Using the method of principal components for selecting candidate wells for improving water injection profile

А methodology of using the method of principal components is suggested for the estimation of the influence of geologo-technological factors within the process of selecting candidate wells for enhanced oil recovery methods, in particular for improving water injection profile. At this point, geological and technological criteria of selecting parts of the field for improving water injection profile have been properly developed and fixed as technological rules and instructions, however, the estimation of suggested additional production of oil produced due to water cut decrease as a result of improving water injection profile remains a complicated and, on the whole, a partly unsolved problem. To solve it, a whole spectrum of techniques is needed, namely, from hydrodynamic to mathematical modeling. Every method has its pros and cons. One of the definite advantages of hydrodynamic modeling is the validity of forecasts based on the fact that the hydrodynamic model is oil field history matching. Also, there are the following disadvantages: the necessity of the existence of an actual hydrodynamic model, the complexity of the modeling procedure, the presence of multiple additional parameters, which are seldom wholly known. Mathematical modeling allows to avoid the problems inherent in hydrodynamic modeling. However, for its proper use, it is required to observe the condition of completeness of initial information. Therefore, generally, the results of mathematical modeling can be used as additional information in the process of making the final decision. The use of the method of principal components allows to create a classification of oilfields and group the fields with similar geological and physical characteristics. Based on the grouping, the analysis of the dependence of the success of measures actions on the features of geological and physical characteristics of oilfields has been conducted. It is shown that on oilfields deposited at a depth less than 2 km and represented by highly viscous, highly sulphurous and heavy oils the undertaking of improving water injection profile based on the cross-linked polymer systems technology is impracticable from the standpoint of economic profitability of the measure. By means of k-means clustering concrete ranges of meanings of geologo-technological characteristics for successful and unsuccessful measures actions are singled out. Applying the suggested methodology in conjunction with the rules of selecting candidate wells for enhanced oil recovery methods allows to lower the percentage of unsuccessful measures actions as well as to evaluate the prospective additional oil production without applying cumbersome hydrodynamic modeling.

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