Use of the dynamic downhole measurements as lithology indicators

US7650241B2 · kind B2 · utility

Assignee

• Baker Hughes Holdings LLC · US

Inventors

• Pushkar N. Jogi · Houston, US
• Joachim Oppelt · Braunschweig, DE
• Gerald Heisig · Spring, US
• Volker Krueger · Celle, DE
• John D. Macpherson · Spring, US

Key dates

• Filing date: Feb 17, 2006
• Grant date: Jan 19, 2010
• Expiry date: Aug 30, 2026

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B49/003
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A drilling system provides indications of the lithology of the formation being drilled by dynamically measuring at least one parameter of interest that is affected by the lithology of the formation being drilled. Suitably positioned sensors make dynamic measurements of parameters such as downhole weight on bit, bit torque, bit revolutions, rate of penetration and bit axial acceleration. One or more processors use the sensor measurements in conjunction with predetermined lithological models to determine whether the measurements indicate a change in formation lithology. Suitable models can be on derived expressions such as rock drillability, drilling response, dynamic drilling response, normalized or dimensionless torque; and formation shear strength. The lithological indications provided by the processor can be used to adjust drilling parameters, steer the BHA, monitor BHA health, and provide depth locations for bed boundaries and formation interfaces.