EVALUATION OF THE EFFICIENCY OF ELECTRIC LOGGING METHODS WHEN STUDYING TIGHTNESS OF CASING STRINGS IN WELLS OF URANIUM DEPOSITS

Abstract

Link for citation: Sharapatov A., Assirbek N., Samanbetov N. Evaluation of the efficiency of electric logging methods when studying tightness of casing strings in wells of uranium deposits. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 7-15. In Rus. The relevance. When exploiting uranium deposits using the method of in-situ leaching, many problematic issues arise. Among them, it is possible to distinguish a violation of the integrity and tightness of the polymer casing, which leads to leakage of solutions due to defects and threaded connections, colmatation, etc. With the help of geophysical wells surveys, namely current logging and resistivity logging, there is a technological possibility of obtaining actual data on the leakage of solutions into the near-wellbore space (their location, size). The distribution of solutions in the annulus lead to technological and environmental violations during the development of deposits. The main aim: comparative evaluation of the effectiveness of current logging and resistivity logging in solving technological problems – assessment of the integrity of polymer pipes and tightness of threaded connections in the casing of uranium wells and determination of the parameters of liquidation of wells with damaged columns based on the data of current logging or resistivity logging in the casing. Objects: artificial defects in the casing for experimental work: holes in pipes with different diameters and locations, leaky connections of casing pipes. Methods. The work was carried out at one of the sites of the Shu-Sarysu province uranium deposit and includes the following activities: preparation of polymer casing strings for the experiment; physical and technical justification of using geophysical wells surveys methods to study the problem; performing measurement work by current logging and resistivity logging methods; performing computational work using current logging, resistivity logging readings and obtaining values of a probabilistic parameter for evaluation of the state of the casing strings and the decision on the operation of wells; comparative analysis and drawing conclusions on the informativeness of borehole geophysical (electrical) methods. Results. Research results showed that to solve the problem of monitoring the technical condition of casing strings, the use of the resistivity logging method is optimal. The conclusions of the research are based on the analysis of the nature of changes in the diagrams of the electrical methods of current logging and resistivity logging, the sensitivity of the measured values of the electric field to defects in the casing. The quantitative values of the parameter % ANO – the amount of current leakage (anomalies) obtained by calculation according to current logging and resistivity logging data are probabilistic in nature. They made it possible to develop recommendations for making technological and/or managerial decisions on the condition of casing strings and the further use of production wells with various defects in them.