G.M. Efendiyev,
Institute of Oil and Gas of the Ministry of Science and Education of Azerbaijan Republic, Baku, Azerbaijan
I.A. Piriverdiyev,
Institute of Oil and Gas of the Ministry of Science and Education of Azerbaijan Republic, Baku, Azerbaijan
M.K. Karazhanova,
Yessenov University, Aktau, Kazakhstan
M.B. Asgarov
Azerbaijan State Oil and Industry University, Baku, Azerbaijan
Abstract. In order to avoid various drilling problems associated with instability of the wellbore walls, lost circulation, etc., it is necessary to use the concept of a “safety window” of the drilling fluid. Calculation of the boundaries of the mud safety window makes it possible to justify the choice of mud density for safe drilling of wells. However, with all its advantages, it is impossible to accurately determine the boundaries of the “safety window” due to their blurriness, which requires the use of appropriate methods based on fuzzy logic and taking into account this type of heterogeneity. This article proposes an approach based on the application of the basic principles of fuzzy set theory to the choice of drilling mud density using the example of several fields in Azerbaijan, Russia and Kazakhstan. An equation for determining density was obtained, calculations were made using this expression for some fields, and the boundaries of the so-called “safety window” were assessed based on geomechanical studies.
Keywords: safety window of mud, uncertainty, decision making, optimal density, pressure gradients, objectives and limitations.
DOI 10.56525/SPOT2999