The objective of optimizing a fracture design is to spend the least amount of money and get the most productivity out of the reservoir by stimulating and contacting as much reservoir rock as possible. This paper presents a unique workflow that addresses in real-time the challenges of perforation and fracture treatment design while accounting for the lithologic and stress variability along the wellbore and its surroundings.
The workflow captures the variability of the stresses and elastic properties along the wellbore by leveraging commonly available surface drilling data and correcting for the frictional losses to estimate the energy spent at the bit in breaking the rock. Immediately after the drilling is completed, the estimated variability of the rock properties along the wellbore is used to design the cluster spacing in a way that ensures perforations are placed in rock with similar treating pressures, improving cluster efficiency. These variable geomechanical logs and minimum stresses derived from surface drilling data are used to model the optimal asymmetric frac design and its resulting geometry. Fracture pressure analysis is done where the modeled surface-treating pressures are calibrated with the observed surface-treating pressures to accurately model the fracture geometry and capture the proppant distribution.
Based on the results of the job pumped, the goal is to provide, in real time, actionable recommendations by performing sensitivity analysis of various fracing parameters that will affect the stimulated reservoir volume and the ultimate recoveries. An analytical tri-linear production forecasting model provides realistic EURs for different fracture design treatments while capturing the physics and honoring the field measured data. Lastly, a detailed economic analysis of the proposed solutions gives the final insight of the dollar value per barrel of equivalent oil produced. The workflow was successfully applied to many wells ultimately improving the IP while minimizing the costs associated with the overall job.
The workflow uses commonly available drilling data to characterize the rock properties which are then used to engineer a completion design on the fly without any increase in associated costs. It also utilizes the treatment pressure data to accurately model the fracture geometry along with providing the sensitive parameters that help overcome the fracing barriers. The implementation of this workflow in realtime serves as a reference tool and guides the field engineers to efficiently stimulate and develop an unconventional reservoir in the most economical way.