Proceedings Volume Cover
SOCIETY OF PETROLEUM ~NGIXEERS OF A134E  
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TKIS IS A PREPRINT --- SUBJECT TO COF@ECTION  
Permeability  
AHww.tion  
of “Sancistune  
Ckmpawd  
Using  
,
A High-Energy  
liquid  
By  
Larman J. Heath, Member AIllE,and Ray V. Huff,  
Bureau of Mines, U. S. Department of the Interior, Bartlesville, Okla.  
This paFer was prepared for the 96th Annual AIME Meeting to be held in Los Angeles, Calif.,  
Permission to copy is restricted to an abstract of not more than 3oo  
Feb. 19 through 23, 1967.  
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.
flow of gas. By altering the permeability of  
Ai3STiLACT  
the sandstone around the wellbore, productivit  
can be increased.  
Thi;study l?asdone to determine the” ‘  
technicalfeasibility of the thermal alteration  
of sandstone.by the in situ ournlng of a high-  
energy compound. A proprietary liquid monopro-  
pellant was burned in several sandstone cores  
-
Sandstones are composed primarily of crys  
There a  
tal phases or modification of silica.  
seven principal cryst&Llinc phases of silice.,  
but the three most common ones zir?quartz,  
tridymite and crist.halite.  
This ,  
to effect an increase in permeability.  
Quartz, the phase  
report summarizes the results .ofpreliminary ;  
tests.  
most generally found in nature, can be ctinver  
to tridymite or cristobalite by heat. The  
stable forms of these silicas are: quartz bel  
86-[oC)tridymite to l,4”[0°Cand cristobalite t  
the liquid form at 1,’(23°C. Within each of  
these crystal modifications there are reversib  
changes or inversions ‘]hichcan be effected by  
the rapid cooling or heati~g of the crystal  
through a fairly definite temperature value.  
For example, the low-high inversion of quartz  
occurs at 573°C. During the heating and also  
during the modification of silica crystals the  
are changes in volume. The density of quartz  
2.65, thatof tridymite is 2.26 and that of  
cristobalite is 2.32. The transformation of  
Attempts were made to burn the propellant  
in 13 different cores, each saturated with the  
Bum,ing was complete in  
combustible liquid.  
three of the cores, while in three other cores  
burning was only partial. The increase in  
permeability for the three completely burned  
cores ranged from 109 per cent to 384 per cent  
and showed an average increase in air permea-  
bility of 216 per cent. Results of’these tests  
based on recorder response, indicated a maximum  
uniform heating of the rock matrix to a temper-  
ature of about h55°C.  
INTRODUCTION .... . .. -. _ -...-...=-. ...... ..  
quartz to.trM@.te .caus_eS<EWnwwe.in  
of.17,> per cent.  
fracturt~g or spalling takes place. In additi  
w?ww  
In most volume changes,  
.140gtg.as-storage =d gas-producing ~eser-  
voirs have adequate capacity but would b“en-efi”t  
from.improved deliverability. .Duringpeqk -,  
demand’periods, the lack of formation permea-  
bility adjacent t? the”wellbore often limits th  
to-its-effec~ onsllica,  
heat ”ctieffect hot’”  
~onlythe dis”soc:iati.oofn~.carbondioxide.from  
carb.ona%es.b.qatlSo_the complete irreversible  
A mani’foldincrease In.  
dehydration of clays.  
permeabilf’tyof sandstone shcwld b?.obta.inedby  
——  
References_.@ il.lus.trat$ort,esn.da Of.pape+...  
.,.