The ability to perforate under optimal reservoir conditions resulted in improved well performance and in higherthan-expected production of 70 MMcf/d of sand-free gas.
Real-time downhole measurement and interpretation optimize reservoir conditions and well performance
Challenge
To minimize perforation damage while maximizing gas production.
Solution
ACTive* Perf real-time downhole measurements to control and accurately place perforating guns while ensuring optimal reservoir conditions.
Results
Minimal perforation damage which led to sooner-thanexpected, higher-than-expected production of 70 MMcf/d of sand-free gas.
Perforation damage in South China Sea
Talisman Malaysia Ltd. (TML) operates more than 130 wells in the South China Sea. Many of these wells do not perform to full potential because of perforation damage at suboptimal reservoir conditions.
Initial attempts to solve the damage problem involved using conventional coiled tubing (CT) perforating to complete the well underbalance. The main advantages of using CT were the ability to displace the wellbore fluid with nitrogen to create the underbalanced condition and a lower overall cost when compared to perforating using a rig.
Although conventional methods were deemed efficient in this application, concerns included perforating off depth due to inaccurate depth control, not being able to detect fired guns, and improper balance conditions. Too little pressure could result in ineffective perforation cleanup; too much could cause the guns to be sanded in after firing.
Downhole data for accurate placement
ACTive Perf provides downhole measurements and downhole tools and techniques to perforate in proper balanced conditons. It also enables
accurate placment of the guns across the right zone
tuning the downhole pressure to the optimal underbalanced condition
controlling when to fire with the eFire electronic firing head system
receiving real-time feedback when the guns fire.
Real-time information was used to complete a TML offshore gas well. The perforating gun was positioned on depth using real-time CCL correlation. Prejob calculations indicated the correct underbalance would be achieved after displacement of wellbore fluid with nitrogen. However, real-time pressure data showed that insufficient underbalance had been achieved. Displacing additional wellbore fluid corrected the underbalance condition.
Pressure nitrogen pulses down the CT were used to fire the gun. The downhole measurements immediately showed that bottomhole pressure and temperature increased, confirming a successful firing.
Exceeding expectations
The ability to perforate under optimal reservoir conditions resulted in improved well performance and in higher-thanexpected production of 70 MMcf/d of sand-free gas.
ACTive live in-well performance
ACTive Perf is part of the ACTive portfolio of CT services that includes ACTive Matrix, ACTive Cleanout, ACTive Isolation, ACTive Lift, and ACTive Profiling. These services enable live in-well downhole measurements, interpretation, and performance optimization.
