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Woods, Lubinski, Hotch and Treicher's Theory on Deviated Holes

HENRY WOODS & ARTHUR LUBINSKI'S THEORY

Henry Woods and Arthur Lubinski stated in 1954 that the size of drill collar just abovethe bit is the limiting factor for the lateral movement of bit causing hole deviation!hey gave a formula to calculate the "inimum #ffective Hole $iameter %"#H$& forlo'ering the casing !he formula is(

"#H$ ) %*it +ize , $rill -ollar .$& / 0

ROBERT S. HOTCH'S THEORY

Later 2obert + Hotch came u3 'ith a theory that 'hile drilling 'ith an unstabilized bitan abru3t change of hole angle can occur if hard ledges are encounteredWith reference to his theory he suggested that the minimum 3ermissible drill collar .$

should al'ays be greater than t'ice the casing cou3ling diameter to be run minus thebit size

ie "inimum $rill -ollar .$ ) 0 -asing -ou3ling .$ *it size

H.E. TRIECHER'S THEORY

At the +ame time H# !riecher 3ointed out that the lateral movement of an unstabilizedbit in non di33ing formation tends to cut a s3iral hole !he s3iralling 'ill be more severein soft formations 'here 3enetration rate is high and this 'ill 3roduce a hole of reduced

drift diameter

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