A rank exploration well drilled in Southwest Louisiana recently with Managed Pressure Drilling (MPD) techniques reached new operating levels for depth, pressure, and temperature. The exploration well reached a total depth of 29,426 ft at a maximum bottomhole pressure (BHP) and temperature of ~30,000 psi and ~500° F, respectively.
Below 15,000 feet, the increased solubility of gas posed a particularly difficult risk for kick detection. The need for precise kick detection was magnified further by the uncertain magnitude of the pore pressure, the reduced kick tolerance, and well conditions conducive to swabbing during tripping operations. Managed pressure drilling techniques were employed to mitigate these risks.
This paper will describe the processes that were used to identify the functional requirements and limitations of the MPD equipment that was selected to achieve the well objectives. The MPD process flow paths were designed early in the planning phase of the project to minimize any potential misapplication of MPD techniques during the execution phase. The paper will also include a description of the substructure vertical space limits that are created when installing MPD equipment. These designs were also completed in the early planning phase because the stack-height design defines the substructure spacing requirements, which can have a significant impact on rig selection and substructure requirement.
The case history presented in this paper will document:
The successful early detection of influxes of less than 3 barrels
The implementation of managed pressure stripping procedures that resulted in increased tripping speeds
The application of MPD techniques that reduced the time spent circulating and managing gas at surface
The above actions saved ample amounts of rig time in each of these areas. Additional MPD techniques were utilized to perform dynamic leak off and in-flow tests which yielded accurate data that will be used to refine earth models for possible future well applications. Key improvement opportunities were identified during the execution phase through daily communication meetings with the service provider, which were used to improve MPD plans, procedures, and reliability.