Development of constraint handling techniques for well placement optimization in Petroleum Field Development - Problem formulation and implementation for FieldOpt software including well index calculation for deviated wells
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Well placement optimization is an important part of Petroleum Field Development.However, in order to improve the optimization procedures, it can be important toincorporate considerations like knowledge about the geology of the reservoir orabout existing or planned well paths. This leads to additional constraints thathave to be satisfied during the optimization. In this thesis we concentrate inparticular on constraints on the well lengths and the distance between the wells. We suggest an alternating projections method to deal with both constraints at thesame time, and develop an efficient numerical method for the solution. Although wecannot prove that the method is convergent, numerical results of our implementationindicate that the approach works as intended. An additional important contribution from this work is theimplementation of a well index calculator. In reservoir simulation, the well index relates the flow rateand pressure of the wellbore to the pressure solution of thesubsurface fluid flow system, and is therefore an essentialpart in computing resulting production volumes. We also implement an algorithm that, given a slantedwell and the physical state of a reservoir, calculatesthe well indices for the well blocks that are intersectedby the well. In particular the well index calculation for deviated wellsis a nontrivial task that is important for well placementoptimization research. This task is already handled by some industry reservoirsimulators, but the implementation is hidden from theend-user. All of the implementations are meant to be an addition to FieldOpt, a petroleumfield development optimization framework that is currently under development bythe Petroleum Cybernetics Group at NTNU.