Optimization Leads to Successful Deepwater Extended-Reach Drilling Offshore West Africa

Topics: Offshore

West Africa has seen a significant shift in drilling activity, mainly in deep water. Many of the major international operators are carrying out important ­exploration-and-development activities there. Typical field-development plans in offshore projects call for step-out directional and extended-reach wells, to reach and develop large areas from a single drilling platform.

Introduction

West Africa has seen a significant shift in drilling activity, mainly in deep water. Many of the major international operators are carrying out important ­exploration-and-development activities there. Typical field-development plans in offshore projects call for step-out directional and extended-reach wells, to reach and develop large areas from a single drilling platform.

A solid drilling plan is required for success with an extended-reach well. The plan should be comprehensive but feasible for achieving the desired results. In this case study, the extended-reach trajectory called for the delivery of build rates in the 17½-in.-hole interval not previously reached in the shallow soft formations, building up to an 85° sail angle. For the 12¼-in. tangent interval, the BHA must hold the angle and step out the well along a faulted shale and later turn the well more than 60° in azimuth to intersect the reservoir properly.

A proprietary, state-of-the-art BHA planning tool was used to model and design the appropriate BHA for each interval. Different iterations were performed to account for potential hole enlargement, build-rate response, vibration mitigation, and hole cleaning. The proposed solution was to use a point-the-bit RSS with attributes to overcome hole enlargement and deliver the planned trajectory and hole quality.

The RSS was used to drill all of the directional intervals. All intervals were drilled casing to casing in one run, with one BHA per section.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE/IADC 163485, “Offshore West Africa Deepwater Extended-Reach Drilling: Drilling-Optimization Case History,” by Hernando Jerez, SPE, Rafael Dias, SPE, and Jim Tilley, SPE, Halliburton, prepared for the 2013 SPE/IADC Drilling Conference and Exhibition, Amsterdam, 5–7 March. The paper has not been peer reviewed.
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Optimization Leads to Successful Deepwater Extended-Reach Drilling Offshore West Africa

01 May 2015

Volume: 67 | Issue: 5

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