Christine Ecker

Bio: Christine Ecker is an academic researcher. The author has contributed to research in topics: Hydrate & Freezing point. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

Methane hydrate rock physics models for the Blake Outer Ridge

Abstract: Seismic analyses of methane hydrate data from the Blake Outer Ridge indicate high Pwave velocity and anomalously low S-wave velocity in sediments containing methane hydrates. In an attempt to explain this observed P-wave and S-wave velocity structure at the transition from gas to hydrates, the effect of different hydrate models on elastic moduli and velocities are explored. After construction of an initial gas model, the properties of the hydrates are estimated using the bound averaging method together with the Voigt and Reuss bounds for elastic moduli. The result suggests that the hydrates becomes part of the rock matrix and softens the pores by fracturing. The additional formation of ice is required to obtain the desired P- to S-wave velocity ratio in the hydrate bearing sediments, indicating temperature conditions around the freezing point of water.

Seismic rock physical modelling for gas hydrate-bearing sediments

Abstract: There are ambiguities and uncertainties in the recognition of gas hydrate seismic reflections and in quantitative predictions of physical information of natural gas hydrate reservoirs from seismic data. Rock physical modelling is a bridge that transforms the seismic information of geophysical observations into physical information, but traditional rock physics models lack descriptions of reservoir micro-structures and pore-filling materials. Considering the mineral compositions and pore micro-structures of gas hydrates, we built rock physical models for load-bearing and pore-filling gas hydrate-bearing sediments, describe the mineral compositions, pore connectivity and pore shape using effective media theory, calculated the shear properties of pore-filling gas hydrates using Patchy saturation theory and Generalized Gassmann theory, and then revealed the quantitative relation between the elastic parameters and physical parameters for gas hydrate-bearing sediments. The numerical modelling results have shown that the ratios of P-wave and S-wave velocities decrease with hydrate saturation, the P-wave and S-wave velocities of load-bearing gas hydrate-bearing sediments are more sensitive to hydrate saturation, sensitivity is higher with narrower pores, and the ratios of the P-wave and S-wave velocities of pore-filling gas hydrate-bearing sediments are more sensitive to shear properties of hydrates at higher hydrate saturations. Theoretical analysis and practical application results showed that the rock physical models in this paper can be used to calculate the quantitative relation between macro elastic properties and micro physical properties of gas hydrate-bearing sediments, offer shear velocity information lacking in well logging, determine elastic parameters that have more effective indicating abilities, obtain physical parameters such as hydrate saturation and pore aspect ratios, and provide a theoretical basis and practical guidance for gas hydrate quantitative predictions.

Blake Outer Ridge dataset

Abstract: Blake Outer Ridge dataset Raw Data /data/2d_real/blake_outer_ridge/cmps-tp.HH Velocity Model N/A Stack N/A Zero-offset Migration N/A Usage AVO/methan hydrates: (Matsumoto et al., 1996; Ecker and Lumley, 1993, 1994; Ecker, 1994, 1995, 1997; Ecker et al., 1997; Ecker, 1998; Mora and Biondi, 1999), imaging/velocity estimation (Biondi and Sava, 1999; Clapp and Biondi, 1999; Sinha and Biondi, 1999; Fomel, 1999) Geometry /data/2d_real/blake_outer_ridge/cmps-tp.HH: in="stdin" expands to in="stdin" esize=4 n1=625 n2=48 n3=1105 n4=1 33150000 elem 132600000 bytes d1=0.004 d2=-0.1 d3=0.05 d4=1 Warning: d2 is negative. Legal, but risky. o1=4 o2=3.825 o3=0 o4=0 label1=Time label2=Trace-record number label3= Non-linear cable group spacing: 100 m at near offsets and 50 m at far offsets. Problem N/A History of Data The data were recorded at the Blake Outer Ridge, offshore Florida and Georgia. A map of the region is shown in Figure 1, highlighting the area of known hydrate distribution as mapped from seismic bottom simulating reflectors (BSR). The part of the seismic line is marked by the rectangular, and extends both from the hydrate region into an area without hydrate. The data were provided by USGS (Keith Kvenvolden, Myung Lee, and Bill Dillon). Preprocessing N/A Proprietary Considerations N/A REFERENCES Biondi, B., and Sava, P., 1999, Wave-equation migration velocity analysis: SEP–100, 11–34. 1email: sergey@sep.stanford.edu 1