Deviation prevention and correction technology for NLSD-1 hole of Nanling Scientific Drilling

Abstract:

NLSD-1 hole of Nanling Scientific Drilling is located at the intersection of the Wuyi northeast structural belt and the Nanling east-west structural belt in southern Jiangxi. The rock bedding， foliation， structural fractures and cleavage are developed with frequent occurrence of soft and hard interbeds， fracture zones and multiple magmatic rock intrusions in the borehole. These geological factors cause serious natural bending of the borehole. In order to ensure the verticality of the borehole， wireline coring hydraulic hammer drilling and tower wireline core drilling were used to prevent borehole deviation. In case of strong deflecting formation where borehole deviation can not be controlled by borehole deviation prevention technology， directional drilling technology was used together with sidetracking for borehole deviation correction to achieve the purpose of artificial intervention of the borehole trajectory. Analysis and research show that the deviation prevention and correction technology has significant deviation prevention and straight keeping effect in deep hole drilling in complex and strong deflecting stratum.