Fine-Scale Simulation of Sandstone Acidizing

Li, Chunlou; Xie, Tao; Pournik, Maysam; Zhu, Ding; Hill, A.D.

doi:10.1115/1.1944027

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…This highly nonuniform structure created by acid in carbonates results in much deeper penetration of acid into the formation than is thought possible in sandstones. Because the wormholes increase effective permeability greatly while only a small portion of the matrix is actually dissolved, the creation of wormholes is an efficient and desirable mode of matrix acidizing (Li et al 2005). Carbonate acidization undergoes mode changes with increase of acid flow rate.…”

Section: Conclusion and Suggestions For Future Workmentioning

confidence: 99%

On the Behavior of the Porous Rotating Disk Electrode

Bonnecaze

Mano

Nam

et al. 2007

J. Electrochem. Soc.

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The behavior of the current from a porous rotating disk electrode ͑PRDE͒ as a function of the rotation rate, electrode geometry, and porosity at large overpotentials is studied experimentally. The current shows a much richer behavior than the flat RDE, including a sigmoidal dependence on the rotation rate. At low rotation rates, the measured current is qualitatively similar to that of an RDE, with the current increasing with the square of the rotation rate. However, at a critical rotation rate, which we term the lower critical rotation rate and which depends on the radius, the thickness, and the porosity of the porous disk, the current increases much more rapidly than predicted by the Levich theory. At a larger, upper critical rotation rate, the current increases more slowly and then approaches a plateau. The plateau value greatly exceeds that predicted by Levich and is about 20 times greater than that for a flat electrode. The results are explained in terms of the angular velocity dependence of the ratio of the effective electrochemical reaction time to the residence time of the fluid in the porous disk. A theory is presented that collapses the data onto a universal curve.

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Section: Conclusion and Suggestions For Future Workmentioning

confidence: 99%

On the Behavior of the Porous Rotating Disk Electrode

Bonnecaze

Mano

Nam

et al. 2007

J. Electrochem. Soc.

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“…Hence, in this research, a general numerical model that is specifically focusing on HBF 4 sandstone acidizing is presented. This model is developed based on the mud acid acidizing modelling approach by Li et al (2004). The HBF 4 model has been developed based on the Finite Element Method (FEM).…”

Section: Hbf 4 Numerical Model Developmentmentioning

confidence: 99%

“…The detail chemical reaction processes are shown in Eqs. (1)- (4) (Li et al 2004 In the form of aqueous solution, HBF 4 will hydrolyze step-bystep to produce HF progressively. The first step of the hydrolysis process is known as the slowest reaction, hence determining the rate of hydrolysis.…”

Section: Chemical Reaction Modelmentioning

confidence: 99%

A numerical modelling and simulation of core-scale sandstone acidizing process: a study on the effect of temperature

Leong

Mahmud

Law

et al. 2018

J Petrol Explor Prod Technol

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A wide and comprehensive understanding of the chemical reactions and mechanisms of HBF 4 is crucial as it significantly influences its performance in stimulating a sandstone formation. In general, it is well-known that HBF 4 is able to provide a deeper penetration into the sandstone matrix before being spent due to its uniquely slow hydrolysis ability to produce HF. In the present study, a 3D numerical modelling and simulation were conducted to examine the capability of HBF 4 in enhancing the porosity and permeability of the sandstone matrix. The model is built in COMSOL® Multiphysics commercial software of computational fluid dynamics (CFD) to simulate the acid core flooding process on sandstone core. The model had been validated against the experimental data in the literature. The results matched with the measured plot data very well. The effect of temperature on the performance HBF 4 sandstone acidizing is evaluated in this study. The simulation results indicated that at low temperature of 25 °C, HBF 4 is not very effective, as justified in its poor porosity and permeability increments of only 1.07 and 1.23, respectively. However, at elevated temperatures, the porosity and permeability enhancement also become increasingly more significant, which showed 1.26 and 2.06, respectively, at 65 °C; and 1.67 and 7.06, respectively, at 105 °C. Therefore, one can conclude that HBF 4 acid treatment performed better at elevated temperatures due to increased hydrolysis rate, which is a governing function in HBF 4 sandstone acidizing. Overall, this model had provided a reliable alternative to optimize various other parameters of HBF 4 acid treatment. Keywords Well stimulation · Sandstone matrix acidizing · Fluoroboric acid · Computational fluid dynamics (CFD) · Finite element analysis (FEM) Abbreviations 3DThree

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“…They found that dissolution and precipitation do not occur simultaneously. Li et al [11] built a linear acid flooding model to simulate linear core flooding at an experimental scale with the consideration of the heterogeneities of minerals and flow fields. Li et al [12] built a radial acidizing model and considered the effect of the temperature field on the reaction, but they did not consider the effect of the heterogeneities.…”

Section: Introductionmentioning

confidence: 99%

A Research on the Effect of Heterogeneities on Sandstone Matrix Acidizing Performance

et al. 2019

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Matrix acidizing is one of the common methods to enhance production in sandstone reservoirs. Conventional acidizing designs generally neglected the effect of heterogeneities of mineral and flow field distributions both in areal and vertical directions and assumed that the acid front propagates with a piston-like style. However, sandstone formations inevitably have small-scale heterogeneities of minerals and flow properties that may give rise to acid propagation in a manner much different from what is predicted based on homogeneous assumptions. In this paper, we conduct a research to numerically investigate how the heterogeneities affect acidizing performance under in situ conditions. Firstly, a heterogeneity model is built for mineral and porosity distributions by using the semivariogram model of geological statistics, based on which we generate spatially correlated porosity and mineral distributions. Next, a model of radial acid flooding is developed based on mass balance and the chemical reactions between the acids and minerals occurring during the acidizing process. The model is numerically solved to investigate the permeability response, acid distributions, precipitate distributions, and the effect of the heterogeneities on acidizing. The results show that the heterogeneities both in areal and vertical directions have a significant effect on acidizing. The flow field heterogeneities have a more serious impact than the mineral heterogeneities. In a plane, strong porosity heterogeneity can give rise to acid fingering and even channeling, which make the acid penetration distance longer than the homogeneous cases. The secondary precipitate has a significant effect when fast-reacting mineral content is high. Vertically, several-fold permeability contrast creates the acid break through the high-perm zone leaving the low-perm zone understimulated. Both flow field and mineral heterogeneities make it possible to create high-permeability channels during the acidizing process and to obtain a longer acid penetration distance.

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Fine-Scale Simulation of Sandstone Acidizing

Cited by 12 publications

References 21 publications

On the Behavior of the Porous Rotating Disk Electrode

On the Behavior of the Porous Rotating Disk Electrode

A numerical modelling and simulation of core-scale sandstone acidizing process: a study on the effect of temperature

A Research on the Effect of Heterogeneities on Sandstone Matrix Acidizing Performance

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