Drilling of Multilateral Wells in Kuwait Aided With Geochemical Analysis

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 16617, ’Drilling of Multilateral Wells Aided With Geochemical Analysis, Kuwait,’ by Taher El Gezeery, Abdul Aziz Ismail, Khalaf Al Anezi, Monirah Al Jeaan, Jeevan Kumar Silambuchelvan, and G.S. Padhy, Kuwait Oil, and Atul Wasnik and Ahmed Al Shoeibi, Geolog International, prepared for the 2013 International Petroleum Technology Conference, Beijing, 26-28 March. The paper has not been peer reviewed. The Burgan reservoir consists of vertically stacked channel sands along with a fault network connected to the aquifer and contains highly viscous reservoir fluid. This dramatically enhances the water mobility and results in severe premature water breakthrough, bypassing zones of oil. This paper describes the use of real-time geochemical analysis to support geosteering of a smart multilateral well located in one of the highest-potential-flow areas of Kuwait. Introduction The Minagish field in Kuwait was discovered in 1959 and is located in the southwestern part of the country. It contains several reservoir intervals in its stratigraphic column, varying from Early Jurassic to Late Cretaceous. The field is situated 12 km northwest of the west Umm Gudair field. The field has been penetrated by more than 180 wells, to contact not only the middle and lower Minagish reservoirs of the Lower Cretaceous but also other shallow reservoirs such as the Mishrif/ Rumaila carbonates and the Wara/Burgan sandstone. The Minagish field structure of the Wara and Burgan formations is a closed elongated asymmetrical anticline oriented in a north/south direction. The top of the Burgan structure is located at approximately 5,500-ft true vertical depth subsea. Burgan Reservoir. This reservoir is informally divided into the upper and lower Burgan sections. Lower Burgan sands are more extensive and blocky in nature, with few variations in their properties. The lower Burgan reservoir section lies above the oil/water contact (OWC) and is of significance from a hydrocarbon-bearing perspective. Upper Burgan sands are mainly in the form of channel sands, ranging in thickness from a few feet to nearly 45 ft, and they have extensive lateral facies variation. The lower part of the Burgan has active bottomwater drive, whereas the upper part of the reservoir has an edgewater-drive system. The reservoir contains high-permeability sands on the order of a few darcies associated with active faults and has highly viscous reservoir fluid (approximately 40 cp at reservoir conditions). This heterogeneous nature of the reservoir accelerates water movement inside the reservoir and results in premature water breakthrough in the existing vertical wells and in horizontal wells, in spite of maintaining the highest standoff from the OWC.