Based on the requirements of ISO 9000: 2015, production operations are described in the process of oil and gas wells construction, which have a decisive influence on the quality of the final product. The quality indicators are given, with which one can evaluate both the production process of the construction and the well as a finished construction. Given quality indicators are proposed to be divided into indicators when designing a well, and indicators for the well construction and operation. The quality indicators adopted during the construction and operation of the borehole are proposed to be systematized into the appropriate quality hierarchy. Hierarchy levels in drilling should be divided by type of work performed in the cycle of well construction, namely: surface hole drilling, well casing, intermediate hole drilling, intermediate well casing, production casing drilling (separately – drilling-in operation or pay-drilling), setting of production casing. The hierarchy of the quality evaluation of the technological process of drilling and casing using the T. Saati method is given. Some recommendations are made for using a pairwise comparison scale for process evaluation. The concept of “reference quality” has been introduced, with which present achieved indicators of drilling and casing quality are compared. The method of calculating the integral coefficient of quality and the corresponding scale of quality of technological processes of drilling and casing is proposed. As a result, it is proposed to determine the integral coefficient of quality through the ratio of the estimation obtained from the priority vector for the actual achieved quality to the estimation for the reference quality. The integral coefficient will not exceed 1.00. Accordingly, a scale is established for the low, good and high quality wells, as completed mining facilities. The directions and quality indicators, which are difficult to express quantitatively, are defined, and with this the new hierarchy of the quality assessment of well as a completed structure is formulated. Quality control is planned to be put on supervisors. The basic principles of quality control in drilling are formulated