Abstract
This paper presents an innovative alternative stimulation approach for unconventional resource development called the Slow & Easy (S&E) stimulation process. This new generation geo-stimulation technology enables the convergence of environmental sustainability, enhancement of production performance, and well & field revitalization. The S&E process is designed to induce subsurface complex fracturing networks resulting in the progressive development of an Optimized Stimulated Rock Volume (O-SRV) in tight, stiff formations such as shales, tight sands, and carbonates. The process utilizes a cyclic injection approach with produced fluids at lower rates and pressures to enhance conductivity of the O-SRV. The extensive development of O-SRV is critical for effective, prolonged reservoir stimulation, leading to more sustained production rates and increased Estimated Ultimate Recovery (EUR) from wells. The lower injection rates and pressures, in addition to the cyclic injection approach, mitigate the risk of induced seismicity and inter-well ‘frac hits’. During its operation, freshwater and chemicals are not used, reducing the environmental impact of the S&E process. Also, as the S&E process requires lower proppant load and horsepower for production, it is a more cost-effective simulation method than conventional fracturing methods. The S&E process has been successfully implemented in over 60 wells worldwide. Typical unconventional reservoirs where the S&E process is applied include conglomeratic sands, dolomitic siltstone, and tuff formations; and typical petrophysical properties are porosity less than 9%, permeability less than 3 mD, and bulk stiffness of 14-30 GPa. Post-stimulation data shows an improvement in well oil productivity by a factor of 8 on average over a 6-month period. Field case histories and post-stimulation production performance are presented in this paper. The S&E process provides improved sustained hydrocarbon production, reduced stimulation costs, and significantly reduced environmental impact. The S&E method offers an innovative and specialized technology solution for more effective stimulation of unconventional resources to meet current industry demands.
