Several criteria are important for a cementing operation as it relates to effective zonal isolation. First of all, studies have shown that cementing operations can be improved by rotating and reciprocating the liner. In addition, it has been shown that increased flow rates (prior to cementing, during cementing, and during displacement) can improve zonal isolation. While currently available expandable liner hanger technology can achieve the required liner movement, rotation, and reciprocation to affect a good cement job, these capabilities alone have not been capable of always meeting cementing needs in every scenario. When expandable liner hangers were introduced to the oilfield, they were immediately accepted. Experience has shown that increasing flow rates (prior to cementing, during cementing, and during displacement) can offer improved zonal isolation. A new liner hanger was designed to increase the annular flow area, subsequently reducing annular friction pressure to allow higher flow rates. The added bypass area would also provide reduced surge to the formation while running the liner. This would shorten liner installation times. In addition, by increasing the bypass area, the possibility of solids bridging at the liner hanger (which can cause loss of circulation during circulating and cementing) would also be reduced. When loss of circulation occurs, proper cement placement is jeopardized. This paper highlights the development of the new smaller-outside-diameter (OD) expandable liner hanger. This project was commenced; the new liner hanger has a pre-expansion maximum outside diameter that is smaller than the outside diameter of conventional liner hanger's tie-back receptacles and integral top-set packers. The new smaller diameter expandable liner hanger maintains the desirable features of existing expandable liner hanger. Computer modeling including Finite Element Modeling (FEA) will show the design analysis for the expandable liner hanger. Additionally, prototype testing will be performed to validate the new design. The new expandable liner hanger design offers the capabilities to rotate and reciprocate during circulating/cementing and displacing; a simple, robust design for installation reliability; and gas-tight liner-top sealing. Introduction An operator in the North Sea had been experiencing issues with zonal isolation due to poor quality cement jobs. The wells had been drilled into depleted reservoirs where the fracture gradients were very close to the formation pressures. One method sometimes used to increase the quality of the cement job is to increase the circulation rate during clean-up and cement placement. Because of the flow restrictions caused by the liner hangers in currently available designs, an increase in circulation rate would not be possible for this particular application without exceeding the fracture gradient in the well. To meet the needs of this project, the operator and service/engineering personnel felt that a new liner hanger that would allow increased circulation rates was needed. A review of the available liner hangers determined that the expandable liner hanger offered the cleanest flow path in its current design as well as it had the simplest design to modify. This provided a starting point for development of an expandable liner hanger that would address the operator's issues in this field development. Since it was recognized that this need was global, the new liner hanger would have application well beyond the North Sea projects, and thus, the design project was initiated.

TX 75083-3836, U.S.A., fax 1.972.952.9435. AbstractLiner hangers and liner-top packers traditionally have been used in liner completions. However, in the conventional systems that employ "cone and slip" technology, the failure rate of the liner top packers as well as the failure of system installation has been an ongoing problem. In conventional systems, mechanical equipment with multiple slips are run and set. The disadvantages of these systems include multiple leak paths, reduced radial clearance, and exposed hydraulic ports, all of which increase the potential for failure. When these failures occur, the cost of the well completion is significantly impacted, and well completion efficiency is decreased.Reasons for unsuccessful liner installations can be attributed to a number of conditions, such as:1. the liner cannot be run to depth 2. the liner hanger/packer pre-sets 3. the setting tool fails 4. the liner top cement job is poor. This paper will discuss an expandable liner system that was developed to address the shortcomings of the traditional systems. The new liner system combines expandable solid liner technology with proven cementing products and service capabilities.The following discussion will include details concerning development of the design, operating procedures, and benefits of the expandable liner hanger as well as how the versatility and adaptability of the system improves its reliability. Several case histories will be discussed to verify the efficiency of the new system.

TX 75083-3836, U.S.A., fax 1.972.952.9435. AbstractMany wells drilled today have complex well paths or are drilled through depleted or problem formations. In these wells, the liner may have to be reamed or drilled in, either to pass through the previously drilled hole or to make a new hole in the problematic formation. In many cases, the liner cannot be run to bottom as planned because unexpected problems are encountered. This situation can cost millions of dollars due to the required remedial work and deferral of production. This paper will discuss a rotary liner drilling application utilizing an expandable liner hanger in the Gulf of Mexico. The primary objectives of the trial were to develop a better understanding of the status of current technologies and how these apply to the challenges of this type of application. ProposalSignificant volumes of oil and gas remain undeveloped within producing fields as secondary objectives that require cost effective re-development. In recent times, it has become economically and technically feasible to access and produce these reserves through sidetracks of the original wells. These sidetracks may be completed as producing wells or water/gas injectors.Conventional methods require drilling through the reservoir, often inducing losses in the depleted interval, pulling out of the hole at a controlled rate, and then run the liner while experiencing losses. Furthermore, conventional liner running methods do not have the capability to rotate the liner while running in the hole, increasing the risk of being differentially stuck across a depleted sand. The ability to drill the liner in a rotary mode across the depleted sand can minimize the risk of losses associated with conventional practices while eliminating the need for a mud motor, which in turn allows the liner to be drilled at low flow rates with low associated equivalent circulating densities (ECD) 1,2 . Furthermore, it minimizes the amount of time that the formation is exposed, further reducing the risks of borehole collapse or trouble while running the liner to bottom. The expandable liner hanger allows hanging the liner and setting the element in one step, eliminating a potential cement squeeze job or an additional trip for a liner top packer.

Valuable lessons have been learned from the development of eight retrograde gas-production wells located in offshore Vietnam operated by the Korean National Oil Company. The intent of this paper is to share these lessons by presenting the concepts considered for well design, the selection process for the completion equipment and techniques, the preplanning for the installations, and the experiences encountered during the actual installations. The completion challenges included isolation of water production below the casing shoe and controlling condensate banking, sand production, and co-mingling multiple production zones in the long openhole sections. A different type of completion that involved an expandable liner hanger (ELH) with an external-sleeve inflatable packer collar (ESIPC) was chosen and installation and cementing were accomplished in a single trip. The ESIPC was deployed just below the water-producing zone, and cement was pumped up the annulus from the ESIPC to where the expandable liner hanger (ELH) was set above it. This would prevent water from entering the wellbore while enabling optimum production. To prove the concept, a stack-up test was done at surface before actual deployment on location to ensure that the cement wiper plugs would pass through the expandable-liner-hanger ball seat and that the concept would perform as intended. Swellable packers were selected from the various proven openhole isolation devices available to the industry to provide the zonal isolation required in the multi-zone intervals. This was the first openhole completion in Southeast Asia in a high-temperature, commingled gas environment in which isolation would be contained solely by swellable packers. Introduction The Rong Doi (RD) and Rong Doi Tay (RDT) gas fields are offshore in approximately 85m of water. They are approximately 300 km southeast of Vung Tau, Vietnam (Fig 1). This high-temperature reservoir (300ºF) is within the Mid-Miocene Dua formation from 3050 to 3900 m true vertical depth sub sea (TVDSS). The formation is an anticline with a four-way dip closure, split by three NNW-SSE sealing faults, and overlain by the Thong formation. Data from three offset wells; i.e., RD 1X drilled in 1994, RDT 1RX drilled in 1996, and RD 2X drilled in 1997, were available.

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