Abstract

Kuwait has an unconsolidated formation with viscous oil at shallow-depth. Drilling and completion of horizontal well at such shallow depth is quite challenging. Industry practice is to use Slant Rig for shallow wells. Drilling experts preferred solution that would not entail Slant Rig for any future interventions and instead suggested using conventional vertical rig to establish feasibility of drilling and completion as a pilot.

Lots of pre-drilling studies were carried out which involved Geomechanics Study to understand Stress orientation, pore pressure and sanding risk; Laboratory test of return permeability on core plugs for drilling fluid design and pore-bridging material selection; XRD & SEM analysis for clay mineral identification; Torque and Drag Analysis for predicted performance during drilling and completion and Particle Size Analysis for sand control design with slotted liner.

Pre-job coordination meetings, Daily briefings, usage of Rotary Steerable System, Geo-Steering and Mid-course correction of trajectory based on Real Time Data Monitoring resulted in well placement in sweet spot. Well by well, rig days got reduced, lateral lengths increased, tangent sections for pump placement optimised and practically no held up occurred during drilling, casing/liner lowering or completion. This was a World record of drilling horizontal well using vertical rig at such shallow depth.

The well completion as verified from Silicon Activation log suggests optimal placement of the slotted liner. This is further vindicated from zero sand and water production, another great achievement for the pilot project. Till date 7 such shallow wells have been drilled with 6 on continuous production for over 2 years in different parts of the field. Successful drilling and completion of these shallow-depth horizontal wells by conventional vertical rig in an efficient and cost-effective manner has confirmed all the pre-drilling assumptions and technological tests for the pilot phase, reaching world record breaking achievement.

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