Analysis of “reservoir–well” system conditions using functional diagnostic methods

This paper presents a functional diagnostic method based on the fractal dimension of time series fluctuations. The fluctuations are conditionally subdivided into two categories: straightening and non-straightening on the fractal plane. A simplified method of fractal dimension calculation of time series is presented. The sensitivity of the method to the data availability is assessed. A criterion for the estimation of process conditions with close fractal dimensions is offered. A non-parametric criterion is given for the fluctuations that do not straighten on the fractal plane. The criterion is shown to be capable of picking up the changes in dynamic system behavior. The suggested method is tested on a model and practical examples. A retrospective analysis of a well performance is presented as an example for practical applications. The calculation algorithm of the suggested criteria is straightforward, accurate, and significant in practical reservoir engineering.

► We present simplified method of fractal dimension calculation of time series.
► The presented method is applicable for practical engineering calculations.
► We propose criterion for the estimation of processes conditions with close fractal dimensions.
► Analysis of a well performance is presented as an example for practical applications.