Applying finite element method,the dynamic characteristics of drill string with cone bit in straight hole were simulated,and the whirl,deformation and the dynamic stress in air drilling were compared with the ones in drilling fluid drilling.

Design and lab evaluation of ideal packing bridging drilling and completion fluids;

Preparation of drilling and completion fluids used for preventing the formation from damage of the high-pressure and low-permeability sandstone reservoirs;

Owing to the water phase trap damage caused by drilling and completion fluids invasion, the logging data do not reflect the real characteristic of gas reservoirs, which results in weak or no well log response and response and gas formation miss.

Design and application of drilling and completion fluid system for formation protection in the key blocks of Dagang Oilfield;

But in fact, wide distribution of average radius of pore throat which ane in reservoir make the changed drilling and completion fluid have good shield temporary blocking effect on only a few well .

Only with clear knowledge of reservoir characteristics, potential damage factors, sensitivity and the damaging mechanisms of drilling and completion fluids, can compatible and reasonable drilling and completion fluid technology be worked out.

The recent progress in protective methods,techniques,and technologies and in drilling/completion fluids for fractured oil and gas reservoirs is reviewed in topics including fractured reservoir classification,reservoir stress sensibility evaluation,fracture wideness estimation,formation damaging and temporarily plugging mechanisms,and drilling/completion fluids.