Foam Recompletion of High-Angle, Low-Pressure Dry Gas Wells, Offshore Louisiana

Abstract

ABSTRACT Planning and executing recompletions in low pressure reservoirs (less than 4 lbm/gal equivalent) present operators with several challenging conditions. These include the necessity to protect against formation damage and fluid loss when using low density brines and well control when using foam as the completion fluid. Low density brines can be effectively used for workover operations in wells to be recompleted in a low pressure reservoir. However, because of the overbalanced condition that exists during workover operations, fluid loss must be controlled by spotting lost circulation pills. These pills can contribute to formation damage and can also affect the gravel placement unless they are effectively removed during the workover operation. In contrast, the formation can be more effectively protected by taking advantage of the low fluid leak-off characteristics and near-balanced pressure when a foam system of the required quality is used as the workover fluid. A workover program using foam as the workover fluid on wells completed in a low pressure, dry gas reservoir (3.5 lbm/gal equivalent) was conducted offshore Louisiana. This program included cleaning sand from the tubing and/or casing below the packer, reperforating and gravel packing. A conventional foam system was used for cleaning the sand, and a stable foam system was used for well control. The gravel placement was accomplished with a Xanthan polymer system. This paper will summarize the operational aspects related to the use of foam, the gravel packing operations and the production results after recompletion.