Development of Marginal Fields Offshore Abu Dhabi
Authors: Jawhari A.R.K. , Garman C.R. , Tsunashima I. 
Published: October 2008

Two marginal fields, offshore Abu Dhabi, in the Arabian Gulf have been developed with the incorporation of several innovative features for the production, control and monitoring of these remote offshore fields. Sharing some facilities of a nearby, larger oil production system allowed cost reduction. Careful consideration needed to be given to the stabilisation of the 25 pipelines for installation in the two fields in very shallow water depths ranging from a shoreline approach to 21 metres.

INTRODUCTION

The Umm A1-Dalkh (UA) and Satah Fields are operated by Umm A1-Dalkh Development Company (UDECO) which is jointly owned by Abu Dhabi National Oil Company (ADNOC) and Japanese Oil Development Company (JODCO). The production from both fields is eventually coming led with that from Zakum Complex. The three fields have different participation by the multinational companies co-operating in the field developments. Both UA and Satah fields are relatively small, remote offshore fields. The economic viability of the developments dictated minimum cost facilities and designs that would require low operating and maintenance costs.

The economic success of the projects was achieved by application of new and developing technologies in several areas including the following:–Distributive control systems–Telemetry monitoring of wellhead platforms–Power generation by solar panels and thermoelectric generators–Control and handling of high pressure crude oil with high hydrogen sulphide (H2S) content–Removal of H2S from produced gas using high load DEA–Stabilisation of pipelines by concrete coating, mechanical anchoring and post trenching.

FIELD DEVELOPMENT

Umm A1-Dalkh Field

The Umm A1-Dalkh field lies in the Arabian Gulf about 30 Km north west of Abu Dhabi as shown in Figure 1. The development consists of a number of platforms which are designed to produce and process 25,000 barrels of oil per day. The processed crude oil is pumped to the Zakum Complex. The vapour pressure of the crude is limited to 135 psia to prevent two phase flow in the pipeline to Zakum Complex. On the Zakum Complex the oil from Umm A1-Dalkh mtxes with Upper Zakum crude oil and is sent to Zirku Island where the crude oil is further processed and stored. The associated gas is used for fuel on the Umm A1-Dalkh Central Production Platform with the surplus gas being flared offshore.

The reservoir has been developed with ten remote, unmanned production wellhead platforms (WHP'S) plus six water injection platforms. Crude oil from the southern sector of the field is routed to a manifold platform from where it flows in one line to the Central Production Complex (CPC). Crude oil from the northern sector of the field is routed directly to the Central Production Complex. The Central Production Complex comprises three platforms: a Central Production Platform (CPP), a Living Quarters Platform (LQP) and Flare Platform (FLP). The CPP receives and processes all crude through 2-stage separation before export to the Zakum Complex. Associated with oil production is a water flood programme. Water is treated at the CPC before being pumped to the unmanned injection wellhead platforms.