Laser irradiation device for catalysis in coordination reactions

Abstract

The present invention relates to adapting a laser system in a reactor for applying laser radiation to promote the thermal catalysis of the coordination reaction of barium sulfate (BaSO4), strontium sulfate (SrSO4) and CaCO3 for application in the fields of drilling and completion, as well as in lifting and drainage systems; in this case, the purpose is to remove scale at an appropriate temperature to complex and subsequently dissolve salt scale in equipment of subsea production systems.

Description

Technical Field

[0001] The present invention relates to adapting a laser system in a reactor for applying laser radiation. In this case, the laser radiation is used to promote the thermal catalysis of the coordination reaction of barium sulfate (BaSO4) and / or strontium sulfate (SrSO4) salts with a chelating agent, with the goal of dissolving these salts. The main purpose of the invention is to apply this technology to equipment used in the fields of oil well drilling and completion, as well as in the fields of oil lifting and discharge, and in offshore production systems. Background Art

[0002] At a water depth of 700 meters, the temperature of the seabed is approximately 4°C. Therefore, in marine production systems at water depths greater than 700 meters, the oil temperature upon reaching the surface is between 9°C and 15°C. In oil fields located within this water depth range, salt scale may form, for example, in risers, production lines, manifolds, wet Christmas trees (WTCs), and production strings. In such cases, chemical treatments for removing these scales limit the complexation reaction to a temperature of approximately 20°C.

[0003] Subsea equipment used in oil production streams, such as wet Christmas trees, production lines, and manifolds, is submerged in the seabed. Heat exchange between these equipment components and the produced fluid causes them to cool down along the distance from the well to the SPU. This decrease in produced fluid temperature can lead to the precipitation of compounds such as paraffin, asphaltenes, and salt scale within these equipment components. In extreme cases, complete blockage can occur where these compounds have accumulated, resulting in production losses from the producing well requiring intervention. Specifically, in the case of salt scale, one of the treatments for clearing the blockage involves the use of chelating agents (e.g., EDTA, DTPA).

[0004] Typically, chelating agents form soluble complexes with cations present in inorganic scale, thereby promoting its dissolution and, therefore, its removal. Salt scale removal treatments are typically performed by pumping a chelating solution through the scaled subsea equipment. Regarding the use of DTPA as a chelating agent, the kinetics of the complexation reaction depend, among other variables, on a temperature range of 60°C to 80°C, preferably 80°C. Therefore, the reduction in temperature caused by heat exchange with fluids produced by the subsea equipment affects the efficiency of the reaction.

[0005] The solution achieved by the present invention is to pump the descaling solution at the appropriate temperature to carry out the complexation reaction in the equipment of the subsea production system.

[0006] In operations using chelating agents to remove salt scale, the solution is typically pumped through a gas lift line into a section of a production line or other equipment where deposits are present and then soaked in. This operation is limited in that the chelating solution cools due to heat exchange with the lift gas line.

[0007] In this way, the need to heat the solution is determined, wherein it is proposed in the present invention to promote the thermal catalysis of the coordination reaction of barium sulfate (BaSO4) and / or strontium sulfate (SrSO4) by using laser radiation.

[0008] US Pat. No. 5,282,995 discloses a method and chemical solution for removing scale deposits of barium sulfate and strontium sulfate. The solution consists of a chelating agent, EDTA (ethylenediaminetetraacetic acid) or DTPA (diethylenetriaminepentaacetic acid), and a catalyst or synergist in an aqueous medium with a pH of 8 to 14. EDTA and DTPA, or their alkaline salts, are the most commonly used chelating agents. The catalyst employed is composed of anions of organic and inorganic acids, such as fluoride, oxalate, persulfate, dithionate, hypochlorite, and formate. When the chelating solution comes into contact with a surface containing scale deposits, the deposits dissolve significantly faster.

[0009] Document BR120120267438 discloses a device for removing gas hydrates from the surfaces of equipment used in seabed production and exploration. The device comprises a main container, a power cord connected to each other, and a laser device connected to an adjustable focus collimator within the container. The laser emits a wavelength between 200 nm and 930 nm. When the radiation strikes the seabed exploration equipment, it heats the hydrates, which in turn heats the hydrates by conduction, causing them to decompose. The front cover of the container has a window for the interface between the container and the aqueous medium, and this window is provided with an anti-reflective film. A method for removing gas hydrates from the surfaces of equipment used in seabed production and exploration using this tool is also described.

[0010] Document BR1120170139065 discloses an anti-biofouling lighting system configured to prevent or reduce biofouling formation on sensitive components. During use, the component susceptible to fouling is at least partially movable and at least partially exposed to water. Biofouling formation is prevented by illuminating the component with anti-fouling light. The anti-fouling lighting system includes at least one laser light source configured to generate and apply the anti-fouling light to the component. The system is arranged so that the component susceptible to fouling is at least partially movable relative to the laser light source during use.

[0011] When seeking solutions to challenges, there are limitations in processing in horizontal wells due to, for example, the difficulty of pumping chemical products with limited locations and temperatures above 20°C. This invention proposes the application of laser radiation to the catalysis of coordination reactions associated with the dissolution of salt scale, aiming to improve the efficiency of descaling treatments in marine production systems.

[0012] There is no document in the prior art that discloses the use and controlled application of laser light to heat complexing solutions to promote thermocatalysis of reactions with barium sulfate (BaSO4) and / or strontium sulfate (SrSO4) salts as in the present invention. Summary of the Invention

[0013] The present invention relates to the development of laser catalysis technology, which aims to increase the temperature in the reaction medium by adapting a laser system in a reactor to apply laser radiation to the coordination reaction of a chelating agent with a scaling salt.

[0014] It is proposed to use laser radiation in a controlled manner to generate the necessary heating for the reaction of the chelating agent with the salt scale of BaSO4 (barium sulfate) and / or SrSO4 (strontium sulfate) or even CaCO3 (calcium carbonate) to occur at the right temperature to achieve better efficiency, thereby making the process of removing scale from equipment in subsea production systems more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will now be described in more detail with reference to the accompanying drawings, which, being schematic and not limiting of the scope of the invention, illustrate examples of its embodiments. In the drawings, there are:

[0016] - Figure 1 The subsea production system consisting of the well production system, WTC and subsea pipeline leading to the SPU (stationary production unit) is shown;

[0017] - Figure 2 shows the thermal profile of water in the Campos Basin;

[0018] - Figure 3 Metal-EDTA complexes are shown;

[0019] - Figure 4 The carbonate thermal decomposition curve is shown;

[0020] - Figure 5 Barite dissolution tests in 0.18 M DTPA, EDTA, CDTA and DOTA in a stirred system at 40°C are shown;

[0021] - Figure 6 The chemical structure of the chelating agent is shown;

[0022] - Figure 7An experimental setup comprising a reactor provided with stirring and irradiation of the reactor wall is shown;

[0023] - Figure 8 An experimental setup is shown which includes a reactor provided with stirring and in which a solution in the reactor is subjected to external irradiation;

[0024] - Figure 9 An experimental setup is shown which includes a reactor provided with stirring and in which a solution in the reactor is internally irradiated;

[0025] - Figure 10 Shown is a scheme for adapting a laser pointer to the reactor of the present invention;

[0026] - Figure 11 A diagram showing an adapter on the lid of a reactor of the present invention;

[0027] - Figure 12 A clamp-on laser pointer adapter coupled to a reactor is shown;

[0028] - Figure 13 A clamp-on laser pointer adapter coupled to a reactor lid is shown;

[0029] - Figure 14 A laser pointer adapter is shown coupled to a reactor using threads and a nut;

[0030] - Figure 15 Shown is a laser pointer adapter attached to the reactor lid with threads and a nut. DETAILED DESCRIPTION

[0031] The present invention relates to the development of catalytic technology, which aims to increase the reaction temperature by adapting a laser system in a reactor to apply laser radiation to the coordination reaction of a chelating agent and an inorganic salt.

[0032] exist Figure 1 The subsea production system consists of a well production system, a WTC, and a subsea pipeline to the SPU. The seabed temperature decreases until a depth of approximately 700 meters. From this depth, the temperature remains at approximately 4°C. Figure 2 Shown is the thermal distribution of water in the Campos Basin.

[0033] The complexing agent used to dissolve salt scale is EDTA (ethylenediaminetetraacetic acid). EDTA is an organic compound that acts as a chelating agent and forms soluble complexes with various metal ions. EDTA acts as a hexadentate ligand; that is, it can complex with metal ions through six coordination sites (i.e., after the four H+ leave the carboxyl group, through four carboxylate anions (-COO-) and through two N), such as Figure 3 As shown in .

[0034] Another commonly used chelating agent is DTPA (diethylenetriaminepentaacetic acid). DTPA is a polycarboxylic acid amino acid consisting of a diethylenetriamine backbone and five carboxymethyl groups. The molecule can be considered an extended form of EDTA and is used in a similar manner. It is a white solid that is soluble in water.

[0035] DTPA conjugate base has a high affinity for metal cations. Therefore, considering that each nitrogen center and each COO- group count as a coordination center, DTPA 5- Pentavalent anions have the potential to form octadentate ligands. The formation constant of their complexes is about 100 times that of EDTA ("Roger Hart, 2005"). As a chelating agent, DTPA binds to metal ions and can form up to eight bonds. However, with transition metals, they form fewer than eight coordination bonds. Therefore, after forming a complex with the metal, DTPA still has the ability to bind other reagents. The literature shows that DTPA ("Wang et al., 2002") is the most effective complexing agent for dissolving barium sulfate ( Figure 5 ), ("Lakatos; Szabó, 2005; Jordan et al., 2012"). Studies on the application of laser radiation to rocks are known in the literature. In fact, the application of lasers to carbonate rocks was developed to verify possible performance gains in drilling operations and to improve the efficiency of perforating operations ("Valente et al., 2012"). The formation of tunnels in carbonate rocks is possible due to the thermal decomposition reactions of carbonates in the range of 600°C to 780°C. Figure 4 , which shows the mass loss curve as a function of the exposure temperature of a carbonate sample. In the area of ​​the sample where the laser radiation was applied, calcium carbonate (CaCO3) decomposes into calcium oxide (CaO) and carbon dioxide (CO2).

[0036] The present invention reports the possibility of applying laser radiation in a controlled manner, promoting the necessary heating for the reaction of the chelating agent with the scale salts of BaSO4 (barium sulfate) and / or SrSO4 (strontium sulfate) or even CaCO3 (calcium carbonate) to occur at the appropriate temperature to achieve higher efficiency, thereby making the descaling process more efficient.

[0037] The application of lasers for descaling operations in subsea production equipment has the following advantages:

[0038] Use chemical treatment to improve descaling efficiency;

[0039] Controlling heat exchange in deep water depths during descaling processes;

[0040] ·Coordinate with production recovery and maintenance in oil well production systems.

[0041] Barite dissolution tests in different chelating agents such as DTPA, EDTA, CDTA and DOTA at a concentration of 0.18 M and a temperature of 40°C using a system with a continuous stirring time of 7 hours can be found in Figure 5 middle.

[0042] The chemical structures of the chelating agents DTPA, EDTA, CDTA and DOTA can be found in Figure 6 middle.

[0043] Table 1 shows the solubility parameters of sulfate in different chelating agents:

[0044]

[0045] Notes:

[0046] kc is determined by the Arrhenius equation:

[0047] kc=A exp(-E a / RT)

[0048] kc = reaction constant (hours -1 )

[0049] A = frequency factor (hours -1 )

[0050] E a = activation energy (kcal / mol)

[0051] R = ideal gas constant (1.987 cal / mol.K)

[0052] T = temperature, Kelvin

[0053] For the application of DTPA as a chelating agent in descaling salt in subsea production systems, the appropriate temperature for the complexation reaction kinetics is 60°C to 80°C.

[0054] Can be used Figure 7 、 Figure 8 and Figure 9 One of the devices described in carried out laboratory tests of laser application for heating the reaction of barium sulfate with complexing agents such as DPTA, DOTA, EDTA, CDTA and mixtures of these chelating agents.

[0055] Heating can be performed in at least three ways: The first way is by applying laser radiation directly to the outside of the wall of the flask or reactor containing the mixture of BaSO4 sample and chelating agent, such as Figure 7 The second way is by applying laser radiation in a flask inside the reactor or outside the reactor to focus directly on the reaction mixture, as shown in Figure 8The third approach is to adapt the laser to be applied directly into the reactor ( Figure 9 In all cases, continuous stirring was maintained to homogenize the heat distribution in the mixture. The experiment should be started with the reaction system at a temperature of about 20°C and heated until it reached 80°C.

[0056] Example 1 : Experiments on direct application of laser radiation to the outside of the flask wall ( Figure 7 ).

[0057] This arrangement has the advantage of not exposing the collimating lens to the vapors generated by heating the sample. On the other hand, it also has the disadvantage that the analysis of the interaction of the photons with the solute (degradation assessment) will be affected by the attenuation imposed by the flask wall, and there is a risk of flask breakage, although this risk can be minimized by adjusting the laser focus. Another disadvantage posed by the attenuation of the flask wall is the reduced efficiency of the heat generated by the laser on the reaction medium.

[0058] Example 2 : Experiments on applying laser radiation directly to samples without coupling to a reactor ( Figure 8 ).

[0059] This arrangement has the advantage of allowing the evaluation of photon-solute interactions, as there are no obstacles promoting attenuation. A disadvantage is the risk of fouling the collimating lens. To minimize this risk, in addition to a vacuum system located opposite the collimator, the reactor can be used within an exhaust hood and a ventilation system coupled to the reactor can be used in the area where the laser collimator is applied, thereby removing the vapors generated during heating.

[0060] Example 3 : Experiments on applying laser radiation directly to samples in conjunction with a reactor ( Figure 9 ).

[0061] This arrangement also has the advantage of allowing the interaction of photons with the solute to be evaluated, but has the disadvantage of risking fouling of the collimating lens. To minimize this risk, a system for venting nitrogen or air in a position opposite to the application of vacuum, coupled to the reactor, can be used, in this way promoting the removal of vapors generated by heating the sample.

[0062] Laser power for laboratory applications

[0063] The power of a laser is measured in watts. To calculate the thermal power, the following formula is applied:

[0064]

[0065] in:

[0066] P – Power (w)

[0067] m – mass of water (kg)

[0068] c – specific heat of the substance

[0069] ΔT – Temperature change (k)

[0070] E f -efficiency

[0071] Δt – time interval

[0072] The specific heat of water is the amount of heat required to raise the temperature of 1 gram of water by 1°C, and its value is 1 cal / g°C.

[0073] To calculate the power, it is estimated that the walls of the flask will reflect 25% of the photons emitted by the laser; that is, the efficiency is estimated at 75%. This value depends on the purity of the substances used and may vary.

[0074]

[0075] Kg – kilogram

[0076] Kcal – kilocalories

[0077] K – Kelvin

[0078] J – Joule

[0079] W – Watt

[0080] The laser power required for the coordination reaction of BaSO4 with the chelating agent was sized by calculation. A reaction volume of 1000 ml and a heating time of 10 minutes were considered. Therefore, to achieve a laser power of 500 watts and a wavelength of 900 to 1060 nm, which has high water absorbance, was used to heat the reaction on the benchtop. This is because absorbed light is converted into energy, and higher energy results in higher temperatures.

[0081] An absorption spectrum relates the amount of energy absorbed as a function of the wavelength of the incident radiation.

[0082] Water was used to calibrate the parameters of the laser applied to heat the reaction medium. However, greater efficiency is expected when radiation of the same wavelength is applied above the mixture to complex and subsequently dissolve the barium sulfate as a function of the absorbance of the dissolved species.

[0083] Compatibility between laser and reactor

[0084] The adaptability of the laser coupling to the reactor was evaluated. The laser system selected corresponded to the one that allowed the best possible coupling to the reactor. For reasons of component size, the collimator in the laser pointer had the smallest diameter in this case.

[0085] like Figure 11 As shown in , the laser pointer system coupled to the reactor cover can have two types of adapters: a clamp type and a threaded nut type, as shown in Figure 13 to 1 As shown in 6.

[0086] The clamping adapter is intended to fasten the pen support (holder) to the reactor cover, e.g. Figure 13 and Figure 14 Stainless steel clips will join and secure the upper and lower parts (welded to the reactor cover) to the holder. In this way, we seek to save space in the area above the reactor cover.

[0087] The adapter with threads and nuts is intended to fasten the pen support (holder) to the reactor cap using a Swagelok connector (nut and threads), such as Figure 15 and Figure 16. In addition to being machined on the reactor cover with threads and nuts, this connector will connect and secure the upper and lower parts to the holder. The adapter will be screwed onto the reactor cover via a Swagelok-type connector. In this way, we aim to save space in the area above the reactor cover.

[0088] It should be noted that while the invention has been described with respect to the accompanying drawings, modifications and adaptations of the invention may be made by those skilled in the art according to specific circumstances, provided they are within the scope of the invention defined herein.

Claims

1. A laser irradiation device for promoting thermal catalysis in the coordination reaction of barium sulfate and / or strontium sulfate salts with a chelating agent in equipment of a seabed production system, wherein: The laser irradiation device comprises a laser pen (1) inserted into a pen holder (2), wherein the holder has a flange (7) which is fastened to a flange (8) of the reactor cover (5) by means of fastening screws (6) passing through the reactor cover (5); furthermore, the laser irradiation device has a quartz glass window (3) between the flange (7) and the flange (8), wherein O-ring seals (4) are used both between the flange (7) and the flange (8) and on the reactor cover (5), Wherein, the chelating agent is diethylenetriaminepentaacetic acid, The laser irradiation device provides a laser with a power of P and a wavelength of 900 nm to 1060 nm, so that the coordination reaction reaches a temperature of 60° C. to 80° C., in: P – power, the unit is watt; m – the mass of water, in kilograms; c – specific heat of the substance, which is 1 cal / g℃; ΔT – temperature change, its unit is Kelvin; E f – efficiency, which has a value of 75%; Δt – time interval in seconds.

2. The use according to claim 1, wherein The fastening screw (6) is of a clamping type (9) or a thread (10) and nut (11) type.

3. The use according to claim 2, wherein The thread (10) and nut (11) type fastening screw (6) comprises a fastening part (12) to fit into the adapter of the reactor cover (5).

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