A New Gelling System for Acid Fracturing

Woo, G.T.; Lopez, H.; Metcalf, A.S.; Boles, Joel L.

doi:10.2523/52169-ms

Cited by 12 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When used correctly, insitu gelled acids improved acid treatment results. 7,8,9 Woo et al 10 discussed the plugging problems inherent with conventional crosslinked acid gellants. Laboratory studies of in-situ gelled acids were reported by Bazin 11 and by Lynn and Nasr-El-Din 12 .…”

Section: Spe 71694mentioning

confidence: 99%

Laboratory Evaluation of In-Situ Gelled Acids for Carbonate Reservoirs

Taylor

Nasr‐El‐Din

2001

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThree different commercial formulations (A,B,C) of in-situ gelled acids are compared in detail at temperatures up to 150 ºF and at acid concentrations from 5 to 20 wt% HCl. In-situ gelled acids are claimed to work by a gelation mechanism that occurs at the rock surface as the acid is neutralized. These acids contain a polymer, a crosslinker, and a breaker in addition to other additives. Detailed viscosity measurements of each in-situ gelled acid were made as a function of pH. A new experimental procedure was developed to partially neutralize the in-situ gelled acid, then the viscosity was measured as a function of shear rate in the range 1 to 3000 s -1 . Relative reaction rates with reservoir rock of the three in-situ gelled acids were compared at 100 ºF. Coreflood experiments were conducted with small acid volumes so that injectivity could be measured before acid breakthrough occurred.In-situ gelled acids significantly retard the rate of acid reaction with reservoir rock. Results showed that acids B and C had similar behavior, while acid A was more reactive with reservoir rock.Viscosity measurements of partially neutralized in-situ gelled acids showed that only with acid C was a significant viscosity maximum observed as the pH of the acid increased. This pH maximum occurred at a value of approximately 2.2 with 5 wt% HCl at 100 ºF. In the absence of breaker and crosslinker, acids A and B were very similar, while acid C showed as little as a tenth of the viscosity at low shear rates. Coreflood experiments showed that in some cases, the in-situ gelled acids irreversibly reduced the permeability of reservoir rock.

show abstract

Section: Spe 71694mentioning

confidence: 99%

Laboratory Evaluation of In-Situ Gelled Acids for Carbonate Reservoirs

Taylor

Nasr‐El‐Din

2001

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

show abstract

“…This is primarily due to the onsite blending and mixing of the base gel and the time that is necessary to produce a consistent base gel. The gelling process is often deliberate to prevent the unhydrated polymer in the reservoir due to the rapid hydration of the polymers …”

Section: Introductionmentioning

confidence: 99%

“…The gelling process is often deliberate to prevent the unhydrated polymer in the reservoir due to the rapid hydration of the polymers. 10,11 On the basis of the reasons mentioned previously, a quadripolymer with adsorption-retarding admixtures, MCJS, was synthesized by the free-radical polymerization of an environmental quadripolymer of AM, AMPS, allyl alcohol polyoxyethylene ether (APEG), and N-dimethyl-N-vinyl nonadecan-1-aminium chloride (DMAAC-18) in this study. Up to this point, no research has been reported on this copolymer, with its effects of adsorption, to be used in the stimulation of deep carbonate reservoirs as a retarded additive.…”

Section: Introductionmentioning

confidence: 99%

Copolymer MCJS as a retarder of the acid–rock reaction speed for the stimulation of deep carbonate reservoirs

Quan

Huang

et al. 2014

J of Applied Polymer Sci

View full text Add to dashboard Cite

The fast reaction rate between hydrochloric acid and carbonates causes the most acid consumption near the wells, and the acid cannot penetrate the deeper places of the carbonate reservoir; this limits the application of acidizing modifications for the reservoir. In this study, we chose acrylamide, 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), allyl alcohol polyoxyethylene ether (APEG), and N-dimethyl-N-vinyl nonadecan-1-aminium chloride (DMAAC-18) to synthesize a quadripolymer (MCJS) that could reduce the reaction rate mentioned previously. The molecular structure of MCJS was characterized by Fourier transform infrared and 1 H-NMR spectroscopy. The molecular weight and molecular weight distribution of MCJS was determined by gel permeation chromatography. Carbonate rock was analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy. The retarding properties of the acid mixed with MCJS (MCJS acid) were investigated, and the resulting reaction rate between the acid and carbonate decreased obviously, even at a low viscosity. Scanning electron microscopy and core flood experiments showed that the MCJS could be adsorbed on the carbonate rock surface and form a hydrated film that delayed the reaction.

show abstract

Reaction Kinetics of Gelled Acids With Calcite

Nasr‐El‐Din

Al-Mohammed

Al-Aamri

et al. 2006

International Oil &Amp; Gas Conference and Exhibition in China

View full text Add to dashboard Cite

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHydrochloric acid is used to stimulate carbonate formations (both matrix and fracturing treatments). However, the reaction rate of the acid with carbonate minerals, especially calcite, is very fast. In addition, the viscosity of HCl solution is relatively low. Acid-soluble polymers are usually added to the acid to increase its viscosity, which is needed to enhance acid diversion during matrix acidizng and reduce acid leak-off rate during acid fracturing. Gelled acid is extensively used in matrix and acid fracturing treatments performed in carbonate formations. However, a few studies have evaluated the impact of these polymers on the reaction rate of the acid. This paper uses a rotating disk instrument to measure the reaction rate of gelled acids with calcite rocks. Measurements were conducted over a temperature range of 25 to 65ºC, a pressure of 1,000 psi, and rotational speeds of 100 to 1,000 rpm. Acid formulations that are typically used in the field were examined. Polymer concentration was varied from 0.5 to 2 wt%. The apparent viscosity of the gelled acid was measured using a Brookfield viscometer. Measurements were done for the same solutions tested with the rotating disk instrument. The temperature was varied from 25 to 100ºC, while the pressure was maintained at 300 psi. The shear rate was varied from 57 to 1,700 s -1 .The results obtained indicated that the apparent viscosity increased notably as the concentration of polymer increased from 0.5 to 1.5 wt%. On the other hand, there is significant decrease in the dissolution rates as the concentration of polymer was increased from 0.5 to 1.5 wt%, where there was no measure difference as the concentration increased to 2 wt%. Reverse and toroidal flows were noted within the rotational spends examined. The etching pattern on the surface of the disk depends, among other factors, on the disk rotational speed and polymer concentration. The dissolution rate was found to be a function of temperature, rotational spend and polymer concentration.

show abstract

A New Gelling System for Acid Fracturing

Cited by 12 publications

References 0 publications

Laboratory Evaluation of In-Situ Gelled Acids for Carbonate Reservoirs

Laboratory Evaluation of In-Situ Gelled Acids for Carbonate Reservoirs

Copolymer MCJS as a retarder of the acid–rock reaction speed for the stimulation of deep carbonate reservoirs

Reaction Kinetics of Gelled Acids With Calcite

Contact Info

Product

Resources

About