WELL CONTROL THE RISING EAST NOVEMBER/DECEMBER INTERNATIONAL ASSOCIATION OF DRILLING CONTRACTORS Drilling

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1 OFFC MGZN OF H NRNON SSOCON OF DRNG CONRCORS Drilling C O N R C O R NOVMBR/DCMBR 2013 D R W CONRO N G W W W. D R N G C O N R C O R. O R G C O M P xpanded containment system under development for GOM; study targets better prediction of pipe shearing characteristics p.57 O N S H RSNG S H M Big changes, big growth on the horizon for sia Pacific drilling landscape p.80

2 xpandable cased-hole liners assist integrated casing remediations conomical solution can provide long-term isolation to extend life of well, maximize injection rates while conserving hole size By uis Godoy, Weatherford fter multiple cement squeezes in a well in Malaysia failed to isolate a damaged casing section, it appeared that abandonment was likely. s with many aging wells around the world, the decision to restore this wellbore s integrity was based on economics. For this offshore well, the difficulty of achieving an effective cement job made the operation appear to be a futile effort. Other solutions, such as conventional liners or straddle packers, were not feasible because valuable hole size would be lost. o make the remediation effective, two goals had to be achieved. First, the cost of the repair had to be balanced by longterm isolation that significantly extends the well s life. Second, the solution had to Figure 1: xtended recovery supports the value of casing remediation through solid expandable liners.

3 ntegrated remediation by the numbers Malaysia: 69-ft expandable cased-hole liner installation conserved hole size with a 7.90-in. post-expansion D and in. drift. Successful isolation was confirmed with pressure test to 3,000 psi. raq: wo 7 5/ 8-in. x 9 5/ 8-in. expandable liners were installed ft lower perforation level was isolated with a ft liner. Upper 13.1-ft interval was isolated with 35.1-ft liner. New Mexico: 4 ¼-in. x 5 ½-in. expandable liner with a post-expanded length of 700 ft was installed in target interval at 5,000 ft. solation allowed new intervals to be fractured at 5,500 psi. maximize injection rates by conserving as much hole size as possible. nstead of abandoning the asset, the operator collaborated with Weatherford to deploy an integrated remediation system that allowed them to find the specific issue, prepare the wellbore prior to fixing the issue and recomplete the well to convert it to a water-alternating-gas injection well. his integrated remediation approach, which includes expandable cased-hole liners, is finding increasing favor across a range of global remediation applications. For the Malaysia well, installation of 69 ft of an expandable cased-hole liner provided a reliable, long-term means of restoring wellbore integrity with minimal loss of inside diameter. Performed on a single trip, the installation conserved hole size with a 7.90-in. post-expansion D and in. drift. Successful isolation of the problem section was confirmed with a post-installation pressure test to 3,000 psi. s a result, the injection well was restored to optimal service condition and given a new, long-term lease on life. global solution he economic and operational challenges and results from the Malaysian casing remediation are much the same as applications in others parts of the world. Onshore and offshore, in producing and injection wells, expandable liner systems are being used to address a variety of critical remedial challenges, such as corroded or damaged casing, water shut-off and sealing off old perforations. With the increasing number of mature fields and the growing risk and complexity of developing new oil and gas reserves, operators are looking for more effective and cost-efficient remediation solutions to maximize production from existing assets. With an integrated remediation approach, restoring productivity often makes economic sense. he cost of remediation to return an asset to its optimal production is typically an easily supported expenditure when considering life-ofwell productivity (Figure 1). ntegrated remediation he development and use of expandable liners is a significant contributor to this growing trend and is resulting in a second look at mature fields that might otherwise have been abandoned. n these wells, expandable cased-hole liners are helping to improve performance by restoring wellbore integrity and maximizing reservoir output. pplied as part of an integrated remediation system, the technology is achieving significant success in restoring long-term casing integrity that reduces intervention costs and extends recovery. Compared with cement squeezes or straddle packers and conventional liners, the expandable liner can be a more reliable and cost-effective tool for restoring casing integrity. Single-trip installation without the shoe drillout required with a conventional liner significantly reduces rig time and NP. ypically, expandable liners are installed in one to two days, allowing the operator to immediately test the well and return it to production. Completions, production and future interventions are optimized because the expandable liner conserves hole size to provide the largest possible wellbore D. Conventional liners and packer methods are often limited or unacceptable because this valuable hole size is lost. he smaller D constrains the completion and ensuing production and reduces options in future production optimization efforts. Using straddle packers to isolate a casing problem can reduce D even more than a conventional liner. While the straddle packers can be removed to allow work deeper in the well, they provide only temporary isolation, not a permanent solution, and they do so at the cost of severely limiting D. n 4 ½-in. and 5 ½-in. cased holes, expandable liners provide a permanent remediation option in smaller diameters where a standard liner is not a viable alternative. Further, while conventional liners are cost-effective over long intervals measured in thousands of

4 Figure 2: xpandable cased-hole liners can be effective for shorter intervals with specific casing repair and isolation problems, while conventional liners may be better for long intervals. feet, expandable liners can be more costeffective for shorter sections with specific casing repair and isolation problems. he other common remediation method, a cement squeeze, can produce unpredictable results and expose the formation to high-pressure risks. Ultimately, it is more of a short-term treatment that will require repeated interventions throughout the well s remaining life. comparison of conventional cement squeeze and solid expandable cased-hole liner costs illustrates the relative economics. n a study of casing remediation methods, the authors found that when considering days versus cost, the total outlay of a single squeeze operation is nearly $225,000, accounting for nine total days from the time the rig is moved on location until the well is back on production (Farley, SP ). Using the same base costs from an ast exas job, it was determined that using a solid expandable liner saved an average of three days while incurring 36% less in associated costs. nother cost factor is that cement squeezes are often not successful on the first attempt. second squeeze in the same operation could increase costs to nearly $291,000 and add two more days of rig time. he fixed cost of a solid expandable casedhole liner could cut those costs in half. Remediation cycle process he operator uses the expandable liner as part of an integrated process that locates the problem, prepares the wellbore, fixes the casing and recompletes the well. t requires no cement and applies no pressure to the formation during the installation process. he process has a history of success in repairing and remediating common problems. he method first employs cased-hole wireline logs to precisely locate problems with casing, water production sources, wellbore obstructions and bypassed production zones. hese logs include advanced imaging and multisensory caliper tools used to locate internal and external defects caused by corrosion, scale, wear and failure. Once the problem is identified, the wellbore is prepared for remediation based on the specific conditions. variety of clean-out mills, such as junk, taper or watermelon mills and other tools, may be deployed to provide a clear path for running the expandable liner. Chemical, hydraulic or other mechanical methods also can be applied prior to the liner installation. he actual remediation step involves installation of an expandable cased-hole liner to cover the problem area. he liners can be run in short and long lengths to precisely cover target intervals. hey are installed in a single trip and require no cement or shoe drill-out (Figure 2). Once casing integrity is restored, a variety of cased-hole completion services are applied to install packers, frac plugs and artificial lift. Global applications Perforation isolation in the Middle ast n northern raq, developing new production from an existing well first required isolation of two perforated intervals in the 9 5/ 8-in. casing. he remediation had to minimize the loss of inside diameter and provide good economics with longterm isolation. t was also important that planned well tests avoid inducing communication across the old zones. o meet the objectives, the wellbore was prepared using cleaning equipment, including casing scrapers and brushes, and a junk mill. Once the casing was prepared, two 7 5/ 8-in. x 9 5/ 8-in. expandable cased-hole liners were installed across the two sets of perforations. he lower perforation interval of 39.3 ft was isolated with a ft liner, and the upper perforation interval of 13.1 ft was isolated with a 35.1-ft liner. Hole size was conserved with a post-expansion drift of in. for a 7.60-in. D.

5 ach installation was performed in a single trip, and, unlike a conventional liner, no shoe drill-out was required. he total operation, including the cleaning run to prepare the casing interior, took 29 hrs. frica casing corrosion Corroded casing and water flow in a shallow well offshore Congo presented multiple challenges. First, it was critical to find a remediation method that was economical in the context of the mature field. Operationally, the remediation had to contend with platform deck space and weight limitations that prevented the use of a workover rig. he presence of H 2 S further complicated the remediation. he corrosion and source of the water flow was first located with wireline services. Prior to installing an expandable liner system, the casing was prepared using fishing and wellbore cleaning services. Weatherford worked with the operator to develop an H 2 S-resistant 5 ½-in. x 7-in., 29 lb/ft expandable liner. he liner covered a corroded interval between 820 ft and 1,312 ft to provide a longterm, stable and cost-effective remediation that brought the well up to full integrity. nstead of a workover rig, a jacking system and specialized equipment were used to overcome platform limitations and run the liner. he single-trip installation provided a post-expansion drift of in. to optimize the completion and production. Water production was eliminated, and the well was put on production at 250 bbl/day of oil. South merica seal-off n an onshore S-type well near Santander, Colombia, watered-out intervals led to installation of a 55-ft, 5 ½-in., 17 lb/ft expandable liner in the wellbore s existing 7 in., 29 lb/ft casing. he objective was to improve production capacity by sealing off upper water-producing perforations and recomplete deeper in the well. o optimize the completion and future production, it was important that the remediation minimize the loss of internal diameter. he expandable cased-hole liner resulted in a reduction of only 0.79 in. he inner diameter of the expanded system was 5.39 in., allowing a drift diameter of in. Due to the tubing overpull and workover equipment limitations, the expansion was performed hydraulically in stages using a setting tool. he pipe was successfully expanded and pressure-tested to confirm restored integrity. US refracs and integrity n operator in New Mexico needed to cost effectively cover and isolate perforations in 5 ½-in., 15.5-lb production casing to seal off watered-out zones and enable the stimulation of new intervals. For this well remediation, the process included preparing the casing interior, installing the expandable liner to isolate the perforations and supporting the completion with specialized equipment. 4 ¼-in. x 5 ½-in. expandable liner with a post-expanded length of 700 ft was installed in the target interval at approximately 5,000 ft. he installation covered and isolated the upper perforations so that newer intervals could be fractured at 5,500 psi. he permanent liner provided an economical solution that eliminated the need for multiple cement squeeze operations. Unlike a conventional liner, the expandable liner maximized the retained hole size for optimal production and to facilitate future well intervention. unique composite frac plug was used to allow the operator to set back inside 5.5-in. parent casing after passing through the installed expandable liner. n a North Dakota well, multiple cement squeezes had failed to mitigate corrosion leaks in 7-in., 26 lb/ft casing. Running conventional casing significantly limited the wellbore D. o re-establish casing integrity, an integrated remediation process was applied. he wellbore was cleaned, and Weatherford s wireline multi-sensor caliper tool was run to identify the extent of damage and determine the best remedy. otalview visualization software processed the caliper data to identify casing restrictions, assess drift D and determine casing damage. he analysis identified severe damage across the 150-ft section, and a 5 ½-in., 17 lb/ft expandable liner was installed. he cased-hole remediation provided a long-term, cost-effective means of restoring casing integrity in the wellbore. he solution brought the well to full integrity standards in less than two weeks. Conclusion n the midst of a fully developed infrastructure, aging wells around the world represent a tremendous opportunity for operators. hese wells typically face age-related casing integrity problems that are critical constraints to their ongoing operations. For many of these wells, conventional remediation techniques, such as cement squeezes, straddle packers and conventional liners, present hurdles to cost-effective remediation. n integrated remediation system that includes expandable liners provides an option that is returning wellbores to service and changing the productive outlook for thousands of wells.