Full text loading...
-
Brittleness Computation without Density for Unconventional Resource Exploration and Development
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
Brittleness (B) and total organic carbon (TOC) estimations are required to identify and produce unconventional resources like gas and oil-bearing shales and tight sands with near zero or no permeability. B is the key property for horizontal well placement, and fracture development and sustainability assessments because fracturing required for production. Conventionally B is estimated from Young’s modulus (E) and Poisson’s ratio (v).
As E is a function of density (ρ), field wise B estimation from E (BE) after seismic inversion may be compromised because ρ is the poorest estimate compared to acoustic impedance (AI) and shear impedance (SI). We introduced a simple quantitatively equivalent BE computation using Eρ. We also showed that it is preferable to use the average B estimation from Eρ and µρ rather than the BE and v brittleness (B_U) average.
The examples of B and TOC estimation first from the well logs, then the rock parameters inverted from 3D land seismic data successfully mapped a brittle shale zone. Core analysis made at another well on the same target shale in this study showed that it is a source rock with API 42o, porosity > 4 %, Sw > 50 % and TOC > 2 %wt.