| Popis: |
The well construction process only allows one chance to install a primary cementing system. The industry has long understood the advantages of the method of pipe movement during cementing operations, yet it is not commonly practiced in spite of API recommendations. One barrier to implementing this methodology has been the availability of tools and technology. Application of a modern casing running tool (CRT), with a top drive allows the casing string to be safely conveyed to bottom, and subsequently rotated and reciprocated during cementing. The standard industry toolbox uses long bails attached to the traveling block, conventional casing elevators and a standard cement head. Practically, this does not allow for rotation during cementation. Rigging up this equipment is time consuming and leaves the pipe motionless on bottom. Cement jobs under these circumstances are more prone to failure and frequently require remedial cementing. Most North American operators are drilling extended reach wells in the prolific onshore shale plays. Long laterals combined with tortuous wellbores make it difficult to conventionally run casing; as a result, usually these sections require casing rotation to pass through challenging trajectories and get to bottom. Moreover, the horizontal shale wells are often completed with multi-stage frac jobs. It is imperative to have high quality cement job to insure zonal isolation, otherwise communication between zones can occur; this can result in a lower quality frac job and well completion. A poor completion can result in lost production and leaks can lead to ground water contamination. After pumping stops, there is no known method to affect additional mud removal from continued pipe movement, but cement job quality is not dependent solely on mud removal. The drilled section is of little value until it is cased and a competent cement job is completed. Dynamic Cementation™ consists of rotating and reciprocating the casing from the time the cement operation commences until cement is set. It can increase the quality of the cement job by increasing mud removal and decreasing pressure loss while cement cures. This paper discusses the benefits of casing movement during cementing, the methodology and results. |
