A Novel Oriented Perforation Approach for Fracturing Deep and Tight Reservoirs

Hydraulic fracture initiation poses a challenging issue on fracturing wells landed in deep and tight reservoirs, often necessitating a high breakdown pressure for fracture initiation. Oriented perforation represents a potential solution to alleviate this issue, not only reducing the breakdown pressure but also enhancing fracture geometry alignment. This paper introduces a novel approach to address this issue, featuring a computational framework for calculating breakdown pressure and optimal perforation direction, along with a new perforation cluster layout design. The developed breakdown pressure model is capable, and applicable to various fracturing scenarios, including deviated, cased hole, and clustered perforation fracturing. It accounts for the casing-cement interaction effect and perforation quality. The optimal perforation direction is defined as the one along which hydraulic fractures can be initiated with the lowest breakdown pressure at a measured depth. Using the minimum breakdown pressure and its associated phase angle, the optimal perforation direction is subsequently calculated in terms of perforation azimuth and dip. This information will be used to control the perforation device, ensuring it rotates and fires at the optimal direction in downhole. Numerical examples are given to verify the model performance and effectiveness first. Then a field well case study is provided to further demonstrate how to use the approach to provide pre-fracturing suggestions in practice. The case study validated the accuracy and reliability on solving breakdown issue. To further enhance fracture initiation, a new perforation cluster layout design is also presented. The two central perforations, positioned next to each other, utilize a relatively larger perforation diameter with a phase difference of \({180}^{^\circ }\) ${180}^{{}^{\circ }}$ . The two central perforations will be aligned at the optimal perforation direction in subsurface, which facilitates faster and easier fracture initiation. Moreover, the new perforation design reduces near wellbore fracture tortuosity and minimizes entry pressure loss. All these efforts working together offer a significant improvement on fracture initiation for stimulating wells in deep and tight reservoirs.