Dec 9, 1988 ... panies Material Association (OCMA) of Oct. 1973. SWDC conforming to OCMA
DFCP 1 and bentonite conforming to OCMA DFCP 4 were used.
United States Patent [191
[11] Patent Number:
Herzog et al.
[45]
[54] USE OF CELLULOSE DERIVATIVES IN
[56]
DRILLING FLUIDS
Wolff Walsrode AG, Walsrode, Fed. Rep. of Germany
63-182301 7/1988 Japan. 794098
Dec. 9, 1988
Foreign Application Priority Data
Dec. 11, 1987 [DE]
Touey ................................. .. 536/91 Swanson ....... .. 252/856 Raehse et a1. .... .. 536/91 Hori et a1. ...................... .. 252/8513
FOREIGN PATENT DOCUMENTS
[21] Appl. No.: 282,166 [30]
References Cited 2,811,519 10/1957 4,110,226 8/1978 4,507,474 3/1985 4,519,923 5/1985
of Walsrode, Fed. Rep. of Germany
[22] Filed:
Nov. 20, 1990
U.S. PATENT DOCUMENTS
[75] Inventors: Dieter Herzog; Bernd Schriewer, both
[73] Assignee:
Date of Patent:
4,972,007
Fed. Rep. of Germany ..... .. 3742105
l/1981 U.S.S.R..
Primary Examiner-—Nathan M. Nutter Attorney, Agent, or Firm-—Sprung Horn Kramer & Woods
[57]
ABSTRACT
[51]
Int. GL5 .................... .. C09K 7/00; C08B 11/193;
C08B 11/00; C08B 11/12
Cellulose derivatives which are substituted in a speci
[52]
US. 01. .................................. .. 523/130; 523/131;
?ed manner by both carboxyalkyl groups and sulphoal kyl groups which are suitable in drilling ?uids.
536/90; 536/92; 536/97; 536/98; 252/8513 [58]
Field of Search ..................... .. 536/90, 92, 97, 98;
523/130, 131; 252/8513, 8.511
10 Claims, No Drawings
1
4,972,007
2
saline drilling ?uid systems in the presence of polyva USE OF CELLULOSE DERIVATIVES IN DRILLING FLUIDS
lent cations and at temperatures of up to 160° C. ' The invention relates to the use of cellulose deriva
tives containing carboxyalkyl and sulphoalkyl groups This invention relates to the use of cellulose deriva
5
CASAC in drilling ?uids, characterised in that
tives containing carboxyalkyl groups and sulphoalkyl
l. the average substitution per glucose unit with a car
groups CASAC in drilling ?uids. In deep well drilling, polymers are used in aqueous alkaline drilling ?uids for reducing the water loss. This
boxyalkyl group DSCA is from 0.4 to 1.8, 2. the average substitution per glucose unit with a sul
prevents the drilling ?uid from ?owing into permeable
3. the sum of DSCA and DSSA is at least 0.9 and 4. the viscosity of a 2% by weight solution in distilled water at a shear velocity of 2.5 sec-1 and a tempera ture of 20° C. is 5 to 50X 103 mPa.s.
phoalkyl group DSSA is from 0.1 to 1.0,
regions of the rock formation during the drilling pro cess. Optimum discharge of the drilled rock from the bore hole is ensured by suitable ?ow properties of the
drilling ?uid.
The carboxymethyl group is a particularly preferred carboxyalkyl group. The sulphoethyl group is a particu larly preferred sulphoalkyl group. In a very preferred
The polymers used should maintain their viscosity and water binding capacity in the presence of electro lytes, especially alkali metal and alkaline earth metal salts, under the temperature conditions prevailing in the
embodiment, the cellulose derivatives CASAC to be used according to the invention consist of a carboxyme
thylsulphoethyl cellulose CMSEC having an average
bore hole.
The products conventionally used for this purpose 20 substitution of sulphoethyl DSSE of from 0.1 to 1.0, in particular from 0.1 to 0.8 per glucose unit and an aver age substitution of carboxymethyl DSCM of from 0.4 to 1.8, in particular from 0.6 to 1.0. The compounds to be
are carboxymethyl celluloses (CMC), starch derivatives and synthetic polymers (G. V. Chilingarian, P. Vora butr: Developments in Petroleum Sci. 11, Elsevier Sci
enti?c Publishing Company, Amsterdam, 1981, Drilling and Drilling Fluids). Synthetic products based on acrylic acids, acrylam
used according to the invention are used particularly in 25
aqueous drilling ?uids, in particular at concentrations in the range of from 0.1 to 4%, preferably from 0.5 to 3%, based on the quantity of water in the drilling ?uid. In a preferred embodiment, the compounds to be used ac cording to the invention are prepared by the etheri?ca
ides and their copolymers have the serious disadvantage that they have less stability in the presence of salts,
especially in the presence of polyvalent ions. Synthetic
polymers which are highly stable in the presence of 30 tion of cellulose in alkaline solution with at least one compound SA which transfers a sulphoalkyl group and polyvalent ions such as calcium and magnesium ions are at least one compound CA which transfers a carboxyal very expensive and therefore frequently out of the ques kyl group, characterised in that tion for economic reasons.
(a) cellulose is suspended, for example in the form of
The synthetic copolymers described in PCT/EP
cellulose pulp, in particular in a secondary or tertiary 82/00264 and EP-A No. 0 152 814 contain polymerised 35 sulphonic acid-containing monomers which play a deci alcohol, (b) the suspension is combined with the compound SA sive role in the stability in the presence of polyvalent and/or CA, preferably at a pH of 0 to 9, ions but have the disadvantage of being very expensive.
(c) the suspension is then made alkaline, preferably to Although starch derivatives are more stable in the pH 13 to 14, in particular by the addition of alkali, presence of polyvalent ions such as calcium and magne 40 (d) etheri?cation is carried out, in particular at a tem sium, they have a lower temperature stability. Starch perature from 55° to 100° C., and and starch derivatives are known to lose much of their (e) compound CA and/or SA is then optionally added if activity at temperatures from 100° to 120° C. and thus indicated, in particular at temperatures from 50° to become unusable. 100° C. and pH 10 to 14 with the formation of a The carboxymethyl celluloses (CMC) known from 45 CASAC. US. Pat. No. 2,425,768 have excellent properties for In another preferred embodiment, the compounds reducing the water loss in aqueous drilling ?uids but according to the invention are prepared by etherifica have a limited stability in the presence of polyvalent tion of carboxyalkyl cellulose CAC in an alkaline solu ions such as calcium and magnesium. The preparation of pure sulphoethyl cellulose (SEC) has been described in US. Pat. No. 2,132,181. The sulphoethyl cellulose disclosed in US. Pat. No. 4,519,923 have the disadvan
50 tion with at least one compound SA which transfers a
tage that pure sulphoethyl celluloses are very expen s1ve.
The use of carboxymethylsulphoethyl celluloses 55
(CMSEC) as viscosity increasing agents for textile printing inks is described in SU No. 79 40 89 which claims the use of carboxy-methyl-sulphoethyl celluloses having a Dsmboxymmy, of 0.4 to 0.55 and a Dsmphmyl of 0.1 to 0.25 as viscosity forming agent in textile print
ing inks. The carboxymethylsulphoethyl celluloses dis
sulphoalkyl group, characterised in that (a) CAC is suspended, in particular in a secondary or
tertiary alcohol, (b) the suspension is combined with the compound SA, preferably at a pH of 0 to 9,
(c) the suspension is then made alkaline, preferably to pH 13 to 14, in particular by the addition of an alkali, and (d) etheri?cation is carried out, in particular at a tem perature of from 55° to 100° C., with the formation of a CASAC.
The cellulose derivatives used according to the in closed in US. Pat. No. 2,811,519 have the disadvantage vention have a much greater stability to polyvalent ions of inferior properties in drilling ?uids and are therefore such as calcium and magnesium than CMC. The prod unsuitable for this purpose. It was an object of the present invention to develop 65 ucts according to the invention also have the good temperature stability of carboxymethyl celluloses. polymers which are stable to electrolytes and tempera The viscosity of a given cellulose derivative to be tures for improved drilling ?uids. These polymers used according to the invention depends on the require should also be economically suitable for use in highly
3
4,972,007
ments of the ?uid system. For adjusting the water loss to below 10 ml (according to the API standard) or at elevated temperatures (140° to 160° C.), the more low
4
at 140° C. for 15 hours. Table 1 shows the rheological data and water loss obtained after aging has been com pleted at 140° C. As seen from Table 1, the Examples
viscosity cellulose derivatives are used. Low viscosity
according to the invention give very good results for
cellulose derivatives are understood for the purpose of 5 water loss in the ?uid system after aging. An ordinary the present invention to be cellulose derivatives which commercial low viscosity carboxymethyl cellulose as 2% aqueous solutions at 20° C. have a viscosity (CMC) is shown in Table 1 as comparison example. below 1000 mPa.s at a shear velocity of 2.5 sec“1. The
concentration of such cellulose derivatives is preferably from 0.5 to 4, in particular from 1 to 3% by weight, h. based on the quantity of water present in the drilling
Table 2a shows the exact composition of the drilling ?uid when highly viscous cellulose ethers are used. The
?uid. High viscosity cellulose ethers are used on account of
ferred to as additive in the Table) is 1%. The samples
quantity of highly viscous cellulose ethers used (re were aged at room temperature for 15 hours and then at
their higher yield, in particular at lower temperatures, and for achieving a water loss of less than 15 ml accord
80° C. for 15 hours. The data measured after aging at 5 80° C. are entered in Table 2b.
ing to the API standard. High viscosity cellulose deriv atives are understood for the purpose of this invention to be cellulose derivatives which have a viscosity > 1000 mPa.s as 2% by weight aqueous solutions at 20° C. and a shear velocity of 2.5 sec—1. Such compounds are preferably used in quantities of from 0.1 to 2% by
weight, in particular 0.5 to 1.5% by weight, based on the quantity of water present in the drilling fluid. The cellulose derivatives used according to the in
In Table 2b, Examples 10 and 11 show markedly lower water losses combined with good rheological
properties compared with a commercial, highly viscous CMC representing the state of the art.
The components of the drilling ?uids, bentonite and salt water drilling clay (SWDC) shown in Tables la and 2a conform to the quality requirements of the Oil Com panies Material Association (OCMA) of Oct. 1973. SWDC conforming to OCMA DFCP 1 and bentonite
vention result in drilling ?uids which have excellent 25 conforming to OCMA DFCP 4 were used. properties even in the presence of polyvalent ions (e.g.
calcium2+, magnesiumz'l') at elevated temperatures (140° to 160° C.). The products according to the invention may be used in all aqueous ?uids which are used for sinking and treating bore holes and deep well holes, in particular in liquids which are required to ensure the stability of the bore hole during treatment of the latter and in liquids which serve to improve the ?ow paths for petroleum
EXAMPLE 1
127.4 parts of ?nely milled (0.02 to 0.5 mm) bleached, re?ned pine sulphite cellulose are suspended in 2187 parts of isopropanol in a thermostatically controlled reactor with suitable stirrer under atmospheric air. 79.67 parts of a 51.3% solution of vinyl sulphonic acid
and natural gas by injection under high pressure (Frac 35 sodium salt in water are added and the mixture is stirred for 15 minutes. 75.46 parts of sodium hydroxide dis ing). The composition of these ?uids may be completely solved in 106.7 parts of water are then added and the different from those given in the examples. reaction mixture is alkalized for 80 minutes at 25° to 30° The compounds to be used according to the invention C. It is then heated to 70° C. within 60 minutes. The may advantageously be prepared by the slurry process using, for example, the following as slurry medium: 40 reaction temperature of 70° C. is maintained for 120
primary, secondary or tertiary alcohols such as metha minutes (reaction time I). 110.81 parts of an 80% by nol, ethanol, isopropanol or tertiary butanol or a mix weight solution of chloro-acetic acid in water are then ture thereof. Other water miscible organic solvents may added and the temperature is maintained at 70° C. for a also be used, e.g. acetone. Celluloses other than that further 90 minutes (reaction time II). The product is mentioned above may be used. The viscosity of the 45 then ?ltered off and washed ?ve times, each time with products may be adjusted as required by known meth 2000 parts of a mixture of three parts of water and seven ods of reducing or increasing the temperature or adding parts of methanol, and ?nally once with 2000 parts of air, H2O or other oxidising substances during or before pure methanol. The product is dried in air for 18 hours alkalization. The reaction time and temperature during
preparation may also be varied. The products obtained after washing are virtually free from low molecular weight impurities. The products still have a residual moisture content after they have been dried in air. EXAMPLES 55 The properties of drilling ?uids are measured and
and ground. The product has the following data: Dry content =
83.7%
DSruIp/xoet/iyl = DScarboxymer/ryl = Viscosity of a 2% solution
0287 Q7“
in distilled 1120 =
77 mPa - s.
assessed according to the internationally recognised standards of the American Petroleum Institute (Stan dard Procedure for Testing Drilling Fluids, API RP 13 EXAMPLES 2 TO 9 B, Sixth Edition, Apr. 1976, issued by the American Table 3 shows the conditions of preparation of Exam Petroleum Institute, Production Department, 300 Carri ples l to 13. These Examples were prepared analo gan Tower Building, Dallas, Texas 75201, USA). gously to Example 1 but part of the isopropanol was The exact composition of the drilling ?uid in mixed replaced by methanol in some of the Examples. salt systems using low viscosity cellulose ethers accord In Examples 2 to 9, addition of the solution of vinyl ing to the invention is shown in Table 1. The drilling 65 ?uids were subjected to various successive stresses in a
roller furnace. The samples are aged at room tempera ture for 15 hours, then at 80° C. for 15 hours and ?nally
sulphonic acid sodium salt and addition of the sodium hydroxide were carried out at the time and temperature
analogous to those of Example 1.
4,972,007
5
6
EXAMPLES 10 TO 11
TABLE Z-continued Behaviour of highly viscous cellulose derivatives in
Examples 12 and 13 were earned out analogously to
highly saline drilling ?uids (according to API‘).
Example 1. The pine sulphite cellulose was replaced by cotton linters.
5
3 M NaOH
The material data of the cellulose derivatives men-
_
tioned in the Examples are entered in Table 4_
TABLE 2b
_
.
.
.
Properties of ?uid after 1532:; aging at 80 C. in a roller
TABLE 1 Behaviour of low viscosity cellulose derivatives in highly saline drilling ?uids (according to API‘). TABLE la.
Composition of the drilling ?uid: 2% bentonite (according to OCMA2 DFCP 4) 2% salt water drilling clay (according to OCMA DFCP 1) 3% additive (see below) 170 g/l NaCl 14 g/l KCl
100 g/l CaClzJI-IZO 10 g/l MgC12.6H2O 3 g/l NaOl-I In Table 1b, Examples 1 to 8 show products according to the invention which have a very low water loss. For comparison, a commercial CMC and three CMSEC not according to the invention are shown. The water loss according to API is 60 ml for CMC and 14 ml, 13 m1 and 16.5 ml, respectively, for comparison examples 9, 10 and 11. The water losses are thus substantially greater than 10 m1. TABLE 1b
Properties of ?uid after 15 hours aging at 140° C. in a roller furnace. Additive, Example No.
CMC '
Apparent viscosity mPa.s Plastic viscosity mPa.s Yield Point lb/ 100 ft2 Fluid loss according to API ml
25.5 15 21 60 '
1
2
3
4
5
6
7
8
9‘
10‘
11‘
14.5 12 5 6.4
23 21 4 3.6
13 12 2 4.4
15 13 4 4.9
17.5 16 3 2.5
27 21 12 3.2
17.5 14 7 5.1
21.5 18 7 3.2
14.5 11 7 14
12.0 11.0 2 13
15.5 13.0 5 16.5
1API = American Petroleum Institute, Standard Procedure for Testing Drilling Fluids, API RP 13 B, April 1976. 2OCMA = Oil Companies Material Association Speci?cations published by The Institute of Petroleum, London. issued by Heyden & Son. London, 1978.
‘Comparison examples.
TABLE 2 Behaviour of highly viscous cellulose derivatives in
Additive, Example No. Apparent viscosity mPa.s
highly saline drilling ?uids (according to APII). TABLE 2*‘ Composition of the drilling ?uid:
40
CMC 54.5
12 36
13 36
Plastic viscosity mPa2.s
20
20
25
Yield point lb/ 100 ft Fluid loss according to API m1
69 63
32 14
22 13
2% Bentonite (according to OCMA2 DFCP 4)
1API = American Petroleum Institute, Standard Procedure for Testing Drilling
2% Sa“ 'We‘ “11mg “"“Y '
F381?“ 35l ‘c3ompanles B‘ A?“ if? -..i A SSOCI?~ .~101'1 s PCClr103i10118 = 3 en
ii i. .1 b y r. 8 PH 15 C 45 Institute of petroleum. London. Issued by I-Ieyden & Son. London. 1978.
it?) 22128668 below) 14 g/l KC] 100 g/l CaC12.2I-IgO 10 g/l MgCl2.6I-I2O
TABLE 3 Data of Preparation of the Cellulose Ethers
Cellu-
Solu-
Cone. of VSSNa Solution
lose
tion
(% by
NaOI-I
weight)
(parts) (parts)
VSSNa Exam-
ple
iPrOH MeOI-I
No.
(parts) (parts) (parts) (parts)
80% by weight CES
H2O
Reac tion temp
Heat ing
Reaction
Reaction
solu-
up
time
time
era
tion
time
I
II
ture
Atmos~
(parts)
(Min)
(min)
(min)
(°C.)
phere air air air N2 N2
1 2 3 4 5 6
2.178 2.178 2.178 2.178 2.178 2.178
— — — — —— —
127.41 127.41 127.41 127.41 127.41 127.41
79.67 278.85 159.34 278.85 159.34 79.67
51.3 51.3 51.3 51.3 51.3 51.3
75.46 75.46 75.46 75.46 75.46 75.46
186.2 135.8 147.4 89.2 147.4 186.2
110.81 92.34 110.81 92.34 110.81 110.81
60 60 60 60 60 60
120 120 120 120 120 120
90 90 90 90 90 90
70 70 70 70 70 70
7 8 9'
2.143 2.143 2.143
47.71 47.71 47.54
127.41 127.41 127.41
101.16 101.16 40.5
30.3 30.3 30.3
62.88 59.74 56.6
113.6 113.6 189.7
92.3 87.67 83.1
30 30 60
30 30 60
90 9O 6O
70 70 70
10‘ 11‘ 12 13
2.133 2.133 2.178 2.178
47.54 47.54 —— —
127.33 127.33 127.33 127.33
101.16 67.44 134.89 202.34
30.3 30.3 30.3 30.3
62.88 62.88 75.46 75.46
146.6 170.1 123.7 76.7
73.82 83.1 92.28 101.51
60 60 60 60
80 80 6O 60
80 80 60 60
70 70 70 70
N2
N2 N2 N2 N2 N2 N2 N2
4,972,007
7 TABLE 4
water at a shear velocity of 2.5 sec-1 and a temper ature of 20° C. is 5 to 50>
