State Key Laboratory of Petroleum Resource and Prospecting

Beijing, China

State Key Laboratory of Petroleum Resource and Prospecting

Beijing, China
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Chen Y.,University of Western Australia | Jin Y.,China University of Petroleum - Beijing | Jin Y.,State Key Laboratory of Petroleum Resource and Prospecting | Chen M.,China University of Petroleum - Beijing | And 5 more authors.
Journal of Natural Gas Science and Engineering | Year: 2017

Rock brittleness is the key parameter in the evaluation of “sweet spot” in the shale reservoir which is characterized with low porosity and low permeability, and numerous methods are presented to qualitatively reveal the essence of rock brittleness. However, the quantitative evaluation of this property is still a tough question with continued attention. This paper proposes a new quantitative evaluation method based on the energy dissipation principle in fracture mechanics, which interprets the degree of rock brittle fracturing as energy efficiency contributing to the new generated surface energy of fractures. The fractal geometry and fractal dimension are introduced to describe fracture surface with intricate geometry. The experimentally constructed correlation between volume density of rock fracture and fractal dimension is incorporated into energy dissipation and fractal geometry of fracture. Finally, the energy-balance equation, which corresponds to the rock brittleness index with volume density of rock fracture, is established. The brittleness indexes of different rock are calculated and compared, and the influence of the confining pressure on the brittleness is also studied. Sichuan Longmaxi shale formation of X well in southwest China is analyzed, which verified the reliability of this quantitative evaluation method in pinpointing the fracturing candidate in hydraulic fracturing engineering. © 2017 Elsevier B.V.


Zhu S.,State Key Laboratory of Petroleum Resource and Prospecting | Zhu S.,China University of Petroleum - Beijing | Zhu X.,State Key Laboratory of Petroleum Resource and Prospecting | Zhu X.,China University of Petroleum - Beijing | And 5 more authors.
Acta Geologica Sinica | Year: 2012

The dolomitic rocks of the Fengcheng Formation are considered to be formed under special geologic conditions, and are significant hydrocarbon reservoir rocks in the Wu-Xia area in the Junggar Basin. Analyses of petrologic characteristics and stable isotope composition indicate that the dolomitizing host rock is volcanic and the dolomitizing fluids probably consists of brine from shore-shallow lakes with great evaporation and salinity in the Fengcheng Formation, which have formed under arid climatic conditions, as well as residual Mg-rich seawater from the underlying Jiamuhe Formation and Carboniferous. Dust tuff in the area has significant plagioclase content. Anorthite and labradorite hydrolysis by C0 2 can be coupled with calcite precipitation. Late Mg-rich brine percolated and replaced calcite formed in the early time, which lead to precipitate dolostones with different occurrences, such as graniphyric, random bedded or lumpy. The diagenetic dolostones with different occurrences resulting from particular formation conditions occurred in different tectonic settings. The dolomitizing fluid has been driven by the thermal convection flow generated by volcanic eruptions. At the same time, the overthrusts of the Wu-Xia growth fault have speeded up the flow of deep Mg-rich water upwards, and induced the water to quickly penetrate and horizontally migrate in the strata. Fracture is the major and the most important reservoir space in dolomitic reservoir of the Fengcheng Formation. Fracture and fault plays a decisive role in controlling the formation of dolostone and the distribution of favorable reservoirs. The deliverability of oil and gas is determined by the development and match relations of dissolved pores and fractures to a certain degree.


Wang D.,CAS Institute of Geology and Geophysics | Wang D.,University of Chinese Academy of Sciences | Wang L.,CAS Institute of Atmospheric Physics | Wang L.,University of Chinese Academy of Sciences | Ding P.,State Key Laboratory of Petroleum Resource and Prospecting
Ultrasonics | Year: 2016

An illustrative theory is developed to analyze the acoustic wave propagation characteristics in the porous media with anisotropic permeability. We focus here on the role of fracture permeability in the unconsolidated porous media, looking in particular at the compressional P-wave phase velocity and attenuation. Two fluid pressure equilibration characteristic time factors are defined, which are corresponding to crack-pore system and crack-crack system, respectively. The theoretical results show that the dispersion and attenuation characteristics of acoustic wave are affected by porous matrix and fracture permeability simultaneously. Due to the fluid exchange that takes place between fractures and pores dominantly, the influence of the fracture connectivity on the wave propagation is very weak when the permeability of background medium is relatively high. However, correlation between wave propagation and fracture permeability is significant when the matrix permeability at a low level. A second attenuation peak occurs for the fluid flow within fractures in high-frequency region for more and more higher fracture permeability. The exact analytical solutions that are compared to numerical forward modeling of wave propagation in fractured media allow us to verify the correctness of the new model. If there exists another approach for obtaining the connectivity information of background media, we can use this model to analyze qualitatively the permeability of fractures or afford an indicator of in-situ permeability changes in a oil reservoir, for example, fracturing operations. © 2016 Elsevier B.V. All rights reserved.


Zhang L.,CAS Institute of Geology and Geophysics | Zhang L.,State Key Laboratory of Petroleum Resource and Prospecting | Hao T.,CAS Institute of Geology and Geophysics | Wu J.,Tongji University | And 2 more authors.
Journal of Applied Geophysics | Year: 2013

Edges of potential-field anomalies are assumed to result from sharp discontinuities or interfaces between contrasting materials, such as faults, unconformities, or intrusive contacts. The superposition effects of potential fields make edge-enhancement techniques necessary to reduce edge mislocation. Distinguishable amplitude difference is the edge feature most widely utilized in common enhancement methods. But edges differ from other anomalies not only in amplitude but also in texture, and in some cases they reveal as weak difference in amplitude but of meaningful contrast in texture. Accordingly, we propose a new texture-based operator for edge enhancement. The operator is a modified version of dissimilarity extracted from modified calculation of the gray-level co-occurrence matrix. The matrix is tailored to fit in with the characteristics of potential-field data and it differs from the common co-occurrence matrix mainly in three aspects: (1) for the modified matrix only the pairs between the central point of a computing window and other points are counted; (2) except from commonly-used eight directions, other directions are added for the windows with direction number depending on the window size; (3) co-occurring pairs are given weight to differ the contribution of joint occurrence in different distance. Moreover, we set standard-deviation-based weight to the common dissimilarity in each window in order to locally enhance edges. We evaluate the utility of the operator based on synthetic models and real data examples of the Huanghua Depression in the Bohaiwan Basin, Northern China, and of the Haijiao area in the East China Sea Basin, Eastern China. The modified dissimilarity is proved advantageous to the total horizontal derivative and common dissimilarity in capturing more detailed features, and provides more straightforward and accurate illustration of edges than the tilt angle does. The edges enhanced in the gravity data of the Huanghua Depression accord well with the faults deduced from an integrated geophysical interpretation. The edges detected in the magnetic data of the Haijiao area illustrate the distribution of rocks. The results show the potential of the texture-based operator to facilitate the interpretation of potential-field data in locating faults, rocks, or contacts, and thus to promote the application efficiency of the data in exploration and engineering. © 2013 Elsevier B.V.


Wang J.-Z.,China University of Geosciences | Wang J.-Z.,State Key Laboratory of Petroleum Resource and Prospecting | Xiang C.-F.,State Key Laboratory of Petroleum Resource and Prospecting | Xiang C.-F.,China University of Petroleum - Beijing | And 2 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2013

This study took into account the analysis of fault density, fault' internal structure and shale mass fraction of the fault zone in ourcrop of Wumishan formation, Bajiaozhai, Zhoukoudian, and also considered the three-dimensional stress numerical simulation and the calcite cross-cut cement relationships in core and microscope observation of carbonate reservoir in Tazhong area. With those in consideration, this study revealed the fault sealing mechanisms in the carbonate sequence, and proposed an experimental method to accurately determine the clay content of the carbonate. The results show that: fault zone has the obvious characteristics of dual structure; the rock in the core part of main fault is gravely damaged, and the fault density is high; with an increase of distance from fault nuclear, and the fault density reduces exponentially; for the surrounding rock, the shale mass fraction of carbonate ranges from 10% to 15%, while for the part of fault nuclear the shale mass fraction increases to 30%-40%, obviously increasing 2-3 times; with an increase of distance from fault nuclear, shale mass fraction steady declines, which demonstrates that high gouge content is still one of the most important mechanisms in the fault of carbonate sequence; the differences of constitute and content of lithology lead to the disparity in strain form. Carbonate minerals, especially calcite is multistage, and crystal widely distributes in crushed zone, which indicates that the cementation is another important fault sealing mechanism.


Jia H.,State Key Laboratory of Petroleum Resource and Prospecting | Jia H.,China University of Petroleum - Beijing | Ji H.,China University of Petroleum - Beijing | Wang L.,Petrochina | And 3 more authors.
Marine and Petroleum Geology | Year: 2016

In this study, we use seismic reflection, well-log and core data to investigate the basin structure and sedimentary filling of the Upper Jurassic and Lower Cretaceous in the Dehui Depression, Songliao Basin, Northeastern China. The Late Jurassic-Early Cretaceous Dehui Depression is an active-fault bounded graben. Unconformity and vertical variations on fault activity reveal that the syn-rift stage of the basin can be subdivided into four sub-stages: (i) early syn-rift stage (Huoshiling Formation), which is composed mainly of fan-delta and shallow lacustrine depositional systems; (ii) rift-climax stage (Shahezi Formation), which consists of sublacustrine fan, fan-delta and deep lacustrine depositional systems; (iii) late syn-rift stage (Yingcheng Formation), which is composed of fan-delta and shallow lacustrine depositional systems; (iv) rift-depression transition stage (Denglouku Formation), which is composed of braid delta and shallow lacustrine depositional systems. Fault evolution and episodic rifting control the basin geomorphology, and thus influenced the depositional systems of each stage, while the climate influenced the sediment type. Besides, our estimation on the hydrocarbon exploration potential of the rift-related successions in Dehui Depression shows that they can sustain the formation of medium-large gasfield. © 2016 Elsevier Ltd.


PubMed | University of Chinese Academy of Sciences and State Key Laboratory of Petroleum Resource and Prospecting
Type: | Journal: Ultrasonics | Year: 2016

An illustrative theory is developed to analyze the acoustic wave propagation characteristics in the porous media with anisotropic permeability. We focus here on the role of fracture permeability in the unconsolidated porous media, looking in particular at the compressional P-wave phase velocity and attenuation. Two fluid pressure equilibration characteristic time factors are defined, which are corresponding to crack-pore system and crack-crack system, respectively. The theoretical results show that the dispersion and attenuation characteristics of acoustic wave are affected by porous matrix and fracture permeability simultaneously. Due to the fluid exchange that takes place between fractures and pores dominantly, the influence of the fracture connectivity on the wave propagation is very weak when the permeability of background medium is relatively high. However, correlation between wave propagation and fracture permeability is significant when the matrix permeability at a low level. A second attenuation peak occurs for the fluid flow within fractures in high-frequency region for more and more higher fracture permeability. The exact analytical solutions that are compared to numerical forward modeling of wave propagation in fractured media allow us to verify the correctness of the new model. If there exists another approach for obtaining the connectivity information of background media, we can use this model to analyze qualitatively the permeability of fractures or afford an indicator of in-situ permeability changes in a oil reservoir, for example, fracturing operations.


Zhu S.F.,State Key Laboratory of Petroleum Resource and Prospecting | Zhu S.F.,China University of Petroleum - Beijing | Zhu X.M.,State Key Laboratory of Petroleum Resource and Prospecting | Zhu X.M.,China University of Petroleum - Beijing | And 2 more authors.
Science China Earth Sciences | Year: 2012

Recently, silicate diagenesis has been the focus of many studies because of its impact on porosity and permeability in sedimentary rocks. In the process of diagenetic evolution, the crystallization, cementation, and corrosion of zeolite (as a diagenetic mineral) have different effects on properties of Permian reservoirs in the study area. In the Permian sediments in the northwestern margin of the Junggar Basin, Zeolite minerals have formed during diagenesis in an open hydrologic system, related to the hydration of abundant volcanic glass. Chemical property of groundwater, pH of pore water, cation property and ratios have directly influenced the transformation among various zeolites and the dissolution of zeolite mineral. The main species of zeolite include analcime, heulandite, and laumontite. Transformations of these minerals during diagenesis are: volcanic glass→clinoptilolite→analcime→heulandite→laumontite. Corrosion of analcime obviously improved reservoir quality. Extensive heulandite cementation developed and intensively reduced reservoir pore spaces. Early zeolite cementation protected pore structure against compaction and provided substance for late dissolution. The dissolution of analcime was closely related with the organic acid recharged by hydrocarbon source rocks and the NaHCO 3 type formation water in the Permian, and was sensitive to permeability of rocks. Within the CaCl 2 type formation water, heulandite and laumontite were hardly dissolved. In the study area, the belt with dissolved analcime is the area for the development of secondary pores and favorable reservoirs. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.


Sun H.,China University of Petroleum - Beijing | Sun H.,State Key Laboratory of Petroleum Resource and Prospecting | Zhong D.,China University of Petroleum - Beijing | Zhong D.,State Key Laboratory of Petroleum Resource and Prospecting | And 2 more authors.
Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development | Year: 2010

On the basis of plate tectonic theory, we analyzed the formation and evolution of passive continental basins in eastern and western Africa, compared exploration data, and discussed the differences in petroleum geological conditions and hydrocarbon distribution in the two regions. Thirty passive marginal basins have been developed due to the break of Gondwanaland and the African plate breaking away from America, Antarctic and India. They are different in hydrocarbon distribution owing to different tectonic-sedimentary evolution processes. Most hydrocarbon resources were accumulated in salt-containing basins and delta basins of West Africa, especially in deep water, much larger than those in East Africa. In those oil-rich basins of West Africa, thick and high quality source rocks and plastic strata were well developed. In addition, thick overlying sediment supply from large water systems contributed to high-maturity source rocks and the formation of deep water turbidity sandstones, traps of growth fault and deformation structures.


Li J.-Y.,State Key Laboratory of Petroleum Resource and Prospecting | Li J.-Y.,China University of Petroleum - Beijing
Applied Geophysics | Year: 2012

Traditionally, fluid substitutions are often conducted on log data for calculating reservoir elastic properties with different pore fluids. Their corresponding seismic responses are computed by seismic forward modeling for direct gas reservoir identification. The workflow provides us with the information about reservoir and seismic but just at the well. For real reservoirs, the reservoir parameters such as porosity, clay content, and thickness vary with location. So the information from traditional fluid substitution just at the well is limited. By assuming a rock physics model linking the elastic properties to porosity and mineralogy, we conducted seismic forward modeling and AVO attributes computation on a three-layer earth model with varying porosity, clay content, and formation thickness. Then we analyzed the relations between AVO attributes at wet reservoirs and those at the same but gas reservoirs. We arrived at their linear relations within the assumption framework used in the forward modeling. Their linear relations make it possible to directly conduct fluid substitution on seismic AVO attributes. Finally, we applied these linear relations for fluid substitution on seismic data and identified gas reservoirs by the cross-plot between the AVO attributes from seismic data and those from seismic data after direct fluid substitution. © 2012 Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.

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