Semi-analytical modeling for water injection well in tight reservoir considering the variation of waterflood - Induced fracture properties – Case studies in Changqing Oilfield, China

Wang, Yang; Cheng, Shiqing; Feng, Naichao; Xu, Jianchun; Qin, Jiazheng; He, Youwei; Yu, Haiyang

doi:10.1016/j.petrol.2017.09.043

Cited by 41 publications

(13 citation statements)

References 5 publications

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“…因此, 目前更多的是依靠各类动态监测资料. 图 1 是长庆大路沟区块 2016 年含水率分布 [18] 2.2 注水诱导动态裂缝的机理在注水诱导裂缝的机理研究方面, 王友净, 宋新民等 [11] , 赵向原, 曾联波等 [19,20] [21][22][23] , 表皮因子, 吸水指数三种方法指标, 利用注水井的注入量和井口测压数据, 能快速, 实时地监测注水井井底起裂或堵塞情况 [24] .针对 [25][26][27][28] . 同时, 裂缝闭合过程中其属性参数也会发生变化, 对最终测压结果的解释有着较大影响.…”

Section: 注水诱导动态裂缝的矿场表现特征unclassified

Development theory and practice of water injection induced fractures in ultra-low permeability reservoirs

Wang¹,

Cheng²,

Qin³

et al. 2021

Sci. Sin.-Tech.

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Section: 注水诱导动态裂缝的矿场表现特征unclassified

Development theory and practice of water injection induced fractures in ultra-low permeability reservoirs

Wang¹,

Cheng²,

Qin³

et al. 2021

Sci. Sin.-Tech.

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“…Low and ultralow permeability reservoirs play an important role in Ordos Basin where water injection development is one of the most commonly used methods to enhance oil recovery. Meanwhile, a lot of oilfield data such as production curves, water injection profiles, and field test data show a characteristic of directional water penetration after a period of exploitation, and water-induced fractures are proved to be widespread in these reservoirs [1,2]. In unconventional reservoirs, fractures were studied as the main channel of fluid seepage in many aspects [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

An Improved Embedded Discrete Fracture Model with Fracture Growth for Water-Induced Fracture Simulation in Low Permeability Reservoirs

et al. 2022

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Water injection is often used to supply formation energy in low permeability reservoirs. A lot of field data shows that fractures nearby the wellbores may extend hundreds of meters because of the poor injectability which is called water-induced fractures. The presence of these fractures significantly changes the flow of injected water thus affecting the development effects. However, few studies of reservoir numerical simulation methods have been presented to simulate the dynamic changes of fractures in the long-term waterflooding process. This study is based on the embedded discrete fracture model (EDFM) in which the fracture system has less dependence on the grid system. By improving the preprocessing algorithm, fracture growth can be considered in EDFM which is called the dynamic embedded discrete model (dEDFM). This new method provides an innovative idea for fracture propagation simulation by attaching new fracture elements to the original fractures once the failure criterion is satisfied. Meanwhile, there is no need to calculate the stress field once the in situ stress is provided, so the computational efficiency is greatly improved compared with the fluid-solid coupling method. Besides, dEDFM has a flexible way of handling fracture elements, so it is suitable for water-induced fracture simulation. Results show that fracture propagation speed is significantly influenced by matrix permeability, in situ stress, and injection intensity, and if the water-induced fractures propagate faster than the original waterfront movement velocity, changing law of the water content rate rising of production wells in different directions will be different. The contribution of this work lies in that it provides a suitable and efficient way for reservoir engineers to deal with water-induced fractures since the propagation of fractures can be considered when it comes to reservoir numerical simulation, and it is helpful for production data prediction and development adjustment in low permeability reservoirs.

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“…In tight reservoirs with natural microfractures, nature fractures are unevenly distributed. In horizontal wells with relatively developed natural fractures, a complex fracture network is formed by expanded nature fractures induced by water injection, which greatly increases the velocity and quantity of fluid exchange between injected water and matrix [3][4][5][6][7]. As the crude oil continues to be produced, the fluid pressure in the reservoir will gradually decrease, and the effective stress acting on the fracture and matrix rock blocks will increase accordingly.…”

Section: Introductionmentioning

confidence: 99%

Study on the Production Mode of Horizontal Well from Water Huff and Puff to Segmented Injection and Production in Tight Reservoir

Cheng

Cao

et al. 2021

Geofluids

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Water huff and puff in horizontal wells in tight reservoirs has achieved good results in replenishing formation energy. However, after multiple rounds of treatment, a rapid decrease in formation pressure takes place making it difficult to maintain stable production. To improve the oil recovery rate of tight reservoirs, it is imminent to change the development mode. In this work, the stress distribution characteristics at fracture tips were analyzed based on Irwin theory and elastic theory. A model of propagation and closure length of fractures was established based on the propagation mechanism of water injection-induced natural fracture and the energy balance principle of fracture mechanics. Surfactant imbibition experiments were carried out according to the imbibition principle of surfactant system, and the propagation law of natural fractures was described with numerical simulation to analyze the seepage characteristics of dynamic fracture network. On the basis of the above works, alternating water huff and puff into segmented injection and production was proposed according to the distribution law of dynamic fracture network. The developing process of an actual well case by these two developing modes was simulated to predict 18 years of cumulative recovery, pressure distribution, and recovery rate. Results showed that when stress intensity factor exceeds the fracture toughness, the natural fractures will extend along their original directions and get connected, forming an irregular fracture network. The lengths of fractures after propagation and closure will not bring about water channeling for they are far shorter than well and interval spacing. Surfactant could diminish the resistance of boundary layer by reducing the wetting contact angle, ending up with an improvement in imbibition efficiency. Radial displacement and dynamic imbibition occur simultaneously in a dynamic fracture network during the early stage of water injection, while static imbibition mainly occurs during injection shutdown period and well soaking. According to comparison, the swept area of segmented injection and production was larger, ending up with a continuous increase of simulated recovery rate and cumulative recovery. The findings of this study show alternating water huff and puff after to segmented injection and production in fractured tight reservoir can allow full play of dynamic fracture network’s potential and achieve effective enhancement in oil recovery rate.

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Semi-analytical modeling for water injection well in tight reservoir considering the variation of waterflood - Induced fracture properties – Case studies in Changqing Oilfield, China

Cited by 41 publications

References 5 publications

Development theory and practice of water injection induced fractures in ultra-low permeability reservoirs

Development theory and practice of water injection induced fractures in ultra-low permeability reservoirs

An Improved Embedded Discrete Fracture Model with Fracture Growth for Water-Induced Fracture Simulation in Low Permeability Reservoirs

Study on the Production Mode of Horizontal Well from Water Huff and Puff to Segmented Injection and Production in Tight Reservoir

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