Sonic and resistivity measurements on Berea sandstone containing tetrahydrofuran hydrates: a possible analogue to natural-gas-hydrate deposits. [Tetrahydrofuran hydrates]

Conference · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6278969

Pearson, C; Murphy, J; Halleck, P; Hermes, R; Mathews, M

Deposits of natural gas hydrates exist in arctic sedimentary basins and in marine sediments on continental slopes and rises. However, the physical properties of such sediments are largely unknown. In this paper, we report laboratory sonic and resistivity measurements on Berea sandstone cores saturated with a stoichiometric mixture of tetrahydrofuran (THF) and water. We used THF as the guest species rather than methane or propane gas because THF can be mixed with water to form a solution containing proportions of the proper stoichiometric THF and water. Because neither methane nor propane is soluble in water, mixing the guest species with water sufficiently to form solid hydrate is difficult. Because THF solutions form hydrates readily at atmospheric pressure it is an excellent experimental analogue to natural gas hydrates. Hydrate formation increased the sonic P-wave velocities from a room temperature value of 2.5 km/s to 4.5 km/s at -5/sup 0/C when the pores were nearly filled with hydrates. Lowering the temperature below -5/sup 0/C did not appreciably change the velocity however. In contrast, the electrical resistivity increases nearly two orders of magnitude upon hydrate formation and continues to increase more slowly as the temperature is further decreased. In all cases the resistivities are nearly frequency independent to 30 kHz and the loss tangents are high, always greater than 5. The dielectric loss shows a linear decrease with frequency suggesting that ionic conduction through a brine phase dominates at all frequencies, even when the pores are nearly filled with hydrates. We find that the resistivities are strongly a function of the dissolved salt content of the pore water. Pore water salinity also influences the sonic velocity, but this effect is much smaller and only important near the hydrate formation temperature.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6278969
• Report Number(s): LA-UR-83-163; CONF-830703-1; ON: DE83006057
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
BENCH-SCALE EXPERIMENTS
CHEMICAL PREPARATION
DATA
DRILL CORES
ELECTRIC LOGGING
EXPERIMENTAL DATA
FURANS
GAS HYDRATES
HETEROCYCLIC COMPOUNDS
HYDRATES
HYDROGEN COMPOUNDS
INFORMATION
LOW TEMPERATURE
MEDIUM TEMPERATURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PERMITTIVITY
RESISTIVITY LOGGING
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SIMULATION
SONIC LOGGING
SYNTHESIS
TEMPERATURE DEPENDENCE
TETRAHYDROFURAN
WATER
WELL LOGGING