A New Finding in the Interaction Between Chelating Agents and Carbonate Rocks During Matrix Acidizing Treatments

Assem, Ahmed I.; Nasr‐El‐Din, Hisham A.; Wolf, Corine De

doi:10.2118/164130-ms

Cited by 5 publications

(1 citation statement)

References 34 publications

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“…The results showed that NTA decomposed completely at 300°F and partially (23%) at 250°F and the authors highlighted the need to investigate alternatives of iron chelating agents at these conditions. Assem et al (2013aAssem et al ( , 2013b examined glutamic N,N-diacetic acid or (GLDA) as an iron chelating agents used with HCl. Acid solutions (5 -20 wt%) with a loading of 5,000 and 10,000 ppm of Fe 3ϩ were tested at 200°F.…”

Section: Introductionmentioning

confidence: 99%

Sodium Gluconate as a New Environmentally Friendly Iron Controlling Agent for HP/HT Acidizing Treatments

Rabie¹,

El-Din²

2015

SPE Middle East Oil &Amp; Gas Show and Conference

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Iron precipitation is a serious problem in acidizing treatments which can damage the formation permeability by restricting the flow channels. Solutions introduced in the past included the use of buffers, reducing agents, and chelating agents. Laboratory and field experiences concluded that chelating agents are the most effective remedy for controlling the iron precipitation. However, substantial limitations hinder the effectiveness and the application of several of the current chelating agents in the industry. These limitations include poor thermal stability at elevated temperatures, higher cost, low solubility in acidic medium, tendency of precipitating calcium products, and serious negative health and environmental impacts.This work introduces sodium gluconate as an efficient and environmentally friendly iron chelating agent. The chemical exhibits an excellent sequestering property for iron over a wide range of pH values, with a chelation power comparatively closer to those reported for EDTA and NTA. The salt is readily dissolved in the acids with a solubility of 600 gm/l.The objectives of this study are to: (1) investigate the ability of sodium gluconate to prevent iron precipitation at different iron loading, (2) examine the efficiency of the new chelant in hydrochloric acid solutions (5, 10, and 15 wt%) at a temperature of 200 and 250°F and chelant to iron molar ratios of 1:1, 2:1, and 4:1, and (3) determine the optimum chelant to iron molar ratio that results in the highest chelation capacity. The effectiveness of the new chemical was examined by determining the percentage increase/ reduction in core permeability.In stirred reactor experiments, iron precipitation was observed at a pH above 2 with the absence of the chelant at iron loading at 5,000 and 10,000 ppm at 77°F. The presence of Na gluconate at an equimolar ratio of the iron loading prevent the precipitation over the investigated range of iron load and temperature.Coreflood results showed that at low injection rates of 0.5 cc/min, 200°F, and 5 wt% HCl with 10,000 ppm Fe 3ϩ the core was damaged and the acid was not able to enter the core due to iron precipitation on the core inlet. At a higher injection rate (2 cc/min) the presence of 5 wt% Na-gluconate enhanced the permeability by 74% (versus 50% when no chelant was added) after injecting 0.75 PV of the acid with a load of 5,000 ppm Fe 3ϩ . At a load of 10,000 ppm of iron (III), the permeability increased to 165% compared to 70% for a controlled experiment. The results of another set of experiments at 250°F and 15 wt% HCl with a load of 10,000 ppm indicated that a 1:1 molar ratio of chelant to iron concentration is the optimum for the maximum chelation capacity compared to the results obtained for other experiments in which the molar ratio of sodium gluconate to iron was 2:1 and 4:1. These results were confirmed by fluid analysis, which showed a significant increase in both ion concentrations at this molar ratio in the effluent samples.

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Section: Introductionmentioning

confidence: 99%

Sodium Gluconate as a New Environmentally Friendly Iron Controlling Agent for HP/HT Acidizing Treatments

Rabie¹,

El-Din²

2015

SPE Middle East Oil &Amp; Gas Show and Conference

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Matrix acidizing: a fouling mitigation process in oil and gas wells

Pourabdollah

2018

Reviews in Chemical Engineering

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AbstractFouling mitigation in underground reservoirs enhances the permeability and the flow capacity of production or injection wells and is carried out by reservoir stimulation methods such as matrix acidizing. This process is known as the most significant method used to improve the production or injection indices of oil and gas wells as well as water and steam wells. Here, different aspects of this process, its chemical advances and novel high-technologies are compared and discussed in order to reveal their advantages and determine under what conditions they are applicable. Knowledge for adapting the proper acid treatment with the well characteristics is another issue that has been considered in this paper. The final goal is to present the state-of-the-art fouling mitigation methods based on novel experiments, simulations and investigations in order to emphasize the engineering aspects of fouling mitigation in oil and gas wells by matrix acidizing.

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Permeametry Pitfalls and Opportunities

Wehunt

Nasr‐El‐Din

2013

All Days

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Permeameters have been used for more than 80 years in the oil and gas industry, either to measure porous media permeability ("K" studies) or to interpret permeability alterations by various unintended or deliberate processes ("ΔK" studies). It is the latter experiment class-the ΔK studies-which are this paper's focus.Darcy's law is an empirical observation that permeability is proportional to the fluid velocity and the applied pressure gradient, and inversely proportional to the fluid viscosity. In experimental utopia, the simplest variable to measure is the only one that must be recorded during an experiment; however, in practice, interpretation errors frequently arise from ignoring factors that are more difficult to measure or predict, such as viscosity changes within cores during a test. Using data from previously published studies, this paper examines some interpretation pitfalls from past experiments and shows how some of these can be avoided. In addition to ignoring changes in factors that are not actually constant, another pitfall is not fully utilizing the available information. This paper identifies permeametry interpretation improvement opportunities for past or future studies using commonly available data, especially for those tests involving, parallel-flow, dual-or multi-cell tests, or carbonate matrix acidizing optimization studies.

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A New Finding in the Interaction Between Chelating Agents and Carbonate Rocks During Matrix Acidizing Treatments

Cited by 5 publications

References 34 publications

Sodium Gluconate as a New Environmentally Friendly Iron Controlling Agent for HP/HT Acidizing Treatments

Sodium Gluconate as a New Environmentally Friendly Iron Controlling Agent for HP/HT Acidizing Treatments

Matrix acidizing: a fouling mitigation process in oil and gas wells

Permeametry Pitfalls and Opportunities

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