TY - JOUR
T1 - Sampling disturbance in hydrate-bearing sediment pressure cores
T2 - NGHP-01 expedition, Krishna-Godavari Basin example
AU - Dai, Sheng
AU - Santamarina, J. Carlos
N1 - Funding Information:
This research was supported by the Department of Energy /JIP project for methane hydrate, administered by Chevron. Additional funding is provided by the Goizueta Foundation .
Publisher Copyright:
© 2014 Elsevier Ltd.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Sampling natural sediments causes unavoidable disturbance as recovered sediments experience changes in stress and strain during drilling, core recovery, transportation, handling, and early stages of testing. In hydrate-bearing sediments, the potential for sampling disturbance may be aggravated, since pressure and temperature changes can lead to hydrate dissociation and gas exsolution. Pressure core technology attempts to recover and characterize hydrate-bearing sediments while preserving them under in situ pressure and temperature conditions, which is an essential requirement to assess the mechanical, physical, chemical, and biological properties of natural hydrate-bearing sediments. Previous studies on near-surface sampling effects are extended in this study to evaluate additional sampling disturbances relevant to hydrate-bearing sediments: (1) hydrate dissociation due to mechanical extension, (2) negative pore pressure generation during unloading (Mandel-Cryer effect), (3) secondary hydrate formation, (4) changes in hydrate mass as a function of changes in pressure and temperature within the stability field, (5) hydrate anomalous preservation and its benefits for pressure core handling and testing, and (6) relaxation/aging following sampling. Results provide valuable insight to sampler design, coring and operation procedures, high pressure chamber design, and pressure core testing techniques.
AB - Sampling natural sediments causes unavoidable disturbance as recovered sediments experience changes in stress and strain during drilling, core recovery, transportation, handling, and early stages of testing. In hydrate-bearing sediments, the potential for sampling disturbance may be aggravated, since pressure and temperature changes can lead to hydrate dissociation and gas exsolution. Pressure core technology attempts to recover and characterize hydrate-bearing sediments while preserving them under in situ pressure and temperature conditions, which is an essential requirement to assess the mechanical, physical, chemical, and biological properties of natural hydrate-bearing sediments. Previous studies on near-surface sampling effects are extended in this study to evaluate additional sampling disturbances relevant to hydrate-bearing sediments: (1) hydrate dissociation due to mechanical extension, (2) negative pore pressure generation during unloading (Mandel-Cryer effect), (3) secondary hydrate formation, (4) changes in hydrate mass as a function of changes in pressure and temperature within the stability field, (5) hydrate anomalous preservation and its benefits for pressure core handling and testing, and (6) relaxation/aging following sampling. Results provide valuable insight to sampler design, coring and operation procedures, high pressure chamber design, and pressure core testing techniques.
KW - Anomalous preservation
KW - Fine sediment
KW - Mandel-Cryer effect
KW - Pressure core
KW - Sampling effect
UR - http://www.scopus.com/inward/record.url?scp=84914122677&partnerID=8YFLogxK
U2 - 10.1016/j.marpetgeo.2014.07.013
DO - 10.1016/j.marpetgeo.2014.07.013
M3 - Article
AN - SCOPUS:84914122677
SN - 0264-8172
VL - 58
SP - 178
EP - 186
JO - Marine and Petroleum Geology
JF - Marine and Petroleum Geology
IS - PA
ER -