The high porosity of the limestone formation of Kaji-Semoga Field, Indonesia, caused a vast amount of lost circulation during the waterflood drilling campaign. An example of major lost circulation was at KS-X22, which caused a major failure in the primary cementing. This failure resulted in a significant increase in water cut, from 45 % to 96 %, within 6 months.

To make KS-X22 economically viable again, it was decided to improve the primary cement quality by remedial cementing. The job was designed as low-pressure balanced plug placement, with 15.8 ppg G class cement pumped down on open-ended tubing. The limited capacity of the onsite batch mixer restricted the cementing process, which could not be done in one stage. But, to our advantage, this limitation enabled us to control the amount of cement required for the following stage, based on the results of the previous stage.

When the job was finished, the cement bond log showed that it had been done perfectly, indicated by the significant change in the free pipe reading (62 mV) to an excellent cement bond (<20mV). The producing phase after the job showed a slower rate in the water cut increase, and currently the well is still producing using ESP, more than 2 years after the remedial cementing job.

This paper will discuss the planning, implementation, and results of remedial cementing at KS-X22 and the lessons learned

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