In 1999 BP added wells to develop small reservoirs adjacent to the Troika Field. The wells were deep, multi-zone subsea completions that produced both oil and gas. When drilling the TA-6 well, there were problems setting the 7" casing, so 5 ½" casing was run inside the 7" across the perforated interval. The screen was downsized to 2 7/8" and placed across the perforated interval at 16,367 to 16,507 ft (TVD). During the frac pack, they did not have a live annulus and could not circulate. Ultimately the crossover seals failed and the washpipe became plugged with gel and proppant, making the pressure gauges ineffective.
The TA-6 well was brought on production in November 2000 and produced for 14 months before experiencing massive sand production. With significant reserves remaining behind pipe, it was decided to perform a workover. The sand was cleaned out and a metal mesh media was run inside of the existing prepacked screen. The workover proved successful and the water cut dropped from 10% at failure to less than 3% after the workover.
This presentation will describe the use of an erosion model to evaluate both the probable cause of the completion failure and the operating conditions of the successful workover.