Challenges Overcome in Drilling and Testing a Deep, Deviated HP/HT Offshore Gas Well

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207506, “Deepest Deviated HP/HT Gas Well Drilling and Testing Challenges on an Offshore Island: Case Study,” by Mubashir Ahmad, SPE, Ayman El Shahat, and M. Osama El-Meguid, ADNOC, et al. The paper has not been peer reviewed. A deep deviated appraisal well in the Upper Khuff reservoir on a small artificial island approximately 100 km offshore Abu Dhabi was drilled and tested successfully. The project was driven by the goal of maximizing ultimate value and benefit for the operator, its partners, the community, and the UAE. The field is in a highly sensitive and ecologically important area and is designated a United Nations Educational, Scientific, and Cultural Organization (UNESCO) Biosphere Reserve. The complete paper presents the challenges faced and overcome while drilling and testing the high-pressure/high-temperature (HP/HT) sour offshore well. Background The operator has pursued the appraisal and delineation of the Arab, Khuff, and Pre-Khuff gas reservoirs in the huge offshore shallow-water field west of Abu Dhabi. During the early 1980s, in order to evaluate the field’s capability, an evaluative program was launched that involved dredging a channel and creating an artificial island, from which a test well was drilled and capped. Many wells have been drilled in the structure since, all in the northwest part of the field. Testing results have indicated impurities [including hydrogen sulfide (H2S) and carbon dioxide (CO2)] ranging from 14 to 33% in some reservoirs.