Publications

Gas production in the Mahakam field is sharply declining and this pushes the Oil Company to challenge the limit to produce more gas without overlooking well integrity. Gravel-pack (GP) is one of the sand control well completion methods used in the Mahakam Field to cope with sand production from shallow unconsolidated reservoirs. 119 oil and gas wells have been completed with gravel-pack completions, with 33% located on offshore production platforms while the rest are in swamp areas. The rule of thumb for operating these gravel-pack wells is to limit the pressure drop across the completion (drawdown) to 1000 psi. This approach has a negative impact in that it restricts production rates. In addition, some gravel-pack completion failures still occur at drawdowns < 1000 psi. This paper analyzes data from all gravel-pack wells (Oil & Gas) in the Mahakam Field, which suggests that drawdown limitation is not the optimum method to predict whether a sand control completion will fail or not. The authors proposes a new method called “Downhole Effluent Velocity limit”, based on the understanding that erosion of the gravel-pack screen is caused by fluid containing fines/particles flowing through the screen. Higher fluid velocities across the screen mean a higher risk of erosion. The new method was tested on four wells with drawdowns > 1000 psi but low flow velocity across the screen. These wells continued to operate with no screen failures with a gain of around 5 MMSCFD. Given the early success of the “Downhole Effluent Velocity limit” guideline, the authors plan to apply it to other wells.