The goals of the project are to:
University of Alaska (UAF), Fairbanks, AK
Argonne National Laboratory (ANL), Argonne, IL
BJ Services, Tomball, TX
One of the basic material requirements in oil and gas well completion operations in Arctic regions where permafrost is present, is the use of a suitable insulating cement that will provide both a good seal to prevent gas leakage and at the same time keep the permafrost interval undisturbed during the production of the oil and gas. Conventional Portland cement has difficulty in setting and performing suitably under Arctic conditions. The freezing and expansion of water in the pores and capillaries of the cement slurry leads to the development of cracks in the structure before the cement is set. In addition, conventional cements do not have sufficiently low thermal conductivity, and are thus not good insulators.
Ceramicrete, the phosphate bonded ceramic borehole cement developed at ANL, may provide an alternative. ANL, in partnership with UAF, proposed to tailor this cement for permafrost regions and demonstrate its application in Alaska. UAF is working with this new material to develop an appropriate "blend" to meet the oil industry's needs.
Tests have been conducted at BJ Services’ Tomball R&D Center using a new formulation of Ceramicrete with and without contamination by Portland cement. These tests have shown positive results for the effective use of Ceramicrete as oilfield cement.
The newly developed Ceramicrete is a rapid-setting, strong, pore-free (low-permeability) insulating cement that shows good resistance to corrosion and the effects of freeze-thaw cycles.
If conventional Portland cement is used as oilfield cement on the Alaskan North Slope, it can form water pockets after setting in the annular volume between wellbore and casing. This can lead to loosening of set cement and in turn can affect well integrity.
Ceramicrete tests have shown that the thickening time of Ceramicrete (with and without contamination from Portland cement) is 5 hours, which meets API standards and avoids the formation of water pockets. Hence, Ceramicrete has an ability to provide improved well integrity.
As well, the amount of heat evolved during the setting of the cement slurry in the case of Ceramicrete is less than that for conventional Portland cement. Thus Ceramicrete can also help to reduce shallow gas migration problems associated with cement-induced thawing of the permafrost around the wellbore.
This lightweight cement is also believed to be more efficient for use in shallow arctic completions. This could mean that Ceramicrete will be quite useful in supporting the development of both shallow heavy oil and gas hydrates resources in the Arctic, while protecting the permafrost.
Annular gas migration during cementing oil and gas wells is a serious problem. Failing to control gas migration can result in gas channeling and costly squeeze jobs. New cementing approaches could help reduce the safety and environmental hazards created by cementing failures.
Project objectives included:
Among the project highlights are the following accomplishments and conclusions:
The latest effort at UAF involves conducting tests regarding freezing point measurement, fluidity, compressive strength, thermal conductivity, heat of hydration, and setting time for a slurry of 95 percent Ceramicrete and 5 percent Portland cement.
The project, which began September 2004, is in its third year. The scheduled date for project completion is September 2007; however, a 1-year, no-cost extension will be requested.
This project was selected in response to DOE’s Arctic Energy Office solicitation DE-FC26-01NT41248, January 2004.
$257,190 (35 percent of total)
Wagh, Arun S., Natarajan, Ramkumar, McDaniel, Richard L., and Patil, Shirish, “Ceramicrete Blends Produce Strong, Low-Permeability Cements for Arctic Use,” Oil & Gas Journal, May 16, 2005, pp. 48-52.
Banerjee, Sudiptya, “Novel Chemically Bonded Phosphate Ceramic Borehole Sealants for Arctic Permafrost,” poster presented at the 2005 American Association of Drilling Engineers Annual Conference, Houston, TX, April 2005. Winner of First Place Award and Sandy Purdy Excellence in Research Award.
Banerjee, Sudiptya, “Novel Chemically Bonded Phosphate Ceramic Borehole Sealants for Arctic Permafrost,” paper presented at the 2005 Society of Petroleum Engineers Western Region Student Paper Contest, March 2005. Winner of Third Place Award.
Banerjee, Sudiptya, “Novel Chemically Bonded Phosphate Ceramic Borehole Sealants for Arctic Permafrost,” M.S. thesis, University of Alaska-Fairbanks, May 2005.