic behaviors due to high sediment concentration (25%-100% by volume). Turbidity currents which represent viscous fluid behavior with low sediment concentration (1%-23% by volume) are not mass-transport processes. Four common bottom currents are thermohaline, wind-driven, deep tidal, and baroclinic types. A distinctive attribute of BCRSs is their traction structures. However, depositional aspects of baroclinic currents associated with internal waves and tides are poorly understood. Seismic facies and geometries are unreliable for distinguishing types of SMTDs and BCRSs in the ancient record. The only reliable method of distinguishing a specific depositional facies is by detailed bed-by-bed examination of sedimentological features in core and outcrop. Short-term events that represent only a matter of hours or days (e.g., earthquakes, tsunamis, tropical cyclones, etc.) are more important in triggering sediment failures than periods of sea-level lowstands that represent thousands of years.

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Control of tectonic-paleogeomorphology on deposition: A case from the Shahejie Formation Sha 3 member, Laizhouwan sag, southern Bohai Sea

Xin Yunlu; Ren Jianye and Li Jianping

, 2013, 40(3): 2140-0.

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Based on seismic and logging data, the characteristics of tectonic-paleogeomorphology of the Laizhouwan sag during the sedimentation of the Paleogene Shahejie Formation Sha 3 member (E2s3) were restored and the control of tectonic-paleogeomorphology on sedimentary systems was analyzed. During the sedimentation of E2s3, the Laizhouwan sag can be divided into eight tectonic units, including the eastern fault-slope zone, northeastern slope, northern slope zone, western slope zone, southern slope zone, central uplift belt, northern sub-sag and southern sub-sag; gullies occur in the western and southern slope zones. Controlled by the tectonic-paleogeomorphology, the fan delta was developed in the eastern Laizhouwan sag and the braided river delta was formed in the south and west of the Laizhouwan sag in the sedimentary period of E2s3, and the developmental place of the main part of the deltaic depositional system was significantly controlled by sub-sags. The fan delta sand body, controlled by the Eastern fault ramp, the braided river delta sand body controlled by the Western and Southern gentle slopes and the gullies, and especially the large braided river delta sand body in the northern sag controlled by the western gentle slope, are important exploration targets for oil and gas.

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Origin of polygonal fault systems: A case from the Sanzhao sag in the Songliao Basin

Ding Xiujian; Liu Guangdi; Sun Mingliang and Wang Pan’gen

, 2013, 40(3): 2141-0.

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Polygonal fault systems are mainly found in fine-grained sediments. They are controlled by layers vertically and characterized by polygonal planform geometry. They are also characterized by small fault throw, high fault density, various strikes, and small lateral extension. Their genetic mechanisms, which are usually recognized as non-tectonic, include density inversion, dewatering contraction, gravitational loading, and dissolution-induced shear failure, with the last one being dominant. Many small extensional faults have been found in the Cretaceous in the Sanzhao sag of the Songliao Basin. Having the characteristics of polygonal faults vertically, horizontally and in shape, they are defined as typical polygonal fault systems. There are more polygonal fault systems in the formation with heavier dissolution, these polygonal fault systems may be formed by the mechanism of dissolution-induced shear failure. Polygonal fault systems are migration pathway for the Putaohua and Fuyang oil layers in the Sanzhao sag and they significantly control on oil-water distribution. The areas where sandstones and polygonal fault systems are developed together are favorable exploration areas.

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Multi-scale method of Nano(Micro)-CT study on microscopic pore structure of tight sandstone of Yanchang Formation, Ordos Basin

Bai Bin; Zhu Rukai; Wu Songtao; Yang Wenjing; Jeff Gelb; Allen Gu; Zhang Xiangxiang and Su Ling

, 2013, 40(3): 2142-0.

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Multi-scale (nano-to-micro) three-dimensional CT imaging was used to characterize the distribution and texture of micro-scale pore throats in tight sandstone reservoirs of the Triassic Yanchang Formation, Ordos Basin. First, the low-resolution Micro-CT was used to reflect the micro-pore texture of the core column with a diameter of 2.54 cm. Then, some samples with a diameter of 65 μm was derived from different areas according the different characteristics of micro-pore texture of the core scanned by low-resolution Micro-CT and scanned by high-resolution Nano-CT. Thus, a three-dimensional texture model of nano-scale micro-pores was reestablished and the permebility and porosity data of the sample could be obtained. On a micrometer scale, the size of the micro-pores varies, and their diameters range from 5.4 to 26.0 μm. The micro-pores are isolated, locally in the shape of a band. On a nanometer scale, the quantity of nanoscale micropores increases, the diameter of which ranges from 0.4 to 1.5 μm. The pore throats are arranged in the shape of tube and ball inside or on the surface of mineral particles(crystals). The ball-shaped micropores in nanoscale, often isolated in the three-dimensional space, show the poor connectivity and consequently act as the reservoir space. By contrast, the tube-shaped micropores in nanoscale show certain connectivity with micro-scale tube-shaped micropores and adjacent isolated ball-shaped micropores in nanoscale. Therefore, these tube-shaped micropores in nanoscale serve as throats and pores. Based on the calcution, the permeability of the samples is 0.843×10-3 mm2 and porosity is 10%.

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Prediction of thin shoal-facies reservoirs in the carbonate platform interior: A case from the Cambrian Xixiangchi Group of the Weiyuan area, Sichuan Basin

Li Ling; Tan Xiucheng; Zhao Luzi; Liu Hong; Xia Jiwen and Luo Bing

, 2013, 40(3): 2143-0.

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This paper presents a geological prediction method of thin shoal facies reservoir through the analysis of shoal facies reservoir’s genetic mechanism of the Middle-Upper Cambrian Xixiangchi Group in the Weiyuan area, Sichuan Basin. The development of shoal facies reservoirs is controlled by shoal thickness. Both sedimentary rates and scales of the shoal are closely related to microtopographic highs, which can develop inheritably for a long time under a stable tectonic background. So we present a prediction method that depositional microtopographic highs and shoal reservoirs’ development probability can be portrayed by the thickness variation of isochronal geological bodies, which mainly composed of grain stone formed in a short time. Based on it, a prediction model was built for thin shoal facies reservoirs of the Middle-Upper Cambrian Xixiangchi Group, where useful geological data are extremely poor. The method was used to predict the distribution of shoal facies reservoirs within the research area. Later drilling showed that the prediction is consistent with the drilling result. This study can provide reference to the exploration of shoal facies reservoirs.

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A capacity prediction model for the low porosity fractured reservoirs in the Kuqa foreland basin, NW China

Yang Feng; Zhu Chunqi; Wang Xinhai; Qu Haizhou; Zhang Fuxiang and Niu Xinnian

, 2013, 40(3): 2144-0.

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Based on the description of fracture parameters and the relation between fracture development degree and capacity, a capacity prediction method was discussed of low porosity fractured sandstones in the Kuqa region. For coring section, fracture parameters are described directly by the core; for non-coring section, fracture parameters are available through imaging logging data, and after correction by difference between statistical parameters of core description and imaging logging interpretation in the coring section, the fracture parameters can be quantitatively described more accurately. The correlation of fracture seam and capacity is good in the gas well test section in Dabei - Keshen area and it is used to derive a formula of cracks capacity coefficient. Gas well capacity can be predicted by the regression formula of cracks capacity coefficient vs. meters gas production index. Also the models of uniform and non-uniform fracture distribution were established, capacity was analyzed based on the cracks capacity coefficient, results show that in fractured sandstone reservoirs if the total fracture number is constant, the capacity is small when fractures have a uniform distribution, the productivity is bigger when fractures are concentrated in one section.

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Nonlinear percolation mechanisms in different storage-percolation modes in volcanic gas reservoirs

Dong Jiaxin; Tong Min; Ran Bo and Li Ning

, 2013, 40(3): 2145-0.

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The non-linear seepage mechanisms in volcanic gas reservoirs were studied using experiment results of rate-controlled Hg penetration, nuclear magnetic resonance, and core displacement tests. According to types of storage space and throats, combined with dynamic production characteristics, the volcanic gas reservoirs were classified into four storage-seepage modes, pore type, inter-granular pore type, micro-pore type and fracture-dissolution pore type. Slippage effect and stress sensitivity influence the seepage characteristics of volcanic gas reservoirs. Slippage effect is obvious in micro-pore type reservoirs, medium in pore type reservoirs, and insignificant in inter-granular pore type reservoirs. Stress sensitivities vary greatly in different storage-seepage modes. Fracture-dissolution pore type reservoirs have the strongest stress sensitivity, pore type reservoirs come second, and inter-granular pore type reservoirs have the weaker. In combination of dynamic production data, a relay gas supply mechanism model of multi-media volcanic gas reservoirs was established. In the high and stable yield period, when differential pressure dominates, gas is supplied from large pores and large fractures, and the single well production is high. In the yield decline period, when compaction plays a leading role, gas is supplied from medium pores and small fractures. In the low and stable yield period, when imbibition and diffusion are the main driving force, gas is supplied from small pores and micro-fractures.

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Evaluation of damage to horizontal wells through equivalent horizontal well length

Liu Bin; Cheng Shiqing; Nie Xiangrong and Zhao Yongjie

, 2013, 40(3): 2146-0.

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The skin factor and additional pressure drop which are used to evaluate the formation damage of vertical wells can not accurately be applied to horizontal wells. A new model for evaluating formation damage of horizontal wells is presented. This method is derived by utilizing and modifying the concept of equivalent horizontal well length presented by Malekzadeh, where the permeability anisotropy is considered and a new calculation method of the equivalent productivity ratio is proposed. The results show that for a damaged horizontal well, the equivalent horizontal well length is shorter than the completed horizontal interval, while for a stimulated horizontal well the equivalent horizontal well length is longer than the completed horizontal interval. The fact that the longer the horizontal well is, the smaller the equivalent vertical well skin factor indicates that the horizontal well is more advanced than the vertical well in oilfield development. A longer horizontal well is more subjected to productivity loss when the well is damaged and it is more productive after stimulation. The application in the Bohai Oilfield indicates that the new method can directly and efficiently determine the magnitude of formation damage around horizontal wells and its impaction on productivity. It also sheds light on reservoir development and its evaluation standard.

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Parameter control methods for the pumping toolstring composed of perforating gun and fracturing plug in a horizontal well

Zhu Xiuxing; Xue Shifeng and Tong Xinghua

, 2013, 40(3): 2147-0.

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According to the technological characteristics of the combination perforation and multistage fracturing using drillable bridging plugs, both the hydrodynamics model of wireline sealing system and the mechanical model of toolstring running in the hole were developed. In these models, the equations governing the sealing pressure of grease injection, structure parameters of toostring and pump rate were established. Based on the presented models, the parameter control methods of pumping and their primary influence factors were investigated through case study. For a development well in low-permeability reservoir, the control methods and the reasonable ranges of grease injection sealing pressure, minimum weight and maximum length of toolstring and pump rate were defined using the control equations. The effects of wellhead pressure, hole configuration and running velocity of wireline on parameter controlling were also analyzed. The results show that, with increasing wellhead pressure, the grease injection rate should be increased to improve sealing pressure, and the minimum weight of toolstring should also increase. Increasing the overall angle change rate could lead to a decrease of the maximum allowable length of the toolstring. The pump rate should be adjusted according to the running velocity of wireline.

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Influence factors of single well’s productivity in the Bakken tight oil reservoir

Liang Tao; Chang Yuwen; Guo Xiaofei; Liu Baolei and Wu Jian

, 2013, 40(3): 2148-0.

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To find out key factors of productivity enhancement quickly and precisely in design and operation of horizontal well fracturing, three methods including, information amount theory, gray correlative method and orthogonal experimental design, were used to calculate and check the productivity parameters of fractured horizontal wells in the Bakken tight oil reservoir, so as to identify their correlations and influences on productivity. The results reveal stages of fracturing, fracture length, horizontal section length and permeability as primary parameters, and formation pressure, porosity, fracture width and subsurface oil viscosity as secondary parameters. The controllable parameters should be considered firstly. Similar influences are obtained from these three methods, indicating that they are extremely practical and consistent. Therefore, all three methods are effective to calculate and check the influences of fractured horizontal wells’ productivity parameters in tight oil reservoirs.

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Horizontal well inflow performance relationship in foamy heavy oil reservoirs

Chen Yaqiang; Mu Longxin; Zhang Jianying; Zhai Guanghua; Li Xingmin; Li Jian and Zhai Huiying

, 2013, 40(3): 2149-0.

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Based on the recovery feature, oil and gas relative permeability law and driving mechanism of foamy heavy oil reservoirs, inflow performance relationship of horizontal wells in this kind of reservoirs was studied using multi-component numerical simulation and reservoir engineering methods. A dimensionless IPR equation of horizontal wells in foamy heavy oil reservoirs was also presented. Applying foamy oil multi-component numerical simulation, the IPR curve of horizontal wells in foamy heavy oil reservoirs was obtained: when the average formation pressure is high, the right end of the IPR curve is slightly upturned which shows foamy oil characteristics; with the decrease of average formation pressure, the characteristics of conventional solution-gas-drive reservoirs begin to appear. After comparing the dimensionless IPR curve of foamy heavy oil reservoirs with that of conventional solution-gas-drive reservoirs, it was found that: when dimensionless pressure is high, for both of these two kinds of reservoirs, dimensionless pressure and dimensionless oil production basically display linear relationship; when dimensionless pressure is low, the right end of the IPR curve of foamy heavy oil reservoirs is slightly upturned and that of conventional solution-gas-drive reservoirs is downturned. The relative error between the oil production calculated by the dimensionless IPR equation of horizontal wells in foamy heavy oil reservoirs and actual oil production is less than 13%. This research result can be used to direct the development of foamy heavy oil reservoirs.

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Bit stick-out calculation for the deepwater conductor jetting technique

Yang Jin; Yan De; Tian Ruirui; Zhou Bo; Liu Shujie; Zhou Jianliang and Tang Haixiong

, 2013, 40(3): 2150-0.

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In view of the absence of a theoretical model for choosing the bit stick-out in deepwater conductor jetting operation, and the existing operational blindness and risks, a bit stick-out calculation model was built up through theoretical derivation and field tests to provide the theoretical basis for the design of reasonable bit stick-out. Theoretical analysis assumes that bit stick-out is the best when the upper edge of the jet flow sprayed from the bit nozzle tip is internally tangent to the lower edge of surface conductor, based on which a formula to calculate the reasonable bit stick-out was derived, and the rationality of the theoretical assumption and correctness of calculation model were proved through field tests. Field test results show that the conductor running speed is in positive correlation with bit stick-out, while the restoration of friction between the conductor and surrounding soil body is in negative correlation with bit stick-out. The calculation model was applied in the drilling operation of 12 deepwater wells in the South China Sea and got good application effects. It saved 14.96 h per well on average, enhanced operational efficiency, and met the safety requirements at the same time.

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Experimental study on propagation of hydraulic fracture in volcanic rocks using industrial CT technology

Jia Lichun; Chen Mian; Sun Liangtian; Sun Zhiyu; Zhang Wei; Zhu Qianqian; Sun Zhen and Jin Yan

, 2013, 40(3): 2151-0.

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To understand the planar and three-dimensional geometry of hydraulic fractures in volcanic rocks, a hydraulic fracturing simulation experiment was conducted using the large-scale triaxial hydraulic?fracturing test system in laboratory. The industrial CT technology was employed to scan the volcanic rock sample before and after fracturing experiment to observe hydraulic fractures. The 3D tomograms and visualized images were obtained from the original CT images. The original CT images indicate that the hydraulic fractures in volcanic rock cross natural pores and/or microcracks, but the fractures don’t propagate in the area where natural pores are abundant. The fractures propagate along the maximum horizontal stress direction. The 3D tomograms and visualized images show that it is difficult to create hydraulic fractures in volcanic rocks due to a high fracture pressure gradient. The ability of fracturing in volcanic rock was analyzed, which indicates that the rock mechanical properties near the borehole are the key factors controlling the initiation and propagation of hydraulic fractures. With relatively high Young’s modulus and compressive strength, volcanic rocks are generally low in fracturing ability. The key in hydraulic fracturing of volcanic rocks is to bring down the fracture pressure gradient.

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Description of steam chamber shape in heavy oil recovery using 4D microgravity measurement technology

Li Yujun; Ren Fangxiang; Yang Liqiang; Zhou Dasheng and Tian Xin

, 2013, 40(3): 2152-0.

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4D microgravity measurement is used to study the underground medium, especially underground fluid variation state and process, using repeated measurements of gravity data at different periods. A model of microgravity variation calculation for the Guantao Formation in the Du 84 block of the Liaohe Oilfield was established according to the practical condition of the steam assisted gravity drainage (SAGD) of super heavy oil reservoir. The distribution of residual gravity that reflects the density change of the steam injection layer and heavy oil layer can be obtained using the target area 4D microgravity measured at different periods through wavelet transformation. With -20 μGal as the main anormaly, the variation of steam chamber shape in the steam assisted gravity drainage can be quantitatively described by analyzing the distribution of steam chamber, and drawing the steam chamber overlapping map of two observations. Numerical simulation and well temperature test verified the feasibility of the technology. The result from the technology can be used to adjust steam injection scheme timely according to the morphological changes in the steam chamber, for example, the Gh12 well has got good results, with oil production going up from 65.4 t/d in May 2010 to 82.8 t/d in May 2012 after adjustment of its injection scheme.

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, Volume 40 Issue 3