CORE DRILL ASSEMBLY WITH ADJUSTABLE TOTAL FLOW AREA AND RESTRICTED FLOW BETWEEN OUTER AND INNER BARREL ASSEMBLIES

摘要

A core drill assembly with replaceable fluid nozzles permitting effective total flow area adjustment (TFA), substantial optimization of hydraulic force at the cutting face to improve rate of penetration (ROP) and core quality. At least one seal assembly to restrict drilling fluid flow while permitting mutual rotation between the core head ID and the lower shoe is disposed in an annulus defined therebetween.