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In recent years, many wells have been constructed that are subject to extreme conditions. Two extreme conditions that can pose a particular challenge during the completion of a well are low temperature, for example in deepwater applications, and high-pressure and high-temperature, encountered in HPHT wells. The products and processes that are normally used to cement wells may be insufficient to create zonal isolation for these extreme conditions. This paper presents methods to help design and execute effective cement jobs for HPHT and deepwater, low temperature wells. First of all, recommendations are outlined for the deepwater conditions. Drilling fluid removal, sealant placement, and sealant sheath strength development are all affected by extreme conditions and are therefore designed accordingly. In order to help determine how strong the sealant sheath needs to be, formation properties are taken into account as well as the operations to be performed during the life of the well. These operations include well testing, stimulation, production, and injection. The paper goes on to discuss the advantages of new products and processes for cement wells under extreme conditions. The laboratory testing procedures, pre-job design procedures, job implementation and evaluation procedures that were used to test the new products and processes are described. Finally, guidelines are given for optimized designs for HPHT and low temperature wells using these products and processes. |
