Improved Prediction of Foam Diversion in Matrix Acidization

1995 ◽  
Author(s):  
S.C. Zeilinger ◽  
M. Wang ◽  
K.R. Kibodeaux ◽  
W.R. Rossen
Keyword(s):  
Matrix Acidization

Applying Fractional-Flow Theory to Foams for Diversion in Matrix Acidization

1994 ◽  
Vol 9 (01) ◽  
pp. 29-35 ◽  
Author(s):  
Z.H. Zhou ◽  
W.R. Rossen
Keyword(s):  
Flow Theory ◽  
Fractional Flow ◽  
Matrix Acidization ◽  
Fractional Flow Theory

Matrix Acidization with Highly Reactive Acids

1971 ◽  
Vol 11 (04) ◽  
pp. 390-398 ◽  
Author(s):  
J.A. Guin ◽  
R.S. Schechter
Keyword(s):  
Mathematical Model ◽  
Pore Structure ◽  
Pore Size ◽  
Acid Treatment ◽  
Explicit Knowledge ◽  
Experimental Studies ◽  
Design Procedure ◽  
Permeability Change ◽  
Pore Size Distributions ◽  
Matrix Acidization

Abstract A mathematical model representing the changes in pore structure attending the invasion of a porous material by a reactive fluid tending to dissolve the solid bas previously been tested and found to be valid. This mathematical model is solved by a simulation procedure using Monte Carlo techniques. The results so obtained are indicative of the acidization of sandstone using a last-reacting acid (diffusion limited). A correlation relating the permeability improvement to the change in porosity is presented and found to be applicable to a wide class of initial pore-size distributions. This means that the designer need not have explicit knowledge of the initial pore structure to utilize the correlation. The generality of the correlation stems from the fact that after exposure to fast-acting acids (diffusion-controlled reactions) wormholing tends to occur in all porous matrices, and the acid allows preferentially through these channels. Thus, the process is independent of the fine pore structure since the fine pores receive no acid Wormholing bas been observed in almost all experimental studies of acidization, thus further confirming the validity of the model. Introduction Matrix acidization as practiced in the petroleum industry is a simple operation. Acids treated so as to prevent their corrosive attack on metal parts contacted are pumped down the wellbore and forced into the pore spaces of an oil-bearing rock. The rate of penetration is normally maintained small enough to prevent fracturing of the reservoir The aim of matrix acidization is to enhance the permeability of the region around the wellbore by permeability of the region around the wellbore by dissolving either a portion of the rock or of the foreign impurities that may have been introduced during the drilling operations. The success of this technique of oilwell stimulation is attested to by the fact that a significant fraction of the acids used for stimulation are injected at matrix rates. There were, moreover, in excess of 87 million gal of hydrochloric acid used last year in carbonate formations with many other special purpose acids such as acetic and formic having also been used for stimulation purposes. Despite the fact that acids have long been routinely used as a means of stimulating oil wells to greater production, there is, as yet, no reliable design procedure incorporating all of the essential features into a prediction of the new production that will result from a given acid treatment of a particular well. This lack of a design procedure particular well. This lack of a design procedure has been responsible for the rather minimal efforts expended in obtaining meaningful reaction rate data, for there is very little enthusiasm for obtaining data which cannot be put to practical application. This paper is an extension of some recently reported work on predicting the permeability change resulting from acid treatment of an oil-bearing rock. It has been proposed that the changes in the microstructure owing to acidization in a porous rock can be simulated by considering the effect of acidization of a collection of small, randomly distributed capillaries that are interconnected to the extent that a fluid will be conducted from point to point under the influence of an external pressure gradient. This model, the capillaric model, has been used with varying success in understanding the behavior of porous media. The use of the capillaric model in determining only the results of the evolution of a pore-size distribution, rather than as a vehicle for predicting a number of mare or less independent phenomena, such as capillary pressure curves and dispersion, is, as has been pressure curves and dispersion, is, as has been noted by Schechter and Gidley, a more limited and perhaps attainable goal. Taking the capillaric model to be correct, Guin et al. have shown that an equation relating the porosity change and the permeability change caused by an ideally retarded permeability change caused by an ideally retarded acid can be derived without any assumptions. SPEJ P. 390

Thermal analysis in matrix acidization

2006 ◽  
Vol 51 (1-2) ◽  
pp. 85-96 ◽  
Author(s):  
F. Medeiros ◽  
O.V. Trevisan
Keyword(s):  
Thermal Analysis ◽  
Matrix Acidization

Effect of Oil Saturation on Acid Propagation during Matrix Acidization of Carbonate Rocks

2014 ◽  
Author(s):  
R. Kumar ◽  
J. He ◽  
H. Nasr-El-Din
Keyword(s):  
Carbonate Rocks ◽  
Oil Saturation ◽  
Matrix Acidization

scholarly journals A decoupled scheme to solve the mass and momentum conservation equations of the improved Darcy–Brinkman–Forchheimer framework in matrix acidization

AIP Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 125305
Author(s):  
Yuanqing Wu ◽  
Jisheng Kou ◽  
Yu-Shu Wu ◽  
Shuyu Sun ◽  
Yilin Xia
Keyword(s):  
Momentum Conservation ◽  
Conservation Equations ◽  
Matrix Acidization

A Comprehensive Model of Matrix Acidization

1997 ◽  
Author(s):  
Yong Fan ◽  
Yuqin Wang ◽  
R.S. Bryant
Keyword(s):  
Comprehensive Model ◽  
Matrix Acidization

Theoretical and Experimental Studies of Sandstone Acidizing

1981 ◽  
Vol 21 (01) ◽  
pp. 30-42 ◽  
Author(s):  
A.D. Hill ◽  
D.M. Lindsay ◽  
I.H. Silberberg ◽  
R.S. Schechter
Keyword(s):  
Fluid Velocity ◽  
Radial Distance ◽  
Acid Mixture ◽  
Specific Information ◽  
Radial System ◽  
Silicate Minerals ◽  
Damaged Zone ◽  
Reaction Characteristics ◽  
The Matrix ◽  
Matrix Acidization

Abstract The matrix acidization of sandstone by a hydrochloric/hydrofluoric acid mixture is described through use of a capillary model. The model was solved first in linear coordinates so that it could be compared with the results of coreflood experiments performed on Berea sandstone. The model predictions showed reasonable agreement with the experimental data and yielded specific information about the reaction characteristics of the sandstone/HCl/HF system. The acidization model then was applied in radial coordinates to generate design curves for a matrix acidization treatment. While these curves strictly apply only to those sandstones having similar mineral compositions, the approach is general. It is based on matching the location of the HF reaction front to the depth of a damaged zone. This method introduces the concept of an optimum injection rate and, in this regard, differs from other design methods reported in the literature. Introduction The matrix acidization of sandstone by an HCl/HF acid mixture is an often-employed oilwell stimulation technique designed to increase permeability in a zone around the wellbore. The acid mixture flowing into the porous medium reacts with the various mineral species present, thus effecting an increase in the matrix porosity and, it is hoped, the permeability. Clearly, one of the factors controlling the depth of acid penetration is the chemical composition of the minerals which the acid contacts. Smith and Hendrickson,1 Gatewood,2 and Lund et al.3–5 have shown that the reaction with calcite is more rapid than with silicate minerals (clay or feldspar), which is, in turn, more rapid than the reaction with silica. Several papers describing the distance of penetration have been published. Smith and Hendrickson1 and Smith et al.6 first suggested the use of linear core tests to predict radial penetration. Farley et al.7 reported tests similar to those conducted by Smith and Hendrickson but measured many additional parameters including the effluent acid concentration, which is quite useful since the effluent concentrations may yield information about reaction characteristics. Experiments conducted in linear systems are difficult to translate in terms of penetration in a radial system, since the fluid velocity varies inversely with radial distance. The obvious approach has been to develop a mathematical model that can be calibrated based on linear flow data and then applied to a radial system. Gatewood2 proposed that the acid penetration distance be determined by assuming that the reaction of HF with the silicate minerals is much faster than with the silica. The distance of penetration is determined in this model by the formation composition and by the stoichiometry of the reactions. Lund et al.5,8 and Fogler and McCune9 developed a model which neglects the reaction of HF with silica but does consider the reactions with the silicate minerals. The advantage of these approaches is that the penetration depth can be predicted based on the formation composition. However, the reaction with silica cannot be neglected in determining the depth of penetration, as will be seen.

scholarly journals Thermodynamically consistent Darcy–Brinkman–Forchheimer framework in matrix acidization

2021 ◽  
Vol 76 ◽  
pp. 8
Author(s):  
Yuanqing Wu ◽  
Jisheng Kou ◽  
Shuyu Sun ◽  
Yu-Shu Wu
Keyword(s):  
Numerical Experiments ◽  
Good Description ◽  
Energy Balance Equation ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Scale Model ◽  
Recovery Stage ◽  
Tertiary Recovery ◽  
Matrix Acidization ◽  
Momentum Conservation Equation

Matrix acidization is an important technique used to enhance oil production at the tertiary recovery stage, but its numerical simulation has never been verified. From one of the earliest models, i.e., the two-scale model (Darcy framework), the Darcy–Brinkman–Forchheimer (DBF) framework is developed by adding the Brinkman term and Forchheimer term to the momentum conservation equation. However, in the momentum conservation equation of the DBF framework, porosity is placed outside of the time derivation term, which prevents a good description of the change in porosity. Thus, this work changes the expression so that the modified momentum conservation equation can satisfy Newton’s second law. This modified framework is called the improved DBF framework. Furthermore, based on the improved DBF framework, a thermal DBF framework is given by introducing an energy balance equation to the improved DBF framework. Both of these frameworks are verified by former works through numerical experiments and chemical experiments in labs. Parallelization to the complicated framework codes is also realized, and good scalability can be achieved.

The Optimum Mixture of Organic Acid and HCL for the Matrix Acidization of a Carbonate Reservoir

2016 ◽  
Author(s):  
H. Jafarpour ◽  
M.F. Ghasemi ◽  
D.G. Petrakov ◽  
A. Khormali
Keyword(s):  
Organic Acid ◽  
Carbonate Reservoir ◽  
The Matrix ◽  
Matrix Acidization
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