Knowledge of rock mechanical properties at subsurface conditions is essential to hydrocarbon exploration and production industry. Current methods to obtain this data include seismic amplitude measurements prior to drilling, while-drilling methodologies (LWD and MWD) using drill acoustics and post-drilling methods that use wireline logging operations. These techniques suffer from low spatial resolution and low accuracy because of either remote detection of rock mechanical properties as in seismic methods or because estimated rock properties no longer reflect in-situ conditions due to the drilling process itself. There is a need for technologies that can accurately evaluate formation properties with minimal modifications to pre-existing systems.
Researchers at the University of Texas at Austin have developed a method for obtaining information about a formation during drilling using a controlled input signal to excite a broad range of mechanical harmonics of the drilling system and recording response. The recorded harmonics are then segmented into those emanating from drill-string structure itself and those of the bit-rock interaction. This provides a more high resolution, reliable estimate of properties compared to other LWD technologies. Additionally, rock properties measured at or in front of the bit-rock interface most closely reflect those of rocks at subsurface conditions because geo-mechanical stresses and pore fluids have not yet been changed by the drilling process itself (i.e., they are still at in-situ conditions).
- Increased signal to noise ratio of measurement
- High accuracy
- Easy implementation with current drilling techniques
- More efficient and reliable formation models
We are looking for industry partners to develop and test the technology in the field. The technology is available for field evaluation and licensing.