AkzoNobel (Canada)

Significant increases in the reaction rate and final conversion of a model polyesterification are reported by the use of microwave heating.

Summary The acidizing of sour, heavy-oil, weakly consolidated sandstone formations under steam injection is challenging because of fines migration, sand production, inorganic-scale formation, corrosion issues, and damage caused by asphaltene precipitation associated with these sandstone formations. These and other similar problems cause decline in the productivity of the wells, and there is a recurring need to stimulate them to restore productivity. The complexity of sandstone formations requires a mixture of acids and several additives, especially at temperatures up to 360°F, to accomplish successful stimulation. Three treatments were tested on a horizontal well in the field: hydrochloric acid (HCl); Chelating Agent B, a high-pH chelant; and Chelating Agent A, or glutamic acid Ν,Ν-diacetic acid (GLDA). The first two treatments with 15 wt% HCl and high-pH (pH = 10) Chelating Agent B produced results below expectations. The third treatment using GLDA was successful, and the well productivity increased significantly. The field treatment with GLDA included pumping the treatment fluid, which was foamed to create proper rheological characteristics and a better-controlled pumping process. The treatment fluids were displaced into the formation by pumping produced water and were allowed to soak for 6 hours. In this paper, we evaluate the field applications of GLDA using geochemical modeling, production data, and analysis of well-flowback fluids after the field treatments.

Despite innumerable years of research, very little is known about the physical structure of rusts on steel, which are presumed to possess a complex structure of pores of various shapes and sizes. There have been few detailed investigations into rust pore structure and no studies that focus specifically on understanding the role that rust porosity plays on the adhesion and performance of protective organic coatings. It is commonly believed that paints that are formulated for “compromised” (i.e. rusty and salty) steel penetrate surface and through thickness pores in order to stabilise and bind the rust together. However, no convincing experimental evidence exists for such a mechanism. Here we develop a detailed, quantitative, understanding of the porous structure of rust and attempt to directly measure its evolution over time. Characterization of porosity in rust layers is non-trivial, as pore sizes span many orders of magnitude and there is no single technique that can measure across the size range. Thus, a range of complementary techniques have been utilised to measure pore sizes: gas (BET) sorption, mercury porosimetry and helium pycnometry, each of which measures different porosity characteristics across different length scales from the “microporous” (i.e. < 2 nm) through the “mesoporous (2 – 50 nm) to “macropores” of size > 50 nm. We find that for rusts developed using cyclic corrosion testing up to 50% of the porous volume exists in the mesoporous and microporous size ranges with surface areas between 20 and 40 m2 g-1 and that there is significant stratification of porosity between "inner" and "outer" rust layers X-ray computerised tomography (XRCT) has been subsequently used to directly image pores at a voxel size of around 1 micron in order to follow the evolution of the pore structure with time as a function of environmental exposure. The figure shows the experimental protocol whereby projection images of a corroded wire sample are obtained using x-ray absorption contrast and later combined to generate the 3D volume reconstruction. Figure 1

<b>Introduction:</b> Volatile organic compounds (VOC9s) present in exhaled breath reflect the metabolic activity of the body and change in the presence of both respiratory disease and lung cancer. Human breath analysis is a non-invasive technique for the rapid identification of gas-phase analytes, such as VOC9s, and offers a new clinical diagnostic tool. Ion Mobility Spectrometry coupled with a Multi Capillary Column (MCC/IMS) allows exhaled breath to be rapidly analysed and characterised with great precision. <b>Aim:</b> To derive a database of exhaled breath profiles from participants with and without respiratory disease and to use this database to determine if breath borne VOC9s can be used to differentiate disease states. <b>Methodology:</b> Breath samples from 323 respiratory patients with and without lung cancer were measured using the MCC/IMS and analysed in real time (mean age 68 years, 195 males and 128 females). Demographic data, medical diagnosis and medical history were also collected. <b>Results:</b> The respiratory data were compared to control data from 182 healthy participants of the general public and NHS staff. All breath profiles collected were analysed using advanced chemometric techniques developed in collaboration with Radboud University, Nijmegen, Netherlands. This analysis determined which exhaled breath VOC9s have the potential to differentiate disease. <b>Conclusion:</b> The study has shown that lung cancer can be identified with 87% specificity and 70% sensitivity from healthy controls, reiterating the potential of breath analysis as a diagnosis tool.

The long-term failure of seemingly intact corrosion resistant organic coatings is thought to occur via the development of ionic transport channels, which spontaneously evolve from hydrophilic regions on immersion, i.e., as a result of localized water uptake. To this end, we investigate water uptake characteristics for industrial epoxy-phenolic can coatings after immersion in deionized water and drying. Moisture sorption and the changing nature of polymer-water interactions are assessed using FTIR for dry and pre-soaked films. More water is found to be absorbed by the pre-soaked coatings on exposure to a humid environment, with a greater degree of hydrogen-bonding between the polymer and water. Furthermore, morphological changes are then correlated to localized water uptake using the AFM-IR technique. Nanoscale softened regions develop on soaking, and these are found to absorb a greater proportion of water from a humid environment.

This study gives a brief overview about using dividing-wall column (DWC) technology in azeotropic and extractive distillation processes aimed to break azeotropes. The relevant case study considered here is the bioethanol dehydration process that requires significant energy to overcome the azeotropic behaviour of ethanol-water mixture. The results of the rigorous Aspen Plus simulations show that energy savings of 10– 20 % are possible for the novel process intensification alternative based on DWC, while using less equipment units as compared to the conventional azeotropic and extractive distillation configurations.

Abstract During matrix acidizing, successful iron control can be critical to the success of the treatment. Iron (III) precipitation occurs when acids are spent and the pH rises above 1, which can cause severe formation damage. Chelating agents are used during these treatments to minimize iron precipitation. In this paper, we studied the effect of iron precipitation in acidizing operations. HCl solutions (5 - 20 wt%) containing 5,000 to 10,000 ppm of Fe3+ were used in these experiments. Biodegradable GLDA (glutamic-N, N-diacetic acid) was studied in the experiments. The effect of varying acid concentration and chelate-to-iron mole ratio was examined. Coreflood experiments were conducted on low permeability Indiana limestone (1 - 5 md) at 200°F. The cores were scanned after treatments using a CT scanner. The core effluent samples were analyzed for total iron and calcium concentrations using ICP-ES. A calcium ion-selective electrode was used to determine the concentration of free calcium ions, i.e. calcium ions not complexed by the chelate, in the core effluent samples. Results showed that the amount of iron recovered depended on both chelate-to-iron mole ratio and the initial permeability of the cores. Calcium is chelated along with iron, which limits the effectiveness of chelating agents to control iron (III) precipitation. Chelating agents are supposed to control iron now that calcium is also chelated, this amount should be accounted for. Acid solutions should be designed considering this important finding for more successful treatments. This paper will discuss the results obtained and give recommendations to enhance the effectiveness of these chemicals in the field.

Abstract For many reasons acidizing treatments represent a real challenge to the oil and gas industry. On one side acidizing can significantly improve the productivity of the well, but on the other side the intrinsic corrosive character of the acids form a severe threat to the well's integrity. Therefore traditional acidizing treatments with fluids involve significant loadings of corrosion inhibitors and corrosion inhibitor intensifiers to help mitigate the corrosion. However, the additives can cause their own damage to the formation, reduce overall effectiveness of the acidizing fluid, and come with significant additional costs to the overall acidizing program. Recently studies with a new environmentally friendly stimulation fluid, glutamic acid diacetic acid (GLDA), were presented for both carbonate and sandstone reservoirs. The studies have shown that GLDA can dissolve calcite &amp; dolomite, does not destabilize clays particles, and can significantly improve permeability in both carbonate and sandstone formations across wide field conditions. In the present paper the corrosion rate of GLDA is compared with other chelates and simple organic acids that are used for carbonate dissolution, such as hydroxyethylethylenediaminetriacetic acid (HEDTA), acetic, citric and formic acid. All corrosion tests were conducted at high temperature and pressure and extended for up to 6 hour at temperature and pressure. The results show that GLDA at 20 wt% has the least impact on low carbon steel, in comparison to the other stimulation fluids examined in this study. A very minimal amount of corrosion inhibitor loading was needed to keep the corrosion rate below the acceptable rate for GLDA, even at elevated temperatures or in the presence of corrosive gases like H2S and CO2. On more corrosion resistant Cr-based metals, like Cr-13 and duplex, the corrosion rate of GLDA is far below the acceptable limit with no corrosion inhibition even at 300°F. Based on the results, GLDA solutions can be used to stimulate carbonate and sandstone wells completed with various types of metallurgies with no or very minimal amount of corrosion inhibitors and effectively maintain the integrity of the tubular &amp; internals.

Abstract Acid treatments in high temperature deep wells drilled in carbonate reservoirs represent a challenge to the oil industry. The high temperature of deep wells requires a special formulation of emulsified acid that can be stable and effective at such high temperatures. At these high temperatures, both the reaction rate between acid and rock, and corrosion rate of tubulars are high. This fact makes protection of tubulars and reducing the reaction rate between rock and acid challenging. A new emulsifier was used to prepare emulsified acids that can be used in stimulating deep wells drilled in carbonate reservoirs. All emulsified acid systems were formulated at 0.7 acid volume fraction, and the final HCl concentration was 15 wt%. A coreflood study was conducted in order to study the efficiency of the new emulsified acid to create wormholes, and to increase the efficiency of the stimulation treatment. Both low and high permeability Indiana limestone cores were used in the present study. The effect of acid injection rate, rock permeability, and emulsifier concentration on the performance of emulsified acid systems were studied. The reaction between emulsified acid and limestone rocks was studied using a rotating disk apparatus at 230 ºF, and rotational speeds up to 1,500 rpm. The results showed, for both low and high permeability Indiana limestone cores, the new emulsified acid system created deep wormholes at all injection rates (0.5 to 10 cm3/min), with no face dissolution encountered during acid injection. The reaction rate between the new emulsified acid and limestone cores was measured using a rotating disk at 230 ºF. The dissolution rate increased as the rotational speed increased, indicating that reaction between emulsified acid and limestone is a mass transfer limited reaction. Both reaction rate and diffusion rate decreased as the emulsifier concentration increased from 0.5 to 2.0 vol%. From these results, the new emulsifier can be used in formulating emulsified acid systems that can be used effectively in stimulation of high temperature deep wells. This paper summarizes the results of testing the new emulsified system, and recommends its use for field application in deep carbonate reservoirs.

Abstract Different fluids have been introduced in the oil industry to be used as alternatives to HCl. Chelating agents such as EDTA (ethylenediaminetetraaceticacid), HEDTA (hydroxyethylenediaminetriaceticacid), and GLDA (L-glutamic acid-N, N-diacetic acid) have been introduced to be used as stand-alone stimulation fluids. These fluids can be used to stimulate water injectors, oil, or gas producers, therefore, the effect of the type of reservoir fluid on the stimulation process should be investigated. In this study, 0.6M concentration of GLDA, EDTA, and HEDTA were used in the coreflood experiments on carbonate rocks at 300°F. The cores were saturated with water, oil, or gas to determine the effect of reservoir fluid type on the performance of the chelating agents with the carbonate cores. The different chelants were injected into the calcite cores saturated by oil and gas after flooding the water into the cores until the residual saturations were reached. The effect of using 10 vol% mutual solvent (ethyleneglycol-monobutyl-ether) in the preflush on the stimulation process was examined. CT was used to scan the cores after the treatments, and the 2D images were used to characterize the wormhole and face dissolution. GLDA at pH of 4 stimulated calcite cores better than HEDTA at 300°F at different injection rates. No face dissolution was observed at low injection rate and high temperature in the case of GLDA. The results obtained with carbonate cores saturated with nitrogen gas were almost similar to those obtained when the cores saturated with water. Using mutual solvent as a preflush in the oil-saturated cores removed most of the oil from the core and water-wet the calcite allowing reaction of chelants with calcite, similar to the case of water-saturated cores.