Horizontal Well Orientation Optimization Based on the Integration of Hydraulic Fracturing Network Simulation and Productivity Prediction

ABSTRACT: Horizontal drilling and large-scale hydraulic fracturing are currently used to increase artificial fracture networks and per well production in unconventional reservoirs. Due to the differences of regional geological characteristics, natural fracture characteristics and geomechanical characteristics, different wellbore directions may lead to different hydraulic fracturing effects and post-frac productivity. If the well orientation is not correct, it can result in poor hydraulic fracturing propagation and inefficient production. The high precision geological model and geomechanical model of platform of typical shale gas blocks in Sichuan were established. First, considering the interaction of hydraulic fracture and natural fracture, interaction of hydraulic fracture each other, hydraulic fracturing network distribution in different in-situ stress orientation, natural fracture azimuth, wellbore azimuth combination cases were simulated. Second, high-precision unstructured grid numerical model was established on the basis of hydraulic fracturing fractures to accurately characterize fracture network morphology and fracture conductivity. The flow characteristics of hydraulic fracturing network was simulated, and post-frac productivity were predicted. Finally, the optimal wellbore orientation under various in-situ stresses and natural fracture combination cases was obtained by combining the fracturing effect and post-frac productivity. The research results show that, under the typical fracturing construction and production conditions in Sichuan shale gas block, the optimal well orientation is not affected by the natural fracture orientation. The fracturing effect and production within the range of 0-30 degrees of horizontal minimum in-situ stress are better. When the angle between natural fracture orientation and horizontal minimum in-situ stress is more than 50°, the overall production becomes better in various well directions. 1. INTRODUCTION Hydraulic fracturing in horizontal well can greatly improve the production capacity of a single well in unconventional oil and gas resources. Due to regional differences in geological characteristics, natural fracture characteristics and geomechanical characteristics of unconventional reservoirs, variability in in-situ stress directions, natural fracture directions and wellbore directions may lead to different fracturing effects and post-frac productivity under the same fracturing construction and production conditions. Therefore, it is very important for horizontal well orientation optimization.