Abstract:

We analyzed one of the promising directions of optimal control over the process of drilling wells – the realization of automated control in real time by the criterion "minimum specific energy consumption". A comprehensive assessment was conducted of the relations between the two optimality criteria of the drilling process – the minimum cost per meter of drilling and specific energy consumption. We used the Farrar-Glauber method for the analysis This is predetermined by the fact that the models that are employed for computing the cost per meter of drilling include the duration of drilling with one bit and footage per bit. However, they can be defined only upon completion of the bit run, which lasts for several tens of hours. This prevents applying the criterion "minimum cost per meter of drilling" to solve the problems of control in real time. In contrast to that criterion, specific energy consumption can be controlled continuously in the course of drilling a well. With the help of the Farrar-Glauber method, we established that there is complete multicollinearity between the criteria "minimum cost per meter of drilling" and "minimum specific energy consumption" at the change of axial force on the bit and the frequency of its rotation. The degree of completeness in the multicollinearity among the examined criteria is found: – at the change in axial force to a bit F: det t=0,305;   (16.003>3.8); F>Ftable (31.808>4.60); t12>ttable (5.639>2.145). – at the change in rotation frequency ω: det t=0,114;   (30.011>3.8); F>Ftable (94.913>4.49); t12>ttable (9.742>1.746). At the change in the consumption of a washing fluid, under conditions of the experiment, the multicollinearity between the investigated criteria of optimal control is missing: Q: det t=0.84;   (2.35<3.8); F>Ftable (2.662<4.60); t12>ttable (1.631<2.145). The obtained results are important and useful for the application of a dualistic approach to solving the problem of optimal control over the process of drilling in real time and the formation of optimality criterion based on the principles of energy-informational approach. This makes it possible to directly process information on the specific energy consumption and to provide intelligent support for the decision-making processes when a drilling master defines optimal drilling mode parameters.  Author Biographies Lev Kopystynskyy, Ivano-Frankivsk National Technical University of Oil and Gas Karpatska str., 15, Ivano-Frankivsk, Ukraine, 76019 Postgraduate student Department of automation computer-integrated technologies

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