The development of arctic resources requires wells to be drilled, cased, andcemented through permafrost. Permafrost presents unique challenges, especiallyto cementing operations, requiring a cement system with the capability toperform in the subfreezing permafrost environment. The performance required isthat the cement provides isolation, exhibits low heat of hydration, and setswith sufficient strength to provide casing support. There are also specifictesting requirements detailed in API recommended practices.
In the polar region, there are several approaches used in the design of cementsystems. The approaches used in Russia, Canada, and USA (Alaska) areillustrated. The design considerations take into account local conditions andrequirements and use knowledge from cementing practices employed in thedrilling industry.
It is important to understand the current cementing practices in use withinthe arctic region. This will allow future improvements as more developmenttakes place and the resources become exploited.
To be successful, hydrocarbon resource development in arctic regions mustmeet the challenges posed by drilling, casing, and cementing wells throughpermafrost layers in the remote arctic environment. The Russian Far East, forexample, is almost completely covered in permafrost and holds significant gasreserves that remain largely untapped due to the remoteness of the area and thecomplexity of drilling through the permafrost layers. Offshore operations areadditionally impacted by sea ice, which does not directly affect cementingoperations; however, the short operational window certainly requires detailedplanning and reliable performance.
The remoteness of arctic locations affects all aspects of development, impacting overall logistics: access, timing, and materials delivery andstorage. In addition, several of the challenges faced during the initialdevelopment phases affect the subsequent cement job and cementing practices. These challenges need to be addressed as part of the overall development plan;they include borehole maintenance, casing centralization, and mud conditioningand removal, and all require careful consideration of the permafrost.