Method of high-viscosity oil well development and operation

FIELD: oil and gas industry.

SUBSTANCE: method of high-viscosity oil well development and operation involves landing of tubing string with well pump with power cable to the well, and landing of capillary tube parallel to the power cable and attached to external surface of the tubing string by clamps. Oil or oil-containing reservoir fluid is produced. Chemical reagent is injected to the well from a tank by a metering pump through the capillary tube. Power cable is inserted to the well through cable gland. Power cable and capillary tube are protected against direct contact with internal well surface by protectors. Electric heater with extension unit, well pump with power cable and sleeve with radial hole to which the capillary tube is connected are inserted into the tubing upwards from the bottom at the wellhead. Electric heater extension unit is connected to the power cable of well pump. The tubing is landed to the well so that its shoe is located at least 2 m lower than bottom of high-viscosity oil reservoir, and electric heater is facing perforation interval of the high-viscosity oil reservoir. At the wellhead, power cable is connected to well pump and electric heater control stations and inserted to the well through cable gland. Capillary tube is inserted to the well through sealed side tap of the well X-mas tree. Electric heater is actuated, and a process break is made for 8 hours to heat bottomhole zone of reservoir in the perforation interval and high-viscosity oil heating at the inlet of well pump. After the process break, well pump is launched simultaneously with the metering pump supplying high-viscosity oil flux via the capillary tube through the radial hole in the sleeve to inner space of the tubing above the well pump.

EFFECT: enhanced well yield, reduced load in the well pump.

1 dwg

 

The invention relates to the oil industry, in particular to methods for production of high viscosity oil.

The known method of extraction of heavy oil (patent RU №2410533, IPC EV 43/24, publ. 27.01.2011 in bul. No. 2), namely that is run into the well and fix it production casing with subsequent perforation in the area of the oil layer, the lower tubing and downhole pump, exercise dosage flow into the annulus of low-viscosity material, ensuring the reduction of oil viscosity, dilute heavy oil flowing into the well through the perforations of the production casing, low-viscosity substance, raise the diluted heavy oil downhole pump at the wellhead and served diluted oil in the collection and preparation of oil, in this case, use double column concentrically arranged and fixed relative to each other columns of tubing, annulus which serves low-viscosity substance in the mixing node, fixed in the lower part of the column of pipes of larger diameter, for dilution of flowing from the well flow heavy oil.

The disadvantages of this method are:

- first, the inefficient use of low-viscosity substances due to the large about�yamam injection in annulus of the mixing node;

- secondly, the low efficiency of mixing, due to the low quality of mixing low-viscosity substances with high viscosity oil and, as a consequence, the increased load on the downhole pump;

- thirdly, the high financial and material costs for implementation of the method (two columns of tubing, mixing, etc.).

Also known a method of extraction of heavy oil (patent RU №2062868, IPC EV 43/22, publ. 27.06.1996 in bul. No. 18) by gravy in the annulus of a diluent, wherein the diluent used in the composition in the following ratio of components, wt.%:

- anionic surfactant - 0,3-0,7%;

- nonionic surfactant - 0,8-1,2%;

the alkali metal hydroxide 5-40% concentration is 0.5 - 8.3 per cent;

- water chlorellaceae type with a content of chloride salts to 20% - the rest.

The disadvantages of this method are:

- first, the inefficient use of diluent in connection with its high flow feeding into the annulus of the borehole;

- secondly, the poor quality of liquefaction without preheating of the heavy oil at the reception of the downhole pump;

- thirdly, the deposition of heavy oil on the walls of the tubing and flowline when lifting, and also high load on wells�th pump.

The closest in technical essence is a method of production of high-wax oil (patent RU №2366811, IPC EV 43/22, publ. 10.09.2009 in bul. No. 25), including the descent into the well of the column tubing with downhole pump with a power cable and capillary tube, spasennoy into the well in parallel with a power cable and fixed to the outer surface of the column of pump-compressor pipes lasami, extraction of the product - oil or oil-containing formation fluid by lifting her from the well of the column tubing with a downhole pump, the flow of chemical from the tank into the well by a pump with a flow rate of 0.3-5.0 kg per 1 ton of extracted product through a capillary tube, lowered into the well and secured to the outer surface of the column tubing with an inner diameter of 3-7 mm at pressures up to 40 ATM that is connected over the entire length of the borehole with the power cable, perform the input of the capillary tube and the power cable into the well through a sealed cable entry and protection from direct contact with the inner surface of the well through protectors, and as hiragana use reagent "glade".

The disadvantages of this method are:

- firstly, the low efficiency of well operation, this is because in bottom-hole zones� layer, where is dosed chemical reagent, oil is "cold", and in this state it selects the downhole pump, so the rate of reaction of a chemical reagent with low oil, and the rate of oil extraction downhole pump high, so only partial exposure to a chemical reagent "glade" at a dose of 0.3-5.0 kg per 1 ton of produced product;

- second, high-viscosity oil gets on the reception of the downhole pump in a partially dissolved state, this reduces performance and increases the load on the downhole pump due to the high viscosity of oil and, consequently, increase the cost of electricity per 1 m3the extracted oil;

- thirdly, as lifting of heavy oil is partially dissolved paraffin is deposited on the inner walls, narrowing the flow area of the column tubing and discharge tubing.

The technical objectives of the proposals are to increase the efficiency of operation of wells with heavy oil, improving the productivity of the well and reducing the load on the downhole pump and the exclusion of deposits of heavy oil on the inner wall of the column tubing and flowline.

The technical problem solved by way of exploration and exploitation of wells with high�owasco oil, including the descent into the well of the column tubing with downhole pump with a power cable and capillary tube lowered into the well in parallel with a power cable and fixed to the outer surface of the column of pump-compressor pipes lasami, extraction of the product - oil or oil-containing formation fluid by lifting her from the well of the column tubing with a downhole pump, the flow of chemical into the well from the reservoir to the pump through a capillary tube, input power cable into the well through a tight cable gland, the implementation of the protection of the power cable and capillary tube from direct contact with the inner surface of the bore protectors.

What is new is that at the wellhead column of pump-compressor pipes upwards equip the heater with an extension cord, submersible pump with a power cable and a sleeve with a radial hole, to which is attached a capillary tube, wherein the extension of the electric heater is connected to a power cable downhole pump, flush the column tubing in the well so that her Shoe was located at least 2 m below the soles of the reservoir with extra-heavy oil, and the heater was located opposite the perforated interval of the reservoir with high viscosity oil with�charger cable at the wellhead is connected to the control stations of the downhole pump and the electric heater and injected into the well through a tight cable gland, a capillary tube is introduced into the well through the side arm sealed wellhead equipment of the well, start to work the heater and produce technological exposure for 8 h for the heating of bottom-hole formation zone in the perforated interval and warm-up of high-viscosity oil at the reception of the downhole pump when the time technological exposure at the same time start in work of a downhole pump and a metering pump that supplies a diluent for heavy oil in the capillary tube through the radial hole in the sleeve into the inner space of the column tubing above the downhole pump.

The drawing shows a method of exploration and exploitation of wells with high viscosity oil.

The proposed method is implemented as follows.

Before the development and exploitation of wells 1 heavy oil at the wellhead 1 column of pump-compressor pipes 2 from the bottom up with electric heater 3 with extension 4, borehole pump with 5 power cable 6 and the clutch 7 with a radial hole 8, to which is attached a capillary tube 9, wherein the extension 4 of the electric heater 3 is connected to a power cable 6 downhole pump 5.

As the electric heater 3 is used downhole stationary heater brand SNT(n)-20 or SNT(n)-35, produced by LLC "ESCO�geolabel" (G. Pskov, Russia). For example, use stationary heater brand SMM(n)-20, having the following technical characteristics:

- rated power - 20 kW;

- outer diameter - 120 mm;

- length - 3300 mm.

The heater has an adjustable capacity, which depends on the temperature of the fluid (heavy oil), in which it is placed.

Thus, in operation, the electric heater when the temperature of heavy oil in the bottom hole formation zone above the nominal temperature, the heater resistance increases, which reduces the output power of the heater and reduce the temperature of heavy oil in the bottom hole formation zone. Conversely, when the temperature of heavy oil in the bottom hole formation zone below the rated temperature of the heater reduces its resistance, resulting in increased output power of the heater and raise the temperature of heavy oil in the bottom hole formation zone.

As the downhole pump 5 is used with the installation electroencephalo pump, such as a brand IOVNBA-30-1000 production company "Borets" (Moscow, Russia).

On the outer surface of the column tubing 2 separate lasami (not shown) is attached a capillary tube 9 and power cable 6 and protect them on� direct contact with the inner surface of the borehole with the help of the protectors 10.

As an extension 4 use heat-resistant cable extender brand UB-10/25-02, produced by LLC "PskovGeoKabel" (Pskov).

Down the column tubing 2 into the well 1 to the Shoe 11 were located at least 2 m below the sole 12 of the reservoir 13 with extra-heavy oil, and the heater 3 was opposite the perforated interval 14 of layer 13 with high viscosity oil. Such an arrangement improves the efficiency of heating of high-viscosity oil.

Power cable 6 at the wellhead 1 is connected to control stations 15 and 16 respectively of the electric heater 3 and the downhole pump 5 and injected into the wellbore 1 via a sealed cable gland 17.

The capillary tube 9 is introduced into the well 1 through the side arm sealed 18 x-Mas tree wellhead 1.

Then proceed to the exploration and exploitation of wells with high viscosity oil.

For this trigger to work the heater and produce technological exposure for 8 h with the aim of warming up the bottomhole zone of reservoir 13 in the perforated interval 14 and heating of heavy oil entering the intake of the well pump 4, for example, to a temperature of 60°C.

In operation, the electric heater 3 when the temperature of heavy oil in the bottom hole formation zone 13, for example, up to 65°C, i.e. above the temperature of 60°C, electroni�ewetel 3 increases its resistance, which leads to the reduction produced by the electric heater 3 power, whereby the temperature of the heavy oil in the bottom hole formation zone 13 is reduced. Conversely, when the temperature of heavy oil in the bottom hole formation zone 13, for example, up to 55°C, i.e. below the rated temperature 60°C, the heater 3 reduces its resistance, which leads to the increase produced by the electric heater 3 power, whereby the temperature of the heavy oil in the bottom hole formation zone 13 is increased.

For example, the temperature is 60°C is the optimum temperature for heavy oil, with which it has optimal physico-chemical characteristics (viscosity, fluidity, density) at the reception of the downhole pump, which allows to reduce the load (the cost of electricity, wear and tear of the pump) at the downhole pump 5.

At the end of time technological exposure 8 h at the same time run into this downhole pump 5 and the pump 19, the feed diluent for heavy oil in the capillary tube 7 through the radial hole 6 in the sleeve 5 into the inner space of the column tubing 2 above the downhole pump 4.

As a diluent for heavy oil using any known chemical composition, for example a hydrocarbon solvent "MIA-prom" to�th of the tank 20 is fed from the pump 19 through the capillary tube 9 with a flow rate of 0.1-0.5 kg per 1 ton of produced product (for example, 0.3 kg per 1 ton of produced product) under pressure, for example, 3.0 MPa in the column tubing 2 above the downhole pump 5 for the purpose of thinning (viscosity reduction) of heavy oil, preheated in the bottom hole formation zone 13 and pumped downhole pump 5 through the column tubing 2 in exhaust duct (not shown).

Heavy oil effectively diluted in the column of pump-compressor pipes at temperatures above 40°C, which is achieved by heating of the heavy oil in the bottom hole formation zone 13 (see drawing) and is supplied into the column tubing 2 above the downhole pump 3 high-viscosity oil with a temperature above 40°C.

Method of exploration and exploitation of wells with high viscosity oil allows you to:

- to increase well productivity by 2.5 times and reduce the load on the downhole pump 1.5 times by pre-heating of bottom-hole zone of the heater and the receipt of high-viscosity oil in the pump intake in a heated state at a temperature below 40°C;

- to improve the efficiency of liquefaction of heavy oil due to the dosage of chemical reagent (diluent) into the inner space of the tubing string above the downhole pump, in which high-viscosity oil is supplied in a heated condition, which ensures optimal dilution (with�iunie viscosity) of heavy oil, thus accelerating the reaction rate of the dilution of high-viscosity oil;

- to exclude the deposition of high-viscosity oil when lifting it from the hole on the inner wall of the column tubing and flowline due to the action of the diluent for heavy oil.

Method of exploration and exploitation of wells with high viscosity oil, including the descent into the well of the column tubing with downhole pump with a power cable and capillary tube lowered into the well in parallel with a power cable and fixed to the outer surface of the column of pump-compressor pipes lasami, extraction of the product - oil or oil-containing formation fluid by lifting her from the well of the column tubing with a downhole pump, the flow of chemical into the well from the reservoir to the pump through a capillary tube, input power cable into the well through a tight cable gland, the implementation of the protection of the power cable and capillary tube from direct contact with the inner surface wellhead protectors, characterized in that at the wellhead column of pump-compressor pipes upwards equip the heater with an extension cord, submersible pump with a power cable and a sleeve with a radial hole, to which is attached a capillary tube, �ri this extension of the electric heater is connected to a power cable downhole pump, down the column tubing in the well so that her Shoe was located at least 2 m below the soles of the reservoir with extra-heavy oil, and the heater was located opposite the perforated interval of the reservoir with extra-heavy oil, with power cable at the wellhead is connected to the control stations of the downhole pump and the electric heater and injected into the well via a sealed cable entry, and the capillary tube is introduced into the well through the side arm sealed wellhead equipment, wellhead, start to work the heater and produce technological exposure for 8 h for the heating of bottom-hole formation zone in the perforated interval and warm-up of high-viscosity oil at the reception of the downhole pump when the time technological exposure at the same time start in work of a downhole pump and a metering pump that supplies a diluent for heavy oil in the capillary tube through the radial hole in the sleeve into the inner space of the column tubing above the downhole pump.



 

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20 cl, 6 dwg, 3 tbl, 2 ex

FIELD: oil and gas industry.

SUBSTANCE: under the method of development of oil deposits with nonuniform permeability comprising successive injection via the injection well of the water suspension containing polymer, mud powder and SAS solution, prior to the suspension injection in the deposit the initial intake of the injection well is determined under pressure in water line ands water mineralisation; in water with salinity level 0.15-40 g/l complex action SASs with pour point not exceeding minus 30°C and kinematical viscosity 35-50 sSt are used, i.e. water-alcohol solution of non-ionic SAS-monoalkyl esters of PEG at the following ratio wt %: specified SAS 0.001-1.0, specified water rest, suspension and SAS solution are injected in volume ratio (1-3):1 depending on initial intake of the injection well - at intake 200-400 m3/day - 1-2:1, 400-500 m3/day - 2-3:1, over 500 m3/d - 3:1, between suspension and SAS solution water with salinity level 0.15-40 g/l or water suspension of polyacrylimide with concentration 0.0001-0.1 wt % is injected. Under another option during this method in water with salinity level 40-300 g/l the complex SAS with pour point minus 40°C max is used, containing complex action SAS with pour point minus 30°C max. and kinematical viscosity 35-50 sSt - water-alcohol solution of non-ionic SAS - monoalkyl esters polyoxyethylene glycol 90 wt % and alkyldimethylbenzylammonium chloride 10 % at following ratio of components in wt %: specified SAS 0.001-1.0, specified water - rest, suspension and SA solution are injected to the deposit in volume ratio (1-3): 1 depending on initial intake of the injection well at water line pressure - at intake 200-400 m3/day - 1-2:1, 400-500 m3/day - 2-3:1, over 500 m3/day - 3:1, and between suspension and solution the water with salinity level 40-300 g/l or water suspension of polyacrylimide with concentration 0.0001 0.1 wt % are injected.

EFFECT: increased oil recovery of the deposit.

2 cl, 4 ex, 4 tbl

FIELD: oil and gas industry.

SUBSTANCE: under method of oil deposit development comprising determination of the injection well intake, oil recovery via the production wells, and injection via at least one injection well of the water dispersion of the water-soluble polymer and alkali metal hydroxide, this dispersion contains in wt %: water-soluble polymer 0.01-0.05, alkali 0.5-1.0, at definite intake values of the injection well the specified dispersion is injected until injection pressure increasing by 20-30%, its flushing in the deposit by the injected water in volume of tubing plus 1.0 m3, alkali composition in volume 10-30% of volume of injection of the specified dispersion is injected until specific intake decreasing by 10-20% and achievement of the injection pressure not exceeding the maximum permitted pressure on production string and production deposits, the specified compositions at specified water salinity under each of three options, and flush by water in volume 10-15 m3.

EFFECT: increased oil recovery of deposits and watercut reduction of production wells, spreading of process abilities.

3 cl, 1 ex, 2 tbl

FIELD: oil and gas industry.

SUBSTANCE: method envisages the usage of aqueous solutions of binary mixtures - inorganic or organic nitrate or hydrate of alkali metals, which are injected through individual channels. The method includes the mounting of equipment in wells at the selected area of a deposit. Each well is equipped with devices to control the temperature, pressure and composition of reaction products in a real time mode. Formation areas in vicinity to the well with a volume of at least 20 m3 are heated preliminarily up to a temperature of at least 100°C by injection of at least 2 t of binary mixture reagents. Cyclic heating of the formation area in vicinity to the well with a volume of at least 100 m3 and weight of 250 t is made up to a temperature of at least 140°C due to a reaction of at least 12 t of the binary mixture reagents. At that the first level of explosion safety is ensured by the alternation of injection of saltpetre solution portions, 1 t each, with portions of industrial water of at least 0.05 t each. The second level of explosive safety in the borehole is ensured by the continuous control and monitoring of the reaction process with the temperature limitation in the well bore below the pre-blasting temperature. This temperature is determined against signs of the reaction self-acceleration at recorded charts of time-temperature and time-pressure curves. In case of these signs the injection of a saltpetre decomposition initiator is stopped to the well. Further injection of the saltpetre solution with the weight of at least 10 t is made to the preheated formation. At that the third level of explosive safety is implemented in the reaction process in the formation, which is catalysed by the heat accumulated during the previous cycles. The third level of explosive safety is ensured by a ratio of the weight of the saltpetre injected to the pores and fractures of the formation to the weight of the rock. The ratio is equal mainly to 1 to 20. Low explosive probability, close to zero, is ensured by a mixture of 95 wt % of rock and 5 wt % of saltpetre. The injection of reagents at all cycles is made at continuous temperature control in the reaction zone and pressure and temperature control in the zone near the packer and in the process of the reagents injection for the purpose of timely cessation of the reaction when the parameters of the reaction exceed limits of permitted modes.

EFFECT: improved efficiency of oil production at worked-out deposits with an increased production safety.

4 cl

FIELD: oil and gas industry.

SUBSTANCE: this invention is related to production of oil-in-water emulsions with low viscosity during operations with oil. The method for reduction of apparent viscosity for hydrocarbon fluids occurring at oil extraction and transportation includes contact of the above hydrocarbon medium with effective quantity of composite containing at least one polymer with at least 25 mole percent of cationic monomers. The invention has been developed in dependent claims.

EFFECT: increase in oil production.

15 cl, 9 ex, 4 tbl, 4 dwg

FIELD: oil and gas industry.

SUBSTANCE: treatment method of underground hydrocarbon-containing formations involves the following: a) provision of a composition including a thickening initiator measuring pH, and a polymer capable of hydration in a certain pH range; b) pumping of a composition with pH value beyond the limits of the above pH range; c) activation of an action of pH thickening initiator for displacement of pH composition to the above range of its values, and d) provision of a possibility of increasing viscosity of the composition and shaping of a plug. According to another version, a processing method of underground hydrocarbon-containing formations involves the following: a) provision of a composition containing a polymer capable of hydration in a certain pH range; b) pumping of the composition with pH value beyond the limits of the above pH range; c) provision of a pH changing thickening initiator; d) activation of the action of the thickening initiator for displacement of pH composition to the above range of its values, and e) provision of a possibility of increasing viscosity of a composition and shaping of a plug. The invention has been developed in dependent claims.

EFFECT: improving efficiency of initiation and control of plug formation.

15 cl, 5 ex, 3 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to oil production, particularly, to from underground oil deposits. In compliance with this invention, at least one production well and one injection well can be used. Temperature distribution in the zone between said wells is analysed. In case temperature is distributed between said zones so that minimum temperature makes at least 20°C, maximum temperature does not exceed 320°C, while their difference makes at least 20°C, aqueous gel-forming preparations are injected via injection well that contain one or several chemical components. These preparations after injection in the deposit form gels under the effects of deposit temperature. Said preparations differ in type and/or concentration of chemical components. Chemical components and/or their concentration are selected to make gel-forming temperature and/or geol-forming time of the second and, if required, any other injected portion, differ from portions injected there before.

EFFECT: higher efficiency of oil extraction due to levelling of injectivity.

19 cl, 4 tbl, 7 dwg

FIELD: mining.

SUBSTANCE: invention relates to mining and can be used for development of hydrated gas accumulations, heat treatment of well working area and recovery of hydraulic connection between bed and well. Proposed device comprises two heater cases, water feed system including two discharge valve arranged in second case. Additionally this device comprises oil-well tubing (OWT) connected with water feed pipe with pump and water tank, heat-resistance packer arranged above said cases, voltage regulator and distributor with OWT joint assembly arranged along its axis. Said distributor has tubular dielectric inserts and adapter with bore aligned with tubular insert bore. Note here that conductor top section is connected with power cable cores via adapter. Second case incorporates discharge valves arranged in its top section and is filled with working fluid and arranged outside said first sealed case. Said first case accommodates perforated electrode discs while central tubular conductor incorporates zero electrodes fitted in electrode gaps outside said heat-resistant insulators. Electrode discs are rigidly coupled with central conductor and isolated by heat-resistant insulators fro heater first case filled with conducting fluid. Said first case has extra pressure and level gages, emergency pressure valve and bottom bushings. Note here that heat-resistant packer is arranged between distributor and second case while OWT is connected with first case via second case.

EFFECT: higher intensity of thermal processing, expanded operating performances.

3 dwg

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