The Influence of the Rock Stress State on Matrix and Fracture Permeability under Conditions of Various Lithofacial Zones of the Tournaisian–Fammenian Oil Fields in the Upper Kama Region

Martyushev, Dmitriy A.; Galkin, Sergey; Shelepov, V. V.

doi:10.3103/s0145875219060061

Cited by 18 publications

(13 citation statements)

References 8 publications

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“…In this study, acid core-flooding tests were carried out at various injection rates on different rock samples, causing the wormholes to differ in structure from one rock sample to the other and even within the same rock type. The size and nature of the wormhole may be responsible for the change in mechanical and physical characteristics of the rock (Artyushkova et al 2021;Martyushev et al 2019;Mustafa et al 2022;Song et al 2021;Zhang et al 2020a). Micro-CT images of two of the acidized rock samples were reconstructed using the 3D Slicer software.…”

Section: Computed Tomography (Ct)mentioning

confidence: 99%

Effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in Ahdeb oil field

Alameedy

Alhaleem

Isah

et al. 2022

J Petrol Explor Prod Technol

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Acidizing is one of the most used stimulation techniques in the petroleum industry. Several reports have been issued on the difficulties encountered during the stimulation operation of the Ahdeb oil field, particularly in the development of the Mishrif reservoir, including the following: (1) high injection pressures make it difficult to inject acid into the reservoir formation, and (2) only a few acid jobs have been effective in Ahdeb oil wells, while the bulk of the others has been unsuccessful. The significant failure rate of oil well stimulation in this deposit necessitates more investigations. Thus, we carried out this experimental study to systematically investigate the influence of acid treatment on the geomechanical properties of Mi4 formation of the Mishrif reservoir. The acid core-flood experiments were performed on seven core samples from the oil reservoir in central Iraq. The porosity, permeability, acoustic velocities, rock strength, and dynamic elastic parameters were computed before and after the acidizing treatment. To determine the optimal acid injection rate, different injection flow rates were used in the core-flooding experiments. The propagation of an acid-induced wormhole and its effect on the rock properties were analyzed and compared to that of intact rocks. Computed tomography (CT) scan and a 3D reconstruction technique were also conducted to establish the size and geometry of the generated wormhole. To analyze the influence of mineralogical variation and heterogeneity and confirm the consistency of the outcomes, acidizing experiments on different rock samples were conducted. The results demonstrate that for all the rock samples studied, the mechanical properties exhibit rock weakening post-acid treatment. The Young’s modulus reduced by 26% to 37%, while the Poisson’s ratio, the coefficient of lateral earth pressure at rest, and the material index increased by 13% to 20%, 23% to 32%, and 28% to 125%, respectively. The CT scan visually confirmed that the acid treatment effectively creates a pathway for fluid flow through the core.

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Section: Computed Tomography (Ct)mentioning

confidence: 99%

Effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in Ahdeb oil field

Alameedy

Alhaleem

Isah

et al. 2022

J Petrol Explor Prod Technol

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“…The proposed model considers a slightly compressible liquid; that is, all the complexities due to the multiphase gas-oil interactions are not taken into consideration [21]. Furthermore, the model presented in this paper does not consider petrophysical properties dependent on the stress state, which even for a Nelson Type I reservoir, imposes a challenge [22].…”

Section: Model Developmentmentioning

confidence: 99%

Spatial Fractional Darcy’s Law on the Diffusion Equation with a Fractional Time Derivative in Single-Porosity Naturally Fractured Reservoirs

et al. 2022

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Due to the complexity imposed by all the attributes of the fracture network of many naturally fractured reservoirs, it has been observed that fluid flow does not necessarily represent a normal diffusion, i.e., Darcy’s law. Thus, to capture the sub-diffusion process, various tools have been implemented, from fractal geometry to characterize the structure of the porous medium to fractional calculus to include the memory effect in the fluid flow. Considering infinite naturally fractured reservoirs (Type I system of Nelson), a spatial fractional Darcy’s law is proposed, where the spatial derivative is replaced by the Weyl fractional derivative, and the resulting flow model also considers Caputo’s fractional derivative in time. The proposed model maintains its dimensional balance and is solved numerically. The results of analyzing the effect of the spatial fractional Darcy’s law on the pressure drop and its Bourdet derivative are shown, proving that two definitions of fractional derivatives are compatible. Finally, the results of the proposed model are compared with models that consider fractal geometry showing a good agreement. It is shown that modified Darcy’s law, which considers the dependency of the fluid flow path, includes the intrinsic geometry of the porous medium, thus recovering the heterogeneity at the phenomenological level.

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“…complex geomechanical environment, in which a thousand-meter-deep shaft was built, can cause the collapse, rock burst, and impact in the rock surrounding the shaft and the main roadway at the bottom of the shaft during shaft construction. Given the problems of rock mechanics and disaster control in deep mine shaft construction [10][11][12], many scholars have studied the basic theory of mechanics in this type of construction. Wang Jinping [13] simplified the vertical shaft as a thick-walled cylinder.…”

Section: Introductionmentioning

confidence: 99%

A Primary Support Design for Deep Shaft Construction Based on the Mechanism of Advanced Sequential Geopressure Release

et al. 2022

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The construction of 1500 m depth shaft in Xincheng Gold Mine, China, faces complex stress conditions such as high geostress (>50 MPa), high ground temperature (>50 °C), high water-pressure (>9 MPa), and highly corrosive. Traditional deep shafts excavated by the sinking and lining method cannot adapt to high geostress problems, such as rock bursts and large deformations, etc., in the deep shaft construction process. To avoid and adjust the high geostress induced the rockburst and large deformations, the mechanism of the advanced sequential geopressure release (ASGR) has been proposed for the ground control in deep shaft construction. In this paper, the safe distance between the concrete lining and the shaft excavation face is determined based on the ASGR mechanism, which can provide the space for geopressure release, and primary support based on rock mass quality and numerical simulation was employed to control the geopressure and deformation. A new support scheme for the deep shaft is proposed, using long bolts to restrain severe deformations, metal mesh, and a double reinforcement bar to improve the induced stress distribution. According to the results, the construction scheme of deep shaft has been improved, and the safe support distance of the proposed scheme is determined to be 12 m, with an interval of three excavation cycles. Compared to the original scheme of shaft lining after excavation, the proposed scheme based on the ASGR mechanism can effectively improve the geopressure release and benefit from controlling the rockburst and large deformation of deep shaft induced by high geostress conditions. The stress distribution in the lining is more uniform, and safety factor of the lining is increased to 2.0, which is benefit the long-term stability of deep shaft.

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The Influence of the Rock Stress State on Matrix and Fracture Permeability under Conditions of Various Lithofacial Zones of the Tournaisian–Fammenian Oil Fields in the Upper Kama Region

Cited by 18 publications

References 8 publications

Effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in Ahdeb oil field

Effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in Ahdeb oil field

Spatial Fractional Darcy’s Law on the Diffusion Equation with a Fractional Time Derivative in Single-Porosity Naturally Fractured Reservoirs

A Primary Support Design for Deep Shaft Construction Based on the Mechanism of Advanced Sequential Geopressure Release

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