Abstract: Shale plasticity in a geological formation is quantified by the steps of measuring a shale volume of the formation, measuring a shale composition of the formation, measuring a shale water content of the formation, and determining a measure of shale plasticity of the formation in response to the measured shale volume, shale composition, and shale water content according to a shale plasticity model. An apparatus for quantifying shale plasticity is disclosed also.

Abstract: Quality of a matrix body of a matrix body drill bit is tested by forming an extension of the matrix material near the nose of the matrix body drill bit. A notch is formed in a mold used to form the matrix body drill bit. The notch is filled with matrix powder during loading of the mold and subsequently infiltrated with binder alloy during infiltration of the matrix body. A matrix body extension is thus formed in the notch. The notch, and thus the matrix body extension, has a ratio of length versus diameter sufficiently high to allow the extension to be removed without permanently damaging the matrix body. The removed extension may then be subsequently tested.

Abstract: An earth boring bit utilizing thermally stable polycrystalline diamond material having a row of closely spaced sharp cutting elements, following by a row of widely spaced, blunt or rounded cutting elements, each cutting element extending from a supporting matrix a predetermined amount to allow the sharp cutting elements to form small relief kerfs in a geological formation, after which the blunt or rounded cutting elements dislodge material between the kerfs. Additionally, cylindrical cutting elements are positioned near the gage or outermost portion of the matrix to enhance gage bore cutting.

Abstract: An earth boring bit utilizing thermally stable polycrystalline diamond material having a row of closely spaced sharp cutting elements, following by a row of widely spaced, blunt or rounded cutting elements, each cutting element extending from a supporting matrix a predetermined amount to allow the sharp cutting elements to form small relief kerfs in a geological formation, after which the blunt or rounded cutting elements dislodge material between the kerfs. Additionally, cylindrical cutting elements are positioned near the gage or outermost portion of the matrix to enhance gage bore cutting.