One of the features of the drilling in YaNAO area is the long section of permafrost. This feature impacts on different technological processes of well constructing. Drilling fluid cools in the annular opposite permafrost without circulation in particular. This feature should be considered in the development of the mud program with oil based muds.
Non-aqueous based fluid is the drilling fluid of choice to drill ERD wells. They make it possible to drill long sections even with the unstable formations. But they have some features, such as quite high rheology and its temperature dependence. The oil-based mud formulation which allows to decrease temperature dependence of rheology was applied in April – July of 2011 on Yurkharovskoye field.
Lab research, extensive computer modeling and hydraulic simulations were performed to take into account temperature and pressure conditions of the north of YaNAO. Main features and results of the new OBM formulation field application are described. Comparative data of the rheology-temperature profiles of formulations used in other regions of Russia are presented in the paper.
The experience of new OBM formulation application in ERD drilling on Yurkharovskoe field provided in the paper can assist with planning and project execution of OBM implementation in Arctic areas.