Drilling tool equipped with improved cutting element layout to reduce cutter damage through formation changes, methods of design and operation thereof

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.

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;
• wherein the two regions exhibit at least one different drilling characteristic;
• placing a plurality of cutting elements within a region of the profile;
• and
• wherein the plurality of cutting elements within the region are positioned at an anticipated location of first contact of the drilling tool with the predicted boundary surface.

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;
• drilling into the predicted boundary surface generally along the orientation of the anticipated drilling path.