Novel Application of Abrasive Jet Perforating to Restore Productivity of a High Potential Inactive Horizontal Oil Producer
Authors: Chishti Sadaf Shoukatali , Craig Steven H , Wheatley Edward Jason , Aldhuhoori Saeed Mohamed , Bukhari Mohamed Abd Elrahman , Li Sima , Kulkarni Prajakta Dilip 
Published: March 2022

This paper illustrates a novel methodology that enabled the safe application of Coiled Tubing (CT) Abrasive Perforation to increase production in a sour horizontal extended reach (ER) oil producer. The well was underperforming at 10% of the anticipated production rate due to a damaged lower completion. To avert a costly workover, abrasive perforation with CT was selected as a safe alternative to conventional explosives-based perforating conveyed on e-line.

The well, with a measured depth in excess of 24K-ft. had a damaged lower completion with closed inflow control devices that significantly impeded production for several years. A CT caliper log had confirmed a parted liner section creating accessibility concerns and made conveyance of perforating guns unsafe. An advanced simulation study was performed to design a CT abrasive perforation operation. The CT conveyed solution provided a more rigid deployment method to navigate a challenging open-hole section prior to reaching the target depth. A complete mock-up test was performed to evaluate systems integration and define the operational parameters, combined with a comprehensive desk top HAZOP study to assess both downhole and surface handling challenges amid the presence of high concentration hydrogen sulphide (H2S).

A major challenge faced during the design stage was to understand solids transport inside both the CT and in the well-bore. This was critical to perform efficient perforations and to avoid the risk of stuck CT in the long horizontal section. Stringent operating limits were established to minimize the influx from the reservoir to reduce H2S production when recovering sand from the surface flow stream. The required flow rate at the tool for each sand jet perforation stage resulted in low annular velocity, requiring accurate simulation of solids transport throughout the operation. A transient CT simulation study indicated buildup of sand within the CT before reaching the nozzle. The results of the modelling showed sand profiles during each sequence of the job and allowed fine tuning of slurry design, fluid requirements, pumping schedule, wiper trip speed and other parameters critical to ensure efficient perforations and cleanout. Accessibility concerns were overcome by use of an advanced metal lubricant and addition of a motor assembly in the bottom hole assembly (BHA) that enabled CT to run beyond the parted liner section. A total of thirteen perforations were performed in three separate coiled tubing runs with additional cleanout runs. The results of the operation increased the production rate to over 90% of well potential, and saved cost and time that would be required to perform a rig-based workover.

Being a first-time technology application for such challenging well conditions, the advanced CT simulations to understand solid transport dynamics added more confidence in the job design that resulted in a safe, reliable, and cost-effective execution. This is a very important case history for similar inactive wells which could benefit from this technology and approach.