Page 171 - Geochemical Remote Sensing of The Sub-Surface
P. 171
148 V.T. Jones, M.D. Matthews and D.M. Richers
0.1
0 I ....... i i
0 5 10 15
Time (days)
Fig. 5-8. Differentiation of methane (1) and heavy hydrocarbons (2) during migration from an
artificial source (from Sokolov, 1971b).
10 5_
10 4 -
E
I~.
~'IO 3-
Cl ,,
C2
Ioo.......--'- .... C3 ,~176176176
I oO o oo~ C4
.::.-'.;'
10 0
ld 1 .
u I I I
07/21/81 08120/81 09/19181 10/19/81 11118181 12/18/81 12131/81
DATE
Fig. 5-9. Arrival at a surface well of hydrocarbon gases following a subsurface coal-bum
experiment at Rawlins, Wyoming (reproduced with permission of the Society of Petroleum
Engineers from Jones and Thune, 1982, Surface detection of retort gases from an underground
coal gasification reactor in steeply dipping beds near Rawlins, Wyoming, SPE 11050).
HYDROCARBON RESIDENCE SITES AT SURFACE
The most important of the direct techniques shown in Fig. 5-6 involve the
measurement of light hydrocarbons, methane through butane. Because of their volatility,
these light hydrocarbons are generally found in the free pore space. The seepage of
