Innovative Approach in Sidetracking Wells in Kuwait Brown Field Development Reduces Drilling Hazards and Improves Well Productivity

Abstract

Mature field necessitates drilling high angle and horizontal wells in order to improve wells productivity, reduce water coning and tapping multiple reservoirs. The operating company has endeavored to convert many of the Vertical wells in its mature fields into High angle and Horizontal wells by Side Tracking, primarily to reduce well cost and overcome restrictions in obtaining clear surface locations. Shale instability related problems were experienced in many Side Track wells in the buildup section. The whole deviation used to be ranging from 62 degrees on the top to 70 degrees on the bottom. The old wells used to be completed traditionally with a DLS of 5 – 5.5 leading to stuck pipe, hole collapse, multiple wiper trips, casing short landing etc. The operating company after extensive techno-economic evaluation has implemented a new and novel drilling technique to allow side tracking from an existing well, with inclination in the hole as low as possible, and land the well successfully with high dogleg severity. The new approach managed to reduce the deviation against the problematic formation to 50 degrees with a high dog leg severity up to 12 degrees / 100 feet. A high Build rate Rotary Steerable tool was used to reduce the measured depth and in some cases reduced inclination when drilling through unstable shale layers overlying the target formation. The High Build Rate tool also reduces the Vertical section thereby landing the well closer to its original hole reducing uncertainties in Landing. The Rotary Steerable was preferred due to its inherent advantage of continuous rotation that reduces differential sticking and enhances hole cleaning. Deep Kick Off increases deliverability of the depleted producer well by enabling placement of ESP Pumps at a deeper depth and overcome deferent formation with defiant pressure which improve mud weight management and overcome the stuck pipe problems in the shale zone by cutting through this shale with a low Inclination. It also enabled shorter measured depth, closer successfully landing and reduced open hole exposure time. Finally, the cost saving in this project can be summarized in reducing the buildup section by 45% which can be translated into a saving of more than 70 K USD per well.