Drilling Technologies for Horizontal Wells of Gulong Shale Oil in Daqing

Some technical challenges were encountered while drilling horizontal wells in the Gulong shale oil block of Daqing Oilfield, such as wellbore instability, difficulties of wellbore trajectory control and wellbore cleaning, and uncertain cementing quality, etc. Therefore, the research on technologies such as the optimization of well platform, well group, and casing program, selection of drilling parameters, wellbore trajectory control, drilling fluid optimization, and cementing optimization were carried out. The drilling technologies suitable for horizontal wells of Gulong shale oil were formed. The technologies have been applied to 10 wells in Gulong shale oil block. No wellbore instability was observed during drilling, and the cementing quality was improved. Compared with horizontal wells in the block without these technologies applied, the average rate of penetration was increased by 79.91%, and the average drilling duration was shortened by 40 days while the average length of the horizontal section was increased by 265.13 m. The field application results show that the technologies can solve the technical difficulties of drilling in horizontal wells of the Gulong shale oil, and provide technical support for its efficient exploration and development.