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Titolo:
SYSTEMATIC DESIGN OF PROFILE CONTROL CHEMISTRY - CONTROL OF GELATION OF MIXED POLY(VINYL ALCOHOL-CO-VINYLAMINE) CROSS-LINKED WITH DIALDEHYDES
Autore:
SHU P; SCHMITT KD;
Indirizzi:
MOBIL RES & DEV CORP,MEPTEC,13777 MIDWAY RD DALLAS TX 75244 MOBIL RES & DEV CORP,CENT RES LAB PRINCETON NJ 08543
Titolo Testata:
Colloids and surfaces. A, Physicochemical and engineering aspects
fascicolo: 3, volume: 110, anno: 1996,
pagine: 273 - 285
SICI:
0927-7757(1996)110:3<273:SDOPCC>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLYVINYL-ALCOHOL);
Keywords:
DIALDEHYDE CROSS-LINKING; GELATION; HYDROLYSIS KINETICS; POLY(VINYLALCOHOL-CO-VINYLAMINE) COPOLYMER; PROFILE CONTROL; TRIETHYL PHOSPHATE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
16
Recensione:
Indirizzi per estratti:
Citazione:
P. Shu e K.D. Schmitt, "SYSTEMATIC DESIGN OF PROFILE CONTROL CHEMISTRY - CONTROL OF GELATION OF MIXED POLY(VINYL ALCOHOL-CO-VINYLAMINE) CROSS-LINKED WITH DIALDEHYDES", Colloids and surfaces. A, Physicochemical and engineering aspects, 110(3), 1996, pp. 273-285

Abstract

Quantitative chemistry and modeling allow us to predict the behavior of a new, environmentally friendly, non-heavy-metal-containing profilecontrol agent as a function of well-bore conditions. We present an analysis of the kinetics and mechanism of gelation delay for dialdehyde crosslinking of mixed poly(vinyl alcohol-co-vinylamine) (PVA-VAM) copolymers. In the present system, gelation at 90-110 degrees C takes place within minutes at pH below 6.5 and not at all at pH above 7.5 when the crosslinking agent is the acetal-protected form of the dialdehyde. We exploit this sharp pH transition by buffering to pH 9-12 and then allowing the pH to drop by in situ hydrolysis of triethyl phosphate. The fact that a pH much below 7 is not needed for gelation means that consumption of acid by carbonate rock will not be a problem as far as gelation is concerned. In fact, neutralization by rock carbonate after gelation can be expected to promote gel stability. The kinetics of the gelation are determined by the hydrolysis kinetics of triethyl phosphate and the stability of the dialdehyde. Triethyl phosphate hydrolysis has both base-catalyzed and uncatalyzed kinetics so it is advantageousto avoid a high pH in order to extend the gel time. It is also important to avoid a high pH in order to minimize the attack of clay minerals. Gelation systems using NaOH, Na(4)EDTA, and Na3PO4 at initial pH below 10 were developed along with a mathematical model which satisfactorily predicts their gelation times. Spectroscopic analysis indicates that the crosslinks formed initially in the mixed polymer system are different from those in poly(vinyl alcohol) (PVA). In PVA the crosslinksare hemiacetal and 1,3-dioxane groups formed from adjacent OH groups but in PVA-VAM the amine function is more reactive and the crosslinks are hemiaminal and dihydro-1,3-oxazine groups. These are potentially more stable than the crosslinks in PVA. We have not determined the nature of the crosslinks formed after aging, but there is some evidence that the oxazine linkages convert to dioxane links. Gels stable at 110 degrees C for 40 weeks have been demonstrated.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 16:08:50