Real-Time Ultra-Deep Azimuthal Resistivity Inversion Helps to Maximize Asset Value in West Kuwait by Locating Uneven Oil-Water Contact

Abstract

Abstract The Burgan sandstone reservoir in the Minagish field of Kuwait is a complex depositional sequence that makes targeting Upper Burgan sands unpredictable due to channeling limiting the reservoir exposure. The area is complicated further by oil-water contact (OWC) uncertainty due to the long history of oil production. The objective of the well was real-time OWC mapping to provide reservoir insight, maximize pay zone exposure and extend the well life through optimizing the completion and production regime. Recent production pulsed-neutron capture (PNC) logging in an offset well showed watering in the Upper Burgan reservoir. This might indicate a change in the level of the OWC or water coning. Utilization of an ultra-deep azimuthal resistivity (UDAR) mapping service was planned to help locate the OWC below the well trajectory and simultaneously identify and track the desired target sandstone sequence. UDAR has proven its capability to map reservoir boundaries and the OWC in real time, during drilling, earlier than with traditional methods. This facilitates real-time geosteering to drill the well in a single run in the productive zone. The wellbore was placed in the desired zone by using UDAR real-time 1D inversion services. While drilling, it was discovered that the OWC was at uneven depths compared to what was expected. The reservoir management team obtained important information to update the oilfield development. UDAR services helped to increase reservoir exposure of the well in the Burgan sand of the Minagish oilfield and enhanced the understanding of the sand deposition structure. It was evident that PNC results in the producing offset well do not represent the OWC level throughout the field; instead, localized measurements may be affected by water coning in that specific area. This information led to a change in the field development strategy. The UDAR real-time 1D inversion enabled optimization of the completion design and perforation intervals, and the understanding of the reservoir potential has been improved. The accurate OWC level evaluation will allow to place more production wells in this location.