North West Java Basin is a mature field in Indonesia with history of seepage to total losses. The Cisubuh upper formation consists of claystones intercalated with limestone and sandstone is the major contributor to the losses. To combat losses in this area, an application of specialized engineered fibrous coarse Lost Circulation Material (LCM) to effectively sealing micro fracture and provides near wellbore strengthening capabilities in unconsolidated formation was deployed. This paper presents the successful application of such specialized engineered organic fibrous LCM in this area.
A specialized fibrous organic based LCM; sourced, manufactured and patented in Indonesia, was deployed to cure the losses. This LCM pill is designed to effectively seal a formation with its 5000 microns of particle size distribution. The LCM material will be combined with an active mud to form a matrix across the loss zone. The matrix works better than conventional cement plug to fill the gap of porosity even in highly porous formation or unconsolidated formation.
This fibers LCM pills have been used successfully to cure total losses while drilling. One lost circulation case occurred at XX-5 well while drilling 17.5 inch hole section with dynamic loss spans from 400 bph to total loss and static loss of 100 to 200 bph. Prior pumping this fibers LCM pill, several conventional methods such as heavy duty LCM and cement plugs have been deployed with little to no success. The losses were eventually cured after pump and soak 50 barrels of this fibers LCM pills through the annulus. Field data was then be collected and analyzed to identify the characteristics of the formation and quantify the impact of this special engineered fibers LCM to the formation. The information is being used to evaluate the economics of using this fibers LCM compared to conventional method. The use of this fibers LCM system has generated significant cost and time saving. The time and cost savings result mainly from reducing the rig time and reducing the volume of undesirable mud lost to the formation.
The authors will describe the problems encountered and illustrate how the application of these engineered fibers LCM has proven their value in lost circulation condition. The 17.5 inch hole section was drilled with no losses to the formation after deploying this engineered fibers and the drilling was continued. This successful implementation of deploying engineered fibers LCM in a severe to total losses might be considered as an alternative standard practice for curing any type and volume of losses.