Abstract

The Greater Burgan Field, located in southeastern Kuwait, covers about 320 sq miles of surface area and is classified as the largest clastic oil field in the world. The field produces mainly from cretaceous age sandstones of the Burgan, consisting of Third, Fourth and Wara formations.

The field was discovered on February 23, 1938, and production began eight years later. The Burgan formation holds most of the hydrocarbon reserves and accounts for approximately 90% of the field production.

Sandstone acidization offers major challenges to the petroleum industry, and previous treatments in this field did not reveal encouraging results. The application of recently introduced advanced fluids and engineering designs for sandstone acidizing has shown successful results. In addition to choosing the correct fluid system for the main acid treatment to avoid secondary precipitations, considerations for choice of appropriate type and correct volume of preflushes to condition the formation and use of proper overflushes proved essential.

This paper describes the application of a new sandstone acidizing system applied to a well completed in the Third Upper sandstone. This well had ceased to flow due to formation damage and was shut in for a long time. Core samples and reservoir rock properties were used to customize the acid system. The understanding of reservoir rock properties and the systematic approach of treatment design were key factors in employing this system. The system was tailored to penetrate deep into the formation while removing near wellbore damage.

Post-job production showed a significant gain from 0 to 949 BOPD of dry oil. To date, production has been sustained more than four years, adding value by saving the cost of repeated acid stimulation jobs and also by adding to the value of additional incremental oil gains.

The post-job analysis of results enabled further optimization of these processes, which would facilitate similar applications in many more wells in the region.

Introduction

The focus of this paper is primarily the Burgan formation of the Greater Burgan Field located in the southeastern part of Kuwait (Fig. 1). The Mauddud, Minagish, and Marrat formations also contribute to the field production, but the Burgan formation accounts for 90% of the reserve and field production.

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