Improving well operation by selecting the optimal length of horizontal sidetracks for fields at the late stage of development

© 2019, International Multidisciplinary Scientific Geoconference. All rights reserved. This paper discusses the method of increasing the recovery rate when developing deposits of terrigenous sediments at a late stage by involving inactive wells into the field development using sidetracks covering undrained areas. In order to estimate the predicted flow rates of wells with horizontal sidetracks, calculations were carried out for seven wells using four analytical methods for wells which are in the pressure observation well stock, suspended well stock, inactive due to the reaching limit by water cut and low oil rate. As a result of the obtained calculations, the oil production rate increases with increasing wellbore length until some values after which further increase of the wellbore length does not impact the oil rate. This proves the inefficiency of drilling the long horizontal wellbore on this reservoir. After determining the optimal wellbore length, these wells were included into the reservoir model. Drilling horizontal sidetracks on terrigenous sediments of the Carboniferous system showed high efficiency compared with conventional drilling of directional wells