The coring and sampling technology under complicated geological condition

The coring and sampling are the important work in drilling engineering, but their qualities are difficult to insure under the complicated geological condition.The paper has studied the problems of coring and sampling in aspects of catching core and sample.After analyzing the troubles,which have existed in the conventional coring tools of our country,the paper emphatically introduced four types of special coring tools,such as rectacular ring-type,core gripper with rotary jaw type,core gripper with slip-collar type and core gripper with slip type,and a kind of bottom hole volute cuttings collector,which are used in Russia.And then some conclusions and suggestions about coring and sampling under the complicated geological condition are of significance for using in China.