CB3-1 dual-lateral horizontal well drilling technology

Well CB3-1 is the irst dual-lateral horizontal well drilled by the Changqing Well Construction Company in Changbei gas ield, each branch of the horizontal interval is designed as 2,000 meters. The drilling target is the member 2 in Shanxi Formation. The paper introduces the technology of optimization design of wellbore proile, the casing window-opening technology, and the barefoot laterally drilling technology. In view of such problems as the poor wellbore stability of large hole, the easily collapsed “Shuangshi bed”, the barefoot laterally drilling, the different depth of production formations, the frequent trajectory adjustment, the prediction of torque and drag, and window entry of branch wells, systematic reasonable technical measures are established. Technical points of drilling in coal seam sections and the drilling luid system of dual-lateral horizontal wells in Changbei block are summed up. The application of PBL circulation joint, Agitator Sub and other advanced downhole tools ensure that the horizontal section pass through the most valuable production formations. The development of CB3-1 well is very important to improve the deliverability in the block.