Method of development of oil-and-gas deposits with bottom water |
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IPC classes for russian patent Method of development of oil-and-gas deposits with bottom water (RU 2519243):
 Method of extraction of oil and other formation fluids from reservoir (versions) / 2518684
Invention group is related to the methods of increase of extraction of heavy or viscous crude oil from an underground reservoir and in variants of its fulfilment is especially related to operations of cold extraction from such reservoir. Substance claim: the method involves oil-bearing reservoir rock and has at least one development well and at least one injection well. The method provides for carrying out secondary recovery operations with the use of displacing fluid; at that, density of extracted oil is within ≤30° API, and the method includes the following operations: (a) overinjection of displacing fluid into reservoir rock with Voidage Replacement Ratio (VRR) from 0.95 to 1.11 until Water-Oil Ratio (WOR) of formed fluids is at least 0.25; and (b) underinjection of displacing fluid into reservoir rock with VRR<0.95 until Gas-Oil Ratio (GOR) of formed fluids is at least twice higher of GOR with dissolved gas of initial oil recovered from a well; at that, during water injection, accumulated VRR is kept within 0.6 to 1.25.
 Development method of non-homogeneous oil deposit / 2517674
Development method of non-homogeneous oil deposit includes drilling as per any famous pattern of vertical, horizontal or directional wells. Borders of zones with various permeability are determined. The well pattern is compacted up to the value of 4 ha per a well. A displacement fluid is injected to each zone through injectors and the product is recovered from the formation in each zone through producers. At that zones with different permeability are divided into low permeable, medium permeable and high permeable. Compaction of the well pattern is made only in low permeable zones. At that the ratio of injectors and producers is selected as at least 1:5 in the high permeable zones, from 1:3 up to 1:5 in the medium permeable zones and from 1:1 up to 1:3 in the low permeable zones. When the flow rate at one zone becomes lower than the commercial production hydrofracturing is made at this site. Then permeability is determined at this site and it is referred to the respective zone with determination of the respective number of injectors and producers.
 Device for dual injection operation to two formations of same well (versions) / 2517294
Device is mounted at the flow string and contains a hanger with two packers. In the hanger cavity there are at least two collars with a hermetical cup installed in collars; the cup is made with a thrust to a butt end protrusion of the hanger and this protrusion has longitudinal channels that form an annular space. In the cup wall at both sides of the lower collar there are two units with calibrated flow sections communicating the cup cavity with the upper well formation through the upper union, the annular space between collars and windows made in the hanger wall at one side and with the lower well formation through the lower union, the annular space below the collars and longitudinal channels of the butt end protrusion at the other side.
 Method for production of soft water for injection into bed / 2516531
Invention relates to production of soft water for injection into bed. The method includes: (a) production of soft water by means of (i) delivery of source water having total dissolved-solids content up to 15000 mg/l and polyvalent cations content more than 40 mg/l to the filter containing a layer of cation-exchange resin in polyvalent cation form; (ii) passage of source water through the layer of cation-exchange resin; (iii) output of soft water for injection from the filter, at that polyvalent cations content in water is up to 40 mg/l; (b) regeneration of cation-exchange resin by means of (i) delivery of regenerant solution to the filter, at that the regenerant solution is represented by natural water with high content of salts, high concentration of monovalent and polyvalent cations so that the softening limit for source water is equal up to 40 mg/l of polyvalent cations where the softening limit is defined as the softening coefficient multiplied by concentration of polyvalent cations in source water (mg/l) and where the softening coefficient is calculated in the following way: (molar concentration of monovalent cations in source water)2/(molar concentration of polyvalent cations in source water) : (molar concentration of monovalent cations in the regenerant solution)2/(molar concentration of polyvalent cations in the regenerant solution).
 Procedure for development of deposit of oil in carbonate collectors / 2515741
Penetration of productive strata and subjacent water-bearing beds is made by injectors with subsequent construction and casing perforation, penetration of productive strata by producers with subsequent construction and penetration of the productive stratum, water-flooding of the productive stratum by downhole pumping in injectors from water-bearing beds to the oil-bearing bed, product extraction from the productive stratum through producers. According to the invention water-flooding of the productive stratum is made under permanent pressure with sequential operational delays of injectors less than 4 days. At that pressure compensation by water-flooding at operational delay of the injectors is made due to the closest injectors. In the process of oil production rate decrease, at water-flooding from water-bearing beds pressure compensation is made by water and/or reagents pumping from the mouths of the injectors.
 Oil deposit development method / 2513962
Direction of reservoir-scale fractures is determined, the formation is drilled by vertical and/or inclined wells and downhole splitters as per square grid pattern and five-spot system is formed with drilling in the centre and corners of the system elements by vertical and/or inclined wells and drilling between the central and corner wells in the development pattern of downhole producing splitter with rounded borehole ending, and working fluid injection through injection wells and product recovery through producing wells. If producing wells are flooded the water-flooding interval is identified and water-flooded intervals are isolated. According to the invention, before drilling of the formation sections with total oil-filled thickness of more than 6 m are determined in carbonate reservoirs and/or sections with net oil thickness of 2 m at least in oil zone and at least 4 m in water-oil zone in terrigenous reservoirs. At these sections before drilling of downhole producing splitter direction of reservoir-scale fractures is specified. The downhole splitter is made with semi-ellipse shape which major axis is directed at angle of 30-60° to direction of reservoir-scale fractures with ratio of minor semi-axis to the major semi-axis equal to 0.1-0.8. At that boreholes of producing downhole splitters are made ascending with minimum distance in the lower part up to water-oil contact of 4 m for carbonate reservoirs and 2 m for terrigenous reservoirs and in the upper part with minimum distance of 1 m up to the roof of productive strata.
 Oil deposit development method / 2513469
Method lies in drilling of a deposit by vertical and/or directional injection wells and horizontal producing wells with crossed and mutually perpendicular boreholes, pumping of the working fluid through vertical and/or vertical and/or directional injection wells and oil extraction through producing horizontal wells. According to the invention, producing horizontal wells should be longer than 4 times of the distance between the producing and injection wells so that horizontal producing wells open the lower interlayers at the borehole beginning and ending, and the upper interlayers in the borehole middle part. In perpendicular direction horizontal producing wells open the upper interlayers at the borehole beginning and ending, and the lower interlayers in the borehole middle part. At that horizontal producing wells form a mesh with location of 1-3 vertical and/or directional injection wells in the centre of each cell. At that minimum distance between horizontal producing well in vertical plane is equal to 1 m. To cut off point of working fluid breakthrough to horizontal producing wells water-swellable packers are installed.
 Oil deposit development method / 2513390
According to the method direction of reservoir-scale fractures is determined, drilling of the deposit by producing and injection wells considering direction of natural fracturing of the deposit, injection of working fluid to the injection wells and product recovery from the producing wells are carried out. Horizontal wells are used. Wells are used as elements of square grid pattern. One side of the square grid is placed along the fracturing direction. Horizontal boreholes of producing wells are placed in parallel to each other in staggered arrangement from the centre of one element of square grid pattern up to the centre of the neighbouring element in the grid placed corner-wise, near the roof of the oil-filled formation. In each producing well, in the productive formation, two water-swellable packers are placed, thus dividing the horizontal borehole into three equal parts. Horizontal boreholes of injection wells are placed in the centre of elements between two parallel neighbouring producing wells and made near water-oil contact or the bottom of the oil-filled formation. Producing and injection wells are made with a certain length of their horizontal boreholes to be determined as per the certain analytical expression.
 Oil deposit development method / 2513216
According to the method direction of reservoir-scale fractures is determined, development elements are formed by drilling of horizontal injection wells as per square grid pattern with parallel placement of boreholes and producing downhole splitters with rounded bottomhole ending which are placed around the borehole of each horizontal well. Pumping of working agent is done through injection wells and recovery of products through multi-hole producing wells. When the latter are water flooded water-flooding intervals are identified and isolated. According to the invention a downhole splitter is made in the semi-ellipse shape which major axis is directed at the angle of 30-60° towards direction of fractures while ratio of the minor semi-axis of the ellipse b/2 towards major semi-axis a/2 is equal to 0.1-0.8. At that boreholes of a downhole splitter have length of (0.6-0.8)·a each in productive part of the stratum and water-swellable packers are installed at them at each 50-250m. The boreholes are placed near the roof of the productive stratum at distance of 0.5 m at least and less than 2 m from the roof. The horizontal injection well is placed in plane along the ellipse major axis of a producing downhole splitter with length of (0,3-0,6)·a of its horizontal part in the productive stratum, at water-oil contact or the bottom of oil-filled formation in profile at distance of 0.2 m at least and less than 1m from it.
 Device for pumping gas-liquid mixture to formation / 2512156
Invention pertains to oil industry and can be used in system of out-contour and contour waterflooding during development of oil deposit with maintenance of formation pressure. The concept of the invention is as follows: device contains inner pipe string equipped with chamber for fluid and gas receipt and outer pipe string, encapsulated assembly. At that chamber for fluid and gas receipt communicates with tubing-casing annulus above the encapsulated assembly; it is made as low-pressure chamber of jet pump with ejector installed at the jet pump input, while it output is communicated with inner tubing string. At that delivery of gas is envisaged to tubing-casing annulus with possibility of its suction to low-pressure chamber of the jet pump. Encapsulated assembly is made as packer and installed in the well being a part of inner tubing string above the formation. Beyond the packer and opposite low-pressure chamber of the jet pump inside the inner tubing string there are through radial grooves for gas delivery. Outer piping string is equipped from below with ejector telescoped into the inner piping string at the input of low-pressure chamber of the jet pump with potential axial displacement in regard to inner piping string and regulation of flow passage of through radial grooves with possibility of their sealed cut-off. At that input of the jet pump is communicated with the outer piping string. Below the jet pump output the inner piping string is equipped with diaphragms with the central slotted openings. Each slotted opening of the following diaphragm is shifted per angle of 15-20° towards clockwise or anticlockwise direction. Below diaphragm inside the inner piping string there's tubular smoothing sleeve for liquid-gas mixture.
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FIELD: oil and gas industry. SUBSTANCE: method of development of oil-and-gas deposits with bottom water includes primary gas cap blowdown by gas wells and withdrawal of at least part of gas with subsequent joint development of gas cap and oil rim by opening-up of last with producing and injection wells, injection of displacement agent into the oil part of the deposit and oil withdrawal. According to the invention, at the beginning of gas withdrawal from the gas cap, withdrawal and pass-by of bottom water into the gas cap are performed. Bottom water is moved along the gas and oil contact and a barrier is created on the gas and oil contact in order to reduce oil cross-flow into the gas cap and embed bottom water in the oil part of the deposit. At that, volumes of gas withdrawal and pass-by water are controlled making sure that gas and oil contact is kept almost immovable. EFFECT: increased efficiency of development of oil-and-gas deposits with bottom water due to more rational utilisation of energy of bottom water and higher gas and oil recovery of formation. 6 cl, 3 ex, 1 tbl, 3 dwg
The invention relates to the oil industry, and in particular to methods development of oil and gas reservoirs with bottom water. Oil and gas deposits consist of gas-saturated part of the reservoir located in the upper arched part of the deposits, called gas cap. Below the gas cap lies oil, and this part of the Deposit is often called the oil rim, even when the area oil area larger than the area of the gas cap. Under the oil rim, as a rule, there aquifer zone of bottom water. There is a method of developing oil and gas reservoirs with bottom water by means of anticipatory development of an oil rim and further development of the gas cap [Development and exploitation of oil and gas condensate fields [J.V. Zheltov, NR. Martos, AH mirzadjanzade, G.S. Stepanova. M., "Nedra", 1979, p.13]. The disadvantage of this method development mode depletion drive is the low efficiency of oil production, due to the rapid decline in production wells, as well as their quick flooding of bottom water and salesovianum" wells gas gas cap. The closest in technical essence is a way of developing oil and gas reservoirs with bottom water through the primary development of the gas cap and selecting at least part of the gas with the consequences is the fact that the joint development of the gas cap and oil rim by opening the last of extraction and injection wells, injection of the displacing agent in the oil part of the deposits and oil withdrawal [Development and exploitation of oil and gas condensate fields / J.V. Zheltov, NR. Martos, AH mirzadjanzade, G.S. Stepanova. M., "Nedra", 1979, p.8-12] (prototype). The disadvantage of this method is low efficiency of oil due to leakage of oil into the gas cap while reducing its pressure when the gas. The technical result of the invention is to eliminate these drawbacks, namely in increasing the recovery factor in the development of reservoirs with bottom water due to more rational use of bottom waters, reduce the cost of producing and water injection, and the increase in gas production and reducing the water content of produced fluids. Required technical result is achieved by the fact that in the known method of developing oil and gas reservoirs with bottom water through the primary design gas cap gas wells and sampling at least part of the gas with subsequent joint development of the gas cap and oil rim by opening the last of extraction and injection wells, injection of the displacing agent in the oil part of the deposits and the selection of oil, according to the invention, at the beginning of the withdrawal of gas from the gas cap shall bypass plantar in the s in the gas cap, the bottom water bypass is performed using the well in which the perforated interval of the aquifer in the area of bottom water and in the area of the gas cap, ensure the promotion of bottom water along the gas-oil contact and create a barrier to gas-oil contact to reduce the flow of oil into the gas cap and the introduction of bottom water in the oil part of the deposits, thus regulating the volume of gas sampling and return the fulfilled of water so that the gas-oil contact, support almost motionless; well bypass bottom water can be used as an injection to return the fulfilled injection water in oil reservoir during the development phase of an oil rim; well bypass bottom water can to be multilateral horizontal sidetracks, and perforation intervals sidetracks are located in the area of the bottom water in the vicinity of the perforated interval of producing wells for development of an oil rim; to return the fulfilled water can swap other fluids such as polymer solutions. The essential features of the method are: 1) Development of oil and gas reservoirs with bottom water by opening the gas cap gas wells and oil rim - producing and injection wells. 2) Pervouchine the th development of a gas cap with a selection of at least part of the gas. 3) Sampling of water from the bottom water. 4) Injection (bypass) selected water from the bottom water in the gas portion of the reservoir at the beginning of the gas. 5) the bottom water Bypass is performed using the well in which the perforated interval of the aquifer in the area of bottom water and in the area of the gas cap. 6) ensuring the promotion of bottom water along the gas-oil contact and create a barrier to gas-oil contact to reduce the flow of oil into the gas cap and the introduction of bottom water in the oil part of the deposits. 7) regulation of the volume of gas sampling and return the fulfilled of water so that the gas-oil contact, support almost motionless. 8) Subsequent pumping of water from selected areas of bottom water in the oil part of the deposits. 9) the Pumping of water from selected areas of bottom water in the oil portion of the reservoir through the same well from which are selected the water. 10) Well to bypass the bottom water may be multilateral, containing lateral trunks. 11) Sampling of water from the bottom water in the vicinity of the perforated interval of the production well designed for oil extraction. 12) the additional Injection of the displacing agent in the oil part of the Deposit and the selection of oil. Signs 1-2 are common with the prototype of significant signs and symptoms 3-12 - the profile is entrusted essential features of the invention. The invention consists in the following. When developing oil and gas fields water type with the primary development of the gas cap there is a drop in reservoir pressure in the gas cap, which causes the flow of oil from an oil rim in the gas cap. This is also skid bottom water. Oil coming into the gas cap in the next extract is very difficult and it is usually considered as lost. In the proposed method, sampling of water from the aquifer plantar region and bypass it in the gas portion of the reservoir with the organization of horizontal water movement along the gas-oil contact (GOC). Under the influence of gravity the water will tend to move along the STC, if the perforations in the well through which perepuskat water, will also be located near the STC, not much above it. This technique creates an artificial barrier (water) on the boundary of the gas-contact restraining the flow of oil into the gas cap by reducing the relative permeability of oil. Bypass water also ensures the maintenance of reservoir pressure in the gas cap that reduces the flow of oil, and selection of water from the bottom water reduces the activity of the plantar water and also reduces the tributaries water in the oil rim. agulira volumes of gas extraction and return the fulfilled of water can be maintained STC practically motionless. This will take significant amounts of gas from the gas cap, reducing the flow of oil from the rim into the gas cap to a minimum. Well, providing a bypass of bottom water suitable rest evenly on the area of the rim; their number can be determined by calculations on models. The approximate condition for the regulation of the selections, providing practical immobility STC is an approximate equality of the volumes of gas and quantities return the fulfilled of water. More precisely, the volume of gas extraction and bypass water are defined on the model. In the proposed method, when input into the development of an oil rim can continue water withdrawal from the aquifer plantar region and bypass it in the oil part of the reservoir with the organization of horizontal displacement. However, research has shown that it is expedient to continue the part of the injected water is directed into the gas cap. Moreover, in the injection well, it is expedient to open and a few meters of the aquifer bottom water, which will minimize the leakage of oil from the oil rim in the plantar area for the downloading. Such a selection and bypass (injection) can be produced using the same wells in the most preferred variant of embodiment of the present invention. This reduces the cost of water treatment, eliminated neobhodimosti lifting water to the surface, i.e. reduced energy consumption remains high reservoir temperature of the injected water. Of course, the produced water can be extracted to the surface and injected into the same or another horizon, but this method is less efficient. Water injection into the oil reservoir can be accomplished through the same well from which a selection is made of the water. To do this well, you can install the pump on the tubing pipe (tubing), and the interval of injection to limit the installation of packers. The pump tube in the interval bounded by the packers should be perforated to ensure receipt of selected water into the oil reservoir. Flow return the fulfilled of water can be adjusted by changing the pump capacity, the volume of water return the fulfilled it is reasonable to expect using mathematical models to search for optimum values. When organizing artificial stimulation of the nature of the hydrodynamic flow in the reservoir varies considerably. If you are developing on the mode of depletion of the oil was forced out due to the rise of oil-water contact in the vertical direction, when the injection of water (displacing agent) in the oil part of the reservoir displacement in the prevailing degree occurs in the horizontal direction along the strata. Artificial stimulation provides growth formation energy, b is more high well flow rates and higher oil recovery. However, under artificial stimulation cones bottom water continue to evolve. This leads to the fact that wells irrigate more than in the normal development of deposits of reservoir type, they are used to disable and oil recovery is substantially less than the potential. Especially this manifests itself in deposits with high viscosity oil. The most preferred variant of the method using water-water injection wells, having a perforation interval in the area of the bottom water in the vicinity of the perforated interval of the well designed for oil extraction. If 1 injection well have 2 or 3 mining, you can pave laterals to each of these wells. In the selection of bottom water in the vicinity of the wellbore of the production well reduced pressure and the conditions for the development of cone bottom water is substantially eliminated. Moreover, you may develop a reverse cone oil - depending on the level of depression on the layer and coordinates of the perforation intervals. Before the breakthrough of water injected into the adjacent injection well and moving along the strata, water cut of the production well may be reduced down to zero. Preventing flooding of the wells with bottom water, m is tenderly to achieve a significantly greater recovery of an oil rim. The choice of optimal parameters of the injection/sampling coordinates of the perforation intervals and the location of the interval of water withdrawal from the aquifer can be done with the help of mathematical modeling. If the activity aquifer is insufficient, can be used additional sources of water for the organization's impact on the field. The invention is illustrated by drawings, where: 1 is a Diagram showing the principle of the invention. Figure 2 - layout of wells. Figure 3 - the Option of using water-injection wells with lateral trunks. The method is as follows. Figure 1 presents the scheme of development of oil and gas reservoirs with bottom water, showing the principle of implementation of the present invention, according to which the development of deposits begin with working gas cap by gas sampling gas wells. This Deposit razvarivat also water-injection wells, in which the perforated seam aquifer in the heel area and in the area of the gas cap. Create a mathematical model of the Deposit and calculate the optimal scenario development. In the selection of gas from gas wells through water-injection wells begins the flow of water from the bottom water into the gas cap, which can regulirovat is by installing the pumps. After selection of a certain volume of gas, starting with the development of oil rims, rubbereva its producing wells; gas sampling gas wells continue. In water wells is also possible to perforate the formation of an oil rim and begin downloading (bypass) water in oil reservoir. If necessary, also drilled an additional injection wells. If the activity aquifer is insufficient, the Deposit may be injected water from other sources. Examples of implementation of the method. Example 1. Figure 2 shows the layout of the wells. The reservoir lies at a depth of 1000 m, is rich in oil with a viscosity of 300 MPa*s at reservoir conditions: temperature 30°C and a pressure of 10.5 MPa. The formation is composed of Sandstone rocks. The total effective thickness of the oil layer 11 m, the gas reservoir is 22 m, the initial saturation 0.65, the average porosity of 33%. This element has drilled 1 gas well and started off gas with an annual rate of 4% of the initial gas reserves. If this were drilled water-injection wells, in which the perforated interval of the aquifer in the area of bottom water and in the area of the gas cap. After 10 years of selection of gas has begun to develop an oil rim, probureu producing wells and having a perforated rim oil in water-injection wells. From the EO gas wells continued. Criterion development is complete in both cases was to achieve a watercut value of 98%. When implementing the method according to the prototype made the selection of gas for 10 years, and then he rasberry element injection and producing wells and began the development of an oil rim with continued gas extraction. The comparison of the results of the development in two ways presented in table 1. The calculations were performed using a commercial simulator.
From table 1 it follows that the proposed method provides significant advantages in comparison with the method of the prototype. Oil production increased by 23.5% by reducing the flow of oil into the gas cap with the growth of volumes of water injection by only 0.4%, and gross liquids decreased by 4.1%. Gas production increased by 1.3 million m3or 0.5%. A significant increase in oil production with a marked reduction in the production fluid suggests that production watercut significantly decreased, including virtually water-free oil received 10% more than by way of a prototype. Example 2. The element layer had the same characteristics as in example 1. Instead of a vertical water-injection wells used in this example is well with two sidetracks directed almost perpendicular to the horizontal producing wells, as shown in figure 3. The design element was performed as in example 1. Due to the regulation of water abstraction horizontal intake trunks and regulation of the flow rates of producing wells in comparison with the base case cumulative oil production increased by 27.8%, and gross liquids decreased 7.9%, respectively, decreased production watercut. Example 3. The element layer had the same characteristics as in examples 1 and 2. The design element was performed as in example 1, but in the development phase of an oil rim in water-injection wells periodically (once a quarter) was added a solution of polymer in the amount of 1000 m3with the concentration of polymer in the solution is 0.5 kg/m3. Compared with the base case cumulative oil production increased by 32.9%, and gross liquids decreased by 11.6%, while gas production increased by 3.9 million m3or 1.5%. From the above examples it is seen that an advantage of the present invention in comparison with the prototype is to improve the technological indices of development, namely the increase in the recovery factor in the development of reservoirs with bottom water due to more rational use of bottom waters, reduce the cost of producing and water injection, natural gas and decrease about what OneNote of products produced. 1. The way to develop oil and gas reservoirs with bottom water through the primary design gas cap gas wells and sampling at least part of the gas with subsequent joint development of the gas cap and oil rim by opening the last of extraction and injection wells, injection of the displacing agent in the oil part of the deposits and oil extraction, characterized in that at the beginning of the withdrawal of gas from the gas cap shall take and pass bottom water in the gas cap, ensure the promotion of bottom water along the gas-oil contact and provide a barrier to gas-oil contact to reduce the flow of oil into the gas cap and the introduction of bottom water in the oil part of the deposits, thus regulate the volume of gas sampling and return the fulfilled of water so that the gas-oil contact, support almost motionless. 2. The method according to claim 1, characterized in that the bottom water bypass is performed using the well in which the perforated interval of the aquifer in the area of bottom water and in the area of the gas cap. 3. The method according to claim 2, characterized in that the hole for the bypass of bottom water is used as the pressure to return the fulfilled injection water in oil reservoir during the development phase of an oil rim. 4. The method according to claim 2, characterized in, is to bypass bottom water use multilateral well containing lateral trunks. 5. The method according to claim 4, characterized in that the hole for the bottom water bypass perforation intervals sidetracks have in the area of the bottom water in the vicinity of the perforated interval of producing wells for development of an oil rim. 6. The method according to one of claims 1 to 5, characterized in that in addition to return the fulfilled bottom water in the reservoir is injected polymer solutions.
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