Solid-Expandable Systems. The Key to Economical Recovery in Mature Fields

Solid-Expandable Systems The Key to Economical Recovery in Mature Fields A White Paper November 2013

Solid-expandable technology provides a low-cost, permanent alternative to cement squeezes. 2013 Weatherford. All rights reserved. 2

Executive Summary When exploiting mature fields, operators are challenged with finding a cost-effective method to enhance production and extend well life. Investments made to restore well integrity must be recouped while the well still produces. For decades most operators have chosen a cement squeeze to establish wellbore isolation, out of many conventional solutions that suit various applications and wellbore geometries. The perception is that a cement squeeze costs less than today s innovative solid-expandable technology. However, in general, one cement-squeeze operation costs more, and multiple squeezes are usually required. Using this approach to maintain isolation throughout the well s life cycle ends up costing more in the long run (Fig. 1). Solid-expandable technology provides a low-cost, permanent alternative to cement squeezes. The MetalSkin cased-hole liner successfully mitigates mature-field challenges, enhances productivity, and extends well life. After the initial investment, no additional costs are required to maintain lifelong wellbore isolation. And unlike other conventional casing-remediation techniques, such as a straddle packer or a scab liner, the resulting inside diameter (ID) is larger to help optimize production and access deeper reserves. Cost (in thousands of dollars) $300 $250 $200 $150 $100 $50 MetalSkin cased-hole liner operation Cement-squeeze operation 1 2 3 4 5 6 7 8 9 10 Days Fig. 1 In comparison to a single cement squeeze operation, the Weatherford MetalSkin cased-hole liner saves the operator approximately $80,000 and three additional rig days. Industry Challenge: Reducing Recovery Costs in Mature Fields As the global demand for oil continues to grow, operators seek alternative solutions with more advantages and cost effectiveness than conventional methods to maximize production in existing mature wells. Mature fields alone account for more than 70% of the world s oil and gas production. The significant recovery opportunities in these fields make casing-remediation solutions critical to the industry. Prior to targeting deeper reserves or stimulating existing zones, operators must repair damaged casing by shutting off water or sealing off old production perforations. Solidexpandable liners are gaining momentum as a casingremediation solution to mature-field challenges, such as zonal isolation, water shutoff, parted casing, perforation isolation, subsidence remediation, and corrosion retrofitting. The liners safely restore wellbore integrity and maximize reservoir output, which results in improved performance that justifies solid-expandable investments in aging wells. Production and declination phase Zonal isolation and water shutoff Mature-Field Challenges Casing splits and parting Subsidence remediation Corrosion retrofitting MetalSkin cased-hole liner isolates single or multiple sections of damaged casing and perforations in existing wells. This system provides larger through-bore than conventional casingremediation systems and is a more reliable, long-term method of isolation than cement. 2013 Weatherford. All rights reserved. 3

A Standard of the Past: Short-Term Cement Squeezes A conventional cement squeeze, or remedial cementing operation, is commonly used to fix poor primary cementing jobs, isolate perforations, or repair damaged casing. A cement squeeze is performed by forcing cement slurry into the annulus of a wellbore with pressure, blocking undesirable fluids and filling unwanted channels for effective zonal isolation. The amount of pressure to force cement into annular voids should be considered during cement-squeeze operations since high pressures can present many risks to a well s formation. A successful cement-squeeze operation that forms a thorough cement bond depends on important prerequisites, for example selecting the correct type of cement slurry and cleaning debris from perforations and channels. Although critical for proper zonal isolation, these prerequisites are not always followed. Sometimes this is because of time constraints. As a result, cement-squeeze repairs are frequently ineffective. In order to maintain isolation over the life of the well, multiple squeeze operations are usually required, and additional costs accumulate with each workover. A Forward-Looking Approach: Solid-Expandable Technology When cement-squeeze methods are used to overcome mature-field challenges, additional workover operations and costs are typically required. On the other hand, solidexpandable technology is a permanent solution for enhanced well integrity and productivity. And operators can now use comparative data to justify the upfront costs. Originally, solid-expandable technology was deployed as a contingency to conventional-technology failures. Today, solid-expandable technology is strategically used in an array of economic solutions for cased- and openhole wellboreisolation challenges, enabling operators to economically access reservoirs that they could not otherwise. Using this technology in casing-remediation applications has increased over the years. With proven field results, it is becoming a reputable solution for mitigating mature-field challenges, including excessive water production, reservoir sweep inefficiency, and aging. A single cement-squeeze operation is estimated to be 17% of a well s cost. However, three remedial cementing operations are typically required to ensure well integrity over the life of the well. Therefore, an operator can expect to spend approximately half of a well s cost when selecting a conventional cement squeeze as a casing-remediation solution. 2013 Weatherford. All rights reserved. 4

Solid-Expandable Benefits for Mature Wells Solid-tubular expandable systems, such as the Weatherford MetalSkin cased-hole liner, provide long-term casing integrity with reduced intervention costs and extended production recovery a significant advantage in casingremediation applications. MetalSkin expandable casedhole liner is a safe, reliable, and cost-effective tool. It can be installed in a single trip and requires no drill out, which significantly reduces rig time, nonproductive time, and associated costs. In many cases, this casing-repair solution can be installed in one to two days without using cement or applying pressure to the formation. Operators can then test immediately and quickly return the well to production. The Weatherford MetalSkin cased-hole expandable liner system features elastomer seal elements that are molded to the outside diameter (OD) of isolation joints, for greater reliability than a cement squeeze. And it provides a larger ID than an isolation straddle, a scab liner, or a conventional liner to enable future drilling, completion, and production or injection operations without substantial loss in hole size. As opposed to conventional solutions that significantly decrease the wellbore ID with additional casing strings, solidexpandable technology increases downhole casing or liner diameters up to 30% and minimizes the telescoping effect. 2013 Weatherford. All rights reserved. 5

Economic Comparison: Cement-Squeeze Versus Solid-Expandable Operation Comparing a conventional cement squeeze to a solidexpandable system by thorough cost analysis proves the most economical solution for mitigating mature-field challenges. For this comparison, each operation is broken down into processes and a percentage of the total cost for each day. At a daily workover rig rate of $6,000 a day, the objective is to repair 5 1/2-in. corroded casing. In this case, the solidexpandable solution is an 80-ft section of 4 1/4-5 1/2-in. expandable cased-hole liner. Table 1 shows the operational processes on each day along with the percentage costs. Fig. 2 to the right shows time versus cost. The first cementsqueeze operation is estimated to cost $225,000 and last a total of nine days, from the time the rig is moved on location until the well is back on production. In comparison, the solid-expandable liner operation saves three rig days, while incurring 36% less associated costs (Farley, SPE 159685). As discussed earlier, cement-squeeze operations typically require additional attempts before zonal isolation is achieved. Assuming another cement squeeze is required for the same operation, the operator can expect to increase costs by approximately $66,000 and rig time by two days. In contrast, the solid-expandable operation requires no additional investments, saving the operator up to 50% in costs compared with conventional cement-squeeze operations. Solidexpandable technology provides more value as a permanent, cost-effective solution to casing-remediation applications, while conserving hole size for optimized completions, production, and future interventions. The expandable-liner approach has a strong, successful track record for repairing and remediating casing problems with significant results in extending well life and maximizing production. Cost Expandable cased-hole operation Initial cement-squeeze operation Future cement-squeeze operation 3 to 4 years Long-term solution 3 to 4 years Time *Graph based on 5 1/2-in. cased-hole well in East Texas and 80 ft of 4 1/4-5 1/2-in. expandable cased-hole liner. Fig. 2 Cement-Squeeze and Solid-Expandable Costs Compared Days Single Cement-Squeeze Operation Percentage Cost Days Solid-Expandable Liner Operation Percentage Cost 1 Move in/rig up. Rig waiting orders. Nipple down tree. Nipple up blowout preventers (BOPs), and test. 9% 1 Move in/rig up. Rig waiting orders. Nipple down tree. Nipple up BOPs, and test. 9% 2 Pull tubing. 5% 2 Pull tubing. 5% 3 Rig up electric line. Run gamma ray and junk basket. Run VertiLog. 12% 3 Clean out run with scraper and string mill. 4% 4 Run in hole. Set retrievable bridge plug (RBP) and test. Isolate leak with tubing and packer. 8% 4 Rig up electric line. Run gamma ray and junk basket. Run VertiLog. 12% 5 Rig up electric line. Dump sand on RBP. Shoot squeeze perforations. Set retainer. 16% 5 Solid-expandable liner 4-1/2 in. 5-1/2 in. 18% 5.5 5.5 Run in hole. Set inflate, pressure test, and retrieve IPP injection production packer (needed if pressure testing MetalSkin cased-hole liner). 8% 6 Run in hole. Sting into retainer. Pump cement. 13% 6 Break ceramic disc, swab, and move rig. 8% 7 Drill out retainer, and cement and pressure test. 12% 7 8 Run in hole with tubing and pull RBP. Pull out of hole. Run in hole with tubing, and land. 16% 8 Cost Savings 36% 9 Break ceramic disc, swab, and move rig. 9% 9 Table 1 Cement-Squeeze vs. Solid-Expandable Operation, Process by Process 2013 Weatherford. All rights reserved. 6

Case Study Providing value to a mature-field operator Challenge: In an aging onshore Colombian well, repair damaged casing with minimal ID loss for a quick return to production. Solution: Weatherford deployed a 5 1/2-in., 192-ft (58.58-m) length of MetalSkin cased-hole liner to cover two damaged casing sections. The liner was expanded between a depth of 3,876 and 4,060 ft (1,181 to 1,237 m) to permanently isolate the unwanted perforations. The final ID of 5.488 in. and drift diameter of 5.363 in. provided the client with enough passage for the desired production string. The liner delivered a long-term, stable, cost-effective solution that brought the well to full quality, health, safety, and environmental (QHSE) integrity without multiple squeezes, the need for drillout, or their cumulative costs. The MetalSkin cased-hole liner can be easily installed with a workover rig. No high-volume pumping equipment is required. 2013 Weatherford. All rights reserved. 7

How to Learn More For more information on solid-expandable systems, please visit weatherford.com. weatherford.com 2013 Weatherford. All rights reserved. Weatherford products and services are subject to the Company s standard terms and conditions, available on request or at weatherford.com. For more information contact an authorized Weatherford representative. Unless noted otherwise, trademarks and service marks herein are the property of Weatherford and may be registered in the United States and/or other countries. Weatherford products named herein may be protected by one or more U.S. and/ or foreign patents. Specifications are subject to change without notice. Weatherford sells its products and services in accordance with the terms and conditions set forth in the applicable contract between Weatherford and the client.