The challenges facing the exploration and subsequent production phase in the deepwater subsalt fields are extensive. The cost involved in deepwater E&P can get to a point where it isn´t financially atractive in terms of profit margins.
One of the big cost multipliers in this environment is related to well intervention. Bringing a rig or ship to do interventions demands a serious increase in expenditure, which is something that the players tend to avoid at, literally, all cost.
Some of the subsea service providers have come up with interesting solutions for this particular deepwater subsea challenge, and Schlumberger looks to be leading the pack in some crutial subsea areas.
Rigless subsea well intervention is the technology and methodology of reentering a subsea well to perform through-tubing work without a MODU, enabling coiled tubing, slickline, or wireline operations.
The addition of coiled tubing services and extension of water depth capability to 3,000 m offer added value at costs that are essentially the same as those for Open Water Wireline (OWWL) services deployed in shallow water depths today.
Schlumberger is introducing two complementary rigless subsea intervention methodologies.
Open Water Wireline (OWWL) and the Spoolable Compliant Guide (SCG), use common well control equipment accessible from a single vessel to create a step change reduction in the cost of a subsea well intervention.
Open Water Wireline (OWWL) enables slickline and electric-line operations services to be performed in subsea wells. This intervention technology has not been deployed in water depths greater than 500 m, much less the 3,000 m water depth the SLB system is designed to operate in. This systems also simplifies the subsea well intervention package control system and hydraulics necessary to maintain separation of the wellbore fluids from the environment.
The Spoolable Compliant Guide (SCG) enables slickline, electric line, and coiled tubing intervention services to be performed in subsea wells. Schlumberger can enable this service to water depths to 3,000 m. The patented SCG employs a flexible guide that connects a vessel to a subsea well control package. A wellbore seal protects the SCG from wellbore fluids and pressure. The guide provides motion compensation and enables injection forces from a surface coiled tubing injector to be transmitted from the vessel.
These two functions allow coiled tubing, electric line, and slickline services to be rigged up and run from the vessel as if they were rigged up and run on a dry tree well from a platform.
They are both innovative solutions that not only reduce overall intervention costs but also simplify the system. These new technologies appear to have great potential for use in the deepwater projects, subsalt or not in Brazil.
If we take into account the recent technological partnership between SLB and Technip, which is addmitedly targeting the subsalt fields in Brazil, then it seams quite probable that these methods will be used in Brazilian deepwater projects, if they are not already being used.
Photo courtesy of Schlumberger