Optimization of Big-Bore High Pressure High Temperature (HPHT) Wells in Low Pressure Reservoir

Since initial production in early 1990s, the Alpha gas field has been experiencing
significant pressure decline. The pressure decline had started to affect the performance
of the field; reduced in overall gas production. Subsequently, the extensive pressure
decline had caused several wells to collapse due to formation subsidence. The project
focused to determine the suitable completion design and casing program for optimum
gas recovery from the low pressure environment. The project utilized WellFlo
simulation program to compare and analyze the results. Among the identified designs to
be simulated are; (1) 10 inch Tubingless Completion (2) Conventional 9-5/8 inch Tubing
and (3) Tapered 9-5/8 x 7-5/8 inch Tubing design. The selected design must be able to
yield significant increase in gas recovery, extending the producing life of the field and
adequate Zonal Isolation to prevent well failure. The 10 inch Tubing1ess Completion had
met the required parameters and was selected as the suitable design for the project. The
10 inch Tubing1ess Completion increased gas recovery by 23.15 Percent (%) and
extended the producing life of the field up to 16.8 years. In addition, the 7 inch Drill-in
Liner provided improved Zonal Isolation between the producing Limestone layer and
overlaying Shale structure.