Riserless Light Well Intervention Multi-Well Hydraulic Stimulation Campaign via Subsea Production Manifold Access Point in Deepwater Gulf of America

Abstract Hydraulic stimulation intervention cost reduction initiatives over the past four years have allowed more frequent economical deepwater interventions in the Gulf of America (GoA). In February 2025, a five well hydraulic stimulation campaign was launched, which significantly reduced intervention costs by accessing all five wells through a single access point on the subsea production manifold. The project was a GoA deepwater hydraulic stimulation intervention first due to utilizing Thermoplastic Composite Pipe (TCP) jumpers and elimination of the intervention package stack hopping constraint. Simultaneous Operations (SIMOPS) restrictions between a Mobile Offshore Drilling Unit (MODU) conducting a multi-year program at the drill center prevented vertical access to the wells by the Riserless Light Well Intervention (RLWI) vessel. However, the procurement and installation of High Collapse Resistant (HCR) Well Service Jumpers (WSJ) made of TCP and additional subsea hardware provided sufficient separation between the vessel thus alleviating the SIMOPS restrictions. bp worked with two main subsea vendors for procurement, fabrication, and modifications of the subsea hardware system. Furthermore, to gain access at a single point on the subsea production manifold hub, a modified Long Term Intervention Pressure Cap (LTIPC) was installed at an unutilized slot on the production manifold to provide pump through capability. The LTIPC contained two gate valves which provided dual barrier isolation to the environment. A construction vessel was used to install and commission the WSJ and associated subsea hardware. This equipment preinstallation allowed the RLWI vessel to mobilize directly to the predetermined asset offset location, deploy the Riserless Hydraulic Pumping Package (RHPP), connect Coiled Tubing (CT) downlines, and begin subsea RHPP regulatory testing. The execution of all five wells was successful with no recorded non-productive time attributed to the installed subsea equipment during the 14 day campaign. The functionality of a designated single subsea production manifold tie-in point proved that future field-specific hydraulic interventions are feasible while the MODU is over the asset drill center without compromising rig schedules and cost.