Process Systems Enterprise Limited
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Integrated Sensors, Modelling and Control for Oilfield Fluids and Processes [NOT FOR PUBLICATION]

This collaborative project between Schlumberger, PSE and Imperial College London aims to develop new sensor systems for in-situ measurements of the thermophysical properties of petroleum reservoir fluids and to develop advanced thermophysical models for inferring the values of properties that are not directly measured.

The sensor systems and property models will be integrated to permit real-time distributed monitoring of reservoir fluid properties and enable advanced reservoir management strategies.

Benefits will include control of injection processes (for example,. CO2 for enhanced oil recovery or sequestration), increased hydrocarbon recovery, reduced environmental impact, and extended life for brown-field sites such as the North Sea fields.

The project is led by Schlumberger Cambridge Research.

 

New and existing physical-property and chemical composition sensors is being integrated with multi-scale modelling to achieve enhanced monitoring and control of oilfield fluids and processes. The objectives of the project are:

The sensor systems and associated models will permit real-time distributed monitoring of reservoir fluid properties and enable advanced reservoir management strategies.

Benefits will include:

Five objectives will be pursued in a closely integrated and co-ordinated project:
  1. Accelerate the development of advanced sensors for in-situ measurements of thermophysical properties of petroleum reservoir fluids
  2. Establish robust molecular-based models for inferring a wide range of physical properties from limited sensor data
  3. Develop a general methodology for deriving reasonably accurate, yet computationally tractable, models of the transient operation of an integrated system comprising reservoir, wells and topside processing facilities
  4. Couple the above model to sensor data, developing a methodology for the optimal, permanent placement and use of sensors in a reservoir formation
  5. Develop model-based strategies for the optimal operation of the integrated reservoir/ wells/topsides system

The project will exploit a range of innovative sensor technologies not currently available for oilfield applications. These include, for example, micro-electromechanical-systems (MEMS), miniaturised vibrating wire, rod or tube sensors, and ultrasonic probes. The challenge is to develop small, robust and stable devices suitable for application under reservoir conditions (high temperature & pressure, harsh chemical environment).

New sensor designs will be combined with advanced thermophysical property models to create new sensor systems capable of inferring key properties that are not measured directly. The provision of these models and the infrastructure to support them is PSE's key role.

The availability of sufficient high-quality reservoir data opens the possibility for the construction of models of the transient behaviour of the integrated system comprising the reservoir, the wells and the topside processing facilities.

In principle, this could be achieved by building software interfaces between standard reservoir simulation tools, well modelling software and conventional process simulators. However, this would probably lead to a system that is neither computationally tractable nor suitable for advanced applications such as model-based mathematical optimisation.

Instead, we propose to develop and demonstrate a novel multi-scale modelling methodology that describes the entire system within a single advanced modelling environment, while making use of information derived from reservoir and well simulators to fit the models of its sub-systems (e.g. the reservoir or the wells).

The above model will be tightly coupled to reservoir data via the use of formal model validation techniques. Conversely, the model itself will be used determine optimal locations of the sensors so as to ensure that the most valuable information is extracted from the reservoir for a given investment in sensors.

Finally, the validated multi-scale model will be used to enhance management of the oilfield via advanced optimisation and control strategies. Overall, this integrated system has the potential to radically change the efficiency of oilfield exploration and exploitation activities.

The project will integrate new sensors, sensor systems and multi-scale modelling to deliver enhanced reservoir exploitation, diminished environmental impact and reduced operating costs.

Properties to be measured directly may include density, viscosity, compressibility, pH, salinity and key chemical compositional indicators, as well as temperature and pressure. Temperature sensing is straightforward and the development of sensors for pressure is well advanced, although there is a need for reduced cost and improved stability. MEMS devices, miniature vibrating elements and ultrasonic probes will all be considered for the measurement of density, viscosity and compressibility. Conductivity indicators, near infrared sensors and NMR probes will also be exploited. Compact, reliable and robust sensors of these types would, by themselves, be very significant in terms of improved hydrocarbon recovery and diminished environmental impact through the avoidance of full-scale well testing.

Still greater impact and greater benefit will accrue from integrating sensors, property models, reservoir models and well/topside facilities models.

The project will investigate the use of model-based optimisation approaches to optimise the placement of sensors in the formation and to exploit to the greatest possible extent the data obtained.

Thermophysical property models will be used to infer important, but not directly measured, properties such as the bubble curve from the available data. This will have the benefit of permitting a much more detailed map of the reservoir fluid properties to be developed with consequential operating benefits.

Ultimately, the combination of local thermophysical property models with reservoir-scale compositional models will offer operators the tools to exploit fields much more effectively than presently possible. This may have important implications for extending the life of 'brown-fieldEsites such as many North Sea fields.

The most obvious benefit of integrated sensors, property models and control strategies will be increased hydrocarbon recovery from both existing and new fields.

Schlumberger already manufactures, and operates on behalf of clients, wire-line tools for reservoir-fluid sampling and property measurements. The new technology may appear first in a new generation of wire-line tools capable of in-situ property measurements without the need to transport samples to the surface. This alone is a significant market opportunity.

PSE's gPROMS software is already used by the world's leading oil companies for modelling upstream operations including topsides processing facilities, oil and gas pipelines, and LNG storage tanks. The integration of reservoir modelling within this framework will greatly increase the value and the appeal of the modelling tool.

The sensor systems and many aspects of the modelling work will have a wider application in the chemical process industries and beyond.

A direct environmental benefit of enhanced reservoir monitoring and control will be a reduced need for well testing. The new sensor and control systems will contribute to environmentally advantageous processes such as carbon dioxide injection for enhanced oil recovery and sequestration, both of which require distributed monitoring and control.

Other areas of application include control of solids deposition and monitoring of steam-assisted heavy oil extraction.

Integrated reservoirs, wells and topside processing facilities are certainly novel, and so is the multi-scale integration of conventional modelling tools with reservoir and wells models. Consequently, there is a risk associated with this part of the project too. However, PSE has extensive expertise and is a recognised leader in the construction of advanced multi-scale models, such as those combining its gPROMS software with computational fluid dynamics (CFD) technology, and also in using these models for deriving significant practical benefits.

The consortium brings together groups with the necessary skills and resources to realise the project goals of developing advanced on-line process monitoring and control systems for reservoir management - integrating sensors, modelling and control for optimising oilfield processes.

In the UK sector of the North Sea, which faces a number of challenges as production declines, the development of these systems would help maximise recovery and reduce environmental impact (e.g. aiding use of CO2 for enhanced oil recovery or sequestration).

Process Systems Enterprise Ltd (PSE) brings experience in multiscale modelling and model-based control strategies that will be used for optimisation of reservoir and well operations. For advanced sensors there will be: 1. MEMS 2. MINDS (miniaturised devices) 3. CCS (chemical composition sensors) For modelling and control systems there will be: 4.Thermophysical property models for reservoir fluids using primary sensor measurements 5.Integrated multi-scale modelling of the reservoir, wells and topside processing facilities 6. Optimal sensor placement, model identification, and model-based optimal operation of integrated reservoir-well-topside facilities