Real-time visualization of 3-dimensional fracture initiation and propagation in deviated and horizontal wells

Abstract

The hydraulic fracturing of deviated and horizontal wells is a reasonably novel technology. The fracture initiation and propagation from these wells often involves multiple fracture initiation, starter fracture "cutting" the wellbore at an angle, starter fractures linking-up, and near-wellbore fracture turning, twisting, and reorientation to the direction that is normal to the minimum principal stress. These phenomena are quite different from those in vertical wells. The hydraulic fracturing of arbitrarily oriented and horizontal wells is, thus, challenging to understand. To provide a means to increase the success of such well stimulation treatments is the motivation for this research. We have studied the phenomena of fracture initiation, propagation, and the near-wellbore fracture geometry in arbitrarily oriented and horizontal wells. We have investigated the effects of important variables including the principal stresses, the wellbore orientation, and the perforation configuration. The optimal fracture initiation pressures, the contact between arbitrarily oriented wells and the fracture plane, and the near-well fracture geometry are determined. Guidelines are provided for the fracture and perforation design. Our study also shows that because of the near-well stress concentration the fracture width at the weflbore is always smaller than the maximum fracture width. This can have important consequences during the execution of hydraulic fractures. A visualization system has also been designed to monitor the fracture initiation and propagation process. This visualization system allows the early detection of design and operation errors and provides for prompt responses to optimize the fracture treatment.