Simon to Somerton: A Review of MWD Drilling Resistance-PPT Presentation

PPT Presentation

Pdf Summary

The presentation reviews the development and application of measuring-while-drilling (MWD) resistance measures, beginning with Somerton’s 1959 laboratory study of rotary drilling. Somerton examined how penetration rate related to rock strength, bit wear, and cuttings, and used dimensionless relationships to compare drilling results. Simon later argued that Somerton’s relationship was a special case of a broader drilling expression based on mechanical work and rock strength. Related measures include Teale’s specific drilling energy and subsequent drilling-energy formulations.<br /><br />MWD profiles from Londonderry, New Hampshire, illustrate how drilling parameters respond to subsurface conditions. In soils, gravel produced distinct peaks, while continuous MWD data provided a more complete profile than SPT sampling with limited recovery. In rock coring, MWD helped identify intervals of lost core and fractured or clay-coated joints. Changes in water pressure, advance rate, and torque reflected differences in these materials.<br /><br />The results suggest that Simon’s expression responds strongly to stratigraphic changes, while Teale’s expression gives comparable results and incorporates both thrust and torque. Thrust contributes relatively little to total energy in rock, but a larger and variable share in soils. Results from coring may differ from destructive drilling.<br /><br />The presentation emphasizes consistent engineering units and cautions that empirical MWD relationships depend on test conditions. Further work should account for drilling-fluid conditions, bit type and wear, overburden stress, and groundwater pressure. Direct thrust and torque measurements near the drill string could improve reliability. MWD should complement—not replace—field observations by the person conducting the drilling.

Keywords

measuring-while-drilling

MWD

drilling resistance

specific drilling energy

Teale expression

Simon expression

Somerton study

rotary drilling

rock strength

subsurface conditions