boring unit drill unit drilling unitbottle neckingbottled gasbottombottom benchbottom cementing plugbottom flangebottom hold downbottom hole apparatus bottom hole devicebottom hole areabottom hole bumperbottom hole cementationbottom hole choke bottom hole flow beanbottom hole flow ratebottom hole flowmeterbottom hole inclinometerbottom hole jet cutterbottom hole packerbottom hole pressure bhpbottom hole pressure gagebottom hole pump sudsurface pumpbottom hole samplebottom hole temperature bhtbottom hole thermometerbottom layerbottom layer foldbottom levelbottom plugbottom pressure testbottom sediments b sbottom slicebottom sludgebottom swellingbottom timebottom water drivebottom water drive fieldbottom water ground waterbottoms upbouguer correctionboulder bowlderboundary layerboundary saturationbowl overshot casing bowlboxbox augerbox billbox bushingbox foldbox to box reducerbrace cross bar stay rod