Measurements while drilling or coring using a wireline drilling machine

Abstract

A drilling system and method for drilling underground boreholes is provided. The drilling system comprises a tool body, a downhole motor, a drill bit mounted on the body to be driven by the motor, a mechanism for driving the tool body axially along the borehole so as to apply weight on the drill bit when drilling, and an electrical cable extending from the surface to the tool body to provide power for the drilling motor. The tool body includes a conduit connected to the drill bit such that drilled material passes from the drill bit through the conduit, and sensors are provided in the conduit for measuring properties of the drilled material.

1 . A drilling system for drilling underground boreholes, comprising:
 a tool body;   a downhole motor;   a drill bit mounted on the tool body to be driven by the motor;   a mechanism for driving the tool body axially along the borehole so as to apply weight on the drill bit when drilling; and   an electrical cable extending from the surface to the tool body to provide power for the drilling motor;   wherein the tool body includes a conduit connected to the drill bit such that drilled material passes from the drill bit through the conduit, and sensors are provided in the conduit for measuring properties of the drilled material.   
     
     
         2 . The system as claimed in  claim 1 , further comprising a pumping system which is operable to pump drilling fluid through the drill bit and conduit. 
     
     
         3 . The system as claimed in  claim 1 , wherein the drill bit is provided with a central aperture so as to drill cores. 
     
     
         4 . The system as claimed in  claim 3 , wherein the sensors measure the properties of the core. 
     
     
         5 . The system as claimed in  claim 1 , wherein the drill bit is configured to create drilled cuttings. 
     
     
         6 . The system as claimed in  claim 5 , wherein the sensors measure the properties of drilled cuttings and any drilling fluids passing through the conduit. 
     
     
         7 . The system as claimed in  claim 1 , wherein the sensors are arranged around the periphery of the conduit. 
     
     
         8 . The system as claimed in  claim 7 , wherein the sensors are configured to provide tomographic measurements across the whole section of the conduit. 
     
     
         9 . The system as claimed in  claim 1 , wherein the sensors measure resistivity, electromagnetic propagation, acoustic response, natural radioactivity, gamma ray, neutron and x-ray radiation, and/or nuclear magnetic resonance. 
     
     
         10 . The system as claimed in  claim 9 . wherein the measurements are used to obtain rock and pore fluid petrophysical and chemical properties. 
     
     
         11 . A method of drilling a borehole through an underground formation, comprising the steps of:
 providing a drilling system comprising:   a tool body;   a downhole motor;   a drill bit mounted on the tool body to be driven by the motor;   a mechanism for driving the tool body axially along the borehole so as to apply weight on the drill bit when drilling; and   an electrical cable extending from the surface to the tool body to provide power for the drilling motor;   wherein the tool body includes a conduit connected to the drill bit such that drilled material passes from the drill bit through the conduit, and sensors are provided in the conduit for measuring properties of the drilled material operating the drilling system so as to drill through the underground formation;   passing drilled material through the conduit; and   measuring properties of the drilled material using the sensors.   
     
     
         12 . The method as claimed in  claim 11 , wherein measured properties are used to provide detection of gas kicks and abnormal cuttings size.