Determining stress parameters of formations from multi-mode velocity data
US6351991B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 2000 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | Jun 5, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/50
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining unknown stress parameters in earth formation measures velocities in four sonic transmissions modes (compression, fast shear, slow shear and Stoneley) at a series of depths. Relationships between measured velocities and other measured values, two independent linear constants, and three nonlinear constants associated with equations of motion for pre-stressed isotropic materials are expressed in a set of four or five velocity difference equations derived from non-linear continuum mechanics. The velocity difference equations are solved using inversion for useful stress parameters, including maximum horizontal stress, minimum horizontal stress, pore pressure, and change in pore pressure over time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.