Integration of Cement Job Data for Better Bond Index Interpretation

Jutten, J.J.; Toma, I.; Morel, Y.; Ferreol, B.

doi:10.2118/21690-ms

Cited by 4 publications

References 9 publications

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Efficiency in Cement Jobs for Fresh Water Formations Isolation During Plug and Abandonment in Canadon Seco Field, South Argentina

Graterol¹

2010

All Days

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In the San Jorge Basin, located in South Argentina, Well Plug and Abandonment (P&A) regulations include the guarantee of fresh water formations isolation from once productive formations. Cement Bond and Variable Density Logging (CBL/VDL) are recorded after a squeeze job to confirm cement integrity in the annulus, allowing protecting the most important fresh water formation in the basin: Patagoniano. Historically, to isolate the Patagoniano multiples of costly squeeze jobs were done to achieve an appropriate result in the CBL/VDL. The main problem from this shallow formation is its high degree of fluid losses, most slurry is lost in these unconsolidated and high-permeability shallow sands (while pumping and during cure). Under this condition costs in the Canadon Seco Field for P&A were exceeded. To overcome this problem, a review of previous results was done and many flaws were identified in the slurry physical characteristics and the used placement techniques. A new slurry and procedure was selected (after being laboratory tested) to be applied in the field; then a campaign of 14 wells was done using the selected slurry and following a general technique; cost/time reduction was drastic in comparison with previous P&A operations. This paper presents the whole procedure for achieving these results and also includes details in each phase of testing/design and execution. Geological and mechanical features of the wells are shown, as well as a description of the new technique / slurry (including concepts) and the obtained field results.

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Efficiency in Cement Jobs for Fresh Water Formations Isolation During Plug and Abandonment in Canadon Seco Field, South Argentina

Graterol¹

2010

All Days

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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

SPE Annual Technical Conference and Exhibition

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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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Integration of Cement Job Data for Better Bond Index Interpretation

Cited by 4 publications

References 9 publications

Efficiency in Cement Jobs for Fresh Water Formations Isolation During Plug and Abandonment in Canadon Seco Field, South Argentina

Efficiency in Cement Jobs for Fresh Water Formations Isolation During Plug and Abandonment in Canadon Seco Field, South Argentina

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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