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Gas hydrates amount estimated from acoustic logs at the Blake Ridge, Sites 994, 995, and 997

Proceedings of the Ocean Drilling Program: Scientific Results 164-20

By:
Edited by:
Charles K. Paull , Ryo Matsumoto , Paul J. Wallace , and William P. Dillon
https://doi.org/10.2973/odp.proc.sr.164.239.2000

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Abstract

The amount of in situ methane hydrates present in marine sediments is estimated at Ocean Drilling Program (ODP) Leg 164 drill sites on the Blake Ridge using acoustic logs. A weighted equation developed for relating the amount of hydrates concentrated in the pore space of unconsolidated sediments to the increase of acoustic velocities is applied to the acoustic logs using three sets of porosity distribution (porosity derived from bulk density logs, core porosity, and linear approximation of core porosity). Generally, the gas hydrate concentration increases with increasing depth toward the bottom-simulating reflector (BSR). The average gas hydrate concentration in the pore space varies between 12.1%, using porosity from the bulk density, and 3.8%, using core-derived porosity. The average hydrate concentrations in the pore space using core porosities are 3.9% (2.2 vol% of sediment), 5.7% (3.3 vol%) and 3.8% (2.2 vol%) at Sites 994, 995, and 997 respectively. These estimated concentrations are comparable to those calculated from chloride anomalies at these sites.

Additional publication details

Publication type:
Report
Publication Subtype:
Organization Series
Title:
Gas hydrates amount estimated from acoustic logs at the Blake Ridge, Sites 994, 995, and 997
Series title:
Proceedings of the Ocean Drilling Program: Scientific Results
Series number:
164
Chapter:
20
DOI:
10.2973/odp.proc.sr.164.239.2000
Volume:
164
Year Published:
2000
Language:
English
Publisher:
Ocean Drilling Program, Texas A&M University
Publisher location:
College Station, TX
Description:
6 p.
First page:
193
Last page:
198