Fixed cutter drill bits including cutter elements with variable exposures

Abstract

A fixed cutter drill bit for drilling an earthen formation includes a bit body having a central axis and a bit face. The bit body is configured to rotate about the central axis in a cutting direction of rotation. The bit face includes a concave cone region extending radially from the central axis, a convex shoulder region extending radially from the cone region, a nose at the intersection of the cone region and the shoulder region, and a gage region extending radially from the shoulder region to a full gage diameter of the drill bit. The drill bit also includes a cutting structure disposed on the bit face. The cutting structure includes a primary blade extending radially from proximal the bit axis through the cone region and the shoulder region to the gage region. The blade has a leading side relative to the cutting direction of rotation, a trailing side relative to the cutting direction of rotation, and a cutter-supporting surface extending from the leading side to the trailing side. In addition, the drill bit includes a plurality of high-aspect ratio cutter element assemblies mounted to the cutter-supporting surface of the primary blade in the cone region. The cutter element assemblies are arranged in a radially extending row proximal the leading side of the primary blade, wherein each cutter element assembly includes a cutter element carrier and a first cutter element fixably attached to the cutter element carrier. Still further, the drill bit includes a plurality of low-aspect ratio second cutter elements directly mounted to the cutter-supporting surface of the primary blade in the shoulder region or the gage region. The second cutter elements are arranged in a radially extending row proximal the leading side of the primary blade. Each high-aspect ratio cutter element assembly has an exposure H1 measured perpendicularly from the cutter-supporting surface of the primary blade to a cutting tip of the first cutter element of the cutter element assembly distal the primary blade. Each low-aspect ratio second cutter element has an exposure H2 measured perpendicularly from the cutter-supporting surface of the primary blade to a cutting tip of the second cutter element distal the primary blade. The exposure H1 of one or more high-aspect ratio cutter element assemblies in the cone region is greater than the exposure H2 of one or more low-aspect ratio second cutter elements in the shoulder region or the gage region.

Dependencies are inferred from the claim text.