Perf, Wash and Cementing Technique Remediates Cemented Annulus to Achieve High Quality Bond Across the Entire Interval in Complex Slot Recovery Operation

Abstract The objective of this abstract is to demonstrate how a complex slot recovery operation was performed to permanently plug the main reservoir and the intermediate formation to facilitate a new sidetrack. There were several challenges to overcome in this well and it was favorable to install the annular barriers as deep as possible just above a 7" tieback packer. The 9 5/8" casing was logged and the annulus condition at the depth was cemented, however most of the interval had patchy cement bond with medium isolating potential. Some of the interval had well bonded heterogeneous cement around the annulus, but not enough continues bond to comply with company standards and regulatory requirements in the country. Based on this challenge, a procedure using the perf, wash, and cementing technique, all in a single trip, was chosen as the best solution as this technique had been very successful in achieving high quality annular barriers across this field for years. High cement content in the annulus was risk assessed and planned accordingly. The decision was made to perforate two different intervals using TCP guns to subsequently drop them in the rat hole. The casing was perforated from 2155 – 2130 mMD and 2111 – 2069 mMD with the overall goal of achieving 86 meters of continues high-quality cement. The next step was to wash the perforated intervals, and that was done effectively with declining standpipe pressure and a unique system that focus the washing fluids into the perforations using inversed swap cups to result in a large amount of cement coming over the shakers. The large amount of cement over the shakers was a testament of the efficiency of the system. It clearly shows the capabilities of restoring barriers by removing patchy cement and provide a new high quality cement plug across the interval. The operation was completed with a flawless cement job utilizing the uniquely engineered Pump and Pull method that is specific to this system and part of the standard operating procedure of the provider. The results speak for itself; the entire operation was a milestone for both the service company and the operator. After the cement set up it was drilled out and the annulus was re-logged to verify the effectiveness of the operation. The result was high quality cement bond across both the perforated intervals and the customer had achieved 86 meters of high-quality cement bond in the annulus. The objective was met, and the complex dual interval operation was successfully executed with industry leading performance. The operation has proved its efficiency in a cemented annulus setting a new benchmark for the system going forward.