Method for improvement of permeability of saline low-permeability oil formation
FIELD: oil and gas industry.
SUBSTANCE: method involves dilution of salt rock with fresh or subsaline water by cyclic action on the formation, each of which includes pumping of a working agent to the saline oil formation through a well, closure of the well for the time of salt rock dilution, extraction of liquid from the formation through the same well. Cycles of action on the deposit are repeated till full coverage of the saline formation by action before opening of oil deposits contained in it and production of all the extracted oil deposits. Water pumping to the formation is performed at maximum possible constant bottom-hole pressure till reduction of the well water intake capacity by 2-8 times in comparison to its value at the pumping beginning, and extraction of liquid from the formation is performed at minimum possible constant bottom-hole pressure before the liquid with volume of at least 1.1-1.5 volumes of the fresh or subsaline water pumped to the formation earlier is removed to the surface.
EFFECT: increasing permeability of a saline formation throughout the area of its propagation, increasing productivity of production wells, increasing the coverage of the formation by action, volume of the removed oil deposits and acceleration of development rates.
4 cl, 1 tbl
The invention relates to the field of exploration and development of oil deposits of any type, low-permeability rock-collectors are everywhere or on separate sites made halitovym or carbonate-sulphate cement and catagenetic minerals halite, calcite and anhydrite.
The known method of increasing the permeability of the bottom zone of the oil reservoir and the productivity of producing wells by hydraulic fracturing bottom-hole formation zone in the injection into the reservoir of fluid under pressure, under which the seam is split, or bedding planes, or along natural fractures. To prevent closure of cracks after removal of the pressure as fluid is pumped coarse sand (proppant), preserving the permeability of these cracks, thousands of times greater than the permeability of the undisturbed formation. Hydraulic fracturing is carried out at pressures up to 100 MPa, with a large flow rate and using complex and diverse techniques [1, S. 150-159].
However, application of this method allows to increase the permeability of only bottom-hole formation zone (within a radius of 60-70 m), and only in a hydraulic fracture. The permeability of the matrix layer even in the wellbore area is not increased.
There is also known a method of increasing the permeability zone is Lasta, presents carbonate rocks, by the injection of hydrochloric acid, under the influence of which the carbonate rock is dissolved, and the permeability is increased [1, S. 130-135].
However, this method is not applicable for the processing of terrigenous reservoirs and carbonate reservoirs allows to increase the permeability only bottom-hole formation zone.
The known method development lenticular deposits of oil by alternating selection of well production and water injection in the same interval through the barrel of one well. Production of reservoir fluids is performed until reaching the pressure at the bottom hole pressure of the oil saturation gas. Next, the extraction is stopped, and the same perforation interval to maintain reservoir pressure begins pumping water, which occurs until the pressure is restored to the initial level .
The disadvantage of this method of development is its narrow orientation only restore reservoir pressure in well bore zone. The method also ignores the mineralogical composition of the rocks composing the layer, does not assess the impact of alternate selections of well production and water injection on the permeability of the formation, not traced mutual communication system "mineralogical composition of reservoir rocks - sakac the water into the reservoir the permeability of the reservoir cover reservoir effect".
The known method for the development of sedentary (high viscosity) oil by cyclic steam injection into the reservoir, which consists in cyclic steam treatments wells periodic injection of steam into the oil reservoir through the production wells. The goal of technology is to warm up the reservoir and oil in bottom-hole zones of production wells to reduce the viscosity of the oil to increase the oil flow to wells . In the production well pump pairs volume 30-100 tons on a 1 m thick layer. The amount of injected steam must be greater, the greater the viscosity of the reservoir oil. After steam injection well is closed and incubated for one to two weeks, i.e., the period required for the heat exchange process, the capillary counter-current distribution of oil and water in a porous medium. Then the well being exploited in 8-12 weeks. Usually organized 5-8 cycles for three or four years, sometimes 12-15 cycles, after which the effect runs out and no longer justifies the cost [1, S. 113-114].
The disadvantage of this method is its purposeful orientation impact only on the properties of high-viscosity oil, high cost, lack of measures and mechanisms to increase the permeability of the oil-saturated gasolinecolor, impact only on the bottom zone of the well at a rather weak influence on a remote part of the reservoir, resulting in the efficiency of cyclic steam treatment is short-term in nature. The application of this method for the development of oil deposits in saline, low-permeability reservoirs is economically impractical.
It is known that the reservoir rocks and subsalt mislevy oil a number of oil and gas regions (Irkutsk amphitheatre and the Tunguska basin in the Russian Federation, the Triassic province in Algeria, sedimentary basins of Michigan in the United States, the Pripyat trough in the Republic of Belarus) partially completed halitovym or carbonate-sulphate cement and catagenetic minerals halite, calcite, anhydrite [4, 5]. It is also known that during the development of oil deposits in saline formations using water flooding system, including the selection of fluid from production wells and water injection into injection wells, the dissolution occurs catagenetic halite water injected into the saline formation, and removal of dissolved salts with associated water production wells. The process of dissolution of halite accompanied by an increase in velocity filtering of injected water and the permeability of the channels through which filtering occurs. There is also a change in the coverage layer impacts the quality .
Established in  the phenomenon of dissolution of catagenetic halite in saline injected into the reservoir him water, not saturated in NaCl can be used for reconnaissance and enhance the development of oil deposits in saline, low-permeability reservoirs.
The closest to the technical nature of the claimed invention is a method for processing bottom-hole zones of oil reservoir  containing solid salt is sodium chloride (halite), which is injected into her agent, such as water, and at first the water is injected into the volume of the bottom zone, leave the rest at the time of dissolution of the salt, then well spent on spouting. When the initial low degree of filling of the pore space salt water injection into the bottom zone lead to the content of sodium chloride which is shed in water less than 1%, and then produce acid processing bottom-hole formation zone. The resulting water will be disposed of by filing in the conduit injection wells.
The disadvantage of this method is its intended effect only on the bottom zone of the oil reservoir regardless of the permeability of the entire reservoir. It is well known that increasing the permeability of the low permeability of the reservoir in the bottom hole zone of the production well only leads to short-term growth of its productivity.The method is not taken into account the presence in the hollow space of the oil reservoir other salts, for example, anhydrite, which in many cases occurs in conjunction with sodium chloride.
The task of the invention is to increase the permeability of the low permeability of the saline layer on the entire area of its distribution with the purpose of prospecting for oil, increasing the productivity of producing wells, increasing the coverage of the formation impact of increased volume of recoverable reserves of oil and the pace of their development.
The problem is solved by a method for increasing the permeability of saline low-permeability oil reservoir, including solid salt is sodium chloride (halite), implying the dissolution of halite work agent - fresh or brackish water by means of cyclic stimulation, each of which includes the injection of the working agent in saline low-permeability oil reservoir through the well, closing the well at the time of dissolution of halite, the selection of fluid from the formation through the same well, according to the invention cycles impact on the Deposit again to a complete coverage of the saline reservoir impact, opening the contained oil and implementation develop all of recoverable oil reserves, while the injection of fresh or brackish water in the reservoir are at the greatest possible permanent downhole pressure up with is to achieve the capacity of the well is 2 to 8 times compared with its value at the beginning of the injection, and the selection of the liquid from the reservoir is produced at the lowest possible permanent downhole pressure to eject the liquid surface of not less than 1.1 to 1.5 volumes of pumped to the reservoir of fresh or brackish water.
The speed of dissolution of halite and duration of the closure phase of the borehole can be determined by calculation according to the results of model studies of the core.
In addition, the perforated interval of the well can set the low-frequency hydrodynamic pulsator, and the injection of fresh or brackish water in the reservoir can maintain in a mode of low-frequency pulsations with a frequency up to 10 Hz to increase its penetrating ability in the saline reservoir and accelerate the dissolution of salts.
In addition, freshwater or brackish water can be acidified by adding 1-5% hydrochloric acid or acetic acid to increase the solubility of salts (calcite, anhydrite and other carbonate-sulphate impurities) contained in the saline oil reservoir.
In the proposed method, the main impact is aimed at catagenetic halite and carbonate-sulfate incorporation, partially filling the channels of the filter, with a view to their dissolution and removal from the reservoir, resulting in increased permeability of the formation, and after each cycle of development that accounts for the size of a zone of increased permeability of the reservoir increases. In addition, the promotion of water in the reservoir, according to the laws of hydrodynamics, will occur mainly in zones and channels of high permeability, including, including the opening of reservoir rocks with initially elevated reservoir properties. Water injection in saline low-permeability layer, unlike hydrochloric acid and hydraulic fracturing, is a controlled process of dissection and creation of high-permeability channels of the fluid filtration of great length.
The method is as follows.
On the area of distribution of the low permeability layer define at least one low on fluid the well uncovered saline low-permeability layer.
Before injection of fresh or brackish water is acidified by adding 1-5% hydrochloric acid or acetic acid to increase the solubility of calcite, anhydrite, and other carbonate-sulfate inclusions.
In the perforated interval of the well establish low-frequency hydrodynamic pulsator.
The injection of fresh or brackish water in the reservoir to produce the maximum possible permanent downhole pressure in a mode of low-frequency pulsations with a frequency up to 10 Hz to increase its penetrating ability into the formation and acceleration of the process of dissolution of salts.
is akaku water into the reservoir lead to reduced capacity of the well is 2 to 8 times compared with its initial response. Exceptions may be made for shorter duration of water injection in the 1st cycle, after which it is necessary to verify the presence of halite in the oil reservoir.
The rate of dissolution of halite and duration of the closure phase of the wells are determined by calculation according to the results of model studies of the core.
The selection of fluid from the reservoir is produced at the lowest possible permanent downhole pressure. Stop selection, depending on the petrophysical properties of the reservoir and their changes caused by water injection and dissolution of halite, calcite and anhydrite, after removing the surface is not less than 1.1 to 1.5 volumes pumped to the reservoir of fresh or brackish water.
At the stage of selection of the liquid in the absence of its oil composition according to the results of studies of the chemical composition of the extracted fluid to determine the presence of produced water, including hydrogeochemical indicators of oil, and their quantitative values evaluate hydrogeological conditions of formation, preservation and destruction of oil deposits in the zone of influence of the well, and then make a conclusion about the presence in the reservoir oil and the conclusion about expediency of continuing exploration for their detection.
Then move on to a second cycle, including the stages of water injection, closure of SLE is dual completion and selection of fluid from the reservoir.
Depending on the composition of the liquid that is extracted to the surface in the first cycle of operation of the well, on the second and subsequent cycles of the proposed method is used to develop detected (open) oil or for the exploration of new oil deposits in the zone of influence of the well.
If the composition of the extracted fluid oil is not present, then the second and subsequent cycles continue the exploration of deposits until then, until you have determined the hydrodynamic coupling of the well with the oil reservoir or aquifer area.
If at the next stage of the selection process fluid from the reservoir receives inflow of formation water, exploration work in the area of the studied wells ceased.
If at the next stage of the selection process fluid from the reservoir receives inflow of oil, continue to develop deposits on the proposed way up until going to be the profitability of the development.
The invention is illustrated by table, which shows the main results of the modeling of the development of oil deposits in the baseline and the proposed method of increasing the permeability of saline low-permeability layer.
The simulation results obtained on test hydrodynamic model, the parameters of which were taken by analogy with minilevel the oil Deposit Slavenskogo field of Republican unitary enterprise "production Association "Belorusneft".
Madelinemadeline in the plan has dimensions of 1020×1020 m On the model it is approximated by a square grid with a step of 20 m (51 calculation block in the X and Y axes). The reservoir thickness is 9.9 m is implemented on the model in the form of three computational layers of equal thickness. The open porosity of the layer is 5%, the initial permeability is 0.003 μm2the initial oil saturation collector - 85,0%, the saturation - 15,0%. The oil density at standard conditions - 853 kg/m3. Oil reservoir penetrated the entire thickness of one well at a distance of 210 m from the Western and Northern boundaries of the modeled area. Water contact is not installed. All external borders impermeable deposits.
The hydrodynamic model is implemented on the basis of the license of the software complex "Eclipse 100" company "Schlumberger Information Solutions". Simulated development period is 15 years and limited conditional dates with 1.01.12 B.C. 1.01.27, Model development data presented in the table.
In the base case production well is modeled throughout the design time (180 months) as the inner boundary of the first kind with constant bottomhole pressure, which at 10.0 MPa below the initial reservoir pressure in the reservoir. The permeability of the reservoir during the whole period of development of deposits remains constant. Under given initial and boundary conditions, the flow rate of the production well is reduced from 6.61 m3/day is the Achal development to 0.07 m 3/day to the end date of operation. For the whole period of development of the cumulative oil production is 6101 m3(the last column of the table). In the last row of the table shows data for the base variant according to the accumulated volume of oil produced at the end of the first, second and third cycles, which makes it possible to compare the results for the cumulative oil production at the end of each cycle under the proposed method with the baseline option.
To increase well productivity by increasing the permeability of the reservoir according to the invention it produce the injection of fresh or brackish water with 1.01.12, 1.01.13, with a constant bottom-hole pressure of 10.0 MPa greater than the initial reservoir pressure reservoir (cycle 1, stage 1 - water injection). Increase formation permeability due to the dissolution of halite water injected into the reservoir, a test model was simulated by increasing the permeability of the formation at the first and subsequent cycles of development of deposits in accordance with the front water movement in the reservoir. In the cell model, the water content reached 70% or more after the water injection, the permeability was increased in 2 times. Stage stop well for dissolution of halite in fresh water (cycle 1, stage 2) hydrodynamic model was not replicated. Test calculations showed that the approximations n the impact on the overall results.
The selection of fluid from the reservoir calculated by the model with constant bottomhole pressure at 10.0 MPa less than the initial reservoir pressure in the reservoir. Duration phase extraction liquid, completing the first development cycle (cycle 1, stage 3), is 24 months (1.01.13 on 1.01.15).
The simulation of the second and third cycles of increasing the permeability of the formation and development of reservoir (injection of fresh water into the reservoir and the subsequent selection of the liquid) was carried out as described above.
Comparing the simulation results with the base case demonstrates the effectiveness of the proposed method in its application to the development of saline low-permeability oil reservoir.
Sources of information
1. Rollin, F., Altunina L. K. Methods and technologies of enhanced oil recovery for collectors of Western Siberia: a Training manual. - Tomsk: Publishing house of TPU, 2006. - 166 C.
2. Samoilov, M. C., Binkow S. L., Antonov, M. S., Khalikov, C. E. Experience in mathematical modeling of development of oil reserves lenticular deposits // Petroleum engineering, 2012. No. 11. - S. 76-81.
3. Surguchev M. L. Secondary and tertiary methods of enhanced oil recovery. - M.: Nedra, 1985. - 308 S.
4. Makhnach A. A. Catagenesis and groundwater. - Minsk: Science and technology, 1989. - 335 S.
5. Mulak Century. Century. and other Hydrochemical methods of analysis and control design of oil is s and gas fields. / Century Century Mulac, C. D. Poroshin, Y. P. Hattenberger, L. A. Minzyamal, O. I. Leukhina. - M.: GEOS, 2007. - 245 C.
6. EN 2139987 C1 IPC E21B 43/00, E21B 43/22, publ. 20.10.1999,
|The timing and impact indicators on Deposit||The cycles and stages of exposure on Deposit||The basic version|
|Cycle 1||Cycle 2||Cycle 3|
|Will continue. stage, months.||to 12.0||24,0||24,0||48,0||24,0||48,0||180,0|
|Downhole pressure., MPa||40,0||20,0||40,0||20,0||40,0||20,0||20,0|
|AVG. press. in deposits at the end of the stage, MPa||30,5||26,7||38,0||21,0||386,1||20,2||20,2|
|Maximum flow rate of SLE. oil, m3/d||-||5,6||-||8,5||-||6,3||6,61|
|The rate of SLE. oil in the early stage, m3/d||-||0,3||-||2,0||-||3,0||6,61|
|The rate of SLE. oil at the end of stage m3/d||-||the 3.8||-||1,1||0,3||0,07|
|The rate of SLE. water in the early stage, m3/d||-||28,1||-||50,1||-||61,9||-|
|The rate of SLE. on the water at the end of stage m3/d||-||0,0||-||0,1||-||0,02||-|
|Pickup SLE. in the early stages, m3/d||12,9||-||21,3||-||33,1||-||-|
|Pickup SLE. at the end of stage m3/d||6,4||-||the 3.8||-||4,2||-||-|
|The accumulated volume of pumped water, m3||3107||-||11998||-||25567||-||-|
|The accumulated volume of oil produced, m3||-||3377||-||9630||-||13562||6101|
|The accumulated volume of extracted water, m3||-||1563||-||6927||-||16089||-|
|The accumulated production volume of fluid, m3||-||4940||16557||29651||6101|
|The accumulated volume of oil produced in the baseline at the end of the calculation phase, m3||-||3537||-||5700||-||6101|
1. The way to increase pron is zeemote saline low-permeability oil reservoir, includes solid salt is sodium chloride - halite, which consists in the dissolution of halite work agent - fresh or brackish water by means of cyclic stimulation, each of which includes the injection of the working agent in saline low-permeability oil reservoir through the well, closing the well at the time of dissolution of halite, the selection of liquid from the reservoir through the same hole, characterized in that the cycles of the impact on the Deposit again to a complete coverage of the saline layer exposed to the opening therein oil and implementation develop all of recoverable oil reserves, in this case, the injection of fresh or brackish water in the reservoir are at the greatest possible permanent downhole pressure to reduce the capacity of the well is 2 to 8 times compared with its value at the beginning of the injection and extraction of liquid from the reservoir is produced at the lowest possible permanent downhole pressure to eject the liquid surface of not less than 1.1 to 1.5 volumes of pumped to the reservoir of fresh or brackish water.
2. The method according to p. 1, characterized in that the rate of dissolution of halite and duration of the closure phase of the wells are determined by calculation according to the results of model studies of the core.
3. The method according to p. 1, characterized in that the interval perforat and well set low frequency hydrodynamic pulsator, and the injection of fresh or brackish water in the reservoir are in the mode of low-frequency pulsations with a frequency up to 10 Hz to increase its penetrating ability in the saline reservoir and accelerate the dissolution of salts.
4. The method according to any of paragraphs.1-3, characterized in that the fresh or brackish water is acidified by adding 1-5% hydrochloric acid or acetic acid to increase the solubility of salts (calcite, anhydrite and other carbonate-sulphate impurities) contained in the saline oil reservoir.
FIELD: oil and gas industry.
SUBSTANCE: this invention refers to hydrocarbon production from a fractured reservoir. The method of hydrocarbon production from a fractured reservoir, which matrix is oil-wetted, includes at least one injector and producer, both interconnected to fractures and the matrix, consists of the following stages: a) injection primarily through the injector of a solution of surfactants, which increase viscosity and penetrate to the network of fractures interacting weakly with the matrix and creating a plug in situ in order to reduce significantly and selectively permeability of fractures and to facilitate passage of the solution at the stage b) to the matrix; b) injection secondarily through the injector of a solution of surfactants, which are capable to interact with the matrix thus preferably improving its oil-wetting and oil recovery, at that the above solution flows preferably through the matrix and upon the latent period of at least 24 hours; c) injection thirdly through the injector of water that leads to increase of surface tension, saturation of matrix, oil recovery and, upon solving of the above plug formed at the stage a) by oil, oil displacement to the producer. Invention is developed in dependent claims.
EFFECT: improvement of oil recovery.
17 cl, 3 dwg, 2 ex
FIELD: oil and gas industry.
SUBSTANCE: invention is related to the oil industry and can be used for the development and oil recovery improvement for inhomogeneous oil pools by waterflooding. In the development and oil recovery improvement method for the inhomogeneous oil pools including waterflooding with cyclic injection of a cross-linked alkali-polymer clayey quartz compound to the pool, wherein a water polymer solution cross-linked by chrome acetate is used as the polymer basis, at first the water solution of hydrolysed polyacrylamide (PAA) and chrome acetate cross-linker is injected, then the solution is flushed by water and a water suspension of a modified Lamco clay and quartz sand mixture is injected and then flushed by water, the above water solution comprises additionally caustic ash with the following concentration of the components, wt %: hydrolysed polyacrylamide PAA 0.01-0.30, chrome acetate 0.1-0.6, caustic ash 0.05-0.1, a ratio in the modified Lamco clay and quartz sand mixture.
EFFECT: improving oil recovery of the inhomogeneous and water-flooded pools at the late stage of development, reducing water cut of the product.
1 ex, 1 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: proposed process comprises pre-flushing of the well with organic solvent. Then, organic solvent and film-forming anger are injected in the well. Film-forming agent represents 5-30% solution of boiler fuel in hydrocarbon solvent in amount of 0.5-2.5 m3/m of the bed perforated depth. Organic solvent buffer is used in amount of 3-6 m3 and aid solution in amount of 1-5 m3/m of perforated bed depth, injected fluids being injected thereafter in the bed.
EFFECT: higher efficiency of processing.
2 tbl, 4 ex
FIELD: oil and gas industry.
SUBSTANCE: invention is related to the oil industry, in particular, to development methods of oil pools with reservoirs difficult to recover using thermal oil recovery methods. In the development method of an oil pool with reservoirs difficult to recover, which is implemented by the injection of an oxidiser and water fringes to injectors and by oil extraction from producers, before the oxidiser injection to the formation an aqueous solution of carbonic acid normal salt with a water-soluble acrylic polymer and an acid bath are injected to the formation. Besides, the injection of the aqueous solution of carbonic acid normal salt with the water-soluble acrylic polymer and the acid bath to the formation is made by turns, in cycles, in order to obtain the required volume of the fringe. When gas is broken to the producers, the highly permeable intervals of the formation are isolated.
EFFECT: improved efficiency of the method at the development of oil pools with normal and high viscosity due to the generation of the area with the required oil saturation, reduced fuel consumption for maintenance of the combustion process, more complete usage of the oxidiser and safer development of the pool with inhomogeneous and fractured reservoirs, increased coverage of the formation area with the combustion and displacement process.
FIELD: oil and gas industry.
SUBSTANCE: in the viscous oil production method in order to form a catalyst bed at a bottomhole with permeability at least equal to the permeability of the bottomhole formation zone, clay drilling mud is injected preliminarily to the bottomhole formation zone, at that the mud comprises clay particles - a catalyst of hydrogen peroxide decomposition and sand particles, which ensure permeability of the catalyst bed or a suspension of the mix containing by wt %: catalyst of hydrogen peroxide - powder of two- or three- or four-valence metal oxide -20-50, sand or proppant - the remaining part. Then injection is made to the formation simultaneously of 10.0-50.0% of an aqueous solution of hydrogen peroxide and 1.0-30.0% of an aqueous solution or a suspension of bicarbonate alkali metal and/or ammonium bicarbonate, and then a water buffer is injected from the formation pressure maintenance system with subsequent oil pumping out.
EFFECT: increasing the extraction degree of viscous oil.
5 tbl, 5 ex
FIELD: oil and gas industry.
SUBSTANCE: method of oil formation treatment includes running of a string with a packer to the well, setting of the packer above the oil formation and subsequent injecting and flushing through the string to the oil formation of hydrocarbon solvent and acid agent in volumes exceeding filtration resistance in the formation zone remote from the well over the same value in the bottomhole zone, process withheld and removal of waste reaction products from the treated area by depression impact on the well. Then the pipe string at the well mouth below the packer is equipped with impulse liquid pulsator. At that a valve is mounted between the packer and liquid pulsator. An ejector pump with a feedthrough accessory is mounted above the packer. The string is run in to the well so that the packer is placed above the formation. Hydrocarbon solvent is injected to the string in pulsed mode, the packer is set, and hydrocarbon solvent is flushed to the formation by process fluid under pressure not exceeding the permitted pressure to the formation. The packer is released and the well remains under exposure. Then the well is washed out and acid solution is injected to the well, the packer is set, acid solution is flushed to the formation by process fluid under pressure not exceeding the permitted pressure to the formation. The packer is released and the well remains under exposure. After exposure period the valve is actuated and impulse liquid pulsator is cut off. The packer is released, the string is run in additionally so that radial openings of the valve are opposite the formation; the feedthrough accessory is removed from the ejector pump and a blind plus is installed instead. Then the packer is set, and reaction products are extracted by process fluid injecting along the string through the ejector pump and the well is completed through its tubing-casing annulus above the packer.
EFFECT: increased efficiency of the bottomhole zone treatment, excluded damage of the well casing string.
FIELD: oil and gas industry.
SUBSTANCE: invention is related to oil and gas producing industry, in particular, to recovery method for natural filtration properties of the reservoir deteriorated during the well construction. The method lies in injection of the complex surfactant (ComSAS) mixed up with a solvent to the productive formation interval upon washing of the string with the subsequent flushing of ComSAS aqueous solution up to static balanced condition and process withhold. At that RaiR ComSAS aqueous solution in 1.5-2.5% concentration is used as ComSAS mixed up with the solvent. Completion of the productive formation is made in environment of the same RaiR aqueous solution with the same 1.5-2.5% concentration. Upon completion operations 2/3 of the above CompSAS aqueous solution volume is flushed to the well and the well is abandoned till it is developed by swabbing.
EFFECT: improved efficiency of the formation simulation, increased productivity of the well as well as reduced period of the well placing on production.
FIELD: oil and gas industry.
SUBSTANCE: invention is referred to oil and gas industry, in particular, to methods limiting water influx to oil and gas wells and balancing injectivity profile. In the formation permeability control method consisting in sequential injection of emulsifying or suspension plug to the formation through an injector or producer; treatment is made simultaneously from the injectors side and producers side at the site; the compound with the following composition, wt %, is used as the emulsifying plug: Addinol-10 4.0, CaCl2 4.0, stock oil 20.0, process water 72.0, and the following composition is used as suspension with the following ratio of the components, wt %: natural fine chalk stone of M-3 brand - 5.0, process water - 95.0.
EFFECT: reduced permeability of flooded reservoir with highly permeability.
2 ex, 3 tbl
FIELD: oil-and-gas industry.
SUBSTANCE: invention relates to oil production. Proposed method comprises lowering the string into well to inject acid compounds via said string into bed. Prior to processing, geophysical survey is executed to randomly divide borehole into intervals depending upon intensity of inflow and type of extracted fluid. Assembly with two packers on string is lowered into processed interval. Intervals are processing with isolation of every interval by assembly with two packers: interval with high-intensity water inflow is processed the first by injection of back water-oil emulsion at flow rate of 6-12 m3/h. Interval with mixed inflow of water and oil is processed the second at injection of back oil-acid emulsion at flow rate of 24-36 m3/h. Oil-saturated interval is processed the first by injection of acid at flow rate of 54-66 m3/h.
EFFECT: decreased well stream watering by 20-70%, higher oil yield.
3 ex, 1 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: invention relates to oil and gas industry. In compliance with this method, CTU flexible pipe is lowered in unplugged well to processed bed roof to inject there through the methanol in amount of 1-2 m3 per 1 m of processed interval and back gasified hydrocarbon emulsion in amount of 2-3 m3 per 1 m of processed interval that contains the following components in wt %: oil - 75-85, 18-20% solution of hydrochloric acid, non-ionic surfactant, disolvan - 0.5-1.5, water making the rest. Emulsion is injected into the bed to the depth of mudded zone including fractures and pores and pores of rocks in well bottom zone but not over 1.5 m in radius, by inert nitrogen. Said emulsion is held for its reaction with mudding particles in perforation interval, in fractures and pores of said well bottom zone for 2-4 hours. Then, gas inflow from the bed is initiated to remove reaction wastes along with gas to fuel spray. Then, the well is operated to design mode to put the well in operation.
EFFECT: prevented destruction of well bottom zone.
FIELD: oil and gas industry.
SUBSTANCE: invention relates to submersible pumping units for operation of wells, where it is necessary to increase the differential pressure drawdown, without deepening of submersible pumping unit, and/or with unsealed production casing. The unit for oil-well operation includes the tubing string, electric submersible cable, electric submersible pump, the hydroprotection and submersible electric motor of which are encapsulated in the pressure-tight housing, which is tightly closed on the housing of the input unit of the electric submersible pump, the liner consisting from the pipe string the top part of which through the bushing is tightly connected to the bottom part of the pressure-tight housing, and in the bottom part of the liner the branch pipe with external sealing elements is located. The unit contains at least one packer with internal through passage channel with the diameter allowing to pass through the packer the tool, equipment and instruments, without extracting the packer. The sealing unit for the tight connection with the branch pipe of the liner is located either in the packer housing, or in the device below or above the packer.
EFFECT: improvement of performance of recovery of formation fluid from the wells.
FIELD: oil and gas industry.
SUBSTANCE: unit includes the wellhead equipment, concentrically located tubing strings of two diameters with electrocentrifugal and jet pumps in the production casing of the well. There is a separating camera located in the bottom part of the well bore under the centrifugal pump, equipped with the sealing housing. The unit has the channel for passing of the separated oil connecting the annular space above the pump with the separating camera, and inlet holes for entering the separated water. The sealing housing of the electric centrifugal pump from below in the interval of the separating camera is equipped with the inlet device made as the liner damped from below. The liner is divided into sections with the inlet holes. At the level of each inlet hole the liner is equipped with a glass used as a hydraulic lock for petroleum drips and inlet of water from the separating camera. The inlet holes are located in a single row along the liner and are made with the diameters diminishing in each subsequent section upwards. The gap between the housing and production casing of the well is used as a channel for passing of petroleum drips. The tubing string of the greater diameter in the wellhead equipment is connected to the water line, and tubing string with the smaller diameter - with the oil line. The bottom of the string with the smaller diameter is tightly installed in the upper cylindrical camera of the commutator installed in the tubing string with the greater diameter at the depth below the working level of fluid in the well. The commutator has vertical peripheral channels for passing through them of the upward flow of water and bottom cylindrical camera for placement of plug-in jet pump, the output of which is interconnected with the upper cylindrical camera. Meanwhile the possibility of supply of working fluid into the jet pump from the centrifugal pump, and pumped off fluid - along the side channel of the commutator from the annular space of the well through the check valve located from the external party of the commutator is provisioned.
EFFECT: downhole separation of oil from extracted product of the well and separate lifting of oil and water to the surface during inter-well pumping-over of water for maintaining of formation pressure.
2 cl, 3 dwg
SUBSTANCE: as per proposed method, a pressure brine-carrying formation is developed by means of a well; high-mineralised geothermal brine is removed from it along a production casing string. After that, along an annular space between production and intermediate casing strings, which is interconnected via the wellhead with ground reservoirs and delivery equipment, as well as with an absorption zone formed before development of the brine-carrying formation at the interval of a geological cross-section of the well below the unit of a regional water-tight stratum. Brine is removed during opening, development and further operation of the formation to the absorption zone and the ground reservoirs with a possibility of using a hydraulic mineral potential of the brine from the reservoirs. Protection of the production string against deposition of hard formations on its walls from the produced brine during its movement from the formation to the well mouth is performed by temperature control of the upper part of the string at the interval of probable temperature phase transition due to continuous or periodic pumping along the brine flow in the string with a possibility of heat transfer to it of a heat carrier with initial temperature exceeding expected brine temperatures without any temperature control at the interval of probable temperature phase transition. According to the invention, heat carrier pumping is performed inside the brine lifted along the production string by arranging in the same string of a closed circulation circuit with the heat carrier in the form of service water. This circuit is made in the form of a coaxial heat exchanger drawn in the string to the depth that is not less than the value of phase transition interval. It consists of a heat-conducting vertical cylindrical housing coaxial to the string, closed in the base and provided from above with holes for water supply to the housing. Inside the housing there is a central pipeline with an open lower end that does not touch the base and an upper end opened for water discharge above the well mouth. With that, water is pumped first via an annular space of the heat exchanger, which is formed with the housing and the pipeline, in the direction opposite to the direction of brine lifting via the production string; then, it is supplied via the central pipeline to the heat exchanger outlet. Use of hydraulic mineral potential of the brine is performed with discharge of a less concentrated fluid formed at use together with discharged excess brine from the formation and reservoirs to the absorption zone. Before the fluid is supplied to a common discharge line, it is filtered from mechanical impurities.
EFFECT: enhanced method's efficiency.
5 cl, 3 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: device comprises the string lowered in the well, packer with the flow shutoff device composed of hollow body with bores. Note here that the pipe arranged aligned with its axis and rigidly coupled tuning is provided with top and bottom lines of bores, shear pins and O-rings. Hollow body top end has centring skid. Shear pins are arranged above top line of bores while there above said pipe has thrust ring arranged at spacing equal to that between said top and bottom lines of bores. Hollow body top bores are located above the packer while bottom bores are arranged below the packer. At initial position, top and bottom bores of pipe and hollow body are intercommunicated to communicate above- and under-packer well space with pipe inner space. Pipe shear pins thrusts against the hollow body top end. To shut off product flow from under-packer space this pipe can displace axially relative to hollow body and communicate it with the pipe inner space via the top line of bores. To shut off produce flow from above-packer space this pipe can displace axially downward after destruction of shear pins unless thrust ring thrusts against hollow body top end and above-packer space communicates with pipe inner space via aligned bottom bores of hollow body and top bores of the pipe.
EFFECT: simplified design, unlimited changeover of product flows.
SUBSTANCE: invention relates to mining industry and can be used for operation of problem blocking wells with sucker-rod pumps. The method involves back-and-forth movement and rotation of a sucker-rod string. Downward movement speed of the sucker-rod string changes proportionally to load variation on a wellhead stock. Travel length of the sucker-rod string can be changed proportionally to load variation on the wellhead stock. Rotation of the sucker-rod string can be performed continuously.
EFFECT: possible elimination of blocking of a sucker-rod string without any disassembly of borehole equipment.
3 cl, 3 dwg
FIELD: oil and gas industry.
SUBSTANCE: method includes rising of oil well fluid through a flow column under impact aimed to change physical properties of the fluid. According to the invention impact on oil well fluid is made by electrode heating in a closed working chamber by means of electric power delivery from the ground surface via a multicore electric cable to the electrodes placed inside the working chamber. In result thermal expansion of the oil well fluid and its flowing to the flow column is ensured via a flow channel with low cross section in regard to its length. At that in order to implement filling of the working chamber and electrode heating of the oil well fluid with its further expansion the unit is equipped with a suction valve to ensure delivery of the oil well fluid to the working chamber, with a pressure valve to ensure flowing of the fluid part from the working chamber to the flow column and batch transportation of the fluid to the ground surface and with a shift force valve with ability of its closure upon complete filling of the working chamber with the fluid and its opening upon heating of the oil well fluid up to the preset value.
EFFECT: improving production efficiency due to temperature impact on the produced oil well fluid.
2 cl, 1 dwg
FIELD: oil and gas industry.
SUBSTANCE: invention suggests the method of borehole and wellhead equipment layout for well survey envisaging injection of injection fluid to the formation and extraction of fluids from the formation, which includes running in of a flow string to the well with a jet pump or a circulation valve intended for compressor operation with isolation of the flow string and annular space. At that the tubing shoe is run in up to the level of upper perforation holes or as much as closer to it. The packer is set at distance of 20 metres at most from the tubing shoe, over the packer or as close as possible to it at one of the flow string pipes one or two circulation valves or a jet pump and a mandrel below them with one or two remote (permanent) pressure and temperature quartz sensors for tubular and annular space. The well head is equipped with a packaging arrangement consisting of a lubricator, two wellhead pressure and temperature sensors to control buffer and annular parameters, a choke chamber with an adjustable choke, a multiphase flow meter, a sampler allowing oil, water and gas sampling in conditions of the well operation, a discharge unit comprising two angled bends and two choke chambers. Connection of a feeder is envisaged for pumping of injection fluid or delivery of working agent from a tank to the buffer line or annular space. The line from the feeder is equipped with a branch pipe via the choke chamber with the adjustable choke back to the tank; a flow meter is mounted in the line from the feeder to the well downstream the branch line in order to control volume of the fluid fed to the well. In order to increase reliability of pressure and temperature measurement one or two self-contained or remote pressure and temperature sensors are mounted under the packer. In order to increase accuracy of phase debit measurement in the formation flow at the flow string over the packer or below it a downhole multiphase flow meter is mounted with functions of continuous monitoring of phase consumption as well as function of downhole pressure and temperature measurement.
EFFECT: for the purpose of direct and back circulation in the well bore a direct and return circulation valves are included into composition of the downhole assembly.
4 cl, 2 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: at construction of production well, vertical shaft is drilled through rocks, including unstable mud shale, with entry into productive seam, going-in of production string to productive seam, cementing of annular space and drilling the shaft from production string into productive seam. At exposure of horizon with unstable mud shale, mechanical drilling rate is set not over 6 m/h for drilling with increased flushing fluid flow rate of about of 30-40 l/s using drilling solutions with density of 1.12-1.40 g/cm3. After well shaft drilling, drilling assembly performs cleanup job over well shaft with working of the shaft by rotary machine at rotor rpm of 40-100 rpm. Drilling fluid mixed with fibres in amount of 6-15 m3 is forced through the shaft and drill assembly reciprocates over the length of drive pipe. For well shaft casing operation string is lowered section-by-section. First 400-1000 m long section is lowered to well bottom on drill tool and annular space if cemented in interval from bottom to first section head. Cement is cured to lower production string second section. Sections are coupled, annular space is cemented and cement is cured. Production string is sealed.
EFFECT: ruled out sticking of drill tool in drilling unstable mud shale.
2 cl, 3 ex
FIELD: oil and gas industry.
SUBSTANCE: method lies in periodical repetition of cycles consisting of pumping, frequency search, stopping delivery and accumulation. At that in order to ensure pumping of fluid from the well equal to its influx the pump set is selected with a higher pump capacity in comparison with fluid influx from formation to the well. In process of cycles performance correction is made for pumping-accumulation time ratio depending on results of operation in the previous cycles until pumping-accumulation time ratio stops varying. The moment of stopping delivery is defined by equation of values of current torque at the shaft of a submerged electric motor and reference torque, which is determined preliminary against sudden drop of torque at the motor shaft at the point of stopping delivery at reduction of feed voltage frequency. The device contains a pump set consisting of a centrifugal pump and a submersible electric motor placed in the flow string and suspended at the sting of buried pipes. At that the submersible motor by its conducting cable is coupled to the frequency converter and control unit placed over the ground. Also the device contains a matching transformer, an evaluator of frequency, current, torque and power, a coupling unit, indication and control unit. At that the conducting cable is coupled to the first input-output of the matching transformer, which is coupled by its second input-output to the input-output of the frequency converter. The frequency converter by its second input-output is coupled to the power supply unit and by its third input-output to the first input-output of the evaluator of frequency, current, torque and power, which is by its second is coupled to the first input-output of the coupling unit, which second input-output is coupled to the fourth input-output of the frequency converter and the third input-output is coupled to the first input-output of the master controller, which second input-output is coupled to the indication and control unit. At that the device arranges receipt of all signals to the units placed above ground through the conducting cable directly from the shaft of the submersible electric motor.
EFFECT: improvement of the method efficiency and operational reliability of the device both in low- and high-yield wells.
2 cl, 3 dwg
SUBSTANCE: proposed device comprises casing, extra production string and flow string. Extra production string is used which does not extend to well head. Flow string is equipped with fixed external coupling secured above extra production string and nearby the top of extra production string. Said coupling represents that with OD larger than ID of extra operation string and not larger than OD of standard string gage for casing and with OD-to-coupling height varying from 0.70 to 0.83.
EFFECT: simplified liquidation of failures, accelerated repair.
2 dwg, 2 tbl
FIELD: oil extractive industry.
SUBSTANCE: method includes lowering a tail piece into well with temperature, electric conductivity and pressure sensors placed on tail piece along its length. Pressure sensors are used in amount no less than three and placed at fixed distances from each other. After that, continuously during whole duration of well operation between maintenance procedures, temperature, conductivity of well fluid, absolute value of face pressure and difference of pressures along depth of well in area of productive bed are recorded. Different combinations of pairs of pressure sensors are used for determining special and average values of well fluid density. When absolute pit-face pressure is lower then saturation pressure for well fluid by gas and/or when average values of density deviate from well fluid preset limits and/or when its conductivity deviates from preset limits, adjustment of well operation mode is performed.
EFFECT: higher efficiency, higher safety.