A Numerical Multistage Fractured Horizontal Well Model Concerning Hilly-Terrain Well Trajectory in Shale Reservoirs with Natural Fractures

Liying Zhu,Jingfei Tang,Wenqi Ke,Jiacheng Dai,Xingyuan Liang,Guoqing Han

doi:10.3390/en15051854

Abstract

Multistage hydraulic fracturing is one of the most prevalent approaches for shale reservoir development. Due to the complexity of constructing reservoir environments for experiments, numerical simulation is a vital method to study flow behavior under reservoir conditions. In this paper, we propose a numerical model that considers a multistage fractured horizontal well with a hilly-terrain trajectory in a shale reservoir with the presence of natural fractures. The model was constructed based on the MATLAB Reservoir Simulation Toolbox and used the Embedded Discrete Fractured Model (EDFM) to describe the interrelationship between the matrix, fractures, and wellbore. The model was then applied to an actual condensate gas well producing from a shale reservoir, and the effects of reservoir parameters on the simulation data were studied based on this well case. The simulation results were highly consistent with the actual production data, which validates the accuracy of this model and proves its potential for predicting future production trends. We extended the discussion to two examples with extreme well trajectories by reviewing the inflow contribution of each hydraulic fracture with respect to fracture pressure, and the changes in static pressure with time. In conclusion, the proposed model is capable of providing simulation results close to reality and thus guiding field design and operation in the fracturing and drilling process.

Highlights

Hydraulic fracturing in horizontal wells is a common practice to effectively extract hydrocarbon resources from the formation in industry
The production contribution of each fracture was calculated by the flowrate at each hydraulic fracture divided by the total flowrate at reservoir conditions
The simulation results of the case well are compared to the actual production data

Summary

Introduction

Hydraulic fracturing in horizontal wells is a common practice to effectively extract hydrocarbon resources from the formation in industry. This approach can be often seen in the production of hydrocarbon fluids from unconventional reservoirs such as shale, tight formation, and coalbed methane [1]. The relationship between formation pressure and saturation with respect to production time can be analyzed by calculating reservoir productivity based on a fractured horizontal well, leading to the law of change in well productivity with time [2]. The calculation of productivity for fractured horizontal wells includes two parts, namely the reservoir and the wellbore. Coupled calculation of matrix and fluid properties and their changes with respect to environmental conditions is performed to obtain the fluid flow distribution within the range of the entire reservoir [4]

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