Experimental and simulation investigations of cyclic water injection in low-permeability reservoir

Xuan-gang, Meng; Zhang, Qiukai; Dai, Xiaoxu; Xue, Saihong; Feng, Xia‐Ting; Zhang, Yi; Tu, Bin; Li, Xiangfang

doi:10.1007/s12517-021-07129-9

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…They achieved the optimal EOR of 5.1% with a 3-month cycle, an injection-stop ratio of 1:3, a pressure of 4017 psi and short well spacing. Meng et al [28] investigated the feasibility of EOR in low-permeability reservoirs by adopting CWI by performing the core flooding experiments and the numerical simulations (CMG). They revealed that the EOR of the low-permeability reservoir was significant by using CWI, reaching 20%.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Yang

Lao

Tong

et al. 2022

Water

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Water injection with an oscillatory pressure boundary is a promising technology, which can achieve a more economical and environment-friendly EOR (enhanced oil recovery). However, due to the unclear critical injection frequency, its oil production performance has been unstable and is far from reaching the optimal level. Here, a numerical model is established for oil recovery by the water injection with the oscillatory boundary condition to find out the critical frequency for the optimal EOR. The correlations between the water injection frequency and the EOR level at diverse oil–water surface tensions and oil viscosities are integrated into the model. Our numerical model reveals that an optimal EOR of roughly 10% is achieved at the critical water injection frequency compared with water injection without an oscillatory boundary. The EOR mechanism is revealed showing that upon water injection with the optimum frequency, the formation of the preferential pathways is inhibited and the pressure transmits to the wall sides to displace the oil. Moreover, it is indicated that the required critical frequency increases with higher surface tension and larger oil viscosity. In addition, the difference between the residual oil saturation at the optimal frequency increases with the increase in surface tension compared with water injection without an oscillatory boundary. Last but not least, it is elucidated that at a constant injection frequency, a higher EOR is achieved when the water–oil surface tension is lower but the oil viscosity is larger. Our work promises economic, eco-friendly and controllable enhanced oil recovery.

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Yang

Lao

Tong

et al. 2022

Water

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“…However, there are few studies on parameter optimization of cyclic waterflooding, and most of these studies focused on the qualitative study of parameter optimization. Previous studies indicated that the development effect of the asymmetric cyclic waterflooding mode with short injection time and long shut-in time is the best compared with other symmetrical cyclic waterflooding modes. , Water channeling is not easy to occur during the asymmetric cyclic waterflooding with short injection time and long shut-in time, which leads to the higher ultimate oil recovery. Besides, they found that high injection pressure is also beneficial for pressure maintenance during the injection stage.…”

Section: Introductionmentioning

confidence: 99%

Parameter Optimization of Asynchronous Cyclic Waterflooding for Horizontal–Vertical Well Patterns in Tight Oil Reservoirs

Kang

Wang

Liu³

et al. 2022

ACS Omega

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Tight oil resources in China are mainly exploited by staged-fractured horizontal wells; horizontal wells face the problems of the rapid decline rate and low primary oil recovery. Pilot tests on the asynchronous cyclic waterflooding for the horizontal–vertical well pattern were carried out in recent years and achieved good performance. However, there are few studies on the influencing factors and parameter optimization of asynchronous cyclic waterflooding, which limits its wide application. This work took the tight oil reservoir in Yanchang formation, Fuxian area, Ordos Basin as its object, and the oil recovery mechanisms of asynchronous cyclic waterflooding for the horizontal–vertical well pattern were analyzed first. Then, the operation parameters of asynchronous cyclic waterflooding were optimized by the numerical simulation method. Among them, the injection proportion was optimized by the fuzzy synthetic evaluation method. Finally, the oilfield test was carried out based on the optimized parameters. The results showed that pressure disturbance and streamline deviation are the main oil recovery mechanisms of asynchronous cyclic waterflooding. The asynchronous mode of the diagonal well row is better than other asynchronous modes. For the injection time interval, injection–production ratio, and the injection and shut-in time, the cumulative oil production all show the trend of increasing first and then decreasing with the increase in these parameters. The optimal injection time interval and injection–production ratio are 0.5 T and 1, respectively. The optimal injection and shut-in time can be calculated by empirical formulas. Ultimately, the fuzzy synthetic evaluation model was established to optimize the injection proportion. Field practices showed that the average daily oil production of horizontal wells was increased from 1.7 to 3.0 m 3 with the optimized parameters, which further verified the accuracy of the optimized parameters. This research can provide theoretical support for the effective development of tight oil reservoirs.

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Response time of waterflooding in low-permeability reservoirs

Cui

Wei

Zhen

et al. 2022

Unconventional Resources

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Experimental and simulation investigations of cyclic water injection in low-permeability reservoir

Cited by 3 publications

References 25 publications

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Parameter Optimization of Asynchronous Cyclic Waterflooding for Horizontal–Vertical Well Patterns in Tight Oil Reservoirs

Response time of waterflooding in low-permeability reservoirs

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