The Use of Expandable Tubular Technology to Enhance Reservoir Management and Maintain Integrity

Abstract

In mature fields, particularly in waterflood operations, well bore maintenance and waterflood effectiveness are critical issues. Many problems can occur over the lifetime of a well that can inhibit the flood performance and create severe maintenance challenges: Some common examples of problems associated with injection wells are:Thief zones developing which take most of the injected water and which resist remediation by squeeze cementing.Heavily corroded areas of the casing string.Changes in the casing profile, such as ovalling, which can create tight spots and hinder remedial work. Conventional "patch" techniques, when applied to these situations, can result in greatly reduced thru-bores inhibiting access and restricting flow to lower zones. A solution to these problems can be provided by the use of expandable tubular technology. In a recent field trial program, a 20 year-old water injection well in the Ventura Field in California was selected for a test of the technology. This well was chosen as it exhibited all of the above problems. A 250 feet section of 5.7" running OD expandable casing, with integral expandable hanger, was run inside 7" casing and expanded across the desired interval. The expansion was accomplished by use of a compliant rotary expansion tool. This expansion system allowed the expanded clad to conform to the irregular contouring of the corroded and ovalled casing thus enabling competent anchoring, clad to casing sealing, maximum reinforcement of the damaged section and a large thru-bore to the lower perforations. Subsequent injection logs indicated that the injected water was once again entering the desired zones both above and below the clad. In this paper the authors will review the problems posed and present details of the planning and installation operations, particularly of the compliant rotary expansion system. They will continue with an analysis of the results achieved and conclude that expandable tubular technology is a powerful tool in remedial work for prolonging the life and improving the performance of mature wells. The Objective The subject well was drilled in 1981, and had been utilized as an injector for several years. The subject contained 1,300' of net perforations, from 4742' to 6577'. Injection surveys revealed that 79% of the injected water was entering a 26' section of the perforations located at 5562'. The remaining 21% of injection water was going into various perforations below the 26' thief zone. This injection profile greatly diminished the effectiveness of the sweep. Numerous attempts to cement squeeze the thief zone had been performed over several years, only to degrade, and allow the injection profile to revert back to the previous status. A remedial solution was required to permanently alter the injection profile. A number of conventional solutions exist which attempt to address this common problem. These include casing patches, scab-liners and retrievable straddles.

Beyond the Limits of Drilling and Completion—Expandables

“…Over the past several years, expandable liners have been widely used. 9 and cased-hole 10 applications. This section will only discuss some of the open-hole systems available and expound on the benefits of the open-hole cladthru-clad, "Steel Mudcake", as applied to addressing drilling hazards.…”

Versatile Expandables Technology for Casing Repair

“…[1][2][3][4][5][6] Previously documented expandables systems share a common trait of requiring full-length expansion from one end to the other of the tubular patch. This minimizes the annular gap between tubular patch and base casing thereby maximizing the resultant internal patch diameter.…”

Numerical and Experimental Study on Working Mechanics of Pear-Shaped Casing Swage

“…At present, scholars at home and abroad have done many studies in the field of casing failure, which mainly includes the studies about the mechanism of casing failure [8,9], casing failure detection technology [10], repair technologies [11][12][13][14][15] (such as grind press plastic technology, PCS technology, casing patch technology, and solid expandable tubular technology), and preventive measures [16].…”