CA1223280A - Set retarding compounds for use in cement slurries - Google Patents

Abstract

ABSTRACT OF TEE DISCLOSURE
Polymers which are the reaction product of N-aminoethylpiperazine and a dihalo or epoxy-halo compound are subsequently phosphonomethylated to provide products which are useful as cement set retarders.

Description

POLYMERIC ALKYLENEPHOSPHORIC ACID PIPERAZINE
DERIVATIVES AS SET RETARDING COMPOUNDS FOR
USE IN CEMENT SLURRIES

The invention pertains to aqueous hydraulic cement slurry compositions containing particular set retarders which are phosphoric acid derivatives of adduces of N-aminoethylpiperazinê and a Doyle or epoxy halo compound.

ydrophobic-substituted phosphoric or pros-phonic acids and their alkali metal salts have been used in cements, primarily soil/cement mixtures, to improve the freeze-thaw properties and salt-resistance.
Six- Jo eighteen-carbon alkyd phosphoric acids or their alkali metal salts ore so described in US. Patent 3,794,506. A plugging mixture for high temperature oil and gas wells comprising Port land cement and 1-hydroxy ethylidene-phosphonic acid trisodium or tripotassium salts as set time extenders is described in Derwent abstract 71376B/39 (1979~ of USSR Patent 640,019. The use of these phosphonate salts at temperatures of 75C
to 150C in amounts of 0.1-0.3 percent by weight is described in the abstract.

31,846-F -1-.

I

Other organic phosphorous acid derivatives are taught to be useful additives in cement compositions as turbulence-inducing and flow-property improver additives (US. 3,964,921 and 4,040,854, respectively).
Another -turbulence-inducer is a pyrolyzes product of urea and a bls(alkylenepyrophosphate) (US. 3,409,080).

AlXylene diphosphonic acids and their water soluble salts are described as set time extenders and water reducing agents for gypsum plasters (US. 4,225,361).
Lignins which have been phosphonoalkylated through an ether linkage or corresponding sulfonates, sulfides, hydroxyl or mine derivatives are taught to be useful primarily as dispersants or surfactants (US. 3,865,803) and are also said to be useful as "cement additives"
without indicating specific uses.
.

Ultra-rapid hardening Port land cement compost-lions are described which contain various acid salt additives (US. 4,066,469). It states that use of acid phosphates as the acid salt additives is excluded since the phosphates have a characteristically powerful retarding property peculiar to them.

Most of the cement used in oil wells is called port land cement. Port land cement is manufactured by calcining raw materials consisting of limestone, clay, shale, and slag together at 2,600F to 2,800F
(1410C to 1520C) in a rotary kiln.

The resulting material, is cooled and inter-ground with small percentages of gypsum to form port land cement. In addition to the above raw materials, other components such as sand, bauxite, iron oxide, etc., may 31,846-F- I
.

be added to adjust the chemical composition depending upon -the type of port land cement desired.

The principal components of the finished port land cement are lime, silica, alumina, and iron.
These components form the following complex compounds:
Tricalcium acuminate, (kiwi Allah), tetracalcium alumina-ferrite, (kiwi Alpha), tricalcium silicate, (kiwi Sue), and dicalcium silicate, (couch).

When water is added to cement, setting arid hardening reactions begin immediately. The chemical compounds in the cement undergo the processes of hydra-lion and recrystallization which results in a set product. The maximum amount of water that can be used with an oil-well cement is the amount which can be added before solids separation occurs. The minimum amount of water is the amount required to make the slurry pump able. Therefore, the normal water ratio is governed by the maximum and minimum limits for a paretic-ular class of cement.
-Thickening time is the time that the cement remains pump able in the well. This is the most critical property of an oil-well cement. The thickening time has to be long enough to be pumped into place and short enough to permit operations to resume quickly. Generally, 3 hours provides the necessary placement time plus a safety factor.

Other factors, such as fluid loss, viscosity and density must be taken into consideration and additives are known to the art-skilled which affect each of these factors as well as that of set, or thickening, time as 31,846 F I

, Lo I

mentioned above. Another parameter which has an effect on set time is temperature. Cement sets more rapidly as the temperature increases. This must be taken into consideration particularly when pumping cement into deeper wells since temperature increases as the depth of the well becomes treater. Temperature also affects the strength of the cement, the strength becoming less as the temperature increases.

Because of this temperature effect, it is important to retard the setting of the cement employed in the deeper wells.

It has now been discovered that certain new phosphonomethylated compounds are useful in aqueous cement slurries as set retarding additives. Some of these compounds are chelating agents, while others are useful as threshold agents in retarding the precipitation of metal ions from aqueous solution. However, not all chelating agents or threshold agents are useful as cement set-retarders.

The polymers useful in the present invent lion are made by reacting N-aminoethylpiperazine (ASP) with a Doyle or epoxy halo compound and subsequently reacting the polymer formed thereby with phosphorous acid and an alkanal (alluded) at a low phi usually 25- provided by the presence of a mineral acid, e.g.
hydrochloric acid. N-aminoethylpiperazine has the structure:

31,846-F -4-I

4~9~~347 ON - SHEA - SHEA
/ N C

I fH2 SHEA NH

and may be referred to by the name 1-(2-aminoethyl~piperazine. Hereina~ter7 it will be abbreviated "ASP".

The ASP can be reacted with any number of Doyle or epoxy halo compound in order to form a diver or polymer.
Any suitable epoxyhaloalkane (epihalohydrin) may be reacted, 1,2-epoxy-3-chloropropane (epichlorohydrin) being preferred. Generally, the epoxy halo compound will have 3-10 carbon atoms. Other epichlorohydrin-type compounds include: 1,2~epoxy-4-chlorobutane, 2,3-epoxy-4-chlorobutane, 1,2-epoxy-5-chloropentane, 2,3-epoxy-5-chloropentane, etc. In general, the sheller derivatives are preferred, although the corresponding broom or idea compounds may be employed. Mixtures of epoxyhaloalkanes may also be employed.

Deludes having prom 1 20 carbon atoms may be used. Saturated dwelled having the formula X(CH2)nX, where X may be chlorine, bromide, iodine or combinations thereof and wherein N is an integer ox from 1 to about 10, but preferably 2 to 6, may be employed. Thus, for example, dichloromethane (ethylene chloride), 1,2-dichloroethane (ethylene dichlorides), 1,2- or 1,3-dichloropropane, 1~4- or 1,2-dibromobutane and the like may be employed.

31,846 F I

..~

I

Aralkylene deludes can also be employed having the formula X-~2C-Ar-CH2-X wherein An is -I
Rl_4 , Rl_3 ' Rl_3 Rl_3 wherein R may be hydrogen, halogen, alkyd, having 1 to 4 carbon atoms, hydroxy and hydroxyalkyl, having 1 to 4 carbon atoms and X is a halogen atom.

Dihaloalkylene ethers can also be employed, e.g. bis(chloromethyl)ether or bis(chloroethyl)ether.
Formulas for such ethers also include X-CH2CH2(OCH2CH2)nX wherein n is 1 to 3 and X
O O
\+~

wherein X is a halogen atom.

I The deludes may also be unsaturated. Thus, 1,2-dichloroethene, 1,~-dichloro-2-butene and the like may be employed.

The conditions for making the polymer are to employ the reactants in an amount of from about 0.2 to about 1 mole of the chain extender compound, preferably about 0.25 to about 0.6, i.e. the diepoxy-, Doyle- or epoxyhalo-compound, per mole of ASP. The temperature of reaction is from about 50 to about 100C, preferably 31,846-F -6-70-80C at a pressure sufficient to maintain the reactants in the liquid phase.

The phosphonomethylation (Mannish reaction) is then carried out on the product in the presence of a strong acid to maintain the pi at less than 1.

While the reaction will proceed at temper-azures over a wide range, i.e., from 85 to 150C, it is preferred that the reaction medium be maintained at refluxing. The reaction is preferably conducted at atmospheric pressure, although sub-atmospheric and super atmospheric pressures may be utilized if desired.
Reaction times will vary, depending upon a number of variables, but the preferred reaction time is 1 to 5 hours, and the most preferred reaction time is 2 to 4 hours.

Although the phosphorous acid and the alkanal may be added together or separately in any order to the reaction mixture, it is preferred to add the phosphorous acid to the polyamide and then to slowly add the alkanal under refluxing conditions.

Approximately equimolar amounts of alkanal and phosphorous acid are employed for the phosphono-methylation of the amine. Excess of either the alkanal or acid can be utilized although large excesses of either would be uneconomical. The preferred process will use an amount of alkanal equivalent to the amine hydrogen available and a slight stoichiometric excess of the phosphorous acid.

31,846-F -7-.

I

Although methanol (formal Hyde is preferred, other alkanals (aldehydes) may be employed in place of methanol such as ethanol (acetaldehyde), prop anal (propionaldehyde), and the like, wherein the alkanal may contain a straight or branched chain containing up to ten carbon atoms.

Thus, the compounds useful in the present invention can be represented by the formula Abeam wherein A is an organic radical having the formula I\ / Z Jo I

-N SHOESHINE or Z-N Shoeshine wherein Z is hydrogen, hydroxyethyl, hydroxypropyl, O
-CH2P-~OM~z, -CH~COM or BY wherein M is hydrogen, an alkali metal or ammonium, and wherein B is a diva lent radical derived from a Doyle, diepoxy or halo epoxy organic compound having one of the following structures Sheehan; -SHEA OUCH ; -~CH-CH2-4O-CH-cH2~n,;
R R
H H H
H2C-C-~CH2~-n~; -H2C-C C-CH2-; -H2C-Ar-CH2-; and OH OH OH
OX
R R R' 1--3 -H2C-O-Ar-C-C~2-, wherein An is R'l_4 ; R 1-3 31,846-F -8-I
go Rl1-4 R'1-4 , wherein n is 1-10, n' is 1-3, and wherein R is hydrogen or methyl and R' is hydrogen, an alkyd radical or a hydroxyalkyl radical having 1 to 4 carbons, a hydroxy radical or a halogen atom, m is 1-10 O
and at least 50% of the Z groups are -CH2P-~OM) 2 groups.

Preferred compounds of the invention are those wherein the B moiety is derived from 1,2-epoxy-3-chloro-propane (epichlorohydrin) or 1,2 dichloroethane, wherein m is 1 or 2, the 2 moiety o is CH2P~OM) 2 and M is H, No or No.

The following examples illustrate the invention:

Example 1 ..
An N-aminoethylpiperazine (REP) based amine was prepared by reacting 22.7 g of N-aminoethylpiperazine (0.176 mole), 9.8 g of 1,2-dichlorethane (DOE) (0.099 mole), and 17.5 g of deionized water (DCE/AEP mole ratio = 0.56) in a 500-ml round-bottom reaction flask equipped with a water-cooled reflex condenser, mechanical stirrer, thermometer with a temperature controller, and an addition funnel. The reaction product was then phosphonomethylated by adding approximately 75 g of concentrated hydrochloric acid and 32.6 g (0.40 mole) of phosphorous acid to the aqueous amine solution and the reaction mixture heated to reflex and maintained for 31,846-F 9-one hour. Aqueous 37% methanol solution (28.1 g -0.35 mole was added through the addition funnel over a one and one-half hour period. The reaction mixture was heated at reflex for an additional three hours and then cooled.

The above procedure is then repeated using different DCE/AEP ratios.

Table I shows the use of some of the above products in retarding the setting of cement. The test procedure for the determination of retardation of setting is as follows: -1. The following ingredients were weighed:
cement - 100 g water 38 g additive - 0-.2 g active

2. Water and liquid additive were mixed;

3. Cement was added to liquid, the bottle tightly closed and shaken to mix;

4. Bottle was placed in a preheated 180F (83C~
bath;
JO Setting of cement was checked after 6 and 24 hours.
A blank (no additive) was run for comparison with each of the additives.

31,846-F -10-TABLE I
Additive Checked at:
mow ratio DCE/AEP 6 hours 24 hours 0.26R~tarded, not set Retarded, not set 0.46 if if if if 1.
o . 5 0 2 ) If O . 56 if Jo if if .
O . 81 Blank* Set Set 0 (1) The additive is the phosphonomethylated product identi-fled by the mow ratio of DCE/AEP.
(2) 1,2-epoxy-3-chloropropane was used in place of DOE for making this additive.
Not an example of the invention.

~31,846-F

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AND EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for retarding the setting of an aqueous cement slurry which comprises adding to said slurry an organic phosphonate, CHARACTERIZED IN THAT
the organic phosphonate is the phosphonomethylated reaction product of (1) a dihalo or haloepoxy organic compound with (2) N-aminoethylpiperazine; wherein the mole ratio of dihalo or haloepoxy compound to the amine compound is from 0.20 to about 1.0, and wherein at least 50 percent of the amine hydrogens are phosphonomethyl-ated.

2. The process of Claim 1 wherein the dihalo compound, if present, is a C1 to C20 compound, and the haloepoxy compound, if present, is a C3 to C10 compound.

3. A process for retarding the setting of an aqueous cement slurry which comprises adding to said slurry an organic phosphonate, CHARACTERIZED IN THAT
the organic phosphonate is a compound of the formula A?BA)m wherein A is an organic radical having the formula or wherein Z is hydrogen, hydroxyethyl, hydroxypropyl, -CH2?-(OM)2, -CH2?OM or BA wherein M is hydrogen, an alkali metal or ammonium, and wherein B is a divalent radical derived from a dihalo, diepoxy or haloepoxy organic compound having one of the following structures , wherein n is 1-10, n' is 1-3, and wherein R is hydrogen or methyl and R' is hydrogen, an alkyl radical or a hydroxyalkyl radical having 1 to 4 carbons, a hydroxy radical or a halogen atom, m is and at least 50% of the Z groups are -CH2?-(OM)2 groups.

4. The process of Claim 3 wherein m is 1 or 2, B is or -C2H4-, and Z is CH?P-(OM)2.