Sandface Completion for a Shallow Laminated Gas Pay With High Fines Content

Abstract

Summary The Shallow Clastics field operated by Sarawak Shell primarily targets two shallow gas-bearing reservoirs, H1 and H2, at approximately 2,650 ft true vertical depth (TVD). An appraisal, early-producer well was drilled with a deviated wellbore through the H1/H2 targets, and a completion design consisting of a cased, perforated, and commingled completion inside 9⅝-in. casing was implemented. The sandface-completion design consisted of a large-outside-diameter (OD) expandable sand screen with a 150 μ-weave opening across the two zones. Upon completion, the reservoirs were cleaned up through a temporary well-cleanup and test-facility to test productivity and evaluate the integrity of the downhole sand-exclusion installation. Fines production, possibly caused by a failure of the expandable screens, steadily increased to the extent that the well was deemed unproducible to the facilities. A re-evaluation of the sand-exclusion method that included more extensive core analysis and the types of wells that would be suitable for development of the H1/H2 reservoirs was initiated. From this review, the operator and a service/engineering company were able to develop an innovative sand-exclusion method that combined several new technologies. To date, four wells have been completed with the new sand-exclusion method and well configuration chosen to address the completion needs. These have been tested and, to date, have proved to be operating satisfactorily. This paper will review the evaluation that led to the revised sandface-completion design, the field implementation of the design, and the key installation success factors that were required. Results and a summary of best practices from the initial installations also will be summarized.