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Патент USA US3098048

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1
3,08,38
Patented July 16, 1963
2
sand with hydrocarbon may be illustrated by com
pounds such as sorbitan monooleate, sold under the
trade name of Span 80; sorbitan sesquioleate, sold under
the trade name of Arlacel C; sorbitan trioleate, known to
3,098,038
TREATMENT @F SUBSURFACE EARTH
F?RMATlQNS
Gene D. Thompson, Houston, Harold M. Hibbs, Tyler,
and Eldred W. Hough, Austin, Tex, assignors, by mesne
assignments, to Eersey Production Research Company,
Tulsa, ©kla., a corporation of Delaware
No Drawing. Filed Apr. 29, 1959, Ser. No. 809,587
16 Claims. (Ci. 252-855)
the trade as Span 85; diglycol laurate; diglycol oleate;
and other compounds which have this property. As
illustrations of other com-pounds useful in this inven
tion, mention is made of: polyoxyethylene sorbitol
10
The present invention is directed to a method for
treating a subsurface earth formation. More particu
larly, the invention is concerned with increasing produc
tion of oil by fracturing a subsurface earth formation.
beeswax derivative, sorbitan tristearate, polyoxyethylene
sorbitol hexastearate, ethylene glycol fatty acid ester,
propylene glycol fatty acid ester, propylene glycol mono
stearate, polyoxyethylene sorbitol 4.5 oleate, glycerol
monostearate, propylene glycol monolaurate, diethylene
glycol monooleate, diethylene glycl fatty acid ester, di
In its more speci?c aspects, the invention is concerned 15 ethylene glycol monostearate, glycerol monostearate
with a method for treating a subsurface earth forma
(self-emulsifying), diethylene glycol monolaurate (soap
tion in which sand is deposited in and adjacent to a
free), sorbitan monopalmitate, polyoxyethylene di
subsurface earth formation.
oleate, tetraethylene- glycol monostearate, polyoxypro
The present invention may be brie?y described as a
pylene ma-nnitol dioleate, polyoxyethylene sorbitol lano
method for fracturing a subsurface earth formation with 20 lin oleate derivative, and polyoxypr-opylene stearate.
water containing a sand-propping agent in which the
The amount of the surface-active agent or salt having
sand-propping agent is lodged in the resulting fractures
a low HLB value may range from about 0.2 to about
to maintain them open. A particular feature of the pres
5 percent by weight based on the water. A preferred
ent invention is rendering the sand-propping agent oil wet
amount may range from about 0.5% to about 2% by
whereby the tendency of the sand-propping agent to 25 weight.
settle out of the water is decreased or substantially
The liquid hydrocarbon employed in the practice of
depressed.
the present invention to wet the sand is suitably one hav
The present invention also involves treating a sub
ing a viscosity from about 1.5 to about 400 centipoi-ses
surface earth formation with a suspension of sand in
at 60° F. and boiling in the range ‘from ‘about 100°
30
the water in which the sand has been wet with oil, the
to about 800° F. Illustrative of the liquid hydrocarbons
suspension being introduced into the subsurface earth
formation through a well bore penetrating the subsurface
earth formation to deposit the hydrocarbon-wet sand in
and ‘adjacent to the subsurface earth formation.
may be mentioned the gasoline, kerosene, diesel oil,
and gas oil hydrocarbons and the individual components
thereof. Kerosene, diesel oil, and crude oils are prefer
entially used. While liquid hydrocarbon fractions ob
In the hydraulic fracturing of subsurface earth for 35 tained from crude petroleum and the like may be satis
mations, the use of aqueous hydraulic fracturing ?uids
factory, under some instances it may be desirable to
has been limited heretofore because of the inability of the
employ pure hydrocarbons boiling Within the range of
fluid to carry sand adequately at low pump rates. Typical
aqueous fracturing ?uids may have sand falling rates
about 100° to about 800° F.
In practicing the present invention, the sand employed
of 20 feet per minute or more. If the pumps introducing 40 is usually round Ottawa sand having a mesh size (U.S.
the aqueous fracturing ?uid into a Well are stopped dur
Sieve Series) in the range from about 10 to about 40
ing a fracture treatment, the sand will usually deposit
mesh. Equivalent sand to the round Ottawa may be
used {and different mesh sizes may be employed. For
present invention, the tendency of the sand to pack
example, angular sand grains may be used ‘and either
tightly and to deposit and clog a well bore is decreased 45 angular or round sand having mesh sizes from about
or entirely suppressed. The present invention involves
10 to about 80 may be used. The sand may be be
preferentially wetting the sand with an oil wetting sur
tween 20 to 40 mesh, 40 to 60 mesh, or 60 to 80 mesh,
face-{active agent contained in a hydrocarbon phase.
or may be distributed over the range of mesh sizes.
Water is added to the oil-wet sand in such quantities that
When employing the present invention in fracturing sub
50
any latent water-in-oil emulsion is broken by an excess
surface earth formations, 20 to 40 mesh Will be preferred
of Water phase. The effect is to make the individual
while when the present invention is employed in form
sand grains less adherent with respect to each other
ing a deposit or pack in the well, 10 to 40 mesh may
and with respect to the tubing or pipe string through
be used.
which the sand grains are introduced. A particular ad~
The amount of sand employed in the practice of the
vantage of wetting the sand with hydrocarbon when 55 present invention may range from about .1 pound per
used in a water suspension is that higher concentrations
gallon of the Water used as a suspending medium and as
of" sand may be employed than are normally used in
a fracturing liquid to about 5 pounds per gallon of
fracturing or treating operations in that the sand assumes
water. A preferred range is from about 0.5 to about
a ?uidized condition in the suspension in the water.
3 pounds per gallon of water. As ‘an example, about
in accordance with the present invention, certain sur
10,000 to 15,000 pounds of sand may be used for each
face-active agents are employed which cause preferential
10,000 gallons of the water used as ‘a suspending medium.
wetting of the sand with the liquid hydrocarbon. These
in the well and form a bridge.
In accordance with the
surface-active agents are those which have a hydrophile
lipophile balance in the range between about 0 to about
8. Hydrophile-lipophile balance (HLB) is a term rec
ognized in the art and is described by W. C. Gri?in
in The Journal Society Cosmetic Chemists, vol. 5,
page 249 (1954), and also “Emulsions: Theory and
Practice,” Reinhold Publishing Corp, New York, 1957,
at pages 189 to 196.
The surface-active agents employed in the practice
of the present invention for preferentially wetting the
The water employed as a suspending medium and/or
as a ‘fracturing liquid may be either fresh water or a
brine.
In fact, it is preferred to employ a brine such
as sodium chloride or calcium chloride which contains
from about 1 to about 5 percent of either the sodium
chloride or the calcium chloride. From about 2 to about
3 percent by weight of either the sodium chloride or
the calcium chloride may be used.
In practicing the present invention, a solution of a
low HLB oil-soluble surface-active agent may be made
3,098,038
A
and the suspension is then forced into a formation under
sufficient pressure to cause ‘fracturing thereof.
up into a hydrocarbon such as kerosene and then ad
mixed thoroughly with sand. The resulting hydrocar
bon-Wet sand then has water added to it in su?icient
amounts to form a suspension, and the suspension is then
pumped into or introduced into a well bore piercing a
subsurface earth formation. When the suspension is used
to fracture a subsurface earth formation, the suspension
The present invention is quite advantageous and useful
in that the hydrocarbon-wet sand is pumpable and does
may be introduced through a pipe string under sufficient
not form packs ‘or bridges across a pipe string which re
sists removal from the well. In ‘short, wetting of the
sand with oil when it is suspended in water renders the
sand in a fluidized condition which may increase the ease
of fracturing. In other words, in the practice of the pres
in the subsurface earth formation with the resulting 10 ent invention there are numerous advantages such that
the sand is maintained suspended in the water for a suffi
lodgement of the oil-wet sand in the so-formed fractures
cient length of time that it may be readily pumped or in
or ?ssures. Thereafter hydrocarbons may be produced
troduced into contact with or ‘adjacent a subsurface earth
from the ‘fractured formation into the well bore and con
formation. As stated hereinbefore, the oil-wet sand does
ducted to the earth’s surface through the usual pipe or
15 not pack tightly and deposit readily from the aqueous
tubing string.
?uid at low pump rates. Also, the hindered settling rate
The present invention also contemplates the formation
in accordance with the present invention allows the use
of a deposit or pack around a casing lining the wall of
of aqueous ?uids with a high sand concentration Without
the well in a subsurface earth formation from which
sanding up the well which heretofore would require the
?ne sand is produced in sui?cient quantity to interfere
with the production of desirable hydrocarbons. When 20 use of drilling operations and the like.
The nature and objects of the present invention having
such is the case, in the practice of the present invention
been completely described and illustrated, what we wish
a suspension of hydrocarbon or oil-wet sand in water
to claim as new and useful and secure by Letters Patent
is introduced into the usual cavity back of the casing and
1s:
the sand formed into a pack such that it retains the ?ne
1. In a method for fracturing a subsurface earth forma
sand which would ordinarily be produced with the 25
tion with 'a suspension of water containing a sand-propping
hydrocarbons from the formation. It is also contem
agent in which the sand propping agent is lodged in and
plated in this aspect of the present invention that a de
m'aitains the resulting fracture ‘open, the improvement
posit or pack may be formed around a screen and liner
which comprises rendering the sand-propping agent wet
by introducing into the screen and liner and out through
the perforations therein a suspension of hydrocarbon 30 with hydrocarbon by contacting the sand-propping agent
with a composition consisting essentially of a liquid hydro
or oil-wet sand in water to deposit the hydrocarbon or
pressure to cause the fracture or opening up of ?ssures
oil-Wet sand back of the screen and liner to retain the
carbon and "a surface-active ‘agent having a low HLB in
stood that the invention is not to be limited to frac
sand to be wet with said hydrocarbon, forming a suspen
turing formations which contain natural gas hydrocar
bons and the like but is also adapted to fracturing forma
tions which contain liquid hydrocarbons. However,
fracturing a subsurface earth formation with said suspen
the range from about 0 to about 8 prior to suspending it
?ne sand which ordinarily would be produced with the
in said water whereby the tendency of the sand-propping
hydrocarbons from the formation.
The present invention is particularly applicable to treat 35 agent to settle is decreased.
2. A method for fracturing a subsurface earth forma
ment of subsurface earth formations or Zones which con
tion which comprises forming a composition consisting
tain natural gas hydrocarbons. It is therefore contem
essentially of a liquid ‘hydrocarbon and a surface-active
plated that the present invention may have speci?c ap
agent having a low HLB in the range from about 0 to
plication to fracturing sands or rock which contain sub
about 8, contacting sand with said solution to cause said
stantial quantities of gas. However, it is to be under
sion of said hydrocarbon~wet sand in water, and then
sion whereby said oil-wet sand is lodged in the resulting
when the invention is used in fracturing formations con 45 fractures.
3. A method in accordance with claim 2 in which the
taining liquid hydrocarbons or in treating such ‘forma
hydrocarbon is kerosene.
tions, it maybe desirable to treat the sand which is lodged
4. A method in accordance with claim 2 in which the
in the fractures or formed into a pack and which has
hydrocarbon is diesel oil.
been wet with oil with a surface-active agent having a
5. A method in accordance with claim 2 in which the
high HLB value in the range from about 13 to about
hydrocarbon is crude ‘oil.
40. Such surface-active agents which may be employed
6. A method in accordance with claim 2 in which the
to make the oil wet-sand preferentially water-wet may he
hydrocarbon is a fraction of crude oil.
exempli?ed by a compound such as polyoxyethylene
7. A method for fracturing a subsurface earth forma
stearate, which is sold to the trade as Myrj 52; Arquad 12,
a quaternary ammonium alkyl compound; Tween 20, a 55 tion which comprises admixing sand with a composition
consisting essentially of a liquid hydrocarbon and a su?i
polyoxyethylene sorbitan monolaurate; Brij 35, which is
cient amount of a surface-active agent having a low HLB
a polyoxyethylene stearate; Glim, which is the trade name
in the range from about 0 to about 8 to cause said sand to
for ethylene-oxide condensation product of an alkyl phe
be wet with said hydrocarbon, forming a suspension of
nol; Alrose O, which is fatty alkylol amide condensation
product; Alkaterge C, a substituted oxazoline; Alkanol 60 said hydrocarbon-wet sand in water, and then pumping
said suspension into a well bore piercing said subsurface
WXM, which is a sodium salt of monoamyl naphthalene.
earth formation under suflicient pressure to form fractures
Other compounds which have HLB values in the range
in said subsurface earth formation and to lodge said hy
from about 13 to about 40 may also be used.
drocarbon-wet sand in :said fractures.
As a speci?c example, oil-Wet sand may be suspended
8. A method in accordance with claim 7 in which the
in an aqueous fracturing ?uid as follows: 21/2 gallons of 65
subsurface earth formation contains gaseous hydrocar
low HLB oil-soluble surface-active agent such as Span
bons.
80, Aptet 277, which is tall oi-1 reacted with ethylene
9. A method in accordance with claim 7 in which the
oxide, or oleic acid, or other low HLB surface-active
subsurface earth formation contains liquid hydrocar
agent, are added to 50 gallons of kerosene and the mix 70 bons.
'
ture then added to 5,000 pounds of sand and intimately
10. A method in accordance with claim 7 in which the
contacted therewith. Water containing sodium chloride
water contains sodium chloride.
or calcium chloride in a desired concentration in a suf
?cient .amount is then ‘added to ?uidize the oil-wet sand.
The hydrocarbon-wet sand is then pumped into a ‘well 75
11. A method in accordance with claim 7 in which the
water contains calcium chloride.
12. A method in accordance with claim 7 in which
3,098,038
the oil-wet sand is treated with a surface-active agent
having a high HLB in the range irom about 13 to about
40 after sand is placed in the fractures.
13. A method in accordance with claim 7 in which the
amount of the surface-active agent having a low HLB is
within the range =from about 0.2% to about 5.0% by
weight, based on the water in which the hydrocarbon-Wet
sand is suspended.
14. A method for treating a subsurface earth forma
6
hydrocarbon has a viscosity from about 1.5 to about 400
centipioises at 60° iF. and boils in the range from about
100° to about 800° F.
16. A method for fracturing a subsurface earth forma
tion which comprises forming a composition consisting es
sentially of an oil and a surface-active agent having a low
HLB in the range from about 0 to about 7, contacting
sand with said solution to cause said sand to be wet with
said toil, forming a suspension of said oil-wet sand in
essentially of a liquid hydrocarbon and a surface-active 10 water, and then fracturing a subsurface earth formation
with said suspension whereby said oil~wet sand is lodged
agent having a low HLB in the range from about 0 to
in the resulting fracture.
about 8, contacting sand with said solution to cause said
tion which comprises forming a composition consisting
sand to be wet with said hydrocarbon, ‘forming a suspen
sion of said hydrocarbon-wet sand in water, and then in
troducing said suspension into a well bore penetrating 15
said subsurface earth formation whereby said hydrocar
bon-Wet sand is deposited in said subsurface earth for
mation.
15. A method in accordance with claim 14 in which the 20
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,742,426
2,802,531
2,960,465
Brainerd ____________ __ Apr. 17, 1956
Cardwcll ___________ __ Aug. 13, 1957
Ten Brink ____________ __ NOV. 15, 1960
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