Drilling tool for reducing cutter damage when drilling through formation changes, and methods of design and operation thereof

A drilling tool for drilling a subterranean formation, comprising:

• a longitudinal axis;
• a body having a face including a plurality of cutting elements disposed thereon;
• wherein at least two cutting elements of the plurality are redundant;
• wherein the at least two redundant cutting elements are positioned at an anticipated location of first contact of the drilling tool with a predicted boundary surface, the predicted boundary surface defined between two regions of the subterranean formation having at least one different drilling characteristic;
• and
• wherein the vector summation of each lateral force associated with the at least two redundant cutting elements exhibits a direction within ±70° of an imbalance force direction exhibited by the drill bit when drilling a homogeneous formation.

A drilling tool for drilling a subterranean formation, comprising:

• a longitudinal axis;
• a body having a face including a profile having a plurality of cutting elements disposed thereon;
• wherein at least a portion of the profile is structured for causing initial contact between a plurality of cutting elements positioned within the portion of the profile and a predicted boundary surface of a subterranean formation;
• and
• wherein the vector summation of each lateral force associated with the plurality of cutting elements within the portion of the profile is less than about 20% of a vector summation of the lateral force of each of the plurality of cutting elements on the drill bit.

A drilling tool for drilling a subterranean formation, comprising:

• a longitudinal axis;
• a body having a face including a profile having a plurality of cutting elements disposed thereon;
• wherein at least a portion of the profile is structured for causing initial contact between a plurality of cutting elements positioned within the portion of the profile and a predicted boundary surface of a subterranean formation;
• and
• wherein the vector summation of each lateral force associated with the plurality of cutting elements exhibits a direction within ±70° of an imbalance force direction exhibited by the drill bit when drilling a homogeneous formation.

A method of operating a drilling tool, comprising:

• providing a drilling tool including a plurality of cutting elements, wherein at least two cutting elements of the plurality are redundant;
• predicting a boundary surface defined between two abutting regions of a subterranean formation, the two abutting regions having at least one different drilling characteristic;
• determining a drilling path, the drilling path oriented for positioning the redundant cutting elements at an anticipated location of first contact of the drilling tool with a predicted boundary surface upon drilling generally therealong;
• and
• drilling into the predicted boundary surface generally along the orientation of the anticipated drilling path;
• wherein drilling into the boundary surface between the two regions of the subterranean formation with the at least two redundant cutting elements changes the magnitude of lateral imbalance of the drilling tool by less than about 20%.

A method of operating a drilling tool, comprising:

• providing a drilling tool including a plurality of cutting elements, wherein at least two cutting elements of the plurality are redundant;
• predicting a boundary surface defined between two abutting regions of a subterranean formation, the two abutting regions having at least one different drilling characteristic;
• determining a drilling path, the drilling path oriented for positioning the redundant cutting elements at an anticipated location of first contact of the drilling tool with a predicted boundary surface upon drilling generally therealong;
• and
• drilling into the predicted boundary surface generally along the orientation of the anticipated drilling path;
• wherein drilling into the boundary surface between the two regions of the subterranean formation with the at least two redundant cutting elements generates a net lateral force associated therewith that is oriented in a direction within ±70° of a direction of an overall imbalance force of the drilling tool when drilling a homogeneous formation.

A method of designing a drilling tool, comprising:

• selecting a cutting element profile;
• selecting a subterranean formation to be drilled;
• selecting an anticipated drilling path for drilling through the subterranean formation;
• predicting a boundary surface between two regions of the subterranean formation, the two regions exhibiting at least one different drilling characteristic;
• placing a plurality of cutting elements within a region of the profile;
• positioning the plurality of cutting elements within the region at an anticipated location of first contact of the drilling tool with the predicted boundary surface;
• and
• placing the plurality of cutting elements within the portion of the profile for generating lateral forces during drilling that substantially cancel with one another.

A method of operating a drilling tool, comprising:

• providing a drilling tool including a plurality of cutting elements within a region of a profile of the drilling tool;
• predicting a boundary surface defined between two abutting regions of a subterranean formation, the two abutting regions having at least one different drilling characteristic;
• determining a drilling path, the drilling path oriented for positioning the plurality of cutting elements at an anticipated location of first contact of the drilling tool with a predicted boundary surface upon drilling generally therealong;
• positioning a plurality of cutting elements within the region of the profile at an anticipated location of first contact of the drilling tool with the predicted boundary surface;
• and
• drilling into the predicted boundary surface generally along the orientation of the anticipated drilling path;
• and
• wherein drilling into the boundary surface between the two regions of the subterranean formation with the plurality of cutting elements within the region of the profile changes the magnitude of lateral imbalance of the drilling tool by less than about 20%.

A method of operating a drilling tool, comprising:

• providing a drilling tool including a plurality of cutting elements within a region of a profile of the drilling tool;
• predicting a boundary surface defined between two abutting regions of a subterranean formation, the two abutting regions having at least one different drilling characteristic;
• determining a drilling path, the drilling path oriented for positioning the plurality of cutting elements at an anticipated location of first contact of the drilling tool with a predicted boundary surface upon drilling generally therealong;
• positioning a plurality of cutting elements within the region of the profile at an anticipated location of first contact of the drilling tool with the predicted boundary surface;
• and
• drilling into the predicted boundary surface generally along the orientation of the anticipated drilling path;
• and
• wherein drilling into the boundary surface between the two regions of the subterranean formation with the plurality of cutting elements generates a net lateral force associated therewith that is oriented in a direction within ±70° of a direction of an overall imbalance force of the drilling tool when drilling a homogeneous formation.