Innovative Pressure-Actuated Toe Sleeve Enables True Casing Pressure Integrity Test and Stage Fracturing While Improving Completion Economics in Unconventional Resources

摘要

During the past several years, the oil and gas industry has increased the development of unconventional resource plays which are expected to hold the future for energy development in many parts of the world. In order to maximize these new reservoirs, horizontal wellbores are typically drilled, and multiple hydraulic fractures must be created to provide enough stimulated reservoir volume (SRV) to produce the wells economically. A traditional plug and perforate completion methodology has been employed to perform multi-stage fracture treatments, gain wellbore access, and isolate fracture stages. This process contains inefficiencies that can significantly impact economics. When the plug and perforate method is used prior to running perforating guns and a frac plug to depth, a flow path must be created at the toe of the wellbore. Typically, this is achieved by using tubing-conveyed perforating guns (TCP) deployed on coiled tubing (CT) or by a wireline tractor pulling perforating guns deployed on electric wireline (E-line). Although necessary, this process is one of the major plug and perforate inefficiencies noted in the above completion method. While it does allow casing pressure testing (either government-mandated or part of the operator's well construction "best practices") prior to fracturing operations, it significantly impacts economics. To address the inefficiencies, new technologies that seek to eliminate these problems, and thus, improve well economics are being developed. This paper explores an innovative pressure-actuated toe sleeve, which can eliminate running TCP on CT or perforating guns on E-line for initiating a flow path but still allows a casing pressure test to be run. Additionally, the pressure-actuated toe sleeve enables this casing test to be completed without having to exceed the casing test pressure to establish the flow path. The design, testing, and use of the toe sleeve will be discussed in the paper.