Abstract
This paper describes challenges, test equipment, test program and results in the development of a screen product and contingency fluid-loss control (FLC) pill formulation to withstand 4,600-psi burst resistance pressure.
In maturing deepwater fields, such as Shell Ursa/Princess where depleted reservoir pressures are significantly below the hydrostatic pressure of a seawater column, a modified screen design was required since screen products currently available were limited to <3,500 psi. FLC pill formulations also required modification because they were only validated to 1,000 psi in the current laboratory test apparatus.
A series of burst tests were conducted on a wire-wrap screen design direct wrapped to 4-in. base pipe. The objective was to determine if the screen could withstand at least 4,600 psi without damage. The wire-wrap design selected to improve the pressure rating was substantially heavier than what has been used in traditional sand-control completions. Initial burst tests with available 316L material averaged 4,600 psi. Two sets of additional burst tests were conducted with Alloy 625 screens on 25 Chrome base pipe to meet injector material requirements. The FLC formulation was modified from conventional design to enhance the pressure response. The last test results averaged over 5,100 psi.
Comprehensive before and after measurements and slot inspections were done; the data were used in Finite Element Analysis to finalize the detailed screen design. No traditional mechanical burst of the screen occurred. Most influential factors were slot size/geometry and pill formulation.
