Abstract: A rotary rock bit is formed as a rock bit body, a bearing shaft supported by the rock bit body, a rotary cutter adapted to be rotatably mounted on the bearing shaft, and at least one bearing that promotes rotation between the rotary cutter and the bearing shaft. Each bearing includes a bearing element having a steel matrix with steel-free volumes distributed therethrough. The matrix is a hypoeutectoid steel having more than about 0.40 weight percent carbon. An anti-galling alloy resides within the steel-free volumes of the steel matrix. The anti-galling alloy is a silver-copper alloy having a composition of from about 60 weight percent to about 95 weight percent silver, balance copper.

Abstract: A rotary rock bit is formed as a rock bit body, a bearing shaft supported by the rock bit body, a rotary cutter adapted to be rotatably mounted on the bearing shaft, and at least one bearing that promotes rotation between the rotary cutter and the bearing shaft. Each bearing includes a bearing element having a steel matrix with steel-free volumes distributed therethrough. The matrix is a hypoeutectoid steel having more than about 0.40 weight percent carbon. An anti-galling alloy resides within the steel-free volumes of the steel matrix. The anti-galling alloy is a silver-copper alloy having a composition of from about 85 weight percent to about 95 weight percent silver, balance copper.

Abstract: A method and apparatus for analyzing amplitude-versus-offset (AVO) seismic data to distinguish sand formations, such as Morrow sands, from limestones and other similar intervals, is disclosed. For each of the traces in the survey, AVO intercept and AVO slope traces are generated, preferably after normalization of the amplitudes of the traces to account for geophone coupling variations. After normalization and conventional processing and corrections, spatial summation may be performed to further improve the traces. AVO trend lines are then generated, preferably on a weighted window basis, to generate localized trend lines against which the intercept and slope values of individual depth points may be compared. This comparison allows the plotting of AVO intercept versus AVO slope deviation from the trend line, from which sand formation interfaces may be identified by their presence in certain quadrants of the intercept-slope deviation cross-plot.

Abstract: A rotary rock bit having a relatively thin-walled porous journal bushing, infiltrated with an anti-galling metal, is shown. The bushing is mounted within the rolling cone cutter and retained axially by abutments and rotationally by an interference fit in conjunction with a metallic conformal layer at the interferingly engaging surfaces to prevent movement of the bushing with respect to the cutter under bit operating conditions.