Autonomous Perforating System for Multizone Completions

Abstract

Abstract Autonomous downhole tools offer a range of advantages over conventional tools controlled manually via umbilicals. For instance, perforating guns or bridge plugs could be dropped or pumped downhole without the use of wireline (slick or electric line), coiled tubing or tractors. Because umbilical intervention is no longer required, the tools may automatically perform an action (e.g., perforate a desired interval) with substantial cost reduction and enhanced safety. The elimination of wireline lubricators, lifting equipment, wires, additional personnel and vehicles minimizes the potential for accidents in this already confined space. This is particularly important during hydraulic fracturing operations where this method may enable faster pumping rates and increased fracture volumes during daylight hours. Use of this technology will also reduce air emissions from support equipment that would no longer be required. This paper describes an autonomous perforating tool currently being developed by ExxonMobil Upstream Research Company. This patent pending technology is based on using a self-destructing disposable perforating tool which is run without a wireline. To accomplish this objective, the custom designed tool has three frangible components: 1) a logging device; 2) an on-board navigation system; and 3) friable perforating guns. The on-board navigation system reads the log signals and performs real-time processing of the depth data. Upon matching of the desired depth, the system issues a firing command to the friable perforating gun assembly. The latter simultaneously initiates the self-destruction of the tool. Thus, the tool is completely destroyed after perforating and the remaining debris fall to the bottom of the hole, where they could be left, flowed back to surface or removed during cleanup prior to tubing installation. The volume of debris is small and does not require drilling additional rat hole. The delivery of the tool is achieved by either gravity free-falling in low-angle wells or by pumping it downhole during hydraulic fracturing or any other pumping operation in high-angle or horizontal wells. An important part of the overall design is the safety system built into the tool to make the system as safe as, or safer than currently used perforating practices.