A working window of opportunity only presents itself from April to mid-September in the turbulent Atlantic waters off the northwest coast of Ireland. When this window opened in Spring 2006, Shell E&P Ireland Ltd began operations to evaluate newly acquired assets in the Corrib field dry-gas subsea development. Prior to acquisition, five wells had been placed in suspension, pending construction of the necessary subsea and onshore infrastructure. Shell had previously determined that only three wells were viable candidates for completion during the current season and commenced operations when the S711 semi-submersible arrived on location in April. The clock started ticking on favorable weather and time quickly became a crucial constraint issue. The project hit a critical mark when a leak was discovered in the 9–5/8 in. production casing on one of the early wells entered. With time running out, Shell approached Enventure to engineer a practical solution that was required within a period of six weeks. Possible solutions for recovery were identified and analyzed before the project management team decided on using solid expandable technology. The solution for this well needed to deliver a production casing string that effectively sealed off the hole. To accomplish this requirement with expandable tubulars, Shell decided to use the Enventure system elastomers for the gas-tight integrity, which required qualification. In approximately six weeks, Enventure and Shell planned and implemented the appropriate tests, coordinated logistical maneuvers to expedite expansions to create the test specimen for qualification and successfully installed the actual system in the production well. This paper will discuss the process used to bring the project to fruition within a tight timeframe. Details will include issues considered, ramifications of possible options, challenges of the operating conditions and circumstances and content and results of the qualification program. This paper will also discuss the philosophical approach of generating a workflow to successfully achieve the stated goals in a short amount of time. Introduction In June 2006, Shell encountered a leak in the 9–5/8 in. production casing in one of its West Atlantic, deepwater subsea wells. The dry gas well is capable of producing in excess of 100 million standard cubic feet per day. The leak, identified after taking the well out of suspension, disappointed the project team as progress to run completion and ultimately put the well in production came to an abrupt halt. After eliminating the possibility of it being in the liner lap, the leak was chased to approximately 1,500m (~4,920 ft) using a DLT packer. In order to progress the campaign, Shell temporarily suspended the well to decide whether to attempt to regain integrity of the production casing or put the well in long term suspension for possible abandonment. After putting the well into suspension, management considered the following four options to address the situation:Abandon and re-drill the wellCut and pull the 9–5/8 in. casingUse a tie-back liner solutionInstall a solid expandable cased-hole liner system Because of time restrictions and the lack of equipment availability with three of the options, Shell chose the solid expandable tubular solution that could be tested, delivered and installed in the timeframe and provide the most robust engineering solution. Although Shell had decided on a definitive approach to the casing leak, several issues needed to be addressed before the solid expandable solution could be implemented. The elastomer technology on the expandable liner selected, specifically Enventure 's 7–5/8 x 9–5/8 in. solid expandable system, had been used in similar scenarios1,2,3,4 but was not qualified to Shell standards. Another issue identified was the lack of gas-tight connections for any expandable casing. Also, several load cases were outside the expandable envelope. Shell and Enventure personnel used innovative engineering to confront the obstacles and to successfully resolve the technical challenges.

A major Middle East Operator has adopted a new type of solid expandable tubular technology to isolate shallow aquifers as well as fractured formations. The technology is based on a steel wired balloon expanding a stainless steal into the well bore. The simplicity of the technology combined with a significantly increased expansion ratio has opened a whole range of new applications to materialize low cost wells. This paper will outline the two trial wells in which the technology was applied, review the benefits of expandable tubulars for these applications as well as looking in candidate selection. Particular emphasis is given on the Operator's experience with the technology. Isolation of shallow aquifers and fractured formations while drilling has been a major challenge for many years in Oman. The requirement for zonal isolation of the shallow aquifers is often compromised by the total losses encountered. Often a cocktail of chemicals followed by multiple cement jobs are used to achieve the objective. The latter can be costly not to mention the extra time incurred and HSE exposure. Also failure to isolate aquifers also increases the risk of cross flow between fractured formations what has been a significant contributor towards free water corrosion of the surface casing strings as well as subsequent issues referring to un-cemented casing strings in thermal wells. Inflating a sleeve into the formation has proved successful in terms of installation reliability, isolation of fractures and isolation of shallow aquifers. Well configuration based on expandable tubular solutions have improved well delivery times what is making this expandable technology a strong case for wells to be drilled in the coming years.

Drilling hard-rock sequences in northern Oman can present a number of distinct challenges. Operations are frequently hindered by formation breakout in rocks with high confined compressive strengths (15,000-50,000 psi). The problem is exacerbated by highly abrasive formations, extreme bottom hole temperatures (160-175C) and the subsequent deterioration of mud properties at vertical depths of approximately 4500-5500m. The main challenge is bit/bottom hole assembly (BHA) sticking while drilling a tectonically stressed sandstone formation. Formation breakouts that occur at or just above the bit can go unnoticed as drilling progresses and are the main sticking mechanisms responsible for turbine stall. The use of durable impregnated bits and motor/turbine BHA can increase drilling performance. However they bring an increased risk of leaving tools in hole (LIH) because the bit and driveshaft are able to rotate independently of the drillstring in a stuck bit event. A conventional motor/turbine has no reliable mechanism to transfer the available high torque from the drillstring to the bit, leaving axial force (pushing/pulling) as the only means to free a stuck bit/BHA. For this reason, the operator is exploring new technological solutions to reduce non productive time (NPT) associated with stuck events. A recent research and development effort has resulted in a new-style turbine, which in the event of stalling or bit sticking, locks the bit to the body of the drive-system so that drillstring torque can be applied to the bit. Transmission of drillstring torque to the bit significantly increases the chance of freeing a stuck bit/BHA. And instantaneous locking while rotary drilling can reduce the risk of becoming stuck by keeping the bit in motion should the turbine stall. During technology trials in 2010 BHAs in nine deep wells were successfully freed after several stuck events. The authors will provide a BHA schematic and the procedural details that contributed to the successful operations.