Proposal and Experimental Trials on an Autonomous Robot for Rigless Well Intervention

Abstract

Summary Well interventions, especially in offshore wells, are costly and usually very time-consuming to conduct. This is related mainly to the need for a rig or a similar unit to perform these operations. In this paper we propose the development of an autonomous robot for rigless well interventions. The robot will be inserted through the tree using a special tool. This proposal will result in significant cost reduction by eliminating the rig when performing light–workover operations in offshore locations. This reduces intervention time because a simpler unit might be used to deploy the robot. Examples of operations that could be performed by the robot are production logging, gas–lift valve replacement, sliding–sleeve opening and closing, and plug insertion or removal. To evaluate this proposal, a conceptual robot was designed. The feasibility of this conceptual robot was evaluated theoretically. After that, a simplified test robot was constructed to test critical aspects experimentally, in laboratories, and in a test well. The traction system, energy storage, and a positioning algorithm were evaluated. In this paper we will outline the intervention strategy proposed, perform a theoretical evaluation of this proposal on the basis of the conceptual robot, and present experimental results obtained with the simplified test robot.