Live Field Models: Myth or Reality?

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Oil and gas field modeling plays a key role in:
- the understanding of physical processes observed in the formation and in wells;
- the working out of a strategy at initial stages of field development;
- exercising control over the oilfield at later stages of field development.

However, many experts admit a big gap between reservoir simulation and the real-time management of an oil and gas field. This gap emerges under the action of several factors. First of all, only a limited number of specialists can use the results of modeling. Actually, we face a problem of modeling just for the sake of modeling. Secondly, these models get out of date quickly or cannot keep pace with the required level of management flexibility and responsiveness. In this case model-aided proactive management becomes impossible and mainly turns into a mere reflection of the ongoing processes. Thirdly, experts in allied fields and management staff very often underestimate the significance of modeling, its potentials and limits. On the one hand, we expect a lot and are eager to get "answers to all the questions" from a model, on the other hand, we cannot use the modeling results for practical purposes.

How can that problem be solved? We called on system analysis to answer that question. One of the principles of this method is a statement of direct dependence of the rate of any system self-organization on its internal feedforward and feedback rate. Thus the processes' rate and periodicity become the most critical factors. Why do the models turn out to be unclaimed? Mainly because the time period required for decision-making by the company's experts and managers is much less than the time needed for a model construction and updating (Fig. 1). So, we get the answers "the day after the fair". Thus, the key parameters, which influence the rate of modelling are the following:
- time needed to get access to the models;
- time needed for their updating.

The necessity of reduction of the time of access and updating resulted in development of a Live Model concept. This approach should reduce the gap between modeling and practical oil and gas field management.

The following objectives were set at creation of the Live Model concept:
- to use the models as interactive means of teaching;
- to make them available to everyone, everywhere, anytime;
- to create the tools of models updating and monitoring.

Interactive Teaching Methods

We developed the WebSim product, which can be used for the creation of interactive teaching methods, where ready templates of hydrodynamic models are employed together with web technologies, ensuring easy access to the modeling system. As a result of this, any specialist can create a simple model within seconds and carry out analysis of the  results using nothing but a web browser. This approach significantly lowers the threshold level of access to the modeling technologies. The interactive teaching methods help experts in other fields to understand better the main principles of modeling, which benefits the quality of team work. It is possible to build one's own model at the www.live-model.com site (Fig. 2).

Models Accessibility

The above approach to web technologies as a means of improving access to models was also applied in practical work involving real oil and gas field models. WebSim can be easily connected to the real models archive and has an option of modelling results viewing. Using this tool any employee of the company can:
- make analysis of the pressure and production rate dynamics both for the oil and gas field as a whole and individually for each well;
- make pressure and phase saturation distribution maps, as well as streamlines visualization;
- with the help of cross-plots ("predicted parameters vs. actual parameters") estimate the quality of the models history matching.

Another important point is that the product's design allows to support models created by different types of simulators.
It helps improving the system's flexibility and removes restrictions on the simulator type used by the company.

Models Updating and Monitoring

Models updating helps avoid unreasonable consumption of human and time resources needed for construction of duplicate models of the same field. Thus, one can store and use all information obtained in the course of following-up regularly updated models. That is why integration of WebSim with engineering and information portal REPOS, which is actually a system of data control for oil and gas companies, became the next step. WebSim can act as an integral part of REPOS or any other similar system. The links between archived hydrodynamic models and administrative-geological hierarchy of the company make it possible to carry out monitoring of model prognostic parameters versus actual production rates, which are automatically entered to the corporate database. The interaction of WebSim with the corporate database and models accessibility helped the oil and gas companies that employed this method to use modelling results in the process of decision-making more efficiently. Live Models are updated automatically based on the incoming dynamics data, which are subsequently used in calculation. In case of necessity, it is possible to make additional adjustments and/or update the model using RSOffice, which is a visual modeling system. RSOffice provides them with convenient tools to solve engineering tasks and to carry out a detailed model analysis. Initial data for that purpose may be imported from the REPOS engineering and information portal both during building-up of a model  and during automatic model updating (Fig. 3).

Conclusion

The Live Model concept may be applied not only for complex 3-D hydrodynamic models. It can be effectively used for models of any class of complexity - from material balance calculation to waterflood sector models.

Live Models are interactive services, which bring the process of modeling to an absolutely new level by increasing significantly the rate of feedback and feedforward throughout the entire system of oil and gas field development management. However, one should keep in mind, that the Live Model concept requires not only up-to-date technical solutions but also the transformation of workflows, the deeper integration of modeling into the company's management system. Besides, is is not only the process of modeling should be adopted to users' needs:  users should also make efforts to master modeling techniques, thus boosting up their qualification.

Only in this case is it possible to achieve a synergetic effect, which will narrow the gap between modeling and management and bring their efficiency to a higher level.

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