Achieving Higher Productivity from Mishrif Reservoir with Multistage Completion Technology: Challenges, Solutions and Performance

Abstract

AbstractHorizontal wells drilled in Kuwait Oil Company (KOC) targeting tight carbonate Mishref reservoir in West Kuwait Minagish development fields provided increased reservoir contact area leading to higher production rate and wider access to available hydrocarbon reserves. Large wellbore radius in these open hole horizontal laterals have resulted in increased friction losses during production phase. Later, with flow equalizing completion techniques, ultimate recovery from the reservoir increased and stable production was achieved during the early phase of the reservoir.However, accessing these long horizontal laterals was a challenge and coiled tubing acidizing treatments helped achieve permeability improvements only upto a certain extent. Majority of the reservoir sections with lower permeability were unaccessed and left untreated. Limited pumping rates through coil tubing could achieve few inches of radial penetration into the formation due to limited amount of acid dosage in the stimulation design. It has also been observed that bullheading treated only the heel section of the horizontal well, especially in the case of carbonate formation where acid stimulation is considered for productivity improvement. Studies carried out via Production and Temperature logging concluded that large sections of the open hole lateral were not contributing to the production due to inefficient distribution of acid across the lateral.Hence there was a need for a completion system which could target those unaccessed, relatively low permeable and untreated zones by providing positive mechanical diversion. With this completion technology, formation treating fluids can be pumped effectively and at maximum desired rates. As a part of the ongoing production strategy, Open Hole Multistage Completion (OHMSC) systems consisting of multiple frac sleeves flanked by open hole packers were deployed in multiple appraisal wells and achieved higher productivity in reduced time.This paper will present details on challenges encountered during wellbore preparation and techniques implemented to deploy OHMSC system in Minagish field. The lessons learnt after executing the project and performance improvement to encounter more challenging reservoir and hole conditions in future are discussed in detail.