Downhole Fiber-Optic Multiphase Flowmeter: Field Installation

Abstract

Abstract In October of 2000, a downhole fiber optic flowmeter was installed in Shell's Mars A-18 well in deepwater Gulf of Mexico. The production tubing-deployed system was installed to a measured depth of 21,138 feet in a highly deviated section of the well, immediately above the producing zones, in 2940 feet of water. This installation represents the first allfiber optic, multiphase flowmeter system deployed in a commercial well. The fiber optic flowmeter delivers real-time measurements of downhole pressure, temperature, flow rate, and phase fraction. It is completely non-intrusive and contains no downhole electronics or moving parts. The meter requires only one wellhead penetration and is deployed on a single fiber optic cable with the production tubing string during well completion, in a manner similar to conventional, electronic downhole monitoring systems. Installation of the flowmeter at Mars was achieved as planned with no additional rig time required. In fact, the entire well completion operation was finished ahead of the budgeted schedule. This in large part is attributable to pre-job planning and preparations for the entire operation. Performance of the flowmeter at Mars exceeded expectations and demonstrates the value of real-time downhole production data. Along with providing the production engineer with downhole pressure and flow rate data to control draw down while the well was being ramped up, data from the flowmeter provided other valuable information such as a temperature and pressure profile of the well during run-in-hole, well behavior during cleanup, and well productivity data.