GEOLOGICAL AND TECHNICAL-AND-TECHNOLOGICAL FEATURES OF CASING OIL AND GAS WELLS, TAKING INTO ACCOUNT THE PHYSICAL AND CHEMICAL STATE OF THEIR WELLBORE

Abstract

The article is devoted to laboratory-analytical analysis and research of the fundamental factors for increasing the reliability of well casing, provided that they are conducted in the thickness of chemogenic deposits, using the example of the deposits of the Dnieper-Donetsk depression, carried out by in-depth study and interpretation of the actual field material of well construction in difficult geological and lithological conditions.
The peculiarities of the well casing cycle, corresponding to the circumstances characteristic of the chemogenic deposits of the Dnieper-Donetsk depression, have been investigated by complex laboratory and
analytical techniques; the influence of technological parameters and aggressive media on the course and results of the formation of a cement stone in borehole and model conditions was evaluated.
The main directions of improvement of technological methods and methods of well casing in difficult geological and lithological conditions are determined. By analyzing the phase composition of the hydration products of laboratory and industrial samples of cement stone, the existence of an objective negative effect on its operational properties of typical representatives of the class of chemogenic deposits is shown. On the basis of actual production data, information on the phenomenon of capping in the chemogenic deposits of the wellbore was refined. The features of the influence of active cuttings of cavernous intervals on the setting of cement slurries are considered. The phenomenon of fluid loss in cement slurries, as well as its dependence on chemical treatment with special reagents of the latter and when added to the composition of various mineralogical groups of clays, has been studied. The existence of a direct dependence of the efficiency of drilling operations on the quality of well casing operations has been proved.
The conditions for the rational conduct and operational efficiency of wellbore casing operations, during its construction in the thickness of chemogenic deposits, correspond to certain parameters of the used grouting systems and measures aimed at eliminating the influence of technological shortcomings of the wellbore.
The obtained results of laboratory and analytical studies, as well as generalization of field data, are basic for the design of operating parameters of the casing string cementing process with guaranteed provision of high technical and economic indicators. The data on the study of the process of cavitation in chemogenic deposits is the initial one for substantiating the design and technological parameters of the device for creating the axial movement of the drilling fluid in the complicated zone of the well.