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Proposal In an effort to increase production in the gas fields of East Texas, horizontal wells have become the standard, as they have in many regions worldwide. Many times the horizontal section is preceded with a drilling liner to cover the build section of the well and isolate weaker fracture gradient zones prior to penetrating the production interval. Previously, many operational challenges were encountered during liner installation, resulting in costly shoe and liner top remedial operations or the inability to reach the total depth of a hole section. Primary among the hurdles are successfully deploying the liner across the weaker zones and negotiating the hole angle. With the recent advancements made in the field of solid expandable tubular technology, several innovative products have developed from the core technology. One of these products is the expandable liner hanger. This product has been proven to greatly enhance liner operations in the well construction industry. Expandable liner hangers offer many novel features not available or applicable to conventional liner hangers. These features include radial geometry and a hanger / packer body construction with no moving parts. The primary benefits of this system are superior seal, improved installation reliability, and a significant reduction in time required to complete the installation and to resume drilling operations. These benefits and others derived from the features listed above will be discussed in detail in this paper including results from a recent case history in the Mossy Grove field of East Texas. Introduction Historically, many problems have been associated with the installation of a liner in oil and gas wells. As wells became more complex and tortuous due to drilling technology innovations, it became apparent that liner systems needed the ability to push, wash, and rotate to get the liner to the required setting depth. This has been accomplished with most modern types of liner hangers and setting tools to some degree, but at the expense of reliability. Conventional liner tops are prone to failure and an informal study performed in 1999 among operators in the Gulf of Mexico highlighted several problems associated with liner tops during the 18 months prior to the survey1(Fig. 1). Prevalent among the failure modes were:Liner top integrity - lap squeezesPacker/hanger/centralization issues - preset, or failure to setShoe integrity - shoe squeezes These results confirm earlier studies that identified the effort and expense that operators required to ensure liner top hydraulic integrity.2 Typical methods of achieving this integrity include:Multiple liner top squeezes after failed primary cementingOne or more "second trip" liner top isolation packers installed to ensure liner top hydraulic integrityTack and squeeze liner setting technique (tacking the shoe with cement and then intentionally squeezing the liner top without attempting to cover the liner top during the primary cementing job) Many failures are caused by the design of very complex liner hangers. Conventional hanger/packer slips and cones provide a lodging place for cuttings to build up. Two results of this build-up are increased equivalent circulating density (ECD) leading to lost circulation and preset of the hanger or packer mechanically as cuttings become wedged under the external components. Pipe movement during cementing operations is also limited with conventional designs, since the hangers are set prior to cementing the wells. This can lead to poor cementing practices and poor cementing results, especially at the shoe and the liner top, where cement assists with the hydraulic seal. Additional concerns arise when trying to work or ream the liner to setting depth in deviated holes where cuttings removal can be difficult. Both rotation and pump rates are limited with conventional equipment. Conventional "drill-in" liner hangers are set or released by applying a differential pressure across the hanger or setting tool. Running and rotation speeds are limited due to slip design and the use of conventional packer elements integral to these tools. This limits the ability to effectively clean the hole.

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Across the globe, liner casing strings are sometimes required. The installation process leads to a variety of challenges from both cementing and tools aspects. Among the challenges are proper isolation of both formation and liner lap, placement of the liner in the desired position, and associated operational time required to return to drilling operations. The use of the expandable liner hanger provides a way to better address each of these issues. Well conditions on the southeast Pinedale Anticline require drilling liners to be set at specific casing points to allow all of the productive strata to be penetrated. Because the strata behind the liner string is also gas productive and completed with multiple hydraulic-fracture stimulation treatments, proper isolation behind the liner is critical right up to the lap of the liner across the intermediate casing shoe. The mechanics of the expandable hanger system eliminate the potential for a premature set. The normal operating procedures require testing conventional liner tops and "dressing" cement left on top of the liner. These operations can require substantial investments of time and money. The new technology simplifies these processes and reduces the time required to return to drilling operations. The cases investigated in this paper have similar wellbore conditions, but were cemented using different methodologies. The first was isolated using a foamed-cementing process, while the second used conventional slurries. Both cases exhibited good isolation, good bond performance across formation and lap, and a faster, more simplified operation compared to conventional mechanical liner-hanger applications. Introduction The incidences of liner job failure have been well documented. In a recent survey conducted with three major operators who routinely set liners for both drilling and production purposes, the following problems were identified as recurring issues:Lap squeeze-leaky lapShoe squeezeStuck liner while running inWiper plug did not release or bump.Packer, hanger, centralization, premature set, or failure to setLost circulationCementing issues The most prevalent occurrences were the leaky lap, resulting in squeeze remediation attempts, and the packer/ hanger/centralization issues, which had a variety of ramifications. Each of these problem categories requires time and money to resolve. Expandable liner-hanger technology can alleviate many of these problems completely and help minimize many of the other issues (Fig. 1).1 This paper reviews two installation processes in southwest Wyoming. These two installations constituted the first such processes in the Rocky Mountain region. The wells presented a substantial number of challenges because this particular area exhibits many instances of lost circulation. Mud rheologies are adversely affected by CO2 present naturally in the producing strata, causing equivalent circulating density (ECD) issues. Many of the wellbores are deviated, fracture gradients and pore pressures are typically in a narrow window, and differential sticking can occur. These jobs use 7-in., 32-lb/ft and 7-in., 26-lb/ft drilling liners to cover potential pay and provide protection for further drilling operations. The use of this tool system minimized potential problems and reduced non-drilling time. Expandable Liner Hanger - The Tool The expandable liner-hanger (ELH) system incorporates the liner hanger body with an integral packer, tieback polished bore receptacle, setting sleeve assembly, and a crossover sub to connect the assembly to the packer. The expandable liner hanger/packer body contains no setting mechanism or external components such as slips, hydraulic cylinders, or pistons. The hydraulic setting mechanism is contained in the setting tool assembly and is completely retrieved, thus eliminating a potential leak path in the flow stream.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper presents laboratory and field data for using a settable spotting fluid (SSF) to help improve the subterranean zonal isolation of primary cement jobs on expandable liner installations. A SSF can add value to the well construction process when well conditions for cementing are less than optimal; i.e., low annular velocity, no pipe movement, poor casing centralization, or poor mud conditions. Many of these unfavorable conditions are present when expandable casing is installed.Past SSF designs used blast-furnace slag and were limited to temperatures less than 90°F (32°C). The new SSF incorporates a hydraulic material with a non-blast furnace slag and is formulated for water-or oil-based wellbore fluids. Although the new SSF is optimal for displacement in the cementing process, the SSF will set to a state for providing zonal isolation if it is bypassed during the cement displacement process. Depending on the time required to run and expand the casing, the SSF can be formulated to remain liquid for a few hours or as long as three weeks. However, the high pH condition and heat of hydration from the placed cement in the annulus can accelerate the set of the SSF to a few hours.The achievement of a near-100% annular seal occurs even when poor cementing conditions are present and without the use of rheologically tuned spacers. Job data from field trials also show improved shoe integrity and higher pipe-to-cement bond, echoing the results from the laboratory tests.