TOOL FOR DRILLING SUPERDEEP WELLS Russian patent published in 1997 - IPC

FIELD: drilling equipment. SUBSTANCE: this relates to equipment for drilling prospecting and producing oil, gas and special-purpose wells intended for scientific investigations such as superdeep wells. To prevent emergency separation into pieces at breakage of drilling tool, it is divided into sections which include drilling tubes and all other completing articles having full-size flushing through-passages. Located inside aforesaid completing articles with possibility for installing, removing and replacement are load-carrying safety lines secured between lower and upper anchor adapters which limit each section. Actual required breaking strength of load-carrying safety line beginning from drilling tool lower point up to higher tube sections with taking into consideration preset safety margin must exceed total load created by masses of all tube sections and tool components located below breakage point together with resistance forces occurred at lifting of drilling tool to surface. EFFECT: high efficiency. 4 cl, 1 dwg