POLYMODALITY OF SECONDARY KAOLINITE DISTRIBUTION IN OPEN SANDY RESERVOIR SYSTEMS

Link for citation: Melnik I.A. Polymodality of secondary kaolinite distribution in open sandy reservoir systems. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 17-29. In Rus. Relevance. Numerous studies of the forms of distributions of the registered characteristics of the investigated environment according to the results of transformation of open systems have shown that the intensities and contents of transformed elements have a polymodal form of statistical distribution in the case of external impact on the system. Apparently, the essence of the phenomenon of statistical polymodality of transformation of systems is universal. Therefore, the universal theory of polymodal distribution formation can be used to analyze samples of secondary mineral contents in permeable sand reservoirs, which are open systems. Obviously, each mode of the polymodal statistical distribution of the transformed elements will be the result of the manifestation of some attractor. The purpose of this paper is to present a universal kinematic theory of the formation of a polymodal statistical distribution of the number of transformed elements of an open system, where secondary clay minerals – kaolinites, due to superimposed epigenesis in a sandy reservoir are considered as the formed elements. The objects of the study are samples of secondary kaolinitization intensity values in sand intervals of oil and gas fields of the Yamal Peninsula and the contents of secondary kaolinite (determined from the core) in Upper Jurassic sand strata of the Stolbovoe oil and gas field. Secondary kaoliniteization is caused by the influence of deep fluids. The research method was determined on the basis of the obtained equation of unified modes of polymodal distribution of the number of transforming elements (in transformation of systems). The number (intensity) of transformed elements is proportional to the ratio of the system transformation time to the flow time of the external influence on the elements of this system. Seven basic constants (attractors) related to the «golden» proportion were theoretically calculated, bringing them into conformity with universal principles of system transformation processes states. Results. Having compared constants obtained theoretically with calculated unified values of modes of empirical data, the states of system transformation processes with respect to each mode have been determined. Analysis of modes calculated in a polymodal distribution of secondary kaolinite intensities and kaolinite content, as well as comparing mode values (with corresponding transformation principle) with empirical data on transformation processes gave evidence for the validity of the universal kinematic theory. Conclusions. Thus, using universal principles of transformation, on the basis of the determined contents of secondary kaolinite in the studied intervals of permeable strata, it is possible to allocate zones with the chemical and hydrodynamic properties and characteristics of interest.