International Journal of Hydrogen Energy, Vol.42, No.29, 18358-18363, 2017
Theoretical research on radial wells orientating hydraulically created fracture directional extended
Hydraulic fracturing of radial wells have become new technologies to effectively develop low permeability reservoir, thin reservoir, fractured reservoir, "dead area" after water injection etc. Influenced by ground stress and reservoir heterogeneity, hydraulically created fracture will probably not extend smoothly to connect the target area along the direction of radial wells, the reservoir stimulation effect is not ideal. Based on the pressure analysis of fracturing initiation of multiple radial holes and the theory of plasticity district, criterion of multiple radial wells orientating directional fracture propagation in the condition of ground stress is derived. In this condition, multiple radial wells will produce a continuous plasticity district in the reservoirs, while maintaining the fracture extending in plastic zone directionally without the effect of ground stress, which guarantees that fracture is interconnected between the radial wells during fracturing operation, to form the main crack along the direction of radial wells' axis plane. In consideration of economy, maximum spacing of radial wells are optimized, in order to provide a reliable scientific basis for effectively implementation of hydraulic fracturing technology in radial wells. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.