Record Erd Senomanian wells on Yamal

Abstract

The article is based on experience of drilling record Senomanian ERD wells on Yurkharovskoe field from the bank of the Tazovskaya Guba towards offshore.Core problem happening while drilling such extended wells is wellbore instability happening in mudstone intervals when drilling close to the bedding.This article is devoted to study of the specific breakout mechanism in mudstone at shallow depth and finding the solution for well trajectory optimization to prevent wellbore instability.The main problem was solved in the work is optimization of shallow Senomanian wells trajectories via geomechanical modeling coupling with drilling experience which allow to find the solution and solve the instability problems while drilling.Drilling experinse of Senomanian wells was analized and used for geomechanical model verification and chose the best wells trajectories.Feature of mudstone collapse while drilling close to bedding at shallow depth was investigated, also termal expansion effect and its inpact on wellbore instability was evaluated.The result of the work was trajectories optimization and succesfull drilling of Senomanian wells on Yurkharovsko? field. Drilled wells have record horizontal displasement from vertical among all wells on YaNAO.The aggregate results of engineering calculations and obtained experience of Senomanian wells drilling have perspective opportunities of design and construction of such wells in YaNAO.