One-Trip Completion System Eliminates Perforations

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 101086, "One-Trip Sand-Control/Liner-Hanger/ Big-Bore Completion System," by C.R. Hoffman, SPE, Baker Oil Tools, prepared for the 2006 SPE Asia Pacific Oil & Gas Conference and Exhibition, Adelaide, Australia, 11–13 September. A new completion system replaces conventional tubing-conveyed perforating (TCP) and gravel packing. This technology also eliminates formation damage caused by perforating and reduces skin values. It is a new-generation, screenless-sand-control completion system. A telescoping conduit containing sand-control media composed of stainless-steel beads was chosen for its durability and erosion and plugging resistance. The system contains no explosives, eliminating many issues. Introduction A joint-investment project team consisting of three major operators, a service company, and an independent tool manufacturer was formed and charged with the task of developing a system that eliminated formation damage and greatly reduced skin values. Conventional perforating is a major cause of formation damage, so the primary goal was to eliminate perforations and still achieve connectivity with virgin reservoirs and maintain full-bore production and/or injection rates. Also, one-trip capability and user-friendliness were of primary concern; if this system were to cost operators more throughout the completion of a given well, it would have no merit in the marketplace. Therefore, the system was designed around conventional liner and cementing techniques. Purpose Fractured and compacted zones, perforation debris, and formation blockages are common types of damage that can occur in a conventional-perforation tunnel. Case histories have proved that skin values are significantly increased over the life of a well as a result of perforation-tunnel depth and fines that accumulate or are never properly cleaned from these tunnels. Studies have shown that for a 7½-in.-deep perforation tunnel, there may be as much as 60 lbm/ft of debris that must be cleaned from the wellbore. By design, this new technology addresses these factors affecting well productivity. The new technology had to satisfy the following criteria: one-trip deployment, primary cementing of casing tubulars, connectivity to a virgin reservoir, and sand control, all while maintaining cost effectiveness. One-trip installations reduce rig costs greatly. This new technology also addresses some of the problems associated with conventional cased-hole gravel packs such as incomplete perforation packing, voids in the annular pack, and poor communication with the reservoir. Drilling the New Well Use of a calcium-carbonate-based drill-in fluid while drilling the production or injection interval is quite common today. A manganese weighting agent may be used in these fluids to increase fluid density. The carbonate-based fluids provide a very thin, very uniform filter cake on the wellbore wall, providing stability to sensitive and unconsolidated formations. Also, the carbonate particles are acid soluble. This is imperative for this new system because when the telescoping conduits extend and contact the wellbore, a small amount of this material may be trapped on the face. With a barite-based mud there would be no way to remove this obstruction because barite is inert.