Portable Microfluidic System for Analysis of Petroleum Samples

Description

1 / 9 “PORTABLE MICROFLUIDIC SYSTEM FOR ANALYSIS OF PETROLEUM SAMPLES” Field of the Invention

[001] The present invention relates to a microfluidic system, with the possibility of portability, applied to fluids produced on offshore or onshore platforms, aiming at the extraction of species associated with the aqueous phase in petroleum samples with low BSW values, making it possible to predict the ionic composition profile of water samples quickly for monitoring, control and decision-making actions in the production chain. Description of the State of the Art

[002] Mineral deposition or incrustation on surfaces is caused by the accumulation of inorganic salts. When present in pipelines and equipment used in oil and gas exploration and processing, incrustation generates major operational problems, damage to pipelines, and risks to environmental safety and operators. This phenomenon occurs not only in offshore oil wells but also in refineries and treatment plants. The origin of the salinity is due to the chemical composition of the so-called formation and injection waters.

[003] Chemical analyses of these fluids are performed using established techniques such as: atomic absorption, inductively coupled plasma optical emission spectrometry, ion chromatography, and / or titrimetry. However, the use of these techniques on offshore platforms is not feasible, as the analyses are performed using large and expensive equipment. Furthermore, before these analyses can be carried out, it is necessary to transfer the ions from the oil dispersion to an aqueous matrix by liquid-liquid extraction (LLE). Reactors with pressure and temperature control are often used to obtain better results in LLE. However, the method is time-consuming and needs to be performed in properly equipped laboratories. Dilution with a known quantity of water Petition 870220009985, dated 04 / 02 / 2022, page 15 / 15 2 / 9 helps in the separation of the dispersed aqueous phase, but is of limited application in the case of matrices with a high potential for forming stable emulsions.

[004] Furthermore, separating the aqueous phase at low BSW values ​​is very difficult and cannot be achieved using traditional techniques, such as centrifugation, without interfering with the sample. Even with liquid-liquid extraction, for example, there is a significant dilution factor, as well as difficulty in recovering the added water and limited extraction efficiency. Therefore, the analysis of the produced fluids involves sampling, landing, and water analysis on land, which greatly increases the time and provides a snapshot of the system from the past, hindering the adoption of appropriate strategies for fouling inhibition.

[005] In carbonate reservoirs, chemical reactions are expected between the rock and the injected fluids. These reactions can cause changes in the composition of the produced water. The dissolution of carbonates, such as calcite and dolomite, increases the concentration of calcium, magnesium, and bicarbonate in the produced fluid. Therefore, the composition of the produced water will not simply be a mixture of the fluids present in the reservoir. It is necessary to know the composition of the water taking into account these interactions between rock and fluid.

[006] To adopt the best strategy for inhibiting fouling in wells and topside, which, in the case of carbonates, depends on a more reliable modeling of reactive transport, it is necessary to know the chemical composition of the fluids involved in the process: injection water, formation water and produced water.

[007] Currently, the analysis to identify fouling species in fluids produced on offshore platforms is carried out on land, which is very time-consuming (sampling, sample unloading, and analysis). This time has been long enough that the platform has experienced production shutdowns due to fouling in the systems before the chemical composition of the produced water is known. Petition 870210114821, dated 09 / 12 / 2021, pages 30 / 42 3 / 9 for the most appropriate definition of the fouling inhibition strategy. Besides the time required to determine the composition of the produced water, another factor hinders obtaining this information: the low BSW value makes chemical analysis impossible, as it is not possible to separate a sufficient volume of water for analysis. Recent analyses have also shown another problem: changes in the equilibria involved and alterations in the measured values. During water separation, a centrifugation procedure is employed.

[008] BRESSAN, LP (2021) “Applications of 3D printed microfluidic devices by FDM in chemistry”, Thesis (Doctorate) - University of Campinas, SP, presents bioanalytical applications for devices produced with a simple protocol to prepare 3D printed microfluidic channels, for the determination of nitrite, total proteins and nitric oxide, in addition to visualization of microorganisms and in the continuous flow synthesis of silver and gold nanoparticles. In this study, a protocol was also developed for the creation of support devices, called scaffolds, in such a way that the pores produced are controlled directly through the printer software.

[009] The article by CAMARGO, CL et al. (2017) “Use of smartphone for turbidimetric detection and control of turbulent microfluidic platform toward full automation of microemulsification-based method”, describes a method for turbidimetric detection and control of turbulent microfluidics with the aim of fully automating the microemulsification-based method (MEC). The method proved to be simple, autonomous, with real-time result logging, and remote data transmission capability. The device was manufactured using polymerization and scaffold removal (PSR) methods to provide assisted intense flow turbulence. This fully automated microfluidic platform was applied to the determination of ethanol in commercial alcoholic beverages, showing improved accuracy and analytical frequency of MEC, and is a potential alternative for point-of-use applications. Petition 870210114821, dated 09 / 12 / 2021, pages 31 / 42 The 4 / 9 feature contributes to the use of this technology by non-specialists, providing in-situ measurements and real-time readings.

[0010] The work of SOUSA, PJT (2011) “Study and optimization of PDMS structures for microfluidic devices”, Dissertation (Master's in Micro / Nano technologies) - University of Minho, Portugal, describes an optimization study of the different stages of the entire fabrication process of PDMS structures, as well as characterizing the structures produced. One of the optimization processes is the use of a thermoplastic material without the need for masks, alignment, exposure or development, requiring only a suitable CAD design to be used by a printer. This study also reveals several applicability groups of PDMS in microfluidics.

[0011] In view of this, no prior art document discloses a portable microfluidic liquid-liquid extraction system applied to the separation of the aqueous phase of petroleum samples with low BSW content and which enables the classification and multi-determination of ions with fouling capacity present in various fluids from carbonate reservoirs, through multidimensional capacitive sensors, such as that of the present invention.

[0012] Thus, the objective of the present invention was to develop a microfluidic platform-based system for extracting species associated with the aqueous phase, considering petroleum with low water content. Furthermore, sensors based on the electronic tongue concept and statistical data processing by machine learning (ML) are used for classification and multi-determination of ions in water samples extracted from petroleum. This system is portable for use on offshore platforms.

[0013] Considering all the system components, namely the microfluidic extraction devices, the capacitance analysis device, along with the smartphone-controlled potentiostat, the assembly results in a portable system that can be applied on offshore platforms and offers a Petition 870210114821, dated 09 / 12 / 2021, pages 32 / 42 5 / 9 analytical procedure with low consumption of samples and chemical inputs. In addition, the system enables fast, high-frequency in-situ analysis of species with fouling characteristics in petroleum.

[0014] The ability to perform these analyses on crude oils with low BSW content represents a significant analytical advance, considering the technical difficulties observed in traditional methods that use liquid-liquid extraction. Evaluation in crude oils with low BSW is essential for characterizing formation water in the oil zone, since higher values ​​of this parameter indicate a greater presence of injected water and rock-fluid interaction. Therefore, the possibility of quickly predicting the ionic composition profile of these water samples becomes a strategy for monitoring, control, and decision-making actions in the production chain.

[0015] From an economic standpoint, it is possible to establish more appropriate fouling inhibition strategies, enabling more proactive than reactive actions on the part of the operation. Reactive transport models can be updated more frequently, making it possible to identify any anomalies or the presence of unmapped species. In this way, unscheduled production stoppages caused by fouling in the production system are avoided. Brief Description of the Invention

[0016] The present invention relates to a microfluidic liquid-liquid extraction system applied to the separation of the aqueous phase of petroleum samples with low BSW content, which are currently performed in land-based laboratories. Additionally, the invention enables the classification and multi-determination of fouling ions present in various fluids from carbonate reservoirs, using multidimensional capacitive sensors. The analysis can be facilitated by a portable potentiostat controlled by a smartphone, but is not limited to this, allowing direct application in offshore environments and its use can be... Petition 870210114821, dated 09 / 12 / 2021, pages 33 / 42 6 / 9 extended to other sectors that require rapid monitoring of the saline composition of water samples, whether from formation, production, or injection. The results will be used to monitor samples with a potential risk of fouling and will serve as a basis for a compilation of results to adjust the history of reactive transport modeling.

[0017] This analytical system can be applied for analysis in both offshore and onshore environments of fluids produced in the field. Brief Description of the Drawings

[0018] The present invention will be described in more detail below, with reference to the attached figures which, in a schematic and non-limiting way of the inventive scope, represent examples of its embodiment. The drawings show: - Figure 1 illustrating a soft lithography and 3D printing technologies, where (1) 2D view and (2) 3D view of the microfluidic chip associated with the extraction step; - Figure 2 illustrates (A - 1) a sensor obtained by the PSR method, the stainless steel capillary probes are ready for use; (B - 2) and (C - 3) show the microfluidic sensors obtained with four and eight pairs of capacitors in parallel, respectively; and (D - 4) a sensor obtained by soft lithography, the interdigitated flat gold capacitors were deposited on glass plates by physical vapor-phase evaporation techniques, and their area and design were defined by photolithography. These represent the electronic tongue in different configurations; Figure 3 illustrates the sequential operation of the extraction system associated with the electronic tongue. Detailed Description of the Invention

[0019] The portable system according to the present invention and illustrated in Figure 3 comprises an electronic tongue, a potentiostat, microfluidic chips and two syringe pumps. The microfluidic chips, both of Petition 870210114821, dated 09 / 12 / 2021, pages 34 / 42 7 / 9 liquid-liquid extraction as well as the electronic tongue system, can be constructed by polymerization and scaffold removal (PSR) methods, soft lithography and 3D printing technologies (Figure 1 (1) 2D view and (2) 3D view).

[0020] Among the materials used, it is possible to mention silicone-based polymers or thermoplastics and epoxy or acrylic resins. In the sensor obtained by the PSR method (Figure 2 (A)), the ready-to-use probes used were stainless steel capillaries. These probes were inserted on both sides of the microfluidic sensor channels in order to obtain gaps of approximately 200 µm between them. These capillaries were short-circuited with copper pieces, obtaining a parallel capacitor association. Then, poly(vinyl chloride) tubing connected the capillaries to each other to complete the microfluidic circuit.

[0021] Figures 2 (B) and (C) show the microfluidic sensors obtained with four and eight pairs of capacitors in parallel, respectively. In the sensor obtained by soft lithography, the interdigitated flat gold capacitors (Figures 2 (D)) were deposited on glass plates by physical vapor-phase evaporation techniques, and their area and design were defined by photolithography. Impedance analyses were performed using portable potentiostats controlled by smartphones, so that the analyses could be carried out on offshore platforms. The capacitances of the electrode pairs were calculated from the imaginary impedance considering the electrodes as ideally polarizable. The statistical treatment of the data by ML was performed using the Python algorithm library. EXAMPLES:

[0022] The following examples are presented in order to illustrate more fully the nature of the present invention and the manner of practicing it, without, however, being considered as limiting its content. Petition 870210114821, dated 09 / 12 / 2021, pages 35 / 42 8 / 9 Example 1: Microfluidic devices.

[0023] The development of easily manufactured microfluidic devices was achieved using epoxy resins with the aid of a scaffold and also through stereolithography (SLA) 3D printing technology. These microfluidic devices were composed of intertwined channels, with dimensions of approximately 400 µm, and operated under turbulent flow regimes and presented desirable characteristics such as portability, low cost, ultrafast extraction capability, low consumption of consumables and samples, chemical and mechanical resistance, and long lifespan.

[0024] This device showed fruitful results with respect to the extraction capacity of the aqueous fraction present in crude oil samples with BSW values ​​below 1%. The extraction capacity was evaluated through water conductivity analyses and by analysis of Ca2+, Sr2+(ICP-OES) and (SCM)2- and Cl- ions (ion chromatography). The experimental conditions of dilution with toluene, diluent volume, flow rate, donor and acceptor phase proportions were studied aiming at maximizing the aforementioned extraction process. Example 2: Electronic language.

[0025] For the quantification of ions in water extracted by the device, an electronic tongue was developed, which consists of a multidimensional electrochemical sensor based on a single probe and universal capacitive detection in microfluidic devices. The fingerprints of the electronic tongue were obtained through a single capacitance experiment on ready-to-use, low-cost probes (stainless steel capillaries), which form electrical double-layer capacitors (EDCs) and were connected in parallel in the polydimethylsiloxane microfluidic device (PDMS).

[0026] These devices exhibited low sample consumption and were prototyped using a scalable, green, and zero-cost technique. Petition 870210114821, dated 09 / 12 / 2021, pages 36 / 42 9 / 9 Clean Room. The multidimensional differential capacitance data of the electrical double layer (Cd) obtained by the sensor were confirmed through macroscopic capacitance measurements and analyses using microscopy and spectroscopy methods. The sensor was used in the classification and multi-determination of mixtures of three ions: Ba2+, Ca2+, and Cl-. Statistical data treatment was performed using supervised ML techniques, such as partial least squares (PLS), random trees (RF), linear discriminant analysis (LDA), SISSO (Sure Independence Screening and Sparsifying Operator), among others. The application of SISSO enabled simple and linear data modeling and selected only 2 Cd data points (at different frequencies) that were associated with the ionic charging of the solution in the electrical double layer and the electrode material. The classification accuracy in the validation samples was 100.0%.The regressions used for multi-determination showed a high correlation across the entire range of metal ion concentrations studied (R2> 0.9996), with an accuracy of 100.0%.

[0027] It should be noted that, although the present invention has been described with respect to the accompanying drawings, it may undergo modifications and adaptations by those skilled in the art, depending on the specific situation, but provided that it is within the inventive scope defined herein. Petition 870210114821, dated 09 / 12 / 2021, pages 37 / 42

Claims

1 / 2 Claims 1- PORTABLE MICROFLUIDIC SYSTEM FOR ANALYSIS IN PETROLEUM SAMPLES, characterized by comprising: microfluidic chips configured to extract an aqueous phase from a petroleum sample having a BSW value of less than 1%, wherein the microfluidic chips comprise microfluidic channels comprising capacitive sensors and the microfluidic chips are configured to operate under turbulent flow; a smartphone-controlled potentiostat configured to analyze impedance using data from the capacitive sensors; and syringe pumps configured to provide flow through the microfluidic chips. 2- SYSTEM, according to claim 1, characterized in that the microfluidic chips are constructed by polymerization and scaffold removal (PSR) methods, soft lithography or 3D printing technologies. 3- SYSTEM, according to claim 1, characterized in that the microfluidic chips comprise silicone, or thermoplastics, or epoxy or acrylic resins. 4- SYSTEM, according to claim 1, characterized in that the capacitive sensors comprise stainless steel capillaries. 5- SYSTEM, according to claim 1, characterized by the capacitive sensors having a spacing of 200 μm between them. 6- SYSTEM, according to claim 4, characterized by the stainless steel capillaries being short-circuited with copper parts, obtaining a parallel association of capacitors. 7- SYSTEM, according to claim 4, characterized by poly(vinyl chloride) hoses connecting stainless steel capillaries to each other to complete a microfluidic circuit. 8- SYSTEM, according to claim 1, characterized by the capacitive sensors having four or eight pairs of capacitors in parallel. Petition 870260044110, dated 11 / 05 / 2026, page 44 / 47 2 / 2 9- SYSTEM, according to claim 2, characterized by the microfluidic chips obtained by soft lithography comprising interdigitated flat gold capacitors deposited on glass plates by physical vapor-phase evaporation techniques. Petition 870260044110, dated 11 / 05 / 2026, pp. 45 / 47

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