Advances in Tieback Cementing

MacEachern, Douglas P.; Algu, Dave; Cowan, Mike; Snell, Eric

doi:10.2118/79907-ms

Cited by 6 publications

References 26 publications

(15 reference statements)

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Ongoing Development of Cementing Practices and Technologies for Kuwait Oil Company's Deep HP/HT Exploration and Gas Wells: Case History

Al-Saeedi

Al-Enezi

Mudhaf

et al. 2011

SPE Drilling &Amp; Completion

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Summary Exploration activities in Kuwait have been focused on the search for high-quality oil from the Jurassic formations and gas in the Triassic/Permian series. The wells drilled to these prospects are very challenging because of high-pressure/high-temperature (HP/ HT) conditions, large casing sizes, oil-based mud, the presence of high levels of H2S and CO2, and a narrow pore-/fracture-pressure window. In particular, the cementing of the deep strings in these wells has been extremely challenging. Over the last 8 years, a concentrated effort has been made to introduce new technologies and materials to improve the cementing practices both from operational and safety aspects. In 2003, the success ratio for deep cementations was highly variable. The Kuwait Oil Company (KOC), along with one of their cementing service providers, worked on a series of changes to practices and materials with the aim of improving job quality with high repeatability. This was based primarily on the technologies being developed in HP/HT wells around the globe, especially in the North Sea, and it resulted in a notable improvement in cementing performance. Technologies and practices that had been developed include spacer technology, application of synthetic retarders, fluid-loss and antigas-migration additive improvements, development of finegrained weighting additives, use of HP/HT rheometers, systematic product control, the minimizing of handling, and safer mixing practices at the wellsite. This paper will discuss the application of these technologies, materials, and practices over an 8-year period as a case history to illustrate the improvements made in achieving consistent cement quality and final slurry placement for the deep-casing and liner strings, and will conclude with recommendations and lessons learned during this process.

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Ongoing Development of Cementing Practices and Technologies for Kuwait Oil Company's Deep HP/HT Exploration and Gas Wells: Case History

Al-Saeedi

Al-Enezi

Mudhaf

et al. 2011

SPE Drilling &Amp; Completion

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Environmental Risk Arising From Well Construction Failure: Difference Between Barrier and Well Failure, and Estimates of Failure Frequency Across Common Well Types, Locations and Well Age

King

King²

2013

Day 3 Wed, October 02, 2013

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Do oil and gas wells leak to the environment? The great majority of wells do not pollute. The purpose of this paper is to explain basic concepts of well construction and illustrate differences between single barrier failure in multiple barrier well design and outright well integrity failure that could lead to pollution, using published investigations and reviews from data sets of over 600,000 wells worldwide. For US wells, while individual barrier failures (containment maintained and no pollution indicated) in a specific well group may range from very low to several percent (depending on geographical area, operator, era, well type and maintenance quality), actual well integrity failures are very rare. Well integrity failure is where all barriers fail and a leak is possible. True well integrity failure rates are two to three orders of magnitude lower than single barrier failure rates. When a series of barriers fail and a leak path is formed, gas is the most common fluid lost. Common leak points are failed gaskets or valves at the surface and are easily and quickly repaired. If the failure is subsurface, an outward leak is uncommon due to lower pressure gradient in the well than in outside formations. Subsurface leaks in oil wells are rare and are routinely exterior formation salt water leaking into the well towards the lower pressure in the well. Failure frequency numbers are estimated for wells in several specific sets of environmental conditions (location, geologic strata, produced fluid composition, soils, etc.). Accuracy of these numbers depends on a sufficient database of wells with documented failures, divided into: 1) barrier failures in a multiple barrier system that do not create pollution, and 2) well integrity failures that create a leak path, whether or not pollution is created. Estimated failure frequency is only for a specific set of wells operating under the same conditions with similar design and construction quality. Well age and era of construction are variables. There is absolutely no one-size-fits-all well failure frequency.

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Environmental Risk Arising From Well-Construction Failure—Differences Between Barrier and Well Failure, and Estimates of Failure Frequency Across Common Well Types, Locations, and Well Age

King

King²

2013

SPE Production &Amp; Operations

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Summary Do oil and gas wells leak to the environment? This paper will show the great majority of wells do not pollute. The purpose of this paper is to explain basic concepts of well construction and illustrate differences between single-barrier failure in multiple-barrier well design and outright well-integrity failure that could lead to pollution by use of published investigations and reviews from data sets of more than 600,000 wells worldwide. For US wells, while individual-barrier failures (containment maintained and no pollution indicated) in a specific well group may range from very low to several percent (depending on geographical area, operator, era, well type, and maintenance quality), actual well-integrity failures are very rare. Well-integrity failure occurs when all barriers fail and a leak is possible. True well-integrity-failure rates are two to three orders of magnitude lower than single-barrier-failure rates. When one of these rare total-well-integrity failures occurs, gas is the most common fluid lost. Common final-barrier leak points are failed gaskets or valves at the surface and are easily and quickly repaired. If the failure is in the subsurface, an outward leak is uncommon because of a lower pressure gradient in the well than in outside formations. Subsurface leaks in oil and gas wells are rare, and routinely comprise exterior-formation salt water leaking into the well toward the lower pressure in the well. Failure frequencies are estimated for wells in several specific sets of environmental conditions (i.e., location, geologic strata, produced-fluid composition, and soils). Estimate accuracy depends on a sufficient database of wells with documented failures, divided into (1) barrier failures in a multiple-barrier system that did not create pollution, and (2) well-integrity failures that created a leak path, whether or not pollution was created. Estimated failure-frequency comparisons are valid only for a specific set of wells operating under the same conditions with similar design and construction quality. Well age and construction era are important variables. There is absolutely no universal definition for well-failure frequency.

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Advances in Tieback Cementing

Cited by 6 publications

References 26 publications

Ongoing Development of Cementing Practices and Technologies for Kuwait Oil Company's Deep HP/HT Exploration and Gas Wells: Case History

Ongoing Development of Cementing Practices and Technologies for Kuwait Oil Company's Deep HP/HT Exploration and Gas Wells: Case History

Environmental Risk Arising From Well Construction Failure: Difference Between Barrier and Well Failure, and Estimates of Failure Frequency Across Common Well Types, Locations and Well Age

Environmental Risk Arising From Well-Construction Failure—Differences Between Barrier and Well Failure, and Estimates of Failure Frequency Across Common Well Types, Locations, and Well Age

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