Systems and methods for drilling boreholes with noncircular or variable cross-sections

摘要: In a pulsed-electric drilling system, nonrotating bit is given noncircular shape to drill correspondingly-shaped borehole, e.g., triangular, rectangular, polygonal, oval, or more complex shape. Some embodiments employ reconfigurable that deploys extensions as needed dynamically vary the cross-section of borehole at selected locations. this fashion, driller able create with preferred cross-sectional to, smallest possible hole while simultaneously providing additional clearance for equipment instrumentation, surface area well inflow, channels improved cleaning, teeth cementing, reduced contact reduce drag on drillstring, any other benefits achievable by customizing cross-section.