Methodology of drilling targets selection under geological uncertainty

UDK: 622.24.001.57
Key words: reservoir drilling targets, probability estimate, decision-making algorithms, selection of optimum strategy
Authors: A.N. Sitnikov, A.A. Pustovskikh, A.S. Margarit, E.V. Belonogov, R.Z. Zulkarniev, A.Yu. Korovin (Gazpromneft NTC LLC, RF, Saint-Petersburg)

An engineer is often faced with uncertainty in the value of parameters required for engineering calculations on the basis of which the decision must be made.

In the company "Gazprom Neft" a project is being implemented to improve the efficiency of business planning, including planning drilling of new wells. During the project a tool has been developed which calculates potential production characteristics of planned well and allows a probabilistic assessment of potential indicators, taking into account the geological uncertainties. Probabilistic assessment is based on the Monte Carlo method with a set of geological and physical uncertain characteristics of a reservoir. To choose the most optimum variant of an asset development several algorithms are offered, each satisfying the pursued goals: maintenance of the level determining parameter, pessimistic case, minimizing loss of benefits and choices based on EMV.

On the basis of proposing probabilistic assessment approach the parameter with the higher uncertainty is identified and possible methods of decreasing the uncertainties by conducting the necessary investigation. Also it carried out the description of the algorithm makes it possible to assess the economic feasibility of an offered research.

On the basis of the proposed approaches and algorithms calculating tool is implemented that extend the functionality of the instrument of ranking reservoir drilling targets. A list of ranking reservoir drilling targets over the current assets of the company is formed including the medium-term plan for drilling. Highlighting a key uncertainty for each target drill has a greater impact on the economic viability of a project. A set of geological prospecting works is formed to minimize a key uncertainty.

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