Bidirectional Subsurface Mechanically Actuated Barrier Valve and Shifting Tool (s) Provide Superior Control and Reliability for Multistage Completions (2011)

Abstract With the availability of increasingly complex completion designs, operators are continually seeking more efficient methods to run completions equipment in multiple stages with added safety and reliability. Specifically, for applications using electrical submersible pumps (ESPs), operators need an efficient and reliable solution to prevent fluid loss when installing and pulling the upper completion. With recent advancements in barrier valve technology, operators can realize savings for their completions systems. Typically, when the upper completion is pulled, the closure mechanism is closed and the manipulation tool is disengaged simultaneously. The upper completion string can then be run back in until the manipulation tool re-engages the mechanical barrier valve and shifts the valve back open so that well production or other work can continue. This paper discusses a new mechanically actuated barrier valve and associated manipulation tools available for use in ESP completions. A relatively new, but field-proven, closure mechanism design, capable of bidirectional sealing, can save valuable rig time when used with specially designed mechanical manipulation tools to open or close the valve. These manipulation tools allow for closing of the valve while leaving the tool engaged into the valve. The operator can then apply pressure to the tubing or annulus to test the valve or other components, eliminating additional runs and saving rig time. A staged-release feature prevents overloading of the actuating components in the event of an installation problem. A hydraulic shifting tool option allows for valve control from the surface for testing and well operations. Design and operation considerations as well as associated manipulation tools will be presented and analyzed. Furthermore, qualification testing performed with respect to the new ISO 28781 standard for subsurface barrier valves will be discussed. Test results will demonstrate the capabilities of the tools combined with varying, yet simple and reliable, running methods. Introduction and Background Electric submersible pumps (ESPs) have evolved over the decades and are more reliable than ever, however, due to the nature of rotating equipment and harsh downhole conditions, ESPs must be pulled several times during the life of the well for maintenance. During this intervention process, the conventional method of well control is to utilize heavy weight kill fluids. This is a simple method of well control, but presents the challenge of safely controlling the well without losing fluids to the reservoir. Fluid losses to the formation can damage the reservoir decreasing oil production and increasing intervention expense necessary to recondition the well and replace lost kill fluids. The industry has responded to the fluid loss dilemma by incorporating mechanically actuated valves. These mechanical actuated valve solutions include shrouded sliding sleeve designs, check valves, flapper valve designs, and ball valve designs. All of these solutions incorporate a mechanical closure mechanism that controls fluid loss; however, the ball closure mechanism presents the most flexibility as it provides several key attributes desired by operators including the capability of multiple cycles, bi-directional sealing, through bore access, and debris tolerance.