High-Profile Rigless Well Interventions with Coiled Tubing Tower

Abstract

Many wellbore recompletion and recommissioning operations requires a post-drilling well interventions without a drilling rig because a rig is either unavailable or uneconomical. Rigless operations are very relevant for the well interventions performed in one of the most challenging offshore development projects in the northern Caspian basin. These complex jobs are heavily impacted by extreme climate conditions, confined offshore installations, and strict safety regulations. To overcome these challenges and to minimize operational risks, a rigless well intervention approach was selected with a specially designed multipurpose coiled cubing (CT) support tower that can perform a wide range of service operations with a unified well rigup. All the services can be kept under a single operational umbrella with a smaller crew, and a common base pattern erected around the well can be transferred to the next service line without major modifications. Several innovative ideas were implemented to fulfill the offshore and operational requirements: A special base section of the tower with telescopic legs fits on the narrow working pad around the well and keeps permanent structures and service manifolds around the wellhead area intact.A specially designed CT tower skid system with a three-axes moving jacking frame on top includes a rotary table to allow the injector head to revolve into the required position. This paper describes the success story of complex rigless well interventions using a newly designed multipurpose CT tower. The provided solution is proved to be more cost effective for the same applications as a drilling rig, and effectively reduced the necessary crew size and equipment footprint. This solution is designed for effective and safe operation in diverse environments, and can be customized to accommodate new solutions that would be and technologies developed in the future.