Seepage Characteristics of a Low Permeability Sandstone Reservoir in Mobei Oilfield, Junggar Basin

Qi, Lisha; Jiang, Zhibin; Wang, Xiaowei; Wang, Jie; Qian, Chuanchuan

doi:10.2113/2021/6944088

Cited by 3 publications

(2 citation statements)

References 3 publications

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“…The relative permeability curve of the investigated area exhibited a concave upward type in the water phase, aligning with the standard shape for oil-water relative permeability curves (Figure 11) [57,58]. Initially, a rapid decline was observed in the oil phase permeability curve, which gradually decelerated as water saturation increased.…”

supporting

confidence: 78%

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

Li,

Qu,

Wang

et al. 2023

Minerals

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Micro-heterogeneity in low-permeability sandstone oil reservoirs significantly influences the uniformity of water injection during development. This leads to the formation of preferred channels for water injection, causing premature water breakthroughs in oil wells. Not only does this reduce oil displacement efficiency, but it also enriches residual oil in the formation, which ultimately impacts the overall recovery rate. This study employed various methods, including thin-section casting, qualitative analysis through scanning electron microscopy, quantitative analysis of X-ray diffraction, high-pressure mercury intrusion and particle size, and experimental techniques, such as wettability and micro-displacement, to investigate the impact mechanism of micro-heterogeneity on water injection development in low-permeability oil reservoirs. A typical low-permeability sandstone oil reservoir in the Ordos Basin was used as a case study. The results reveal that the reservoir’s micro-heterogeneity is determined by the heterogeneity of the interstitial material, porosity, and particle size. Micro-heterogeneity plays a critical role in the flow characteristics and oil displacement efficiency of low-permeability oil reservoirs. The less the micro-heterogeneity, the better the water injection development outcome. This study suggests a technical policy adjustment method that is critical for guiding the development of low-permeability water injection oil reservoirs, thereby improving the effectiveness of water injection development.

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supporting

confidence: 78%

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

Li,

Qu,

Wang

et al. 2023

Minerals

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“…However, conglomerate reservoirs are a special kind of lithologic reservoir, and they still present problems worldwide due to their complex and variable lithology, the complex modal characteristics of pores, poor reservoir physical properties, and strong heterogeneity [ 7 , 8 , 9 , 10 ]. Water flooding is one of the common development methods for conglomerate reservoirs, but long-term water flooding can form a high permeability water-flow channel between injection and production wells during the high water cut period, which intensifies the heterogeneity of the reservoir, resulting in the inability to displace the remaining oil in the low permeability area, low water injection sweep coefficient, much remaining oil, and inefficient or ineffective injection water circulation [ 11 , 12 , 13 ]. In view of the above problems, researchers have carried out a large number of studies, among which the use of gel to plug high permeability areas can effectively improve reservoir heterogeneity, improve the sweep efficiency of injected water, increase oil production, and reduce the water cut significantly.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Gel Flooding during the High Water Cut Stage in a Conglomerate Reservoir of the Xinjiang A Oilfield

Xin

Liu

et al. 2023

Polymers

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Influenced by water injection, a dominant flow channel is easily formed in the high water cut stage of a conglomerate reservoir, resulting in the inefficient or ineffective circulation of the injected water. With gel flooding as one of the effective development methods to solve the above problems, its parameter optimization determines its final development effect, which still faces great challenges. A new optimization method for gel flooding is proposed in this paper. Firstly, the gel flooding parameters were obtained through physical experiments; then, an experimental model of gel flooding was established according to the target reservoir, and parameter sensitivity analysis was carried out. Next, a history matching of the gel flooding experiment was carried out. Finally, history matching of the target reservoir was also carried out, and a gel flooding scheme was designed and optimized to determine the best parameters. The experimental results showed that the gelation time was 4 h and the gel viscosity was 6332 mPa·s; the breakthrough pressure, resistance factor (RF), and residual resistance factor (RRF) all decreased with the increase in permeability. The gel had a good profile control ability and improved oil recovery by 16.40%. The numerical simulation results illustrated that the porosity of the high permeability layer (HPL) had the greatest impact on the cumulative oil production (COP) of the HPL, and the maximum polymer adsorption value of the HPL had the largest influence on the COP of the low permeability layer (LPL) and the water cut of both layers. Benefiting from parameter sensitivity analysis, history matching of the gel flooding experiment and a conglomerate reservoir in the Xinjiang A Oilfield with less time consumed and good quality was obtained. The optimization results of gel flooding during the high water cut stage in a conglomerate reservoir of the Xinjiang A Oilfield were as follows: the gel injection volume, injection rate, and polymer concentration were 2000 m3, 50 m3/d, and 2500 mg/L, respectively. It was predicted that the water cut would decrease by 6.90% and the oil recovery would increase by 2.44% in two years. This paper not only provides a more scientific and efficient optimization method for gel flooding in conglomerate reservoirs but also has important significance for improving the oil recovery of conglomerate reservoirs.

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Effects of Confining Pressure on Permeability in a Single Fracture Based on the Deformation of Hydraulic Aperture at Low Fluid Velocities

Wang

Qian

et al. 2022

Lithosphere

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The fluid flow in fractured rock was determined by the aperture of fractures, which is influenced by the complex variation and wide distribution of in situ stress conditions. While extensive studies focused on qualitative analysis of the experimental phenomena, much less was the quantitative mechanism of permeability under confining pressure in theory, which is frequently required in rock engineering projects. In this work, we proposed a new negative exponential model to quantitatively describe the flow rate Q, seepage pressure Ps, hydraulic aperture eh, and permeability k under different confining pressures Pc at a low flow rate. Hydromechanical tests with two experimental modes (constant Q test mode and constant Ps test mode) were conducted on cutting shale samples, and test data were collected. Furthermore, regression analyses were performed on the test data, based on the proposed model. Results suggest that the negative exponential model quantitatively predicts the seepage properties (Q, Ps, eh, and k) under the changeable in situ stress conditions in the application of low flow velocities in natural fractures, such as the development of oil/gas reservoirs and controlling of solute transport in the main aquifer. The proposed model assists in understanding and applying the behavior of the fluid flow in fractured rock under in situ stress conditions at low flow velocity.

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Seepage Characteristics of a Low Permeability Sandstone Reservoir in Mobei Oilfield, Junggar Basin

Cited by 3 publications

References 3 publications

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

Optimization of Gel Flooding during the High Water Cut Stage in a Conglomerate Reservoir of the Xinjiang A Oilfield

Effects of Confining Pressure on Permeability in a Single Fracture Based on the Deformation of Hydraulic Aperture at Low Fluid Velocities

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