ANALYSIS OF TECHNOLOGIES FOR COLLARING LARGE-DIAMETER SECTIONS OF OIL AND GAS WELLS

The article considers issues on construction of deep oil and gas multi-column wells with an extended trunk. Drilling of such wells is relevant, for example, on offshore fields, where drilling from the shore with a vertical deviation of over 1000 m is much more economically feasible than from floating vehicles.For drilling wells with an extended trunk and passing through zones incompatible with drilling for geological reasons, it is necessary to begin construction of a well with landing a large diameter direction – often up to 720 mm. The article analyzes the emerging problems and ways to solve them by drilling large-diameter wells and landing casing string. The results of practical experience in conducting work in the Pechora Sea and at the Astrakhan gas condensate field are summarized, on the basis of which recommendations for carrying out similar works are given.When constructing wells, especially starting with a large diameter, it is not always possible to drill a well efficiently, even with drilling equipment ideally suited to specific geological and technological conditions. And this, in turn, can lead to losses of production time and materials, and in the extreme case – to emergency works. Based on the analysis carried out, the article proposes an algorithm of technological operations for drilling wells and landing large diameter directions, which increases the probability of successful drilling to the design depth.