TTSS Retrieval via Coil Tubing Deployment Method in Sarawak Waters

Abstract This paper delves into the operational hurdles encountered during coil tubing operations within a specific field in Sarawak, Malaysia. Focused primarily on the sand clean-out process and the challenge of retrieving a lengthy Through-Tubing Sand Screen (TTSS), this paper presents practical solution through the utilization of the coil tubing deployment method. This paper comprehensively outlines the operational techniques used by the project team during the coil tubing sand clean-out operation and the TTSS retrieval via coil tubing deployment. The project design process, involving evaluation of methods and equipment suitable for this operation, is also discussed in this paper. The success of this project proves that a combination of efficient choices, with the utilization of coiled tubing for cleanout, and collaborative work between coiled tubing and other service providers for the TTSS retrieval, can be implemented for retrieval of lengthy downhole accessories. Sand production has become one of the most difficult challenges for mature oil fields, adversely affecting well deliverability and potentially contributing to well shut-in and surface equipment failure. Offshore facilities are not typically designed to handle sand long-term, resulting in well closures when sand production becomes excessive. Various efforts can be implemented to enhance the sand handling capacity or minimize sand exposure to surface, among them is by installing a Through-Tubing sand screen (TTSS). TTSS is easy to install, and its low-cost wireline operation makes it one of the preferred choices to address sand issues. This method, however, requires periodic maintenance and replacement to remain efficient. Excessive sand production caused by failures in both primary and remedial sand control measures eventually leads to the accumulation of sand within the production tubing. A longer TTSS can be installed to increase the longevity and durability of the TTSS. However, installation of long accessories also presents a retrieval challenge. One solution as presented in this paper is to utilize the coil tubing to provide efficient cleaning of debris above the TTSS and sufficient jarring force to release TTSS from tubing. The retrieval of TTSS on surface, however, is limited by the stackup length afforded on surface to allow proper securing of well prior to retrieval. This challenge is overcome by implementing coiled tubing deployment method to secure TTSS on surface into coiled tubing stackup, isolate well from surface safely, and handing over to wireline for the full retrieval of tool above wellhead. The overall workflow of this project allows for the successful retrieval of the TTSS to surface and can be considered in mind when designing the installation and/or retrieval of other lengthy toolstring/downhole completions.