Theoretical and Experimental Study on Optimal Injection Rates in Carbonate Acidizing

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 892-901 ◽  
Author(s):  
Kai Dong ◽  
Ding Zhu ◽  
A. Daniel Hill
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Injection Rate ◽  
Experimental Results ◽  
Acid Injection ◽  
Optimal Injection ◽  
Mode Size ◽  
Interstitial Velocity ◽  
Injection Rates

Summary Optimal acid-injection rate is critical information for carbonate-matrix-acidizing design. This rate is currently obtained through fitting acidizing-coreflood experimental results. A model is needed to predict optimal acid-injection rates for various reservoir conditions. A wormhole forms when larger pores grow in the cross-sectional area at a rate that greatly exceeds the growth rate of smaller pores caused by surface reaction. This happens when the pore growth follows a particular mechanism, which is discussed in this paper. We have developed a model to predict wormhole-growth behavior. The model uses the mode size in a pore-size distribution—the pore size that appears most frequently in the distribution—to predict the growth of the pore. By controlling the acid velocity inside of it, we can make this particular pore grow much faster than other smaller pores, thus reaching the most-favorable condition for wormholing. This also results in a balance between overall acid/rock reaction and acid flow. With the introduction of a porous-medium model, the acid velocity in the mode-size pore is scaled up to the interstitial velocity at the wormhole tip. This interstitial velocity at the wormhole tip controls the wormhole propagation. The optimal acid-injection rates are then calculated by use of semiempirical flow correlations for different flow geometries. The optimal injection rate depends on the rock lithology, acid concentration, temperature, and rock-pore-size distribution. All these factors are accounted for in this model. The model can predict the optimal rates of acidizing-coreflood experiments correctly, compared with our acidizing-coreflood experimental results. In addition, on the basis of our model, it is also found that at optimal conditions, the wormhole-propagation velocity is linearly proportional to the acid-diffusion coefficient for a diffusion-limited reaction. This is proved both experimentally and theoretically in this study. Because there is no flow-geometry constraint while developing this model, it can be applied to field scales. Applications are presented in this paper.

Study on the Pore Size Distribution of the Bicomponent Spunbond Nonwoven Geotextiles

2016 ◽  
Vol 852 ◽  
pp. 1404-1408
Author(s):  
Heng Zhang ◽  
Xiao Ming Qian ◽  
Qi Zhen
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Research Work ◽  
Quantitative Description ◽  
Experimental Results ◽  
Ultrafine Fibers ◽  
Nonwoven Materials ◽  
Work Samples ◽  
Pore Properties

Pore size plays a key role in the performances, such as transportation, filtration and separation, of bicomponentspunbond nonwoven geotextiles which fibrillated by hydroentanglement method. In this research work, samples of polyester (PET) - nylon6 (PA6) hollow segmented-pie bicomponentspunbond nonwoven materials were selected. A modified pore size prediction model has been proposed to predict the pore properties, and comparisons between theoretical and experimental results also discussed. The results show that the bicomponent fibers has been splitting into ultrafine fibers under the effect of the hydroentanglement method, and ultrafine fibers oriented mainly in the X-Y directions (plane direction). There is a good agreement between experimental results and experimental results, and the model of the pore size distribution is suit for the PET/PA6 bicomponentspunbond nonwoven geotextiles can be determined. The model provides a quantitative description of pore distribution for those nonwoven materials claimed to constitute with a series of types fiber.

STRUCTURE AND PROPERTIES OF UNCONSOLIDATED AGGREGATES

1962 ◽  
Vol 40 (7) ◽  
pp. 818-831 ◽  
Author(s):  
J. Naar ◽  
R. J. Wygal
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Experimental Results ◽  
Structure And Properties ◽  
Theoretical Predictions

An analysis of the arrangement of particles in unconsolidated aggregates allows the prediction of some of their properties such as porosity, permeability, and pore-size distribution. Experimental results obtained from systems of spherical beads and from a mixture of sands are in agreement with the theoretical predictions.

Characterization of dual-structure pore-size distribution of soil

2009 ◽  
Vol 46 (2) ◽  
pp. 129-141 ◽  
Author(s):  
X. Li ◽  
L. M. Zhang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Void Ratio ◽  
Experimental Results ◽  
Dual Porosity ◽  
Porosity Structure ◽  
The Relationship ◽  
Comprehensive Study

The microporosity structure of soil provides important information in understanding the shear strength, compressibility, water-retention ability, and hydraulic conductivity of soils. It is a soil characteristic that depends on sample preparation method and wetting–drying history. A comprehensive study of the microporosity structure of a lean clay with sand was conducted in this research to investigate variations of the microporosity structure during compaction, saturation, and drying processes. Scanning electron microscopy was used to observe the microporosity structure of soil sample surfaces. Mercury intrusion porosimetry was used to measure the microporosity structure quantitatively by showing the relationship between cumulative pore volumes and pore radius. The experimental results show that a dual-porosity structure (i.e., interaggregate pores and intra-aggregate pores) forms during the compaction process. The interaggregate pores are compressible and the associated volume is closely related to the final void ratio of the compacted sample. Changes to interaggregate pores is dominant during compaction, but changes to intra-aggregate pores is dominant during saturation and drying. Based on the experimental results, a dual-porosity structure model was developed by relating the pore-size distribution to the void ratio. Consequently, the pore-size distribution at any void ratio can be predicted.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

CALCULATION OF OPTIMAL INJECTION RATE FOR DISPERSED WATERFLOODING SYSTEM

2017 ◽  
pp. 63-67
Author(s):  
L. A. Vaganov ◽  
A. Yu. Sencov ◽  
A. A. Ankudinov ◽  
N. S. Polyakova
Keyword(s):  
Injection Rate ◽  
Oil Field ◽  
Injection Well ◽  
Water Migration ◽  
Mutual Location ◽  
Optimal Injection ◽  
Technical Measures ◽  
Injection Rates

The article presents a description of the settlement method of necessary injection rates calculation, which is depended on the injected water migration into the surrounding wells and their mutual location. On the basis of the settlement method the targeted program of geological and technical measures for regulating the work of the injection well stock was created and implemented by the example of the BV7 formation of the Uzhno-Vyintoiskoe oil field.

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