Method and apparatus for calculating and correcting for directional drilling tool face offsets

Abstract

A method for correcting for tool face offset in directional drilling components, namely between a directional sensor reference point and a high side of a bent sub. Graduated markings applied on an outer surface of a UBHO sub containing the directional sensor and a reference marking on drill pipe indicating high side of the bent sub, or alternatively graduated markings applied to drill pipe relative to the high side of the bent sub and a reference marking on the outer surface of the UBHO, are together utilized to determine the tool face offset, which is then provided to a software program to permit the software programme to then indicate a correct bent sub angular orientation to the directional drilling operator at surface. Bottom hole components utilizing graduated markings on one of such bottom hole components and having a reference marking on the other of the components, are also disclosed.

1 . A method for determining and correcting for any angular offset between a directional sensor reference point and a high side of a bent sub assembly when said directional sensor and said bent sub are coupled together, comprising the steps of:
 (i) utilizing
 (a) a series of graduated markings applied on an outer surface of a housing member containing said directional sensor each of identifiable but individually different angular relation to a reference point of said directional sensor, and a reference marking on a bent sub assembly to which said housing member is threadably connected indicative of a high side angular location of said bent sub assembly; or 
 (b) a series of graduated markings applied on said bent sub assembly in known relation to said high side of said bent sub assembly, and a reference marking on said housing member in known relationship to said reference point of said directional sensor; 
   to determine via said graduated markings an angular offset of said directional sensor reference point relative to said high side of said bent sub assembly; and   (ii) providing said determined angular offset to a software program to permit said software program to adjust directional sensor output received from said directional sensor to then indicate a correct bent sub assembly angular orientation.   
     
     
         2 . A method for determining and correcting for an angular offset between a directional sensor reference point and a high side of a bent sub assembly when said directional sensor and said bent sub are coupled together, comprising the steps of:
 (i) utilizing
 (a) a series of graduated markings circumferentially applied on an outer surface of a housing member containing said directional sensor, wherein individual numerical values associated with said graduated markings increase progressively positively in an angular direction from a zero position indicative of said reference point and increase progressively negatively in an opposite angular direction from said zero position, and 
 (b) a reference marking applied on a bent sub assembly which is indicative of bent sub assembly high side angular location, 
   to determine positive or negative angular offset of said directional sensor reference point relative to said high side of said bent sub assembly; and   (ii) providing said determined angular offset to a software program to permit said software program to then correct sensed directional sensor orientation by said angular offset to indicate a correct bent sub angular orientation.   
     
     
         3 . A method for determining and correcting for an angular offset between a directional sensor reference point and a high side of a bent sub when said directional sensor and said bent sub are coupled together, comprising the steps of:
 (i) utilizing:
 (a) a series of graduated markings circumferentially applied on a bent sub assembly, wherein numerical values respectively associated with said graduated markings increase progressively positively in an angular direction from a zero position indicative of said high side angular location of said bent sub assembly and increase progressively negatively in an opposite angular direction from said zero position, and 
 (b) a reference marking applied on an outer surface of a housing member containing said directional sensor indicative of an angular reference point for said directional sensor; 
   to determine positive or negative angular offset of said directional sensor reference point relative to said high side of said bent sub assembly; and   (ii) providing said angular offset to a software program to permit said software program to then correct sensed directional sensor orientation by said angular offset to indicate a correct bent sub angular orientation.   
     
     
         4 . A method for directional drilling of a well with a drill string which utilizes a directional sensor and possesses a bent sub assembly, comprising the steps of:
 (i) securing a housing containing said directional sensor to said bent sub assembly;   (ii utilizing a series of graduated markings circumferentially applied on an outer surface of said housing member containing said directional sensor which markings individually bear a known relation to a reference point for said directional sensor, and a reference marking on said bent sub assembly in known relation to a high side angular location of said bent sub assembly; or   utilizing a series of graduated markings applied on said bent sub assembly each in known angular relation to a high side angular location of said bent sub assembly, and a reference marking on said housing member indicative of said directional sensor reference point;   
       to determine angular offset of said directional sensor reference point relative to said high side of said bent sub assembly; and
 (ii) providing said determined angular offset to a software program to permit said software program to then correct angular directional orientation sensed by said directional sensor by said angular offset to indicate a correct bent sub angular orientation. 
 
     
     
         5 . A bottom hole assembly for use in directional drilling, comprising:
 (i) a housing member containing a directional sensor for sensing orientation of the drill string;   (ii) a bent sub assembly threadably coupled indirectly or directly to said housing member;   (iii) (a) a series of graduated markings circumferentially applied on said bent sub assembly in known angular relationship to a high side of said bent sub assembly, wherein numerical values associated with said graduated markings increase progressively positively in an angular direction from a zero position indicative of said high side angular location of said bent sub and increase progressively negatively in an opposite angular direction from said zero position, and
 (b) a reference marking on said housing member indicative of said directional sensor reference point. 
 or 
 (a) a series of graduated markings applied on an outer surface of a housing member containing said directional sensor, wherein numerical values associated with said graduated markings increase progressively positively in an angular direction from a zero position indicative of said reference point and increase progressively negatively in an opposite angular direction from said zero position, and 
 (b) a reference marking applied on said bent sub assembly indicative of bent sub high side angular location; 
   
     
     
         6 . An orienting sub for use in directional drilling, comprising:
 (i) a housing member containing a directional sensor for sensing orientation of the drill string, said directional sensor fixedly secured to said housing member sub in known angular relation to said graduated markings thereon; and   (ii) a series of graduated markings applied circumferentially on an outer surface of a housing member containing said directional sensor, wherein numerical values associated with said graduated markings increase progressively positively in an angular direction from a zero position indicative of said reference point and increase progressively negatively in an opposite angular direction from said zero position, adapted to allow determination of angular offset of said directional sensor reference point relative to said high side of said bent sub assembly.   
     
     
         7 . An bent sub assembly for use in directional drilling, comprising:
 (i) thread coupling means to allow threadable coupling to an orienting sub containing a directional sensor;   (ii) a series of graduated markings applied circumferentially on an outer surface of said bent sub assembly, wherein numerical graduations associated with said graduated values increase progressively positively in an angular direction from a zero position indicative of a high side of said bent sub and increase progressively negatively in an opposite angular direction from said zero position, adapted to allow determination of angular offset of said high side from an orienting directional sensor reference point on said orienting sub when threadably connected thereto.