Successful Coil Tubing Based Selective Stimulation of a Remote Well in Challenging Offshore Environment - A Case Study

Abstract

Well XX-1 is a newly drilled producer well in offshore west coast of India. The well has a deviation of 65 Deg and is completed with 3–1/2" screens with 2.31" SSD's in 6" open hole. Post production line-up, the well PI was found to be very low (<1). Thick viscous debris in the lower completion made access to the screen SSD's using slickline conveyed tools difficult and inconclusive - Hi Tech Downhole Camera runs confirmed that the lower completion was filled with mud. Tidal and current conditions ruled out any kind of Barge and Catenary based CT operation. Further, the platform had helideck as the working deck having a limited load handling capacity & crane load rating. To remediate the poor well performance, a platform based coil tubing stimulation operation utilizing a modular and compact unit was proposed. A 20 T modular crane was installed on the platform and a detailed platform structural load analysis was carried out for spotting the CT unit and auxiliary equipment. Chemical & compositional analysis of the debris & formation cuttings was done to determine the appropriate stimulant recipe as no stimulation history for the field was available. CT conveyed Inflatable packer was used to isolate the lower section of the completion. Advanced flow activated downhole tools like double ended shifting tool & Impact hammers were utilized to selectively manipulate and stimulate all the desired zones in one run. Post stimulation there was a 10 fold improvement in well PI with the well production increasing to 2600 BOPD from an initial rate of 300 BOPD. The technique & setup has a huge cost implication as the cost of Catenary and barge is eliminated. The same technique is now planned to be applied to stimulate other wells in the field with logistical & technical constraints.