Field Application of Emulsified Acid-Based System to Stimulate Deep, Sour Gas Reservoirs in Saudi Arabia

Nasr‐El‐Din, Hisham A.; Solares, Jose Ricardo; Al-Mutairi, Saleh Haif; Mahoney, M.D.

doi:10.2118/71693-ms

Cited by 77 publications

(10 citation statements)

References 42 publications

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“…An accurate knowledge of acid reaction rates of deep gas reservoirs can contribute to the success of matrix and acid fracture treatments. Many studies of acid stimulation treatments of the Khuff formation, a deep, dolomitic gas reservoir in Saudi Arabia, have been published (Nasr-El-Din et al 2001, 2002a, 2002bBartko et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Anomalous Acid Reaction Rates in Carbonate Reservoir Rocks

2006

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It is generally assumed that the reaction of acid with limestone reservoir rock is much more rapid than acid reaction with dolomite reservoir rock. This work is the first to show this assumption to be false in some cases, because of mineral impurities commonly found in these rocks. Trace amounts of clay impurities in limestone reservoir rocks were found to reduce the acid dissolution rate by up to a factor of 25, to make the acid reactivity of these rocks similar to that of fully dolomitized rock. A rotating disk instrument was used to measure dissolution rates of reservoir rock from a deep, dolomitic gas reservoir in Saudi Arabia (275°F, 7,500 psi).More than 60 experiments were made at temperatures of 23 and 85°C and HCl concentration of 1.0 M (3.6 wt%). Eight distinctly different rock types that varied in composition from 0 to 100% dolomite were used in this study. In addition, the mineralogy of each rock disk was examined before and after each rotating disk experiment with an environmental scanning electron microscope (ESEM) using secondary and backscattered electron imaging and energy dispersive X-ray (EDS) spectroscopy. Acid reactivity was correlated with the detailed mineralogy of the reservoir rock. It was also shown that bulk anhydrite in the rock samples was converted to anhydrite fines by the acid at 85°C, a potential source of formation damage.

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Section: Introductionmentioning

confidence: 99%

Anomalous Acid Reaction Rates in Carbonate Reservoir Rocks

2006

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“…Hence, the carbonate dissolution phenomenon is similar for acid microemulsions and macroemulsions. Macroemulsions are successfully applied in both matrix acidizing and fracture acidizing treatments [25,[35][36][37]. These case histories demonstrate the use of emulsified acids as the main treating fluid to increase the depth of stimulation at treatments up to about 176°C.…”

Section: Industry Applications: Carbonate Acidizingmentioning

confidence: 97%

Microemulsion Applications in Carbonate Reservoir Stimulation

Fredd¹,

Hoefner²,

Fogler³

2017

Properties and Uses of Microemulsions

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Carbonate reservoir stimulation involves the injection of reactive fluids, most commonly hydrochloric acid (HCl), into the porous media to enhance the permeability and increase hydrocarbon production. This process results in the formation of highly conductive flow channels, or wormholes, and relies on the deep penetration of reactive fluids into the formation to maximize stimulation success. However, the rapid rate of reaction of HCl with the carbonate rock often limits the depth of live acid penetration. The reaction is mass transfer limited under typical reservoir conditions. As a result, the acid diffusion and convection rates significantly influence the success of the treatments. Microemulsions prepared with HCl as the dispersed phase offer a solution to significantly reduce the effective diffusivity and, hence, increase the depth of stimulation. This chapter presents the results of laboratory studies of carbonate dissolutions using acid microemulsions and highlights case histories of industry applications using macroemulsions for carbonate reservoir stimulation.

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“…Water in oil emulsions provide better retardation due to the low diffusivity created by the oil phase around acid droplets, which allows for minimum acid volume contact with t h e r o c k − t u b u l a r s u r f a c e . T h u s , m o s t r esearch 18,26,[29][30][31][32][33][34][35][36][37]39,40,[42][43][44][45][46][47][48][49][50][51]53 has adapted W/O emulsions due to their desirable retardation effect and corrosion inhibition in comparison to O/W emulsions, 27,28 as depicted in Figure 5.…”

Section: Emulsion Type On the Basis Of The Dispersionmentioning

confidence: 99%

A Review on Use of Emulsified Acids for Matrix Acidizing in Carbonate Reservoirs

Yousufi,

Mohyaldinn Elhaj,

Dzulkarnain

2024

ACS Omega

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Almost 60% of oil and 40% of gas reserves worldwide are contained in carbonate reservoirs where acidizing stimulation is more challenging compared to sandstone reservoirs. Utilization of emulsified acids in matrix acidizing operations has been the most effective technique for more than half a century. This is due to the colloidal system's ability to generate deep, narrow conduits toward production zones under controlled retarded reactivity with the rock surface, along with the excellent sweep efficiency and corrosion inhibition of the well equipment. This Review attempts to review the various kinds of emulsified acids that are used for matrix acidizing of carbonate formations. The Review is trying to trace the innovations that have, gradually, been applied for enhancing the performance of emulsified acids for a variety of conditions, their limitations, and the developmental solutions such hybrid emulsifiers and pickering emulsions. In addition, the Review also discusses the parameters, characteristics, and measuring techniques required for the successful synthesis of a stable and quality emulsion while considering the environmental concerns raised toward the application of an emulsified acid system. From the reviewed publications, it can be summarized that macroemulsions are best suited for matrix acidizing applications over microemulsions due to low emulsifier concentrations and high acid volume retention; similarly, water in oil emulsions provide better retardation in a comparison to oil in water emulsions. The small droplet size of the emulsion yields high viscosity and stability. The compositional balance between each component present in the acidizing system is a crucial factor for optimum performance. Moreover, for future practice, much focus is required to design emulsified acids as ecofriendly systems that can leave the least amount of toxicity during and after implementation.

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Field Application of Emulsified Acid-Based System to Stimulate Deep, Sour Gas Reservoirs in Saudi Arabia

Abstract: TX 75083-3836, U.S.A., fax 01-972-952-9435. Abstract

Cited by 77 publications

References 42 publications

Anomalous Acid Reaction Rates in Carbonate Reservoir Rocks

Anomalous Acid Reaction Rates in Carbonate Reservoir Rocks

Microemulsion Applications in Carbonate Reservoir Stimulation

A Review on Use of Emulsified Acids for Matrix Acidizing in Carbonate Reservoirs

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