Successful Deployment of new Extended RockstrongTM Coring System: Record Coring Delivery and Recovery Achievement in ADCO Exploration well – UAE case History

Abstract

This paper presents how extensive pre-job planning and proper utilization of new technology led to actualizing the coring objective of a well safely including successful coring through the hydrogen sulphide (H 2 S) rich Habshan 1 and 2 formations in an onshore field of the Abu Dhabi Company For Onshore Oil Operations (ADCO) in the United Arab Emirates.Well AK1 is part of a wider field appraisal plan to be used for data gathering and building a conceptual field development plan. The challenges were multiple, not only from the planning and coring bottom hole assembly (BHA) design point of view, but also in terms of effective health, safety and environment management during execution posing environmental and technical challenges to the desired data gathering objective.The appraisal well AK1 well design required 12 conventional coring BHA runs over a 27days duration including coring with an 8 -1/2" coring BHA through a 12-1/4Љ hole section. With detailed forward planning, use of new extended coring technology, operational focus and health, safety & environment (HSE) consciousness at the forefront, 6 continuous cores in 15 rig days with a record total core length in excess of 1,300 ft was successfully cut with 100% recovery factor through Shilaif, Mauddud, Top Nahr Umr, Unit 22a, Unit 22, Habshan, Habshan 1, Habshan 2 and Dense below Habshan 2 formations with H 2 S contents way in excess of safe limits saving 12 days rig time and almost $1m USD of planned well cost in the process.This paper aims to share how this was recently achieved highlighting some of the challenges faced in terms of planning and sharing the experience gained from successful execution of well AK1, including coring through H 2 S bearing formations, with respect to optimized core acquisition and handling for the benefit of other operators in the region.

Application of Resonance Enhanced Drilling to coring

“…Core samples covering 30, 60, or 90 ft sections are common and provide valuable reservoir geological and petrophysical properties for geoscientists [13]. Many new technologies aimed at improving drilling efficiency and enhancing core quality are being developed based on these two methods, such as logging-while-coring technology [14], new liner systems [15,16], pressure coring technology [17][18][19][20], anti-jam coring systems [21,22], extended coring technology [10,23], turbine driven coring systems [24] and wireline continuous coring [25,26].…”