Construction of an efficient development mode for buried-hill fractured reservoirs in Bohai Bay

Ge, Lizhen; Tong, Kaijun; Meng, Zhiqiang; Zhu, Zhiqiang; Zhu, Xiaolin

doi:10.26804/ager.2020.02.05

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…Based on these basic means, fracture parameters such as density, length, and filling degree can be statistically analyzed and empirically determined. In particular, X-ray computed tomography (CT) scanning can quantitatively visualize the dynamic evolution process of microfractures from initiation, expansion, to destruction and is, therefore, a favorable technique for the characterization of multiscale fracture parameters ( [21]; Zhu et al, 2011;[22] [23]). Second, the relationship among fracture development and distribution as well as principal curvature of fold has been mainly acquired from structural features.…”

Section: Introductionmentioning

confidence: 99%

Development Characteristics and Quantitative Prediction of Multiperiod Fractures in Superdeep Thrust-Fold Belt

Zhang

Feng

2021

Lithosphere

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For a superdeep imbricated thrust-fold belt in the Kuqa depression of Tarim Basin, NW China, the structural fractures have a great impact on the tight gas reservoir productivity. In this research, structural fractures were characterized from core data and imaging logging data. Numerically, the finite element (FE) method was applied to simulate the 3-D paleotectonic stress field of the key fracture-generating period as well as the present-day stress field in the Keshen gas field. Based on previously developed geomechanical models, we further derived the models of fracture aperture and porosity under the palaeostress field. A fracture permeability model considering fracture filling degree and stress was developed based on the Fracture Seepage Theory. Finally, we obtained a series of calculation models for the present-day fracture aperture and permeability. The predictions based on these models agreed well with actual measurement results, with most of the relative errors less than 20%. The developed 3-D FE geomechanical model and fracture parameter prediction method hold great promise for characterizing fractures in other deep low-permeability reservoirs.

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Section: Introductionmentioning

confidence: 99%

Development Characteristics and Quantitative Prediction of Multiperiod Fractures in Superdeep Thrust-Fold Belt

Zhang

Feng

2021

Lithosphere

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“…For the production of unconventional oil and gas in tight sandstone and shale formations, people are mostly concerned with the stress sensitivity effect on reservoir rock permeability [1][2][3]. Rock microstructure intrinsically determines the rock storage capacity and flow capability [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Microscopic Stress Sensitivity Analysis with In Situ SEM Study and Digital Core Deformation Simulation

2021

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Rock stress sensitivity is typically investigated macroscopically. In contrast, a new method combining in situ Scanning Electronic Microscope (SEM) study and digital core deformation simulation is developed in this paper, providing an effective way to investigate the relationship between microstructural deformation and decreasing permeability. The simulation method might replace in situ SEM study under certain scenarios. First, the in situ SEM study was implemented, and the microstructure deformations of rock samples during uniaxial loading were observed and recorded. The SEM images at different stress states were analyzed by digital image correlation (DIC) technique to investigate the principles of these deformations. A deformation simulation method was correspondingly proposed. The simulation effectiveness was demonstrated by comparing the simulation and the in situ SEM study results. To validate the simulation method for the three-dimensional (3D) digital core, porosity-permeability integrated measurements under triaxial stresses were conducted to obtain macroscale data under different stress states for a tight sandstone sample. A 3D digital core was reconstructed by micro-CT imaging with the same rock sample. Under the constraints of the measured porosity changes, the 3D digital core deformation was simulated. A series of simulated cores at different stress states were used for pore network model extraction, and the corresponding permeability was calculated. A comparison of the permeability changes of the simulation and porosity-permeability integrated measurements indicated consistently that the simulation method can characterize the 3D digital core stress sensitivity. In addition, the in situ SEM study results revealed that the throats deformed more severely than the pores by generating the pore and throat diameter frequency distributions at different stress states. Therefore, we concluded that throat deformation is more critical than pore deformation for permeability reduction.

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“…The development of numerous karst reservoirs is usually based on long-term tectonic uplift and strong denudation. − In contrast, the Dongwu movement was a short-term tectonic uplift, with a duration of about 0.5–2.5 Ma . Several studies revealed that the residual thickness of the Maokou Formation in the Sichuan Basin varies from 180 to 360 m, and the maximum eroded thickness does not exceed 200 m .…”

Section: Introductionmentioning

confidence: 99%

Calculating the Eroded Thickness Corresponding to a Short-Term Tectonic Uplift with Milankovitch Theory: A Case Study of the Middle Permian Maokou Formation in Southeastern Sichuan Basin, Southwest China

et al. 2021

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The Middle Permian Maokou Formation in the southeastern Sichuan Basin is a typical carbonate karst reservoir. At the end of the Middle Permian, a short-term tectonic uplift (Tungwu movement) occurred in the upper Yangtze region, causing the formation of dissolved fissures and holes. To determine the location of the high-quality reservoir, this paper calculated the eroded thickness using the Milankovitch theory. Based on the gamma logging data of the six wells in the southeastern Sichuan Basin, the dominant frequency and the astronomical time scale were evaluated via frequency spectrum analysis, continuous wavelet transform, and empirical mode decomposition. In addition, we analyzed the relationship between Fischer curve characteristics and the variation of lithology. Last, four methods were used to calculate the eroded thickness, and the rationality was analyzed. Consequently, we identified four levels of Milankovitch cycles, i.e., middle eccentricity (e2), short eccentricity (e3), long obliquity (o1), and short obliquity (o2). Also, the Fischer curves of the six wells were divided into two forms related to local structural uplift. The residual strata of the Maokou Formation comprised three complete third-order cycles, and the boundaries were the 15th, 34th, and 54th e3 cycles. The deposition rate of bioclastic limestone was the lowest (2.12–5.36 cm/ka with an average of 3.30 cm/ka), whereas the deposition rate of argillaceous limestone was the largest (2.27–5.25 cm/ka with an average of 4.09 cm/ka). Among the four methods, the missing formation deposition rate method exhibited the most precise calculation results, while that of the seismic data method was relatively low. Generally, the eroded thickness of the Maokou Formation in southeastern Sichuan was in the range of 0–140 m, i.e., the eroded thickness in the west and south of X14 was relatively large (>100 m), while the area north of LS1 experienced the weakest denudation (eroded thickness < 40 m).

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Construction of an efficient development mode for buried-hill fractured reservoirs in Bohai Bay

Abstract: Construction of an efficient development mode for buried-hill fractured reservoirs in Bohai Bay.

Cited by 7 publications

References 18 publications

Development Characteristics and Quantitative Prediction of Multiperiod Fractures in Superdeep Thrust-Fold Belt

Development Characteristics and Quantitative Prediction of Multiperiod Fractures in Superdeep Thrust-Fold Belt

Microscopic Stress Sensitivity Analysis with In Situ SEM Study and Digital Core Deformation Simulation

Calculating the Eroded Thickness Corresponding to a Short-Term Tectonic Uplift with Milankovitch Theory: A Case Study of the Middle Permian Maokou Formation in Southeastern Sichuan Basin, Southwest China

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