The discussion of complex washover technology applied to NB35-2-A6mh well

NB35-2-A6mh well is a multilateral well.Run in expandable tubular and whipstock to drill the up-lateral and run in the Ф177.8 mm liner after the completion of the down-lateral, then washover the liner and the whipstock to connect the up-lateral and the down-lateral.In this thesis, the complexity and the field operation's problems of the washover liner and the whipstock are introduced, the reason of the unsuccessful washover is discussed, and some suggestions to assure washover are made.All of these can offer a reference for washover liner and whipstock in the TAML-Level 4 completion.