Effect of Fracturing Fluid/Shale Rock Interaction on the Rock Physical and Mechanical Properties, the Proppant Embedment Depth and the Fracture Conductivity

Zhong, Ying; Kuru, Ergün; Zhang, Hao; Kuang, Jianchao; She, Jiping

doi:10.1007/s00603-018-1658-z

Cited by 33 publications

(13 citation statements)

References 25 publications

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“…In order to understand the effect of water distribution on methane adsorption, Li et al 20 investigated water adsorption isotherms and concluded that water uptake of clay-rich shales would reduce the methane adsorption capacity. Dutta 21 , Rutqvist 22 and Zhang et al 23 suggested that the retention of fracturing fluid in shale due to water adsorption can cause the expansion and dispersion effect of clay, and the capillary pressure in the pore throat was very large, which was unfavorable to the production of shale gas. Even though there are a few studies on the water adsorption behavior of shales, the characteristics of water adsorption and desorption on the shale reservoir rocks are still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on water adsorption and desorption isotherms of the Longmaxi shale in the Sichuan Basin, China

Shen

et al. 2020

Sci Rep

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the understanding of water adsorption and desorption behavior in the shale rocks is of great significance in the reserve estimation, wellbore stability and hydrocarbon extraction in the shale gas reservoirs. However, the water sorption behavior in the shales remains unclear. In this study, water vapor adsorption/desorption isotherms of the Longmaxi shale in the Sichuan Basin, china were conducted at various temperatures (30 °C, 60 °C) and a relative pressure up to 0.97 to understand the water sorption behavior. Then the effects of temperature and shale properties were analyzed, and the water adsorption, hysteresis, saturation and capillary pressure were discussed. The results indicate that water adsorption isotherms of the Longmaxi shale exhibit the type II characteristics. The water molecules initially adsorb on the shale particle/pore surfaces at low relative pressure while the capillary condensation dominates at high relative pressure. Temperature favors the water sorption in the shales at high relative pressure, and the GAB isotherm model is found to be suitable for describe the water adsorption/desorption behavior. The high organic carbon and full bedding are beneficial to water adsorption in the shales while the calcite inhibits the behavior. There exists the hysteresis between water adsorption and desorption at the whole relative pressure, which suggests that the depletion of condensed water from smaller capillary pores is more difficult than that from larger pores, and the chemical interaction contributes to the hysteresis loop for water sorption. The capillary pressure in the shales can be up to the order of several hundreds of Mpa, and thus the desorption of water from the shales may not be as easy as the water adsorption due to the high capillary pressure, which results in water retention behavior in the shale gas reservoirs. these results can provide insights into a better understanding of water sorption behavior in the shale so as to optimize extraction conditions and predict gas productivity in the shale gas reservoirs.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation on water adsorption and desorption isotherms of the Longmaxi shale in the Sichuan Basin, China

Shen

et al. 2020

Sci Rep

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“…Along with proppant embedment which reduces the fracture opening (see e.g. Zhong et al, 2019), the presence of these clusters of fine particles results in fracture clogging, a loss of permeability of the hydraulically-driven fracture with time, and in a decrease of the hydrocarbon production with time eventually (Guerra et al, 2018). A common way to restore the fracture conductivity is to "refrac" the reservoir, which means to implement the same procedure as for the initial fracking phase in the reservoir (see e.g.…”

Section: Introductionmentioning

confidence: 99%

Fracture cleaning: Experimental study on the unclogging process within a propped fracture under a dynamic stimulation

Borderie

Sénéchal

Jacques

et al. 2021

Journal of Petroleum Science and Engineering

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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“…It is easy to soften and swell after being soaked in water [22]. In the process of fracturing, opening flow, and production, it is necessary to pay attention to the influence of pressure fluctuation on the conductivity of branch fractures and to accurately grasp the stress sensitivity of branch fractures [23,24]. After shale is soaked in water-based fracturing fluid, the damage caused by the leak off of gel-breaking fluid and the risk of shale hydration swelling especially need to be focused on to prevent excessive open flow pressure from causing shale particles on the wall of branch fractures to fall off and causing proppant to embed in the fractures, which will cause the fracture conductivity to decrease [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation on the Conductivity of Branch Fracture with Low Sand Laying Concentration and Its Influencing Factors in Shale Oil Reservoirs

et al. 2021

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The productivity of shale oil reservoirs is mainly determined by the hydraulic fractured reservoir volume. The branch fractures with low sand laying concentration are the main channels connecting the shale matrix and the main fractures. Maintaining the branch fracture conductivity is significant to the production of shale oil. In this study, a series of shale branch fracture conductivity and soaking experiments were conducted using a core flooding device and a small reactor, and the influences of different factors on the fracture conductivity were evaluated. The results show that when the sand laying concentration in fractures is less than 3 kg/m2, the branch fractures present a significant stress sensitivity. Particularly when the sand laying concentration is less than 1 kg/m2, and the closure pressure is greater than 15 MPa, there will be a risk of proppant embedded and fracture closed. The antiswelling agent has an inhibitory effect on the shale swelling. When the concentration of the antiswelling agent in the gel-breaking fluid is 2%, the swelling factor of shale powder is only 1.84%. Comparatively, the 0.5% of the antiswelling agent has a poor effect which can cause the shale rock to crack when the effective stress decreases. It can cause the fracture conductivity to decline by 70-90% when the gel-breaking fluid flows back associated with the shale oil. The probability of core breaking and proppant embedding will increase. The frequent shut-in and rapid open-flow for production can accelerate the damage of fracture conductivity. It is necessary to optimize the fracturing fluid and the open flow scheme to prevent the rapid decline of production in shale oil reservoirs.

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Effect of Fracturing Fluid/Shale Rock Interaction on the Rock Physical and Mechanical Properties, the Proppant Embedment Depth and the Fracture Conductivity

Cited by 33 publications

References 25 publications

Experimental investigation on water adsorption and desorption isotherms of the Longmaxi shale in the Sichuan Basin, China

Experimental investigation on water adsorption and desorption isotherms of the Longmaxi shale in the Sichuan Basin, China

Fracture cleaning: Experimental study on the unclogging process within a propped fracture under a dynamic stimulation

Experimental Evaluation on the Conductivity of Branch Fracture with Low Sand Laying Concentration and Its Influencing Factors in Shale Oil Reservoirs

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