The article presents the geological structure and describes the history of the Bolshetirskoye oil field - one of the most prospective fields of the Irkutsk region. The Osinskian productive horizon is represented by weakly fractured limestones and dolomites of the pore-cavern type formed as a result of secondary processes fr om limestones. The formation is characterized by abnormally high pressure and a significant content of hydrogen sulfide. Conditions incompatible with further drilling occur when drilling a reservoir: absorption of the drilling mud and gassing. The article considers the types of geological complications obtained during well drilling and also their systematization has been performed. The results of identification of geological reasons of failure to meet a drilling deadline are given. The experience of managed pressure drilling (MPD) technology is described. The chronology of drilling horizontal wells No. 161 and 169 is presented. The obtained experience clarified the idea of the geological structure of the carbonate-halogen sedimentary cover of the Early-Cambrian age. Lateral and vertical geological regularities of the occurrence of complications are determined. It make possible to upd ate the concept of wells drilling. The number of wells has been determined wh ere technological innovations must be applied in order to successfully achieve the se t geological tasks.
References
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