RU2358093C1 - Method of processing bottomhole zone of well - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention can be implemented for activation or recovery of operation of oil and gas wells by means of thermal-chemical treatment and cleaning borehole environment from asphalt-resinous and paraffin sediments of various kinds. The method of processing bottomhole zone of well consists in lowering flow string - FS through a casing pipe into a treated interval of well; notably, uncontrolled valve-plug - UVP is secured on pins on the lower end of FS; further, as far as lowering of catalyst goes, the method consists in filling hydrogen peroxide and acetate buffers divided one from another with UVP, in creating back pressure by means of filling a gap between flow string and casing pipe with water; and in building pressure in FS; after jump of pressure conditioning of process is performed and back pressure is relieved; via FS water is pumped into the treated interval of the well; as catalyst; 5% water solution of copper sulphate and suspension of ferroplatinum in benzene or kerosene, or 5% water solution of manganese and suspension of cuproplatinum in benzene or kerosene are filled into FS one after another - the said solution of copper sulphate first, then the said suspension of ferroplatinum, or the said solution of manganese, then the said suspension of cuproplatinum; hydrogen peroxide is stabilised with common soap or starch; after hydrogen peroxide, but before water filling there is performed filling of additional reagent - 5% water solution of hydroquinone, with separation of the said hydrogen peroxide from the said suspension and hydroquinone solution by means of UCP and acetate buffers.

EFFECT: increased efficiency of bottomhole zone processing and utilisation of released energy, also reduced costs for well bottomhole zone processing.

1 dwg

Description

The invention relates to the oil industry and can be used to activate or resume the operation of oil and gas wells by thermochemical treatment and cleaning the near-wellbore space from tar and paraffin deposits of various kinds.

A known method of heat treatment of the bottom-hole zone of a well using hydrogen peroxide (Beiles J.X., A new method of heat treatment of the bottom-hole zone of a well using hydrogen peroxide, "Oil and Gas Technologies", No. 5-6, 1998). The method involves the injection into the formation of hydrogen peroxide in the amount of approximately 1564 liters per meter of power of the produced formation, technological exposure for the decomposition of 40% hydrogen peroxide for about 25 days and the subsequent commissioning of the well. Also in the method, options for using 30% and 50% concentrations of hydrogen peroxide are considered. The disadvantage of this method is the long period of technological exposure and shutdown of the oil well, as well as the low efficiency of processing the bottom-hole zone of the well associated with the shallow penetration of reagents into the bottom-hole zone of the well.

A known method of processing the bottom-hole zone of a well, adopted as a prototype (RF patent No. 2279538, E21B 43/25, 07/10/2006, bull. No. 19). A method for processing a bottomhole zone of a well includes a descent into a workout interval of a well through a casing of a tubing and a heat-generating substance, pressurization, technological shutter speed of a well and a depressive effect on a heated treatment zone, according to the invention, an uncontrolled valve is fixed on the studs on the lower end of the tubing a plug that forms a container with the interior of the tubing, and as it descends into the tubing hydrogen peroxide is poured, after which an acetate buffer neutral to hydrogen peroxide is supplied, which is separated from it by a second uncontrolled valve plug, then a 5th manganese solution and water are supplied, while the density of the acetate buffer is higher than the density of the manganese solution, and the density of the manganese solution is chosen more water density, after lowering the tubing in the processed interval of the well create a back pressure filling the gap between the tubing and casing with water, then create pressures e in the tubing, after which, through the tubing, water is pumped into the treated interval of the well, and after technological shutdown, the back pressure is removed and the bottom-hole zone of the formation is depressed by washing it with an aerated acetate buffer. The disadvantage of this method is the lack of efficiency in processing the bottom-hole zone of the well associated with shallow penetration of reagents into it.

The technical result of the method is to increase the efficiency of processing the bottom-hole zone of the well due to the deeper penetration of reagents into the bottom-hole zone of the well.

The technical result is achieved by the fact that in the method of processing the bottom-hole zone of the well, including the descent into the processed interval of the well through the casing of the tubing with an uncontrolled valve plug fixed to the studs at its lower end, filling as the catalyst is descent, hydrogen peroxide, acetate buffers with their separation from each other by uncontrolled valve plugs, water, creating back pressure by filling the gap between the tubing and casing with water, create pressure in the pump-compressor a quarrel pipe, after the jump of which technological soaking is carried out and the backpressure is removed, and water is pumped through the tubing into the treated interval of the well, according to the invention, a 5% aqueous solution of copper sulfate and a suspension of ferroplatinum in gasoline or kerosene or 5% are used as a catalyst an aqueous solution of manganese and a suspension of cuproplatinum in gasoline or kerosene, poured into the tubing one after the other - first, the specified solution of copper sulfate, then the specified suspension of ferro latins or first the indicated manganese solution, then the specified suspension of cuproplatinum, hydrogen peroxide is used stabilized with laundry soap or starch, after which, before pouring water, an additional reagent of a 5% aqueous hydroquinone solution is filled, separating the specified hydrogen peroxide from the specified suspension and hydroquinone solution with an uncontrolled valve plugs and acetate buffers.

The application of the proposed method in comparison with the prototype can improve the efficiency of processing the bottom-hole zone of the well due to a deeper penetration of reagents into it.

The method of processing the bottom-hole zone of the well is illustrated in the drawing, where:

1 - tubing;

2 - casing;

3 - uncontrolled valve plug, fixed with studs on the lower end of the tubing 1;

4 - the processed interval of the well;

5 - downhole filter;

6 - hydrogen peroxide;

7 - the second uncontrolled valve plug;

8 - acetate buffer;

9 - 5% aqueous solution of hydroquinone;

10 - water;

11 - emergency valve;

12 - control valve;

13 - pressure gauge;

14 - pump;

15 reservoir;

16 - a catalyst, a suspension of ferroplatinum in gasoline or, respectively, a suspension of cuproplatinum in gasoline or kerosene;

17 - 3rd uncontrollable valve plug;

18 - catalyst 5% solution of copper sulfate or 5% solution of manganese.

Native platinum (ps), a group of platinum minerals that are disordered natural solid solutions of Fe, Cu, Ni, lr, Rh, Pd, Sn, Os, Ru, Au, Ag, Bi, Pb in platinum. Usually they contain 2-3 basic (mineral-forming) metals and various amounts of impurity metals. Their main element is platinum; in the crystal structure it is a solvent metal; its structure is inherited by P. Atoms of minor mineral-forming and impurity elements are statistically distributed in the inherited structure of platinum, as if dissolving in it. The following PS minerals possess similar crystal structures: solid solutions of Fe in Pt - polyxene (2.5–11.9 weight% Fe) and ferroplatinum (12.0–28.1% Fe); lr in Pt is iridic platinum (10.4-37.5% lr); Pd in Pt - palladium platinum (19.4-40.0% Pd); Sn and Pd in Pt are palladium stannoplatinum (16-23% Sn and 17.2-20.9% Pd). The content of impurities in minerals P. s. reaches: in polyxene - 8.8% lr, 6.8% Rh, 6% Pd, 3.3% Cu and 2.3% Ru; in ferroplatinum, up to 14.3% Ni, 14% Cu, 12.9% Pd, 7.5% lr, 5.8% Rh and 3% Bi; in iridic platinum - up to 11% Os, 4% Pd and 2.5% Ru; in palladium platinum - up to 3% Au; in palladium stannoplatinum - up to 2.5% Bi. Polyxene and ferroplatinum with an Rh content of more than 4% are called rodium platinum, ferroplatinum with a content of more than 7% Cu - cuprous ferroplatinum or cuproplatinum; ferroplatinum, in which more than 3% Ni, is sometimes called nickel platinum. Ferroplatinum and polyxene are the most common minerals P.S. The predominant part of the precipitation of ferroplatinum and polyxene and a density of 13100 to 21500 kg / m ³ , the smallest - ferroplatinum (13100-16000 kg / m ³ ) and palladium stannoplatinum, the largest - pure natural platinum. Native platinum is a catalyst for the reaction of hydroquinone and hydrogen peroxide. The most effective for a number of indicators (for example, the lowest density) are ferroplatinum, cuproplatinum and palladium stannoplatinum. To carry out the operations of the method, native platinum is crushed to a size less than the minimum pore diameter (approximately 60-70 mesh) of the processed interval 4 to ensure unhindered, deep and uniform penetration of reagents into it. Then crushed native platinum is added to kerosene or diesel fuel in the required amount (about 2-5 vol.%), Depending on the volume of the processed interval 4 and its thermophysical properties, after which a suspension of ferroplatinum or cuproplatinum is created using, for example, ultrasound, after which served in the well. Kerosene and diesel fuel have the necessary properties for the preparation of a sufficiently stable suspension of ferroplatinum or cuproplatinum. The injection volume of kerosene or diesel fuel is taken from the condition of ensuring deep penetration of a suspension of native platinum into the processed interval 4.

A 5% aqueous solution of hydroquinone is used as the main reagent. Hydroquinone (para-dihydrosibenzene) has the chemical formula C ₆ H ₄ (OH) ₂ . These are light gray crystals, well soluble in water. Hydroquinone is used as an intermediate in the manufacture of dyes, a developing substance in photography, an antioxidant, and a polymerization inhibitor. When hydroquinone interacts with hydrogen peroxide in the presence of native platinum, a reaction will occur with the release of heat. To ensure a sufficiently effective reaction, a 5% hydroquinone solution should be used (a higher or lower concentration will not lead to the desired effect). The injection volume of a 5% hydroquinone solution is taken based on the porosity of the treated interval 4 with the condition of providing a more complete coverage of the zones of residual oil saturation.

Copper sulfate (copper sulfate), CuSO ₄ , colorless crystals dissolve in water. CuSO ₄ × 5H ₂ O crystallizes from aqueous solutions - copper sulfate (bright blue), which is used in agriculture (for pest control and for dressing grain) and in the preparation of mineral paints. A 5% aqueous solution of copper sulfate is used in conjunction with a suspension of ferroplatinum as a catalyst to increase the reaction temperature. The injection volume is taken at the desired reaction temperature.

As an additional catalyst, you can use a 5% aqueous solution of manganese, which allows to increase the heat of decomposition of the solution in the oil reservoir. A solution of manganese is supposed to be used in conjunction with cuproplatinum.

The method of processing the bottom-hole zone of the well is as follows. On the casing pipe 2 into the processing interval 4 of the well, the tubing 1 is lowered with an uncontrolled valve plug 1 fixed to its lower end with a pin, sealing it. As the tubing 1 is lowered, a predetermined volume of catalysts 16 and 18 is poured into it, for which a 5% aqueous solution of copper sulfate and a suspension of ferroplatinum in gasoline or kerosene or a 5% aqueous solution of manganese and a suspension of cuproplatinum in gasoline or kerosene poured into the tubing one after the other. Then, acetate buffer 8 is poured and a second uncontrolled valve plug 7 is installed and hydrogen peroxide 6 is supplied. After supplying hydrogen peroxide 6, an uncontrolled valve plug 17 is installed and acetate buffer 8 is poured. Then a 5% aqueous solution of hydroquinone and water are added. After the descent of the tubing 1 into the processed interval of the borehole 4, counter-pressure is created by filling the gap 10 between the tubing 1 and the casing 2 with water 10. Then create pressure on the internal capacity of the tubing 1 using the pump 14. After the pressure surge caused by the cut of the studs of the uncontrolled valve plug 3, fixed by a pressure gauge 13, the water 10 is pumped into the processed interval 4 of the well through the tubing 1, taken based on the required processing depth of the treated interval 4 wells. After technological exposure, the back pressure from the gap between the tubing 1 and the casing 2 is removed and a depressive effect is applied to the bottomhole zone of the well by washing it with drilling fluid collected on the surface in the reservoir 15. Acetate is used as a buffer fluid 8 neutral to hydrogen peroxide a buffer having a chemical formula of the form CH ₃ COOH + CH ₃ COONa (5% solution), which will increase the safety of the process and reduce the cost of oil production. To prevent the occurrence of critical pressures during the technological operations of the method, an emergency valve 11 and a control valve 12 are installed.

Injecting in a given volume of hydrogen peroxide 6 directly through the tubing 1 can lead to premature decomposition of hydrogen peroxide 6 directly in the pipe 1, since it interacts with the well fluid containing hydrocarbons and produced water. In addition, hydrogen peroxide 6 is in direct contact with the walls of the tubing 1, and iron oxides are catalysts for the decomposition reaction. Therefore, it is proposed to place a predetermined volume of hydrogen peroxide in a container formed by the internal space of the tubing 1 and plug valves 7 and 17 located in the tubing 1. The plug valves 7 and 17 are made, for example, of elastic or brittle material. To prevent the occurrence of a reaction, hydrogen peroxide is stabilized with soap or starch and additionally separated on both sides, in addition to plug valves 7 and 17 with acetate buffers 8. When installing the lower end of the tubing 1 with reagents in the treated interval 4 of the well, the annulus (between the casing 2 and tubing 1 with pipes) are filled with water 10 and the wellhead is closed (sealed) to create back pressure with hydrostatic pressure, ensuring effective penetration of agents in the bottomhole zone of the well. During the reaction with a 5% aqueous solution of hydroquinone in the presence of a 5% aqueous solution of copper sulfate and a suspension of ferroplatinum in gasoline or kerosene or a 5% aqueous solution of manganese and a suspension of cuproplatinum in gasoline or kerosene, poured into the tubing one after another, during the decomposition of hydrogen peroxide 6, various decomposition products are released with the evolution of temperature, which increase the mobility of oil and significantly reduce its viscosity. During the reaction, the pressure at the wellhead rises. As it begins to fall at the wellhead, the annulus opens. To create a depressive effect on the bottom-hole zone of the formation and remove colmatants, molten paraffins, and also asphalt-resinous deposits in the tubing 1, aerated drilling fluid is supplied to create circulation and clean the bottom-hole zone of the formation similar to the well development process. After that, the well is put into operation.

The application of the proposed method for processing the bottom-hole zone of the well provides the following advantages:

- improving the efficiency of processing the bottom-hole zone of the well;

- improving the efficiency of use of released energy;

- reducing the cost of processing the bottom-hole zone of the well.

Claims (1)

A method for treating a bottomhole zone of a well, including a descent into a work interval of a well through a casing of a tubing with an uncontrolled plug valve fixed to the studs at its lower end, filling in as the catalyst is descent, hydrogen peroxide, acetate buffers with their separation from each other uncontrolled plug valves, water, creating back pressure by filling the gap between the tubing and casing with water, creating pressure in the tubing, after which Slow down the process and remove back pressure, and pump water through the tubing into the treated interval of the well, characterized in that a 5% aqueous solution of copper sulfate and a suspension of ferroplatinum in gasoline or kerosene or 5% aqueous solution are used as a catalyst manganese and a suspension of cuproplatinum in gasoline or kerosene, poured into the tubing one after another - first, the specified solution of copper sulfate, then the specified suspension of ferroplatinum or first the specified solution Rhana, then the specified suspension of cuproplatinum, hydrogen peroxide is used stabilized with laundry soap or starch, after which, before pouring water, an additional reagent is filled - a 5% aqueous solution of hydroquinone, separating the specified hydrogen peroxide from the specified suspension and hydroquinone solution with uncontrolled plug valves and acetate buffers.