Achieving Sustainable Production Optimisation by Automating Asset-Level Production Engineering Tasks Usually Performed Manually

Production optimisation ensures that wells and facilities are at all times operating at their peak performance to maximise production or to maximise revenues. The current manual production optimisation approaches are both time consuming and error prone due to the complexity and large volumes of data that have to be considered. Frequent changes in well and surface equipment downtime, maintenance work, evolving reservoir conditions, etc., usually make it impossible for engineers to keep the asset tuned for optimal operating conditions. In addition production enhancement studies that are not linked to an automated optimisation system have limited value because their recommendations quickly become out of date. Nigel Blott (Nigel.Blott@e-petroleumservices.com) of Edinburgh Petroleum Services (EPS) (www.e-petroleumservices.com) offers one possible solution to this problem. Working closely with its clients, EPS has developed the i-DO comprehensive system of engineering, IT implementation and software technology over a three-year period of research, development and implementation in mature assets.

Introduction

A new system has been developed to provide sustainable automated production optimisation. Called i-DO™ for "intelligent daily operations", it links real-time downhole, surface and corporate data sources to ensure that reservoir, well and facility models are constantly monitored and updated to reflect actual operating conditions; the calculation engine then simultaneously optimises hundreds of critical parameters. The system can handle very complex producing networks having hundreds of wells. The ability to gather and interpret data online as well as implement many of the changes electronically means production optimisation can be sustained effectively with minimum manpower and expense. The key advantage of the system is keeping the asset operating at peak performance.

With a truly intelligent system such as this, engineers are streamlining and automating a number of production engineering tasks associated with asset management. Since no two fields or reservoirs behave exactly alike, the i-DO optimisation capability is not tailored to solve specific problems. The system can be applied without modification to a wide range of production optimisation problems, including downhole controls in smart wells and intelligent completions.

To help engineers overcome the variety of challenges they face in mature assets, the field-proven AIM-GAIN-SUSTAIN™ methodology has been developed to deliver early value and minimize i-DO implementation costs. The methodology includes the engineering consulting, processes and training needed by most producers to improve asset performance.

System Description and Application

The i-DO system leverages the investment of SCADA and other communications and control systems, which are being installed in an increasing number of fields worldwide. Used on a daily basis to manage mature assets and make operational decisions, the system integrates production data management and reservoir modelling with transient pressure analysis, well modelling and surface network modelling and optimisation (Figure 1). The flexible open software architecture allows third-party and legacy applications to be incorporated with relative ease.

Figure 1: The real-time field data captured in SCADA and data historians are accessed by i-DO along with economic parameters from corporate data stores. A set of integrated calculation engines performs data validation and analysis, model update and optimisation functions. The user interacts with i-DO to trigger business and engineering processes and validate results through a Web browser. (Click iamge for larger view)

Rather than having engineers perform individual tasks, a number of processes are automated in pre-defined schedules, triggered by specific events or initiated manually:

• Well models are automatically updated to match production tests
• Network facility models are updated for current conditions
• Daily production data are allocated to wells
• Root cause analysis of unscheduled downtime determines the focus of maintenance efforts for maximum impact
• New reservoir models can be created, short-term production forecasts generated, transient analysis of downhole pressure data determines current reservoir pressure and estimates permeability and skin
• Data are stored and data trending, production and reservoir surveillance reports are generated.

The system can be successfully deployed on several types of assets.

• Mature, artificially lifted oil fields producing at high rates with continuous gas lift (fields with sucker rod pumps or PCPs will see few gains)
• Fields with intermittent gas lift
• Gas condensate and light/volatile oil fields
• High rate dry gas fields

Assets that generally would not benefit include heavy oil and tight gas.

Implementation Track Record

Figure 2 depicts the three-stage integrated process used to cost-effectively implement a sustainable production optimisation system.

The AIM or asset inspection methodology stage defines production optimisation feasibility, identifies debottlenecking opportunities and establishes a business case and costing for production engineering changes.

During the GAIN stage, well and surface network models are built and engineering recommendations are made to increase uptime or improve deliverability. The GAIN stage usually provides immediate results and enough payback to fund the SUSTAIN stage where new production optimisation technology is implemented, processes are transformed and people are trained so they can maintain a sustainable production optimisation system.

Figure 2: The AIM-GAIN-SUSTAIN process focuses on increasing production volumes, lowering downtime and reducing lifting costs. (Click image for larger view)

The benefits of sustainable production optimisation are significant and have been proven with many clients (Figure 3). Gains achieved from i-DO range include 2 to 5 percent improvement in uptime along with a 3 to 7 percent improvement in produced volumes and overall reduction of lifting costs by 5 to10 percent. In many cases these benefits can substantially change the overall economics of the asset.

Figure 3: The i-DO comprehensive system of engineering consulting, IT implementation and software technology has been perfected over a three-year period of research and development combined with real-world application in assets in Venezuela, Kuwait and the North Sea.

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