Slow completion reduces operational efficiency and delays production
Vinogradova field in northern Russia contains oil reserves estimated at more than 75 million tons. Most reserves are classified as tight oil with a thin, low-permeability, undersaturated reservoir.
Another service provider completed four wells in the field for RITEK-Beloyarskneft, but the stimulation operations were lengthy. The wells were completed with sliding sleeves that were run into the well with the liner. During the stimulation operation, each sleeve was opened using a specialized bottomhole assembly run on coiled tubing (CT). However, the service company was unable to leave the CT in the well during the fracturing operations, which meant that each frac port required two CT runs: one to clean out the well and one to close the previous port and open the next port. As a result, the average completion time for the three wells, with an average of 8.3 stages per well, was more than 61 hours per stage or 23 days per well.
For the next several wells, RITEK-Beloyarskneft wanted a faster solution to reduce the nonproductive time related to waiting for CT runs.
CT options improve efficiency and stimulation design
Schlumberger proposed an integrated BroadBand Precision service to optimize the completion and fracturing operations for well productivity, operational efficiency, and quality.
The completion was designed with reclosable CT fracturing sleeve technology as part of the casing string. During the stimulation operation, CT would be used to open and close each sleeve, stage by stage, as in the earlier wells. However, because the service was integrated, the fracture stimulation operation could be designed for pumping down the CT-to-liner annulus, enabling the CT to remain in the well and significantly reducing the completion time.