Sanford, John Robert, Eni Petroleum, Cordeddu, Cristina, Eni Petroleum Co. Inc., Edwards, William, Goldking Production Company, Baccigalopi, Glenn David, BJ Services Company
Typically, deepwater subsea completions are characterized by significant production rates which require large completion hardware. Slim-hole designs (defined as 5½" production casing and smaller) are usually avoided due to increased risk and production concerns.
However, as the deepwater Gulf of Mexico basins grow more mature, sidetracks and challenging new drills become frequent. Sidetracks out of 7¾" to 7" production casing are being performed, ending with 5½" or 5" casing at TD. Additionally, many new drills either have to penetrate multiple depleted intervals or require more aggressive directional plans to reach smaller targets. Both scenarios can result in slim-hole designs.
Historically, the two (2) riskiest phases of the completion are wellbore displacement and sand control. This paper presents the design, the risk assessment, the installation and the actual results for three (3) subsea slim-hole deepwater completions. A summary of the completions are as follows:
As a result of proper planning, the Case Histories were successfully executed in Gulf of Mexico deepwater. However, performance expectations from these type wells must be risked and managed.