Acoustic Velocity Log Numerical Simulation and Saturation Estimation of Gas Hydrate Reservoir in Shenhu Area, South China Sea

Abstract

Gas hydrate model and free gas model are established, and two-phase theory (TPT) for numerical simulation of elastic wave velocity is adopted to investigate the unconsolidated deep-water sedimentary strata in Shenhu area, South China Sea. The relationships between compression wave (P wave) velocity and gas hydrate saturation, free gas saturation, and sediment porosity at site SH2 are studied, respectively, and gas hydrate saturation of research area is estimated by gas hydrate model. In depth of 50 to 245 m below seafloor (mbsf), as sediment porosity decreases, P wave velocity increases gradually; as gas hydrate saturation increases, P wave velocity increases gradually; as free gas saturation increases, P wave velocity decreases. This rule is almost consistent with the previous research result. In depth of 195 to 220 mbsf, the actual measurement of P wave velocity increases significantly relative to the P wave velocity of saturated water modeling, and this layer is determined to be rich in gas hydrate. The average value of gas hydrate saturation estimated from the TPT model is 23.2%, and the maximum saturation is 31.5%, which is basically in accordance with simplified three-phase equation (STPE), effective medium theory (EMT), resistivity log (Rt), and chloride anomaly method.

Design of Well Log Processing System for Gas Hydrate

“…During the same period, Japan and Canada were successful in conducting hydrate drilling in the Canadian Northwest Delta. In 2007, China successfully collected gas hydrate physical samples from drill holes in the South China Sea [3,4].…”

Numerical Analyses on Controlling Factors for Hydrate Differential Accumulation in the Shenhu Drilling Area, South China Sea

“…Therefore, this area is a target area for hydrate resources. 23,28,29 On the basis of the fact that no hydrate at site SH5, research into the main factors for hydrate absence was the focus of this paper.…”

“…There are a large number of bottom simulating reflector (BSR) regions, which can indicate the occurrence of free gas. Therefore, this area is a target area for hydrate resources. ,, On the basis of the fact that no hydrate at site SH5, research into the main factors for hydrate absence was the focus of this paper.…”

Numerical Simulation of Response Characteristics of Audio-magnetotelluric for Gas Hydrate in the Qilian Mountain Permafrost, China

“…In permafrost regions, gas hydrates may exist at subsurface depths ranging from about 130 to 2000 m (Collett 2002, Lu et al 2011. Gas hydrates in offshore continental margins have been mapped at depths below the sea floor ranging from about 100 to 1100 m (Collett 2002, Dickens 2001, Huo and Zhang 2009, Xiao et al 2013. As a new clean alternative energy source of huge reserve, gas hydrates have attracted more and more attention, and more than 100 regions have directly or indirectly found the occurrence zones Collett 2011, Moridis et al 2011).…”