Water-Soluble Polymers for Aqueous Drilling Fluid Additives

12 Water-Soluble Polymers for Aqueous Drilling Fluid Additives Robert Gow-Sheng Chen and Arvind D . Patel

Downloaded by MICHIGAN STATE UNIV on July 17, 2013 | http://pubs.acs.org Publication Date: May 5, 1986 | doi: 10.1021/ba-1986-0213.ch012

Magcobar Group, Dresser Industries, Inc., Houston, T X 77251

A series of novel sulfonate- and carboxylate-containing, low molecular weight, water-soluble polymers was developed for use as mud thinners and stabilizers in aqueous drilling fluids. The rheology of these polymers in aqueous drilling fluids was evalu ated by using the Fann Model 35 VG meter and Fann Model 50C viscometer. Viscosity, yield point, gel strength, and filtrate loss were utilized to characterize these polymer-treated mud samples. Thermal stability was compared with that of existing commercial dispersants. The unique composition and functionality, as well as the inherent chelating capability, of these polymers make them superior dispersants. They significantly reduce viscosity, yield point, gel strength, and filtrate loss over a wide range of temperatures.

A

Q U E O U S D R I L L I N G F L U I D S H A V E B E E N W I D E L Y U S E D to d r i l l s u b t e r r a -

n e a n o i l a n d gas w e l l s . T h e s e f l u i d s a r e u s u a l l y p u m p e d d o w n t h r o u g h the d r i l l s t e m o f the r o t a r y r i g , c i r c u l a t e d a r o u n d the d r i l l b i t , a n d r e t u r n e d to the s u r f a c e t h r o u g h the a n n u l a r passage b e t w e e n the d r i l l stem a n d w e l l w a l l . I n most d r i l l i n g operations, c o n t r o l l i n g the viscosity, g e l s t r e n g t h , y i e l d p o i n t , a n d f i l t r a t e loss o f the d r i l l i n g f l u i d s w i t h i n a g i v e n r a n g e is v i t a l l y i m p o r t a n t ( J ) . T h i s c o n t r o l is u s u a l l y a c h i e v e d w i t h d r i l l i n g f l u i d a d d i t i v e s , s u c h as d i s p e r s a n t s a n d filtrate loss c o n t r o l agents. Treatment of aqueous drilling fluids w i t h phosphate-containing m a t e r i a l s d e f l o c c u l a t e s c o l l o i d a l c l a y s a n d d r i l l e d s o l i d s . H o w e v e r , these c h e m i c a l s a r e g e n e r a l l y u n s t a b l e at the h i g h t e m p e r a t u r e s e n c o u n t e r e d i n d e e p w e l l s a n d , as a r e s u l t , lose t h e i r effectiveness as c o l l o i d a l d i s persants. L i g n i t e has b e e n u s e d i n a q u e o u s d r i l l i n g f l u i d s t o c o n t r o l t h i x o t r o p y . T h e effectiveness o f l i g n i t e as a d i s p e r s a n t is l i m i t e d b e c a u s e it is sensitive to c o m m o n l y e n c o u n t e r e d c o n t a m i n a n t s s u c h as g y p s u m a n d 0065-2393/86/0213-0197 $06.00/0 © 1986 American C h e m i c a l Society

In Water-Soluble Polymers; Glass, J.; Advances in Chemistry; American Chemical Society: Washington, DC, 1986.

198

WATER-SOLUBLE POLYMERS

d r i l l e d s o l i d s . A l s o , l i g n i t e is less e f f e c t i v e as a d i s p e r s a n t i n d r i l l i n g d e e p w e l l s w h e r e e l e v a t e d t e m p e r a t u r e s are e n c o u n t e r e d . L i g n o s u l f onates c o m p l e x e d w i t h t r a n s i t i o n m e t a l s h a v e b e e n u s e d i n the p a s t as d i s p e r s a n t s (2). T h e y s h o w g o o d d i s p e r s i o n p r o p e r t i e s i n a q u e o u s d r i l l i n g f l u i d s at b o t t o m o f the h o l e t e m p e r a t u r e s b e l o w 320 ° F .


In recent years, an increasingly large n u m b e r of synthetic a n d naturally occurring water-soluble polymers have been investigated a n d used i n t h e o i l f i e l d as d r i l l i n g f l u i d a d d i t i v e s (3). A n i o n i c p o l y m e r s w i t h c a r b o x y l i e o r s u l f o n i c a c i d f u n c t i o n a l i t i e s a r e o f s p e c i a l interest as d i s p e r sants o r f i l t r a t e loss c o n t r o l agents. L o w m o l e c u l a r w e i g h t h o m o p o l y m e r s o f a c r y l i c a c i d a n d its a l k a l i m e t a l o r a m m o n i u m salts h a v e b e e n u s e d as dispersants (4). A c r y l i c a c i d acrylamide r a n d o m copolymers, partially hydrolyzed polyacrylamides a n d p o l y a c r y l o n i t r i l e s , w h i c h a r e f l o c c u l e n t s at h i g h m o l e c u l a r w e i g h t , s h o w d i f f e r e n t p r o p e r t i e s a n d act as d e f l o c c u l e n t s at l o w m o l e c u l a r w e i g h t (5). L i g n o s u l f o n a t e - g r a f t - p o l y ( a c r y l i c a c i d ) is also c l a i m e d to b e a d i s p e r s a n t (6). T h e s e t y p e s o f p o l y m e r s , h o w e v e r , are sensitive to d i v a l e n t i o n c o n t a m i n a n t s a n d are o n l y m a r g i n a l l y e f f e c t i v e i n d r i l l i n g f l u i d s that c o n t a i n r e l a t i v e l y h i g h c o n c e n t r a t i o n s o f c l a y o r d r i l l e d s o l i d s . T h e preparation procedure a n d viscosity data for sulfonate-cont a i n i n g c o p o l y m e r s h a v e b e e n r e p o r t e d e a r l i e r i n great d e t a i l (7). S u l f o n a t e d s t y r e n e - m a l e i c a n h y d r i d e c o p o l y m e r s h a v e b e e n u s e d as t h e r m a l l y s t a b l e d i s p e r s a n t s (8). H i g h m o l e c u l a r w e i g h t c o p o l y m e r s o f 2 - ( a c r y l a m i d o ) - 2 - m e t h y l p r o p a n e s u l f o n i c a c i d are c l a i m e d to b e e f f e c t i v e v i s c o s i f i e r s ( 8 - 1 0 ) , f i l t r a t e loss c o n t r o l agents ( I I ) , a n d f r a c t u r e a c i d i z i n g gellants (12). R e c e n t l y w e s u c c e s s f u l l y d e v e l o p e d a series o f w a t e r - s o l u b l e p o l y m e r s f o r use as a q u e o u s d r i l l i n g f l u i d s t a b i l i z e r s a n d d i s p e r s a n t s (13-15). T h i s c h a p t e r o u t l i n e s the p r e p a r a t i o n a n d l a b o r a t o r y e v a l u a t i o n o f these polymers.

Experimental Section Materials. Reagent grades of acrylic acid, tetrahydrophthalic anhydride, 2-(acrylamido)-2-methylpropanesulfonie a c i d , eugenol, maleic anhydride, Nvinyl-N-methylaeetamide, sodium hydroxide, sodium bisulfite, formaldehyde, and potassium persulfate were used as received. S o d i u m lignosulfonate from Georgia Pacific Corporation had a number-average molecular weight between 1000 and 12,000. Graft Copolymerization. A series of graft copolymers was prepared b y cografting of sodium acrylate, sodium tetrahydrophthalate ( T H P A ) , and sodium 2-(acrylamido)-2-methylpropanesulfonate [ N a A M P S (Lubrizol Corporation)] onto sodium lignosulfonate. T h e reactions were conducted i n a 250-mL threenecked flask equipped with a mechanical stirrer, a condenser, and a nitrogen line. T h e feed composition of the product, designated C - 1 4 1 , was 33 g of acrylic a c i d , 24 g of N a A M P S , 23 g of T H P A , and 20 g of sodium lignosulfonate i n 180 g of


12.

C H E N A N D PATEL

Use as Aqueous Drilling Fluid Additives

199


water. The p H of the reaction medium was adjusted to 9.0 with sodium hydroxide. The reaction medium was then deareated with nitrogen for 20 min, and 5 g of potassium persulfate was added. After 3 h of reaction at 60 °C, the resulting polymer was precipitated into acetone. The graft copolymer was further purified by dissolution in water followed by precipitation into acetone. The product was vacuum-dried at 60 °C for 24 h. Conversion, determined gravimetically, was 99.6f. The number-average molecular weight of the product was 6500. Eugenol-Maleic Anhydride-N-Vinyl-N-methylacetamide Terpolymer. A series of random terpolymers of eugenol, maleic anhydride, and N-vinyl-Nmethylacetamide (VMA) was prepared in 1,2-dichloroethane by using azobisisobutyronitrile as the initiator. The feed composition of the terpolymer, designated P-127, was 30.7 g of eugenol, 46.2 g of maleic anhydride, and 23 g of V M A . The reaction procedures were similar to those just described for the preparation of graft copolymers. The reaction was carried out at 70 °C for 2 h, and the resulting polymer was vacuum-dried at 45 °C for 24 h. Conversion, determined gravimetically, was 98.8%. Sulfomethylation. Terpolymer P-127 was further sulfomethylated as follows: 30 g of polymer and 15 g of sodium bisulfite-formaldehyde adduct were dissolved in 70 g of water, and the p H of the solution was adjusted to 10.0. The reaction mixture was heated at 60 °C for 12 h. The sulfomethylated polymer P-127-B was precipitated into acetone and further purified by dissolution in water followed by precipitation into acetone. The polymer was vacuum-dried at 60 °C for 24 h. The number-average molecular weight of the product was 7000. Infrared Measurement. Polymer P-127-B was dissolved in distilled water, coated onto a silver chloride minicell window, and vacuum-dried at room temperature for 1 h. The IR spectrum was recorded with a Perkin-Elmer 283 spectrophotometer. Membrane Osmometry. Number-average molecular weights of the samples were measured with a Knauer membrane osmometer in aqueous 0.2 M NaCl solution at 30 °C. Polymer concentrations ranged from 1.0 to 2.5 g/dL. Aqueous Drilling Fluid. A 12-lb/gal. aqueous drilling fluid containing 198 g of barite, 18 g of Wyoming bentonite, 20 g of X-act clay (primarily a calcium montmorillonite), and 0.2 g of soda ash in 325 g of tap water was prepared by using a Premier mill dispersator at high speed. The aqueous drilling fluid was then prehydrated for 24 h prior to use. Rheological Measurements. The drilling fluid was contaminated with 4 g of gypsum/350 m L of drilling fluid and was then treated with 3 g of polymer sample and 6 g of chromium lignosulfonate; the p H of the samples was adjusted to 11.0 with sodium hydroxide. Treated samples were rotated constantly in an oven for 16 h at each temperature in the sequence 200, 300, 400, and 425 °F. Plastic viscosities, yield points, and gel strengths after each aging step were determined by using a Fann Model 35 V G meter. The viscosity-temperature relationships of the drilling fluids were obtained by using a Fann Model 50C viscometer. Samples were heated at 3.8 °F/min from 80 to 450 °F and were then cooled. The viscosity was recorded throughout the temperature range. The working pressure was kept between 500 and 700 psi.


200


American Petroleum Institute Filtrate Loss. Filtrate losses of the drilling fluids were measured in Fann filter press cells in accordance with American Petroleum Institute approved procedure RP-13B (16). Filtrate losses over a 30min period were measured at room temperature at 100 psi. Rheology and filtrate loss data for the prepared polymers and similar commercial polymers are shown in Table I.


Results and Discussions P o l y m e r D e s i g n . MOLECULAR WEIGHT CONTROL. Controlling the molecular weight is vitally important in preparing polymeric defloeculents for aqueous drilling fluids. F o r example, high molecular weight poly(acrylic acid) is used as a thickener or a flocculent for aqueous drilling fluids, whereas low molecular weight poly(acrylic acid) has been used as a deflocculent. Molecular weight can be controlled b y regulating reaction temperature, solvent, initiation system, monomer and initiator concentration, b y using scavengers, or b y introducing functional monomers with high chain-transfer capability. Salts of tetrahydrophthalic acid ( T H P A ) (structure I ) are extremely useful in preparing low molecular weight water-soluble polymers. D u r -

Table I . Comparative Performance of Commercial and Synthetic Dispersant Polymers Aging Temp (°F)

Polymer Base mud without polymeric dispersant fl

3 g of sample T

c

3 g of sample D P

3 g of C-141

3 g of P-127-B

d

200 300 425 200 300 425 200 300 425 200 300 425 200 300 425

Plastic Yield Initial:10-min Filtrate Viscosity Point Gel Loss (lb/100 ft ) (lb/100 ft ) (mL) (cps) 2

2

—

48 43

9 3

1:3 1:39

12.2

b

b

b

43 28 59 37 32 50 33 31 51 30 29 64

27 0 6 22 0 5 5 0 10 0 0 10

1:29 1:1 2:23 1:13 1:1 1:14 1:1 1:1 2:10 2:2 2:2 2:9

b

— —

11.8

— —

11.9

— —

9.5

— —

9.0

The base mud is a 12-lb/gal. of fresh water mud containing 6 g of chrome lignosulfonate and 4 g of gypsum per 350 mL of mud. The polymer was too thick for this value to be measured. ^Sample T is the sodium salt of poly (acrylic acid), M = 5000. "Sample DP is the sodium salt of the terpolymer of acrylic acid, acrylamide, and AMPS, M = 4700. The composition is as follows: 78 mol % sodium acrylic acid; 10 mol % acrylamide, and 12 mol % NaAMPS.

a

b

n

N



12.

201


C H E N A N D PATEL

i n g f r e e - r a d i c a l p o l y m e r i z a t i o n , T H P A has a h i g h c h a i n - t r a n s f e r c o n s t a n t because of

its a l l y l i c

resonance.

The

molecular

weight

of

THPA-

c o n t a i n i n g p o l y m e r s is t h e r e b y l i m i t e d . S o d i u m l i g n o s u l f o n a t e is a n e x t r e m e l y i n e x p e n s i v e s u l f o n a t e d m a terial containing h y d r o x y p h e n y l p r o p a n e

units (structure II:

R

=

H,

C H 3 , o r SC>3~Na ). T h e s e units p r o v i d e g r a f t i n g sites w h e r e g r a f t c o p o l y +

m e r i z a t i o n c a n p r o c e e d i n the p r e s e n c e o f a f r e e - r a d i c a l i n i t i a t o r (17, 18). H y d r o x y p h e n y l p r o p a n e units also r e g u l a t e the m o l e c u l a r w e i g h t o f the r e s u l t i n g g r a f t c o p o l y m e r b e c a u s e o f t h e i r r o l e i n c h a i n t r a n s f e r . T h e n u m b e r - a v e r a g e m o l e c u l a r w e i g h t o f the g r a f t c o p o l y m e r p r e p a r e d b y u s i n g T H P A a n d s o d i u m l i g n o s u l f o n a t e , C - 1 4 1 , w a s 6500. An

a l l y l i c b e n z e n e c o m p o u n d , e u g e n o l (structure III) w a s u s e d i n

p r e p a r i n g the s u l f o m e t h y l a t e d t e r p o l y m e r , P - 1 2 7 - B , to r e g u l a t e m o l e c u lar w e i g h t . T h e n u m b e r - a v e r a g e m o l e c u l a r w e i g h t o f P - 1 2 7 - B w a s 7000. CHARGE DENSITY.

C h a r g e d e n s i t y is also a n i m p o r t a n t p a r a m e t e r

i n d e s i g n i n g d i s p e r s a n t s . C a r b o x y l a t e u n i t s i n the p o l y m e r

backbone

i n c r e a s e c h a r g e d e n s i t y ; thus, the r h e o l o g i c a l p e r f o r m a n c e i n u n c o n t a m i n a t e d d r i l l i n g f l u i d s is e n h a n c e d . S o d i u m a c r y l a t e a n d s o d i u m t e t r a h y drophthalate

were

used

to

enhance

the

charge

density

of

graft

copolymers. S o d i u m t e t r a h y d r o p h t h a l a t e units also e x h i b i t a c h e l a t i n g a b i l i t y ; this c h e l a t i n g a b i l i t y m a k e s t h e m e x c e l l e n t d i v a l e n t c a t i o n s t a b i l i z e r s . A d d i t i o n a l l y , s o d i u m t e t r a h y d r o p h t h a l a t e units e n h a n c e the a b s o r p t i o n b e t w e e n p o l y m e r s a n d c l a y p a r t i c l e s a n d r e d u c e f l o w resistance a n d g e l development i n aqueous drilling fluids. N a A M P S is also u t i l i z e d i n p r e p a r i n g g r a f t c o p o l y m e r s .

NaAMPS

units e x h i b i t a n e n h a n c e d m o n o - a n d d i v a l e n t i o n s t a b i l i t y a t t r i b u t a b l e to


202



=1

their exceptionally capability.

h i g h ionization constant

and

hydrogen-bonding

C o m p o s i t i o n a l a n a l y s i s o f the g r a f t c o p o l y m e r w a s n o t s u c c e s s f u l , b e c a u s e the s t r u c t u r e o f s o d i u m l i g n o s u l f o n a t e is p o o r l y d e f i n e d (19). S o d i u m maleate was used i n p r e p a r i n g p o l y m e r P-127 to enhance charge density. I n a d d i t i o n to increasing charge density, s o d i u m maleate units also c h e l a t e c a l c i u m i o n s e n c o u n t e r e d i n a d r i l l i n g o p e r a t i o n . P o l y m e r P - 1 2 7 w a s f u r t h e r s u l f o m e t h y l a t e d to i n t r o d u c e s u l f o n i c a c i d g r o u p s a n d , as a r e s u l t , t o i m p r o v e d i s p e r s a b i l i t y i n a q u e o u s d r i l l i n g fluids. N - M e t h y l a c e t a m i d e functionalities of

terpolymer P-127

were

h y d r o l y z e d u n d e r a l k a l i n e c o n d i t i o n s to the c o r r e s p o n d i n g N - m e t h y l a m i n e g r o u p s , w h i c h w e r e t h e n s u l f o m e t h y l a t e d b y u s i n g the f o r m a l d e h y d e - s o d i u m bisulfite adduct. T h e activated benzene ring a n d b e n z y l h y d r o g e n o n e u g e n o l u n i t s p r o v i d e d a d d i t i o n a l r e a c t i o n sites f o r s u l f o m e t h y l a t i o n . I R s p e c t r o s c o p y ( F i g u r e 1) w a s u s e d to a n a l y z e the s u l f o m e t h y l a t e d p o l y m e r , P - 1 2 7 - B , q u a l i t a t i v e l y . I R a b s o r b a n c e s at 1200 a n d 1043 c m

- 1

c a n b e a t t r i b u t e d to S = 0 s t r e t c h i n g , w h e r e a s the a b s o r b a n c e

at 620 c m

- 1

polymer

P - 1 2 7 - B w a s s u l f o m e t h y l a t e d . Q u a n t i t a t i v e analysis o f

c a n b e a t t r i b u t e d to C - S s t r e t c h i n g . T h e s e d a t a i n d i c a t e that the

s a m p l e is i n p r o g r e s s .

Performance. T h e control of apparent viscosity, gel strength, y i e l d p o i n t , p l a s t i c v i s c o s i t y , a n d filtrate loss o f the a q u e o u s d r i l l i n g f l u i d s is extremely important i n a drilling operation. Unsatisfactory performance o f t h e d r i l l i n g f l u i d s m a y result i n serious p r o b l e m s . A 12-lb/gal. water-base drilling fluid containing 4 lb of g y p s u m ( C a S 0 * 2 H 2 0 ) p e r b a r r e l w a s u s e d to e v a l u a t e the p e r f o r m a n c e o f the s a m p l e s . T h i s test d r i l l i n g f l u i d represents the severe c o n d i t i o n s o f d i v a l e n t c a t i o n c o n t a m i n a t i o n s . M o n o v a l e n t c a t i o n c o n t a m i n a n t s , s u c h as 4


12.

CHEN AND PATEL

203



100

4000

2500

2000 1800 1600 1400 Wavenumber ( c m )

800

600

400

200

1

Figure I. IR spectrum for polymer P-127-B.

s o d i u m , a r e less d e t r i m e n t a l to the d r i l l i n g fluids t h a n d i v a l e n t c a t i o n s s u c h as c a l c i u m . G E L STRENGTH.

G e l s t r e n g t h is a m e a s u r e o f the t h i x o t r o p i c p r o p -

erties o f a f l u i d a n d d e n o t e s the f o r c e o f f l o c c u l a t i o n u n d e r static c o n d i t i o n s . G e l strengths o f the p o l y m e r - t r e a t e d m u d s a m p l e s w e r e m e a s u r e d b y the F a n n M o d e l 35 V G m e t e r a n d are l i s t e d i n T a b l e I. T h e d i f f e r e n c e b e t w e e n the i n i t i a l g e l s t r e n g t h a n d that t a k e n after a 1 0 - m i n rest p e r i o d is u s e d t o j u d g e h o w t h i c k the m u d w i l l get d u r i n g the p e r i o d s w h e n c i r c u l a t i o n is s t o p p e d , f o r e x a m p l e , w h e n r e m o v i n g the d r i l l i n g p i p e . B o t h t h e g e l strengths a n d the d i f f e r e n c e b e t w e e n the 1 0 - m i n g e l and

initial gel for the C - 1 4 1 - a n d P - 1 2 7 - B - t r e a t e d m u d s r e m a i n e d l o w

t h r o u g h o u t t h e h e a t a g i n g c y c l e s . S u c h " f r a g i l e " gels r e q u i r e l o w p u m p p r e s s u r e t o start o r restart c i r c u l a t i o n a n d c a u s e f e w e r p r o b l e m s d u r i n g d r i l l i n g operations. T h e gel strength differences for m u d s treated w i t h c o m m e r c i a l s a m p l e s T a n d D P a f t e r b e i n g h e a t - a g e d at 200 ° F a r e 28 and

12 l b / 1 0 0 f t , r e s p e c t i v e l y . S u c h " p r o g r e s s i v e " gels r e q u i r e i n c r e a s e d 2

p u m p p r e s s u r e t o start c i r c u l a t i o n a n d m a y cause m o r e p r o b l e m s . T h e b a s e m u d a l s o e x h i b i t s p r o g r e s s i v e g e l s t r u c t u r e after s u c h h e a t - a g i n g . Y I E L D P O I N T A N D PLASTIC VISCOSITY.

The

yield point in drilling

f l u i d s t e r m i n o l o g y is the resistance t o i n i t i a l f l o w , o r the stress r e q u i r e d t o start f l u i d m o v e m e n t . T h i s resistance is d u e t o e l e c t r i c a l c h a r g e s o n o r n e a r t h e s u r f a c e o f c l a y p a r t i c l e s s u s p e n d e d i n the m u d . T h e y i e l d p o i n t o f m u d s t r e a t e d w i t h C - 1 4 1 a n d P - 1 2 7 - B a r e w i t h i n the d e s i r e d r a n g e


204


after each heat-aging c y c l e . H o w e v e r , the y i e l d points o f m u d s treated w i t h s a m p l e s T a n d D P i n c r e a s e d d r a s t i c a l l y after h e a t - a g i n g at 200 ° F f o r 16 h . S u c h h i g h y i e l d p o i n t s a r e u s u a l l y n o t d e s i r a b l e i n d i s p e r s e d aqueous drilling fluids.


A q u e o u s d r i l l i n g f l u i d s c o n t a i n s o l i d s that c o n t r i b u t e t o the a p p a r e n t v i s c o s i t y . T h e p l a s t i c v i s c o s i t y is a m e a s u r e o f the i n t e r n a l resistance t o f l u i d f l o w attributable to the concentration, t y p e , shape, a n d size o f solids present. T h e base m u d shows a higher plastic viscosity after heata g i n g ; this i n c r e a s e r e f l e c t s h i g h e r f r i c t i o n b e t w e e n c l a y p a r t i c l e s . T h e plastic viscosities o f p o l y m e r - t r e a t e d m u d s are substantially l o w e r . V I S C O S I T Y - T E M P E R A T U R E RELATIONSHIPS.

The

viscosity-temper-

ature r e l a t i o n s h i p o f the d r i l l i n g f l u i d is v e r y i m p o r t a n t , b e c a u s e the d r i l l i n g fluid m a y b e circulated m a n y times w h i l e drilling a deep w e l l a n d m a y b e exposed to different temperature gradients. T h e viscositytemperature relationships f o r drilling fluids containing polymers design a t e d as T , D P , C - 1 4 1 , a n d P - 1 2 7 - B a r e d e m o n s t r a t e d i n F i g u r e s 2, 3, 4, a n d 5, r e s p e c t i v e l y . T h e t e m p e r a t u r e a n d f l u i d v i s c o s i t y w i t h r e s p e c t t o t i m e are represented b y d o t t e d a n d s o l i d lines, respectively. D r i l l i n g fluids c o n t a i n i n g p o l y m e r s T a n d D P f l o c c u l a t e at 135 a n d 195 ° F , r e s p e c t i v e l y . A s t h e t e m p e r a t u r e increases f u r t h e r , t h e f l u i d v i s c o s i t i e s i n c r e a s e d r a s t i c a l l y . M u d c o n t a i n i n g C - 1 4 1 f l o c c u l a t e s a t 415 ° F , a n d its v i s c o s i t y p r o f i l e is r e l a t i v e l y u n a f f e c t e d b y t h e h e a t i n g a n d c o o l i n g c y c l e f r o m

60

120

180

Time (min) Figure 2. Viscosity-temperature profile for drilling fluid containing polymer T. The temperature of flocculation was 135 °F.



12.

C H E N A N D PATEL


60

205

120 Time (min)

Figure 3. Viscosity-temperature profile for drilling fluid containing polymer DP. The temperature of flocculation was 195 °F.

u

60

120

180

Time (min) Figure 4. Viscosity-temperature profile for drilling fluid containing C-141. The temperature of flocculation was 415 °F.



206 400 •

«600

400 &

o •t 200 c o


200

|

Heating 120

180

Time (min) Figure 5. Viscosity-temperature profile for drilling fluid containing P-127-B. The temperature of flocculation was 380 °F.

a m b i e n t t o 4 5 0 ° F . T h e m u d c o n t a i n i n g P - 1 2 7 - B flocculates at 380 ° F . B e c a u s e t h e d r i l l i n g fluid m a y b e e x p o s e d t o s u c h t e m p e r a t u r e s d u r i n g a d r i l l i n g o p e r a t i o n , these results i n d i c a t e that C - 1 4 1 a n d P - 1 2 7 - B c o p o l y m e r s a r e e f f e c t i v e i n s t a b i l i z i n g the r h e o l o g y o f s u c h a fluid.

Conclusion T h e unique composition of the l o w molecular weight water-soluble p o l y m e r s d e s c r i b e d makes t h e m effective dispersants f o r aqueous d r i l l i n g fluids.

Acknowledgments W e thank Dresser Industries, M a g c o b a r G r o u p , f o r permission to p u b l i s h this w o r k .

Literature Cited 1. Gray, G. R.; Darley, H . C . H . ; Rogers, W . F . Composition and Properties of Oil Well Drilling Fluids; 4th ed.; Gulf Publishing: Houston, T X , 1980; pp 1-36. 2. Javora, P. H . ; Green, B. Q. U.S. Patent 4 220 585, 1980. 3. Gray, G. R.; Darley, H . C . H . ; Rogers, W . F . Composition and Properties of Oil Well Drilling Fluids; 4th ed.; Gulf Publishing: Houston, 1980; pp 526-601. 4. Burland, P. D . ; Stephenson, J. L . ; Stobart, E . H . U.S. Patent 3 764 530, 1973. 5. Siegele, F . H . ; Ondera, E . V . ; Liberatore, M . A. U.S. Patent 3 434 970, 1969. 6. Felicetta, V. F., Wenzel, D. E. U.S. Patent 3 985 659, 1976.



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207

7. Chen, R. G.-S. Ph.D. Dissertation, University of Southern Mississippi, Hat tiesburg, 1982. 8. Perricone, A. C.; Young, H. F. U.S. Patent 3 730 900, 1973. 9. McCormick, C. L.; Chen, G.-S. J. Polym. Sci. 1982, 20, 817. 10. Neidlinger, H. H.; Chen, G . - S . ; McCormick, C. L. J. Appl. Polym. Sci. 1984, 29, 713. 11. Uhl, K.; Bannerman, J. K.; Engelhardt, F. J.; Patel, A. D. U.S. Patent 4 471 097, 1984. 12. Deysarkar, A. K.; Dawson, J. C.; Sedillo, L. P.; Davis, S. K. J. Can. Pet. Technol. 1984, 23, 26. 13. Chen, G.-S.; Patel, A. D.; Sample, T. E., Jr. U.S. Patent 4 521 578, 1985. 14. Patel, A. D. U.S. Patent 4 525 562, 1985. 15. Patel, A. D., Sample, T . E., Jr. U.S. Patent pending. 16. American Petroleum Institute Recommended Practice Standard Procedures for Testing Drilling Fluids, API RP 13-B, 9th ed., Dallas, T X , May, 1982. 17. Tirzinya, Y. E.; Zoldners, Y. A.; Surna, Y. A. Khim Drev. 1975, 6, 98. 18. Chen, R.; Kokta, B. V . In Graft Copolymerization of Lignocellulosic Fibers; Hon, D. N.-S., E d . ; ACS Symposium Series 187; American Chemical Society: Washington, D C , 1982; p 285. 19. Pearl, I. A. The Chemistry of Lignin; Dekker: New York, 1967; pp 1-6. R E C E I V E D for review October 23, 1984. A C C E P T E D August 9, 1985.


Water-Soluble Polymers for Aqueous Drilling Fluid Additives

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