Benefits From Implementing an Integrated Asset Operations Modelling System

Abstract

Abu Dhabi Company for Onshore Oil Operations (ADCO) chose the North East Bab (NEB) field complex and asset to pioneer intelligent field technologies and work-practices within the company from development, to production start-up in 2006 and in subsequent enhancement projects. This paper describes implementation and operational experience from the online production optimisation and monitoring software now used as part of the asset team's work-flows.

Offline modelling of the NEB complex started in 2006 to demonstrate the feasibility of the concept.  In what is now becoming standard practice, an offline integrated model of the reservoir performance, production, gas-lift, water and WAG injection wells and surface facilities was set up.  Experience from using this model and workshop sessions with all disciplines within the NEB Asset team were then used to specify and commission a commercially available web-based system.

The online system is being used by the team to help optimise reservoir, well and plant performance. Common access to up-to-date information throughout the organisation has encouraged faster decision making and prioritisation of measurements with resulting optimal improvement implementations in the field.  The system monitors performance against reservoir management targets for production/injection and facilitates diagnosis of any deviations from plan by highlighting flow-assurance issues from the reservoir to well to process plant to export pump. The methodology used is transparent to any user and so confidence can be established in the continuously updated results for well and network flow assurance, reservoir pressure estimation and voidage monitoring. The increasing focus on information, rather than raw data, is improving operational efficiency and the team plan regular enhancement of the system features.

The paper illustrates, using field examples, the benefits being realised from the online performance monitoring and full loop optimisation of both production and injection wells.

Introduction

The NEB project was described in an earlier paper (Saadawi, 2006). The project consisted of a grass roots development of three separate oil fields: Al-Dabbiya, Rumaitha and Shanayel with associated oil, gas and water production facilities and gas and water injection equipment.  The wells in each field flow to a number of remote stations or clusters.  Pipelines connect these clusters to two central processing plants (CPP) located at Al-Dabbiya and at Rumaitha. The Al-Dabbiya CPP is shown diagrammatically in Figure 1. The CPP processes oil, gas and water from the Al-Dabbiya wells and exports the oil to a trunk pipeline. High pressure gas for enhanced recovery either through direct injection or water alternating with gas (WAG) injection is compressed at the CPP along with processed gas from Rumaitha CPP and make-up gas from gas producers and a dedicated gas network grid. The CPP also pumps water to the injection or WAG wells from supply wells.

The wells and facilities are monitored and controlled by a distributed control system (DCS), with control from an operating centre near the fields. There is a high degree of instrumentation installed with the status of most valves available on the DCS along with pressures and temperatures throughout the system. The majority of wells can be remotely controlled by choke or shut-in and started. These capabilities were designed to improve efficiency and also minimize the need for travel to the wellsite. These features improve safety for the workforce and also help protect the environment in this highly sensitive coastal area.