Successful Through-Tubing Gravel Pack Unlocks Production in Mature Fields Offshore Brunei

Abstract

Sand production remains one of the key risks to maintaining field production rates and maximizing ultimate recovery from mature fields offshore Brunei. Due to the operational challenges and the HSE risks resulting from sand production in the surface facilities, sand producing wells are shut-in prematurely, locking-in well production and remaining hydrocarbons. Very fine, poorly sorted formation sands and uncertainty in general about formation sand particle size distribution leads to a challenge in designing robust downhole sand control completions. Sometimes we get it wrong resulting in the failure of the original sand control completion. Low cost options to remediate sand production through the deployment of wireline conveyed thru-tubing standalone screens are typically not reliable in this environment and often considered as a last resort option. In addition most of the existing wells are old, have well integrity problems and completed with small 3-1/2" tubing that limit the application of mechanical thru-tubing options. Expensive rig interventions to workover or redrill sanded out wells are typically not justified by the low remaining reserves. To overcome these challenges Brunei Shell Petroleum embarked on an effort to identify and field test a viable rig-less remedial sand control solution for unlocking production and maximising recovery from existing wells. This paper documents the work done to select the right technology and the right well candidates for a field trial, the design and planning effort that resulted in the first successful application of a Thru-Tubing Gravel Pack (TTGP) in the NW Borneo region. A well previously producing sand has now been producing sand free for about a year. In addition the paper provides valuable learnings to those wishing to deploy thru-tubing gravel packing technology in existing wells.