| Popis: |
Traditionally, coiled tubing (CT) in Russia has had very limited service diversity. Its use has been concentrated at wellbore cleanouts and nitrogen kickoffs after fracturing treatments. We used coiled tubing equipment and technologies to supplement stimulation operations in one of the world’s largest oil fields, Priobskoe, which has up to five separate layers per well. Conventionally, well completions here have involved complicated workover operations with tubing, packers, and wireline perforating after each stimulated layer. Average wells with three layers took 30 days to complete. CT provided a significant improvement in completion efficiency, reducing the cycle time to just 10 to 12 days. The first option of the completion and stimulation technology assumed "through casing" operations, eliminating the use of frac strings and a packer, which is a significant achievement under Russian regulations. This was done with a 4-in.-OD perforator and casing with increased strength. A year later, a second option for the technology was introduced to operate on regular strength casing through tubing. A slimmer abrasive perforator that could fit into the packer’s internal bore developed for this option was particularly effective for sidetrack and horizontal completions. In total, 95 wells were analyzed with more than 250 stimulation stages. This includes an operational and technical review of the tools and techniques used to compare the efficiency of the whole cycle of completion, resources requirements and amount of risks and non-productive time associated. Also a productivity comparison of CT combined with fracturing technology versus standard process of wireline/workover/stimulation sequence will be given. |
