Solving Well Construction Challenges Without Downsizing the Well, Using Solid Expandable Liners

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn the pursuit of profitable well construction, operators are challenged to drill cost-effective wells while being prepared for the unexpected. Flows, lost zones, sloughing shales, and over-pressured zones are typical examples of unplanned well events that occur while drilling through troublesome formations.Using conventional remedial methods, such as drilling fluid additives or lost-circulation pills, can prolong nonproductive periods and dramatically increase drilling costs. Setting a drilling liner earlier than planned creates the risk of introducing an expensive sidetrack or losing the well altogether.Solid expandable casing solutions, applied historically as a last-resort effort to save the hole section or even the well, typically carry with them a reduction of hole size, while the use of cement in conjunction with expandable slotted products has been used successfully without loss of hole size; however, for the most severe challenges, solid expandable products are needed.This paper describes an alternative solid expandable liner system that can address a wide variety of well construction challenges without the need for downsizing a well section.Openhole expandable "full-bore" liners that use proven cement-less formation-to-casing sealing elements can be used to address troublesome formations during drilling operations, allowing continued drilling of the well with the same size bit post remediation. Additional expandable openhole full-bore liners can be installed below the first if other trouble formations are encountered.Typically, these solid expandable full-bore liners need only remediate short wellbore sections and therefore can become very cost efficient compared to long solid expandable liners. The tiedback expandable openhole liner (OHL), which must be tied back to the previous casing string, dictates that the next hole section be reduced in size. Applying these fullbore systems immediately on encountering well challenges can significantly reduce the flat time on the drilling curve.The monobore well is under development, but the expandable full-bore system could be commercially available in the near term. This new openhole wellbore remediation tool can offer immediate and significant financial benefits to well construction. As a contingency solution, the system can be used to downsize wells, reducing well construction costs at the well or field level.

Research on the Optimum Velocity of Expansion Cone in Solid Expandable Tubular Technology

“…At home and abroad in recent years expandable tubular technology has been successfully applied in drilling engineering, well completion, workover and other fields [2][3][4][5][6][7].…”