The Evolution of Riserless Wireline Subsea Intervention in Deepwater Gulf of Mexico, Doing More with Less

Riserless Light Well Interventions (RLWI) were conducted within the niche deepwater subsea environment of the Gulf of Mexico (GoM). The drivers for RLWI were mainly cost reduction and acceleration of intervention scopes, to ultimately improve well-productivity and prevent production deferrals. The RLWI operations discussed here focus on Miocene aged horizons in three assets: one high-pressure high-temperature asset completed with 15,000-psi equipment and vertical subsea trees (VXT) - asset 1, another asset completed with 10,000-psi equipment and horizontal subsea trees (HXT) - asset 2, and a third asset completed with both 10,000 psi and 15,000 psi equipment with both vertical and horizontal trees -asset 3. These assets are operated in water depths ranging from 5,400-ft to 6,800-ft respectively. For all three assets, RLWI was facilitated using a well control package (WCP) deployed onto the VXT or HXT, along with an auxiliary umbilical assembly (AUA), which provided the hydraulic control capability for the barrier valves/rams on the WCP. The umbilical hydraulic supply was located on the RLWI vessel (Fig. 1).