During drilling cementing plug in wells located on carbonate crack reservoirs in the Tahe Oilfield, it is very difficult to complete such operation without failure because of irregular open hole diameter, extensively fractured formation, measured depth error, etc.

For increasing ROP and shortening Drilling cycle, partial exploration and development companies have been adopting three-stage casing schematics for long open holes in Tahe Oilfield since 2001, and have achieved good application effects.

The DH4-8 well, located at Donghetang Oilfield in Tarim Basin, Xinjiang, is a directional production well with the deepest open hole sidetrack point and the longest open hole section.

Application of steering drilling system in long open hole directional well;

It is easy leaking in long open hole, long sealing sections, multiple pressure regime because the geologic condition is very complex in this area, which bring about many difficulties in cementing operation.

Based on such conditions as complex geology, long open hole as long as 5000 m, large deviation angle, hole collapse, long horizontal section, high temperature and great formation pressure coefficient changes etc.

A new skin factor model for open hole completion of horizontal wells under Non-Darcy flow;

Study of prediction model for sand production in open hole completion;

Removing technique of oil based mud cake in open hole completion of horizontal well.;

By analyzing for risk and feasibility of open hole well testing, actual experiences and lessons applied in Shengli oilfield have been summarized systemically and study on mud, setting site, down hole, string structure and work system has been done, a general way and technical point has been suggested which helps to push forward this tech and increases economic benefit.