First Wireline and Elevated Pressure Coring in UAE - Saved 30% of Coring Time for Shallow Reservoirs & Delivered Realistic Fluids and Gas Saturations

Abstract

Abstract For many years, coring operations suffered from frequent jamming due to abrupt changes in lithology and rock properties. Core jamming leads to potential core damage, excessive number of trips, longer operation time and thus higher cost. Frequent and abrupt lithology and rock property changes are natural occurring phenomena. To mitigate the implications of core jamming, a robust coring technology platform has been deployed, which allows alternating between coring, pressure coring and drilling without pulling out the drillstring. The applied wireline-retrievable coring technology offers an efficient and cost effective way to trip-out large diameter core, thus achieving high recoveries of high quality cores. It also allows the Operator to almost decide real-time to drill ahead or to retrieve additional cores without performing additional trips. The coring/pressure-coring/drilling assembly is designed in such a way that it is efficient to switch from coring to pressure-coring or to drilling modes and vice versa, without tripping the drill pipes. By eliminating trips, this technology is extremely cost effective for multiple coring targets, especially when incorporating inter-drilling sections. The wireline-retrievable coring technology was also successfully applied to obtain pressure core, deploying breakthrough technology for the first time in the Middle East that retains the hydrocarbon content in its native state, with no lost gas, until core retrieval and evaluation on surface. This paper describes a case history of the first deployment of the wireline-retrievable coring/pressure-coring in the UAE and the Middle East, while saving significant rig time compared to conventional coring.