Production Enhancement Strategy in Lower Burgan Reservoir: Greater Burgan Field, Kuwait

摘要

A comprehensive development strategy for BGSL1 reservoir of Burgan Formation, deposited in Lower Cretaceous, of Greter Burgan field, Kuwait was formulated to increase the production of the low productive heterogeneous reservoir. The BGSL1 reservoir was deposited in shore face dominated coastline with protected tidal bay. The heterogeneous nature and low Sand: Shale ratio makes development of this important reservoir difficult. After studying the production performance of BGSL1 reservoir, mainly four technical challenges are identified. These are 1) wet production, 2) low productivity index, 3) short self-flow life and frequent work over needed and 4) Complexity in terms of lower API crude, multiple oil-water contacts and heterogeneity. Initial study for BGSL1 reservoir was started by revisiting all the wells drilled to BGSL1 reservoir. Remaining Oil distribution maps of each sub-layer were prepared which had given clear understanding of potential of this reservoir. BGSL1 reservoir remaining oil map was divided into several compartments. On the basis of volume, 24 compartments were identified as under-developed in terms of their current off-take rate to current remaining oil volume. Some of the compartments are preferred for development than other due to development opportunities for more than one reservoir. Development of BGSL1 is highly challenging. The reservoir may require planning single dedicated completions with artificial lift. A novel approach was adopted to screen the candidates for artificial lift, which was based on highly underperforming wells, where self-flow with good rate is not possible due to high water cut and declining production. Evaluation of these ESP candidates were done with remaining oil column, bypassed oil & partially swept zone potential with rock quality, PI measurement and historical plot of liquid rate & water cut to review the well deliverability and to estimate water cut with ESP. The technical challenges were resolved to a great deal. For reservoir complexity like multiple oil-water contacts & heterogeneity, unit wise estimation of remaining oil has helped. High viscosity oil mapping helped to isolate low API / high viscous oil. It was seen that study helped to achieve a rise of oil production and using these practices helped to reach highest production over last decade.