No abstract

Hydraulic fracture initiation can be a challenging issue for fracturing deep and tight gas reservoirs, which generally requires a high breakdown pressure for clustered perforation hydraulic fracturing treatment. Oriented perforation represents a potential solution to alleviate this issue, which can not only lower breakdown pressure but also deliver a better oriented fracture geometry. In this paper, we present a new strategy to tackle this issue, which includes a framework to calculate the breakdown pressure, optimum perforation direction, and a new perforation cluster layout design. The optimum perforation direction is defined as the one, along which hydraulic fractures can be initiated with the lowest breakdown pressure for a perforation cluster. It can be used to control the perforation device rotating and fired at the right direction in subsurface. Further we present a new perforation cluster layout design, which can alleviate the near wellbore fracture tortuosity and deliver a better fracture initiation when it is aligned along the optimum perforation direction in the subsurface. The two parts of the strategy working together, fracture initiation from a perforation cluster can be achieved a lot of easy than using the conventional perforation method. This new perforation strategy can further alleviate the near wellbore fracture tortuosity, minimize fluid flow restriction and reduce pressure friction loss during hydraulic fracturing treatment. Otherwise multiple and reoriented nonplanar fractures originated from the wellbore perforation cluster likely lead to a premature screen-out, which can negatively impact fluid injection to achieve a desired stimulation performance. Hydraulic fracturing treatment in deep and tight gas reservoirs can be improved through the following actions: calculating breakdown pressure and optimum perforation direction, using new perforation cluster layout design, and aligning the perforation cluster in the optimal direction in subsurface.