Mathematical Model for the Fluid-Gas Spontaneous Displacement in Nanoscale Porous Media considering the Slippage and Temperature

Kang Liu,Daiyong Cao,Zhongyue Lin,Yingchun Wei

doi:10.1155/2018/3245498

Kang Liu, Daiyong Cao + Show 2 more

Open Access

https://doi.org/10.1155/2018/3245498

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Abstract

The fracturing fluid-gas spontaneous displacement during the fracturing process is important to investigate the shale gas production and formation damage. Temperature and slippage are the major mechanisms underlying fluid transport in the micro-/nanomatrix in shale, as reported in the previous studies. We built a fracturing fluid-gas spontaneous displacement model for the porous media with micro-/nanopores, considering two major mechanisms. Then, our spontaneous displacement model was verified by the experimental result of the typical shale samples and fracturing fluids. Finally, the influences of temperature, slip length, and pore size distribution on the spontaneous imbibition process were discussed. Slippage and temperature significantly influenced the imbibition process. Lower viscosity, higher temperature, and longer slip length increased the imbibition speed. Ignoring the temperature change and slippage will lead to significant underestimation of the imbibition process.

Highlights

During hydraulic fracturing process in the unconventional gas formation, a relatively large volume of fracturing fluid is pumped into formation, which can greatly stimulate the gas production [1, 2]
Water will be imbibed into matrix in the fractured reservoir by many influences, including capillary pressure [3,4,5], chemical osmotic pressure [6], pore network [7,8,9], and clay mineral [10], which is called spontaneous imbibition
The spontaneous imbibition is the dominant mechanism of the water transport into the formation because of the high capillary pressure by nanopores [17,18,19]

Summary

Introduction

During hydraulic fracturing process in the unconventional gas formation, a relatively large volume of fracturing fluid is pumped into formation, which can greatly stimulate the gas production [1, 2]. In this process, water will be imbibed into matrix in the fractured reservoir by many influences, including capillary pressure [3,4,5], chemical osmotic pressure [6], pore network [7,8,9], and clay mineral [10], which is called spontaneous imbibition. Ignoring the variation in temperature will lead to inaccurate results and errors

Mathematical Model

Experiment and Validation

Results and Discussion

Conclusions