In recent years, the structure and reserves are determined further using sidetrack drilling in old wells by deepened geological knowledge and reservoir engineering research.

Horizontal well drilling technology by slim hole casing window sidetracking in Daqing Oilfield;

It is base upon general casing cutting windows,aiming at bad feasibility stratum,through optimizing desi gn sidetracking technology,changing tool,optimizing measure and choosing bit,we succeed in casing window sidetracking of ultradeep well KS101C.

Cased hole directional window cutting drilling is a special drilling technology.

The three methods,including window opening lateral drilling method,perforation method by rebuilding pump chamber and direct perforation method,are characterized by low cost and short construction period.

This article introduces the engineering flow and technical measures for casing side-tracking of complicated accidental wells according to well .