Varel International Ind., L.p.

Varel International Ltd.

Cary Andrew Maurstad

Steven Wayne Drews

Zane Michael Pettiet

Scott Buteaud

A bit for drilling a wellbore includes: a body; and a cutting face including: a blade protruding from the body; and a row of cutters, each cutter including: a substrate mounted in a pocket formed adjacent to a leading edge of the blade; and a cutting table made from a superhard material, mounted to the substrate, and having a working face. A first subset of the row of cutters is oriented at a negative side rake angle. A second subset of the row of cutters is oriented at a zero or slightly positive side rake angle. The first and the second subsets are alternating. An innermost cutter of the first subset has a maximum absolute value of the negative side rake angle. The absolute value negative side rake angles of the rest of the cutters decrease as their distance from a center of the cutting face increases.

Fixed cutter stabilizing drill bit

A bit mold is milled using a turning stage which forms a base mold component and a base gagering component. Next, a blade milling stage is performed in which the base mold component and base gagering component are milled to define integral junkslot formers separated by blade regions. Lastly, a pocket milling stage is performed in which the blade regions and integral junkslot formers of the base mold component are milled to define a plurality of cutter pockets in primary and perhaps secondary rows. Each cutter pocket includes a seat portion and a face portion. The milling of the pocket milling stage provides, at one or more of the cutter pockets, a facet. This facet is provided in an area about the junkslot former associated with the face portion of the cutter pocket, the face portion having, due to the presence of the facet, a surface for matching a cutter core displacement end surface without voids of a size which would require the use of fill material. The facet is also provided on either side of the pocket associated with the seat portion to avoid the need to clay the sides of the displacement for providing top-loading clearances. The milling process at the pocket milling stage further supports definition of relief and erosion resistance features in the mold.

Single mold milling process

A PDC bit includes a plurality of blades. A blade includes a primary cutter row and a secondary cutter row. Primary PDC cutters on the primary cutter row are set in accordance with a single set methodology. Backup PDC cutters on the secondary cutter row are set in accordance with a methodology wherein a radial position of each backup PDC cutter in the secondary cutter row is offset from a radial position of each primary PDC cutter in the primary cutter row. The blade further includes a tertiary cutter row. Additional backup PDC cutters on the tertiary cutter row are set in accordance with a methodology wherein a radial position of each additional backup PDC cutter in the tertiary cutter row is offset from a radial position of each primary PDC cutter in the primary cutter row. The backup cutter setting methodology is effectively radially positions the included backup PDC cutters (in the secondary cutter row and/or tertiary cutter row) between primary PDC cutters in the primary cutter row.

Shoulder durability enhancement for a PDC drill bit using secondary and tertiary cutting elements

A PDC bit includes a plurality of blades including primary blades and secondary blades. The included primary blades are set with PDC cutters in accordance with a 'single set' methodology. The included secondary blades, however, are set with PDC cutters using a type of 'plural set' methodology such that the radial positions of cutters on a secondary blade match the radial positions of cutters on a single set primary which is immediately preceding that secondary blade. Plural secondary blades can be positioned to follow a single primary blade, and the cutters on those plural secondary blades will have radial positions matching the cutters of the immediately preceding single set primary blade.

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Livingston, TX, United States of America

Cary Andrew Maurstad