Abstract:
Shale gas deposits have emerged as an important energy source with growing demand during
the previous decade. TOC is a significant component for unconventional reservoirs that is
often quantified using conventional approaches, including geochemical lab analysis of side
wall cores and cuttings of formations. However, such research methods produce data in a
non-continuous and time-consuming manner. High resolution and continuous information
acquired from well logs can help to solve this challenge. To estimate TOC from well logs,
many approaches has been attempted. Among these approaches, four have been selected to
quantify TOC in the current study: Density Log, Spectral Gamma-Ray Log, Delta logR, and
Multivariate Fitting. Apart from TOC other Geochemical parameters LMI (log-based
Maturity index), LOM (log-based Organic Maturity), BI (Brittleness Index), and Kerogen
Volume were estimated and computed using well-based characterization. LMI estimated by
well log data 0.67, LOM estimated by well data 10.2, Brittleness Index 0.5 and volume of
kerogen between 4 to 5% and TOC was calculated using Passey's method was 1to2%,
Schmoker's, Multivariant technique up to 2 to 3 percent TOC, while Spectral Gamma Ray
log provides average 1 to 1.5 TOC in the formation. Calculated results from well data show
promising results. For analyzing the spatial distribution of TOC, the Hampson-Russel
software was used for seismic inversion, which resulted in impedance volume estimate. The
interpreted seismic cube was used to perform model-based inversion of supplied 3D seismic
data. Tajjal-01 seismic to well tie technique yielded a statistical wavelet. The wavelet is
convolved with the well's reflectivity series roughly approximates the proximal seismic
traces. The available seismic data, well data, calculated TOC, and interpreted horizons data
were used as input for inversion. The software found an excellent 99.96% correlation in the
cross plot between computed TOC and predicted TOC.
