As the oil and gas industry has matured, three broad-reaching and long-standing issues that affect virtually every well have assumed heightened importance: conservation of hole size, hydraulic isolation of selected zones, and maximization of well life. All of these issues involve one of the industry's most fundamental technologies, wellbore tubulars. Until recently, resolving these issues with conventional tubular technology was becoming ever more difficult, especially in deep-drilling and extended-reach applications, in wells utilizing liner hangers, and in aging wells containing deteriorating casing. A revolutionary new technology—expandable tubulars—has recently been introduced and has successfully addressed these issues in commercial applications. The basic concept underlying expandable-tubular technology is simple: a mechanical expansion device, known as an expansion cone or mandrel, is propagated through downhole tubulars utilizing hydraulic pressure. The progress of the cone expands the tubulars to the desired internal and external diameters in a plastic deformation process known as cold drawing. In drilling applications, a specially-designed liner hanger utilizing the new expandable-tubular technology conserves hole size by eliminating the need for a conventional liner hanger/liner hanger packer, and provides a superior pressure seal compared to the old technology. In cased wells, expandable casing is cladded to existing casing, either to repair or strengthen the existing casing, with minimal decrease in wellbore inside diameter (ID) and flow potential. Expandable tubular solutions have been successfully installed in the Gulf of Mexico, in U.S. inland wells, as well as in large-scale field trials. This paper briefly describes the technical concepts upon which expandable tubulars are based and gives an overview of expandable-tubular applications. The paper then focuses on the most recent field installations, including systems installed during the first quarter of 2000. Discussions of field examples will contain customer objectives, job design, installation procedures, ultimate results and best practices learned. Technology Overview Previously published papers have discussed the concepts of Solid Expandable Tubular (SET) technology1 and the effect of the expansion process on the system's tubulars2,3 and connectors4. In this light, the basics of SET technology will be reviewed, and the emphasis will be on how to best apply the early products of this new technology. Through the review of several case histories, it will be demonstrated how Solid Expandable Tubular products were used to cut drilling costs, to rejuvenate plug-and-abandon (P&A) candidates, and to bring more exploration and development dollars to the bottom line. The Expansion System Operation The underlying concept of expandable casing is cold working steel tubulars to the required size downhole - a process that is mechanically very unstable by its nature. Thus, there are many technical and operational hurdles to overcome when taking cold drawing processes and accomplishing them in a downhole environment. The Expansion System Operation The underlying concept of expandable casing is cold working steel tubulars to the required size downhole - a process that is mechanically very unstable by its nature. Thus, there are many technical and operational hurdles to overcome when taking cold drawing processes and accomplishing them in a downhole environment.

Solid expandable tubulars have been used to assist in the success and slimming of deepwater wellbores over the past two years. The expandable openhole liner system expands and seals the outside diameter of an expandable casing against the inside diameter of a string of conventionally set casing, thus slimming the wellbore compared to conventionally cased wellbores. Further slimming of wellbores was realized with the capability of expanding and sealing sequentially installed expandable casing strings, or "nested" expandable liners. This procedure decreases reduction of a typical hole size by approximately 50%. Nesting was the next step in the evolution of creating a monodiameter system, that is, a wellbore that has the same inside diameter from surface to total depth (TD). The first nesting of two expanded casings in a well was successfully completed in a drilling application in the Summer of 2001, a milestone toward creation of the monodiameter wellbore. Using nested expandable systems facilitates the employment of smaller, more economical drilling vessels to drill deepwater wells (wells drilled in water depths of 1,500 to 10,000 ft). The monodiameter system is created when the junctions of the nested expanded casing liners are "over-expanded, resulting in a single internal diameter (ID) wellbore. This type of well exhibits the ultimate diametric efficiencies" a constant ID from the top of the well to its TD. The first monodiameter "over-expanded" sealed liner overlap was produced in the lab in late 2000, opening the door for the creation of the monodiameter drill liner, followed by the production-quality monodiameter liner system. This paper reviews the evolutionary steps taken to date toward the realization of true monodiameter technology and discusses the installations that have served as milestones. This paper also discusses the potential savings realized when wellbores are slimmed using expandable systems, combined with more economic drilling vessels and the associated reduced spread-rates. Technical Evolution Solid expandable tubular technology essentially changes how to install the main load-carrying member around which all well designs are built, namely, the casing. The monodiameter system became a feasible idea with the advent of successfully expanding solid tubulars. This revolutionary concept was proven with the successful expansion of solid tubulars (initially automotive steel) by forcing an expansion cone through the tubular with hydraulic pressure and expanding it ?20%. After demonstrating conceptual proof, attention turned to refining the existing materials to address specific downhole conditions. These developments consisted of replicating desired automotive steel properties in Oil Country Tubular Goods (OCTG), changing the cone material makeup from a combination of ceramic and steel to one of all steel, and replacing welded connections with specially threaded, expandable connections. L-80 casing was developed with exceptional fracture toughness in order to achieve consistent success of expansion without pipe body failure.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMaximizing hole conservation while optimizing well economics in both conventional and deepwater wells is a continual challenge. Addressing these challenges with new technology has provided some significant solutions, but the uncertainty when utilizing new technology with no proven track record must be risk-weighted.Solid Expandable Tubulars (SETs) have been installed in both openhole and cased-hole wellbores from November of 1999, in a variety of environments in wells on land, offshore and in deepwater to solve a range of drilling and completion challenges.This paper will discuss the drilling case histories in depth including:• Descriptions of drilling challenges surrounding the use of SETs and their next best alternatives

Initial liner top integrity is a primary concern for most operators. If the liner top fails routine or regulatory integrity tests, expensive and time-consuming remedial operations increase direct costs for equipment and services. This remediation delays well completion, which ultimately delays revenue generation. These expenses often exceed the initial cost of the liner equipment. Liner top failure continues to challenge the industry despite improvements in integrally run liner top packers, special cements, and cementing pratices. Even newer generation liner top packers, run either integrally with the liner hanger or as a second trip packer, have multiple sealing surfaces that must function under rigorous conditions to achieve liner top isolation. The expandable liner hanger has been developed and successfully field-tested as an alternative to conventional "cone and slip" liner hangers and liner top isolation packer systems. The expandable liner hanger combines the functions of the liner hanger and the isolation packer into a single component. The expandable liner hanger uses elastomeric "bands" to provide the axial load capacity of a conventional liner hanger and the annular sealing capability of the liner top isolation packer. The expandable liner hanger is expanded hydraulically with the liner running/setting tool assembly. During expansion, the elastomeric bands are compressed into contact with the ID of the supporting/intermediate casing, virtually eliminating the annular space between the liner hanger and the casing. This paper discusses expandable liner hanger design criteria and testing undertaken to qualify the expandable liner hanger as a reliable liner top isolation system. Initial field installations and the lessons learned are also discussed. Introduction The importance of the liner-casing overlap is illustrated by the efforts and expense taken by operators to ensure hydraulic integrity of the overlap. Typical methods of achieving pressure integrity include the following:Cement "squeezes," including a liner top packer as a component of the initial liner hanger settingOne or more "second-trip" liner top isolation packers installed to control gas migration at the liner top The typical liner top is complex in its design (Fig. 1) and can develop leaks due to a myriad of causes1. A recent informal survey of several GOM operators revealed that 30 to 50% of pressure seals in overlaps fail. One operator made a concerted effort to improve liner running and cementing procedures. Data gathered over an 18-month period was used to shed light on possible causes of overlap failure by gathering information on liner/casing sizes, types of equipment, overlap length, mud data, annular cross section, equipment, and service suppliers. The study concluded the chances of having a liner overlap seal failure did not depend on any single factor and the chances for an incident were nearly the same regardless of the factors associated with any given well2.

Maximizing hole conservation while optimizing well economics in both conventional and deepwater wells is a continual challenge. Addressing these challenges with new technology has provided some significant solutions, but the uncertainty when utilizing new technology with no proven track record must be risk-weighted. Solid Expandable Tubulars (SETs) have been installed in both openhole and cased-hole wellbores from November of 1999, in a variety of environments in wells on land, offshore and in deepwater to solve a range of drilling and completion challenges. This paper will discuss the drilling case histories in depth including:Descriptions of drilling challenges surrounding the use of SETs and their next best alternativesRisk analysis leading to the use of SETsDiscussion of the advantages and disadvantages of using SETsOperational lessons learned during installations of SETs Technology Overview Previously published papers and articles have discussed the concepts of Solid Expandable Tubular technology1 and the effect of the expansion process on the system's tubulars2,3 and connectors4. In this paper, the basics of SET technology will be briefly reviewed, emphasizing how the early products of this new technology have been applied in the drilling environment. Presentation of several case histories will demonstrate that Solid Expandable Tubular products can provide additional tools for the drilling "tool box", ultimately cutting drilling costs and bringing more dollars to the bottom line. As of this writing, 15 jobs have been performed, of which three were unsuccessful. Since learnings often are the results of problems, heavy emphasis will be placed on problems and the lessons learned. The Expansion System. The underlying concept of expandable casing is cold-working steel tubulars to the required size downhole - a process that, by its nature, is very unstable mechanically. Thus, there are many technical and operational hurdles to overcome when using cold-drawing processes in a downhole environment. An expansion cone, or mandrel, is used to permanently mechanically deform the pipe (Fig. 1). The cone is moved, or propagated, through the tubular by a differential hydraulic pressure across the cone itself and/or by a direct mechanical pull or push force. The differential pressure is pumped through an inner-string connected to the cone, and the mechanical force is applied by either raising or lowering the inner-string (Fig. 2). The progress of the cone through the tubular deforms the steel beyond its elastic limit into the plastic region, while keeping stresses below ultimate yield (Fig. 3). Expansions greater than 20 percent, based on the inside diameter of the pipe, have been accomplished. However, most applications using 4–1/4 inch to 13–3/8 inch tubulars have required expansions less than 20 percent.