Greater Burgan Field has been producing from more than 70 years and brings many challenges with the maturing field. During the last decade almost all the new wells drilled were completed as dual completions to simultaneously produce from two different formations in Burgan. As the workover rig activity tremendously increased with the increased number of new wells per year, it has been a constant endeavor to carry out maximum well intervention jobs possibly by rig less operations to reduce rig related OPEX and well production down time during rig work over.
One of the biggest long term challenges was to carry out well interventions in dual completions short tubing, which was used to be considered inaccessible due to presence of tubing long in the well bore. In view of above, most of the intended well interventions in tubing short were normally used to be proclaimed as work over candidate thereby increasing load on limited work over rigs.
First time in Burgan a dual completion well was carefully identified to carry out water shut off job by chemical application and adding perforation by oriented perforation gun in short tubing. The tubing short was producing from BGSU reservoir and became ceased to flow due to lateral water encroachment which was evident from the recent PNC log. The formation layer below BGSM was still having oil potential and was intended to produce after shutting off the upper layer BGSU. The Tubing Long was producing from deeper reservoir BGSL around 1200 BLPD with 50% W/C.
This paper elaborates the procedures adopted during the execution of the job and selection process of the chemical squeeze technology. The best suitable chemical technology was selected after carrying out a careful & detailed approach towards different vendors. The step by step detailed program was prepared to squeeze the chemical in to existing perforations, cleaning to the desired depth, testing the squeezed perforations and adding new perforations below with oriented perforations gun.
The results were quite encouraging with sustainable oil gain of 1400 BOPD and the detailed cost/pay back analysis indicated the payback period of only 1.5 days of production.
This successful job has opened a new era in the history of Burgan field and many other water shut off jobs may be successfully carried out without the need of rig work over. This not only will reduce the work load on rig work overs and save rig cost significantly but will also allow to increase the well productivity with a very short period of well down time.