Three-dimensional combined graded plugging and adjusting method and pipe column for heavy oil reservoir

Abstract

The invention discloses a three-dimensional combined graded plugging and adjusting method for a heavy oil reservoir. The method comprises the following steps that S1, a target oil reservoir is judged; s2, performing three-dimensional combined graded profile control; the method is suitable for the technical field of oil field development, the development effect of a high-water-content well for oil well liquid production caused by edge-bottom water heavy oil reservoir water invasion can be improved, water invasion is overcome, the oil well liquid production efficiency is improved, and the oil well liquid production efficiency is improved. Especially under the condition that water layers and steam channeling are easy to communicate after multiple rounds of steam injection processes of a thermal production well, the overall recovery efficiency and economic benefits of the edge-bottom water heavy oil reservoir are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield development, and in particular relates to a three-dimensional combined graded plugging and regulating method and a pipe string for heavy oil reservoirs. Background Art

[0002] Heavy oil is a kind of oil with huge storage capacity in modern society. It plays a very critical role in the application of petroleum resources. However, heavy oil has a large molecular weight and relatively high viscosity, so it is not conducive to mining.

[0003] Currently, heavy oil reservoir development primarily involves water flooding and steam thermal recovery. Water flooding is primarily used for heavy oil reservoirs with insufficient formation energy, while steam thermal recovery is primarily used for heavy oil reservoirs with sufficient natural energy, particularly those with bottom water. The Shengli Oilfield alone boasts nearly 300 million tons of thermally recovered heavy oil reservoirs in geological reserves, of which over 40% rely on bottom water energy and have crude oil viscosities between 50 and 500 mPa·s. Heavy oil reservoirs commonly contain marginal bottom water. These reservoirs are generally categorized by the size of the water body into weak marginal bottom water (water-to-oil volume ratio ≤ 1.5), moderately strong marginal bottom water (1.5 < water-to-oil volume ratio < 5), and strong marginal bottom water (water-to-oil volume ratio ≥ 5). Bottom water reservoirs account for approximately 50% of these reservoirs.

[0004] Currently, the development of reservoirs containing bottom water manifests in two ways: first, when the bottom water advances as a whole, it boosts oil and gas production; second, when the bottom water infiltrates the oil layer along high-permeability layers in the form of bottom water cones or ridges, it causes reservoir flooding, increasing the water cut in production wells and reducing oil production, severely impacting production and even forcing the shutdown of large areas of oil and gas wells. Furthermore, heavy oil reservoirs, due to their high crude viscosity and large oil-water mobility ratio, are often produced using steam stimulation, which accounts for over 70% of heavy oil production. However, for heavy oil reservoirs containing bottom water, with increasing steam stimulation cycles, the reservoir's formation energy gradually decreases. Without external energy replenishment, a pressure deficit develops at the bottom of the stimulation wells. Under the pressure differential, bottom water intrudes into the reservoir, causing flooding and a rapid increase in water cut, impacting development effectiveness. Furthermore, within the reservoir, as the number of stimulation cycles increases, steam crossflow channels develop between stimulation wells, further impacting the effectiveness of steam stimulation development. Therefore, after multiple cycles of steam stimulation in bottom-water heavy oil reservoirs, water intrusion and steam channeling become severe, reducing steam stimulation effectiveness. The high viscosity of the crude oil and the high strength of the water body easily lead to bottom water coning, which is currently a development problem in these bottom-water heavy oil reservoirs. Consequently, these reservoirs currently suffer from low recovery rates, high water content, and slow oil production rates, necessitating a shift in development methods to improve development outcomes.

[0005] During production, in order to prevent the intrusion of bottom water and form large channels with dominant water flow, water plugging and profile adjustment treatments are often carried out to increase the swept volume of water flooding or other displacement technologies, thereby further improving the crude oil recovery rate of the oil reservoir. Application number CN201710740174.5 is a deep plugging and adjustment process using a combination of microorganisms and clay glue. The process involves screening alkali-producing microorganisms in the test reservoir, determining the ratio of alkali-producing microbial fermentation liquid to clay glue, determining the total injection amount of alkali-producing microbial fermentation liquid and clay glue, and preparing a mixed solution for field testing. The present invention has the characteristics of simple process, high plugging and adjustment strength, low investment cost, and significant effect of reducing water and increasing oil production. The comprehensive water content of the oil well is reduced by more than 10%, and the production increase is greater than 50%. However, this technology is limited to deep plugging and adjustment using a combination of microorganisms and clay glue, and does not solve the steam over-coverage and gas channeling phenomenon, nor the problem of combined plugging with steam injection.

[0006] Patent application number CN201310390996.7 primarily provides a method for first flushing residual oil from high-permeability areas with a surfactant solution, followed by the injection of a reverse profile-control polymer solution. Because the viscosity of the reverse profile-control polymer solution is higher than that of the surfactant solution, it drives the surfactant solution deeper into the reservoir. After the well resumes production, the reverse profile-control polymer solution, driven by the injected water, migrates along the surfactant solution's reflux channel, displacing residual oil from low-permeability areas and forming a plug. A composite water-blocking agent is then injected to provide a strong plugging effect on the high-permeability areas, reducing their fluid flow capacity. Cement is then applied to seal the near-wellbore area to prevent the injected agent from returning to the wellbore. Finally, the polymer solution is used to displace the oil, achieving wellbore flushing. This process effectively seals the high-permeability areas within the formation while improving oil washing efficiency, fully tapping the remaining oil within the formation, increasing the oil production potential of individual wells, and boosting recovery rates. However, this technology is limited to the plugging, adjustment and washing processes of oil wells, and does not solve the problems of determining the range of plugging agent discharge, the water outlet position of the oil well, and the implementation method of the plugging agent in the oil reservoir.

[0007] In summary, the current plugging and regulating technology and tubing for heavy oil reservoirs have certain problems. There is an urgent need for a three-dimensional combined graded plugging and regulating technology and tubing for heavy oil reservoirs. According to the migration characteristics and plugging features of different types of plugging agents in the reservoir, the vertical, horizontal and high permeability strips can be plugged respectively, the migration direction of steam in the reservoir can be adjusted, the time of steam breakthrough can be extended, the sweep efficiency of steam can be greatly improved, and the thermal utilization rate and development effect of steam can be improved. Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects of the prior art and provide a three-dimensional combined graded plugging and regulating method and a pipe string for heavy oil reservoirs.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, a three-dimensional combined graded plugging and adjustment method for a heavy oil reservoir comprises the following steps:

[0011] S1 Target reservoir determination;

[0012] S2 three-dimensional combined graded plugging regulation;

[0013] S3 well stewing and effect tracking.

[0014] Preferably, in step S1, determining the target reservoir specifically includes:

[0015] Collect basic physical property data of oil wells and determine whether they meet the requirements for the implementation of three-dimensional combined graded plugging and regulation based on the activity of edge and bottom water and the viscosity of heavy oil.

[0016] Preferably, in step S2, the three-dimensional combined graded plugging adjustment specifically includes:

[0017] S21 three-dimensional combined graded plugging control string optimization;

[0018] S22 plugging agent dosage and displacement calculation;

[0019] S23 plugging agent injection sequence optimization;

[0020] S24 injects steam.

[0021] Preferably, in step S21, a vertical well adopts a thermal recovery vertical well three-dimensional staged plugging and regulation integrated process string; a horizontal well adopts a thermal recovery horizontal well three-dimensional combined staged plugging and regulation integrated process string; and a balanced steam injection string is used for steam injection into unpropelled intervals.

[0022] Preferably, in step S22, the calculation of the plugging agent dosage and displacement specifically includes:

[0023] The production profile test of optical fiber is used to determine the water-producing area of ​​the oil well and calculate its water-producing range to guide the determination of the plugging agent dosage and displacement.

[0024] Preferably, in step S22, the water plugging agent dosage calculation formula is:

[0025]

[0026] Where: V is the amount of water plugging agent, m 3 ; L1 is the length of the horizontal section water-producing layer, m; r is the width of the bottom water contact layer, m; H is the height of the bottom water contact layer, m; φ is the reservoir porosity, %; α is the bottom water layer volume integrity coefficient;

[0027] Among them, L1 and α are calculated through the optical fiber liquid production profile.

[0028] Preferably, in step S22, the water plugging agent displacement calculation formula is:

[0029]

[0030] Where: q is the water plugging agent displacement, m 3 / d; K is permeability, 10 -3 μm 2 ;h is the oil layer thickness, m; is the average pressure of the oil layer, MPa; S h is the skin coefficient; γ o is the radius of the oil layer, m; γ a is the radius of the water layer, m; μ w is the viscosity of water, mPa.S; μ m is the viscosity of the water plugging agent, mPa.S; K rw relative permeability of water;

[0031] Among them, p1 is the bottom hole injection pressure, MPa; p2 is the surface injection pressure, p2 = p1-ρgh.

[0032] Preferably, in step S23, the blocking agent injection sequence includes:

[0033] First inject nitrogen foam, then inject temperature-resistant gel, then inject thermosetting plugging agent, and finally inject high-temperature steam.

[0034] Preferably, in step S23, the selection conditions of the nitrogen foam are: the foam volume is greater than 150 ml under the conditions of 300° C. and 10 MPa, the foam half-life is greater than 250 s, the foaming agent is kept at a constant temperature at the steam injection temperature for 24 hours, and the foam volume, foam half-life and resistance factor are all maintained at more than 90% of the original.

[0035] Preferably, in step S23, the nitrogen foam displacement range is 600m 3 / h~1200m 3 / h.

[0036] Preferably, in step S23, the injection amount of nitrogen foam is determined according to the formation pressure. When the formation pressure is less than 5 MPa, 120,000 standard cubic meters are injected; when the formation pressure is 5-6 MPa, 100,000 standard cubic meters are injected; when the formation pressure is 6-8 MPa, 80,000 standard cubic meters are injected; when the formation pressure is greater than 8 MPa and less than 15 MPa, 50,000 standard cubic meters are injected.

[0037] Preferably, in the step S23, during the process of injecting nitrogen foam, the volume ratio of the normal temperature foaming agent, the medium temperature foaming agent and the high temperature foaming agent is 3:4:3.

[0038] Preferably, in step S23, the conditions for selecting the temperature-resistant gel are that the water plugging rate of the target block core is at least greater than 80%, and the gel strength is at strength level D or above after being subjected to a high temperature of 200° C. for 24 consecutive hours.

[0039] Preferably, in step S23, the conditions for selecting the thermosetting plugging agent are: initial viscosity less than 30 mPa.s, curing temperature greater than 80°C, plugging pressure greater than 3 MPa / m, plugging rate greater than 98%, temperature resistance greater than 300°C, and erosion resistance greater than 70PV.

[0040] Preferably, in step S23, when the oil layer thickness is less than 5m, the amount of thermosetting agent used is 75-90m 3 When the oil layer thickness is greater than 5m and less than 10m, the amount of thermosetting agent is 90~105m 3 When the oil layer thickness is greater than 10m and less than 15m, the dosage of thermosetting agent is 105~120m 3 .

[0041] Preferably, in step S23, when the edge water distance is less than 100m, the combination of thermosetting plugging agent + temperature-resistant gel is preferentially used; when the edge water distance is greater than 100m and less than 300m, the combination of temperature-resistant gel + nitrogen foam is preferentially used; when the edge water distance is greater than 300m, nitrogen foam is preferentially used.

[0042] Preferably, in step S24, after the plugging agent is injected, the steam injection temperature field is used to heat and enhance the plugging strength of the plugging agent, and a balanced steam injection string is used to inject steam into the unpropelled layer.

[0043] Preferably, in step S24, the requirement for steam injection is: the bottom hole dryness is greater than 40%, and the wellhead dryness is greater than 75% in the east and greater than 70% in the west.

[0044] Preferably, in step S24, the amount of steam injected is: the initial steam injection intensity is 5 to 10 t / m, and increases with each cycle, with a cycle increase of about 5%.

[0045] Preferably, in step S3, after the steam injection is completed, the well is shut down, and the oil production effect after the well is opened is tracked in real time.

[0046] In the second aspect, a three-dimensional combined graded plugging and adjustment string for heavy oil reservoirs is used for a three-dimensional combined graded plugging and adjustment method for heavy oil reservoirs, including a three-dimensional graded plugging and adjustment integrated process string for thermal recovery vertical wells, which includes a casing arranged in the vertical well, two insulated oil pipes are vertically arranged in the casing, the two insulated oil pipes are connected by a compensator, the lower end of the lower insulated oil pipe is provided with a bell mouth, the outside of the lower insulated oil pipe is provided with a thermal sensitive seal and a magnet, the outside of the insulated oil pipe is provided with an optical fiber, the optical fiber is fixed by a magnet, and the upper end of the optical fiber is connected to a signal processor.

[0047] In the third aspect, a three-dimensional combined graded plugging and regulating string for heavy oil reservoirs is used for a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, including a three-dimensional combined graded plugging and regulating integrated process string for thermal recovery horizontal wells, which includes a three-dimensional combined graded plugging and regulating integrated process string for thermal recovery vertical wells, which includes a casing and an oil pipe inside the casing, an optical fiber is provided on the outside of the oil pipe through a magnet, a signal processor is connected to the upper end of the optical fiber, and a packer is provided on the outside of the horizontal section of the oil pipe.

[0048] In the fourth aspect, a three-dimensional combined graded plugging and regulating string for heavy oil reservoirs is used for a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, including a balanced steam injection string, which includes an insulated oil pipe, the vertical section of the insulated oil pipe is connected to the sucker rod through a thickening pump, and the outer side of the horizontal section of the insulated oil pipe is sequentially provided with a thermal packer, an anti-sticking straightener, an interlayer packer, and an injector from left to right.

[0049] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0050] The present invention can improve the development effect of oil wells with high water content in the oil production caused by water invasion in edge and bottom water heavy oil reservoirs, overcome water invasion, especially in the case where water layers and steam channeling are easily communicated after multiple rounds of steam injection in thermal recovery wells, thereby improving the overall recovery rate and economic benefits of edge and bottom water heavy oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a process flow chart of the present invention;

[0052] Figure 2 It is a technical flow chart of the present invention;

[0053] Figure 3 This is a schematic diagram of water blocking by a blocking agent according to the present invention;

[0054] Figure 4 It is a schematic diagram of the scope of influence in the temperature field plane of the present invention;

[0055] Figure 5 This is a schematic diagram of the structure of the pipe string for the thermal recovery vertical well three-dimensional combined graded plugging and adjustment integrated process of the present invention;

[0056] Figure 6 This is a schematic diagram of the structure of the pipe string for the three-dimensional combined graded plugging and regulating integrated process for thermal recovery horizontal wells of the present invention;

[0057] Figure 7 This is a schematic diagram of the structure of the balanced steam injection column of the present invention;

[0058] Figure 8 It is a schematic diagram of gel displacement optimization of the present invention;

[0059] Figure 9 This is a flow chart of the plugging agent injection sequence of the present invention;

[0060] Figure 10 Schematic diagram of resistance factors of different foam systems of the present invention;

[0061] Figure 11 is a graph showing the change in gel strength with temperature of the present invention;

[0062] Figure 12 This is a graph showing the volume retention rate of the thermosetting plugging agent of the present invention as a function of temperature;

[0063] Figure 13 This is a graph showing the change in consolidation strength of the thermal blocking agent of the present invention with temperature;

[0064] Figure 14 This is a schematic diagram of the optimization of the usage limit of the plugging agent of the present invention;

[0065] Figure 15 is a schematic diagram of steam injection parameter optimization of the present invention;

[0066] Figure 16 This is a three-dimensional combined graded plugging and oil-increasing curve diagram of the present invention;

[0067] Figure 17 This is a curve diagram of the three-dimensional combined graded plugging and regulation and oil production increase in horizontal wells according to the present invention.

[0068] Figure numerals: 1. bell mouth; 2. thermal packer; 3. compensator; 4. insulated oil pipe; 5. casing; 6. magnet; 7. optical fiber; 8. signal processor; 9. packer; 10. oil pipe; 11. injection device; 12. interlayer packer; 13. anti-sticking centralizer; 14. thickening pump; 15. sucker rod. DETAILED DESCRIPTION

[0069] The following examples further illustrate a specific embodiment of the three-dimensional combined graded plugging and regulating method and tubing string for heavy oil reservoirs of the present invention. The three-dimensional combined graded plugging and regulating method and tubing string for heavy oil reservoirs of the present invention are not limited to the description of the following examples.

[0070] Example 1:

[0071] A three-dimensional combined graded plugging and adjustment method for heavy oil reservoirs, such as Figure 1 As shown in the figure, first, the target reservoir is identified, and the three-dimensional combined graded plugging and adjustment string is optimized. Based on the optical fiber liquid production profile test, the water production area of ​​the oil well is determined, and its water production range is calculated to guide the determination of the plugging agent dosage and displacement. Secondly, the displacement control is adopted in the injection process and injection technology, and different displacement ranges are provided for different oil layer thicknesses. Then, a graded method is adopted for the plugging agent, and the injection sequence of the plugging agent is optimized. A two-dimensional and three-dimensional graded plugging and adjustment method is used, in which gel (thermosetting) is used to plug large channels and nitrogen foam is used to plug capillary channels. Then, during the steam injection process, the steam injection temperature field is used to heat and enhance the plugging strength of the plugging agent. A balanced steam injection string is used to inject steam into the unpropelled layer to improve the steam injection effect. Finally, the well is shut down and the effect is tracked.

[0072] Example 1:

[0073] A three-dimensional combined graded plugging and adjustment method for heavy oil reservoirs, such as Figure 1 As shown, the following steps are included:

[0074] S1 Target reservoir determination;

[0075] S2 three-dimensional combined graded plugging regulation;

[0076] S3 well stewing and effect tracking.

[0077] Furthermore, in step S1, the target reservoir is determined, specifically including:

[0078] Collect basic physical property data of oil wells and determine whether they meet the requirements for the implementation of three-dimensional combined graded plugging and regulation based on the activity of edge and bottom water and the viscosity of heavy oil.

[0079] Further, such as Figure 2 and Figure 3As shown in the figure, during the plugging agent injection process, nitrogen foam is injected from the oil pipe. According to the Jiamin effect, the smaller the pore throat radius, the greater the additional resistance generated. The foam will preferentially enter the high permeability water zone with larger pore diameter. Since the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high permeability water space, forming a gas cap in the upper space to prevent gas channeling. The injection order of nitrogen foam is to inject the medium and normal temperature foaming agent first, and then inject the high temperature foaming agent, so as to achieve the longitudinal plugging of the medium and normal temperature foaming agent at the proximal end and the high temperature foaming agent at the distal end. After the foam occupies the upper space, the temperature-resistant gel is injected. Since the nitrogen foam has occupied the upper space, the temperature-resistant gel relies on the characteristics of high permeability of the water outlet channel and low permeability of the oil outlet channel. The temperature-resistant gel preferentially enters the lower space of the high-permeability water outlet large channel. Then the thermosetting plugging agent is injected. The thermosetting plugging agent pushes the gel to move deep into the water outlet channel and seals the gel, realizing the water blocking of the proximal thermosetting plugging agent and the distal temperature-resistant gel on the plane; finally, steam is injected, and the steam injection temperature field and the sensitivity of the plugging agent to temperature are used to enhance the plugging strength of the plugging agent, thereby achieving a three-dimensional combined graded plugging effect.

[0080] Further, such as Figure 4 As shown in the figure, the steam injection temperature field heats and strengthens the plugging strength of the plugging agent. After saturated steam or superheated steam is injected into the oil layer, a temperature field is formed in the reservoir, extending outward from the steam injection point, and the reservoir temperature gradually decreases. Depending on the change of the steam injection temperature field and the sensitivity of the plugging agent to temperature, a three-dimensional graded plugging and adjustment method is formed, in which a medium-normal temperature foaming agent is formed at the proximal end and a high-temperature foaming agent is formed at the distal end in the vertical direction; in the plane, a thermosetting plugging agent is injected at the proximal end and a temperature-resistant gel is injected at the distal end.

[0081] Furthermore, in step S2, the three-dimensional combined graded plugging adjustment specifically includes:

[0082] S21 three-dimensional combined graded plugging control string optimization;

[0083] S22 plugging agent dosage and displacement calculation;

[0084] S23 plugging agent injection sequence optimization;

[0085] S24 injects steam.

[0086] Furthermore, in step S21, vertical wells use a thermal recovery vertical well three-dimensional staged plugging and regulation integrated process string; horizontal wells use a thermal recovery horizontal well three-dimensional combined staged plugging and regulation integrated process string; steam is injected into unused layers using a balanced steam injection string.

[0087] Furthermore, in step S22, the calculation of the plugging agent dosage and displacement specifically includes:

[0088] The production profile test of optical fiber is used to determine the water-producing area of ​​the oil well and calculate its water-producing range to guide the determination of the plugging agent dosage and displacement.

[0089] Furthermore, in step S22, the water plugging agent dosage calculation formula is:

[0090]

[0091] Where: V is the amount of water plugging agent, m 3 ; L1 is the length of the horizontal section water-producing layer, m; r is the width of the bottom water contact layer, m; H is the height of the bottom water contact layer, m; φ is the reservoir porosity, %; α is the bottom water layer volume integrity coefficient;

[0092] Among them, L1 and α are calculated through the optical fiber liquid production profile.

[0093] Furthermore, the plugging agent displacement is optimized. The displacement of the plugging agent is related to the oil layer thickness. The displacement of the gel is calculated by referring to the steam injection rate formula:

[0094]

[0095] Since the blocked large channels are completely filled with water, the calculated flow rate is mainly the flow rate of water.

[0096]

[0097] Since the bottom water layer has communicated with the oil layer, resulting in an increase in water cut, water plugging is required. Consider the influence of the water layer radius:

[0098] γ w =γ o +γ a ;

[0099] Furthermore, in step S22, the water plugging agent displacement calculation formula is:

[0100]

[0101] Where: q is the water plugging agent displacement, m 3 / d; K is permeability, 10 -3 μm 2 ;h is the oil layer thickness, m; is the average pressure of the oil layer, MPa; S h is the skin coefficient; γ o is the radius of the oil layer, m; γ a is the radius of the water layer, m; μ w is the viscosity of water, mPa.S; μ m is the viscosity of the water plugging agent, mPa.S; K rw relative permeability of water;

[0102] Among them, p1 is the bottom hole injection pressure, MPa; p2 is the surface injection pressure, p2 = p1-ρgh.

[0103] In summary, choosing a reasonable gel displacement is not only related to the thickness of the oil layer, but also to the permeability and mobility of the reservoir. Since the permeability of the water outlet channel is high and the permeability of the oil outlet channel is low, the gel selectively enters the water outlet channel during the gel injection process, forming a fingering effect. However, the gel displacement cannot be too high to prevent the water outlet channel from being quickly blocked while also blocking the oil outlet channel. Therefore, while maintaining the production pressure difference, the construction pressure and construction displacement should be reduced as much as possible to give the gel time to fully enter the high-permeability water outlet channel.

[0104] Based on this, according to the indoor research and on-site equipment indicators, the relationship between oil layer thickness and plugging agent displacement was optimized, such as Figure 8 shown.

[0105] Furthermore, in step S23, the plugging agent injection sequence includes:

[0106] First inject nitrogen foam, then inject temperature-resistant gel, then inject thermosetting plugging agent, and finally inject high-temperature steam.

[0107] Furthermore, during the plugging agent injection process, nitrogen foam is injected first. Relying on the characteristic that the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high-permeability water space. Nitrogen foam is in the upper high-permeability space. Compared with the oil outlet pores, nitrogen foam is more likely to form in the water outlet pores, blocking the water outlet pores. The foam is sensitive to oil saturation. It cannot form stable foam in places with high oil saturation. It can form a stable foam system for high-permeability layers with low oil saturation, producing a plugging effect. Steam is then added to enhance the plugging strength of the plugging agent through the steam temperature field. The effect of temperature on the plugging effect of nitrogen foam is as follows: Figure 10 As shown in the figure, there is an optimal temperature range for the plugging effect of the foaming agent. Relying on the different plugging effects of different foaming agents in different temperature ranges and the characteristic that the steam temperature field in the reservoir gradually decreases with the distance from the action, the order of adding the foaming agents is reasonably designed. The medium-normal temperature foaming agent is added first, and the high-temperature foaming agent is added later. This maximizes the plugging effect of the foaming agent under the steam temperature field and realizes the efficient plugging effect of nitrogen foam during the steam injection process.

[0108] Furthermore, during the plugging agent injection process, after the nitrogen foam is injected, the heat-resistant gel is injected. Relying on the characteristics of high permeability of the water outlet pores and low permeability of the oil outlet pores, the heat-resistant gel preferentially enters the lower space of the high permeability water outlet pores. Finally, steam is injected to enhance the plugging strength of the plugging agent through the steam temperature field. The specific effect of temperature on the gel is as follows: Figure 11 As shown in the figure, according to the characteristic that the steam temperature field in the reservoir gradually decreases with the distance of action, when the temperature field reaches the distal gel, the temperature is already below 160°C. Within this temperature range, the gel strength increases with increasing temperature, thereby improving the gel strength.

[0109] After the nitrogen foam and gel are completely injected, a thermosetting plugging agent is used to seal the high-permeability water outlet. The thermosetting plugging agent is a low-viscosity liquid at room temperature. Once injected into the high-permeability water outlet zone of the formation, it solidifies at formation temperature to form a high-strength, high-temperature-resistant phenolic resin, sealing the high-permeability layer and steam channeling channels. The thermosetting plugging agent's functions are to protect the gel, which has low steam shock strength, and to protect the gel, which is resistant to temperature differences, ensuring long-term effectiveness.

[0110] Furthermore, in step S23, the selection conditions of the nitrogen foam are: the foam volume of the test foam is greater than 150 ml at 300°C and 10 MPa, the foam half-life is greater than 250 s, the foaming agent is kept at a constant temperature at the steam injection temperature for 24 hours, and the foam volume, foam half-life, and resistance factor are all maintained at more than 90% of the original.

[0111] Furthermore, in step S23, the nitrogen foam displacement range is 600m 3 / h~1200m 3 / h.

[0112] Furthermore, in step S23, the injection amount of nitrogen foam is determined according to the formation pressure. When the formation pressure is less than 5 MPa, 120,000 standard cubic meters are injected; when the formation pressure is 5-6 MPa, 100,000 standard cubic meters are injected; when the formation pressure is 6-8 MPa, 80,000 standard cubic meters are injected; when the formation pressure is greater than 8 MPa and less than 15 MPa, 50,000 standard cubic meters are injected.

[0113] Furthermore, in step S23, during the process of injecting nitrogen foam, the volume ratio of the normal temperature foaming agent, the medium temperature foaming agent and the high temperature foaming agent is 3:4:3.

[0114] Furthermore, in step S23, the selection conditions for the temperature-resistant gel are that the water plugging rate of the target block core is at least greater than 80%, and after being subjected to a high temperature of 200°C for 24 consecutive hours, the gel strength is at strength level D or above.

[0115] Furthermore, in step S23, the conditions for selecting the thermosetting plugging agent are: initial viscosity less than 30 mPa.s, curing temperature greater than 80°C, plugging pressure greater than 3 MPa / m, plugging rate greater than 98%, temperature resistance greater than 300°C, and erosion resistance greater than 70PV.

[0116] Furthermore, the thermosetting plugging agent has the characteristics of high temperature resistance and can maintain a high volume retention rate of compressive strength for a long time at high temperature, such as Figure 12 As shown in the figure, the volume retention rate is greater than 92% when heated at 350°C for 30 consecutive days.

[0117] Furthermore, the thermosetting plugging agent has the characteristics of high strength, such as Figure 13As shown in the figure, the consolidation strength of the thermal blocking agent is greater than 1 MPa at a high temperature of 350°C.

[0118] Furthermore, in step S23, when the oil layer thickness is less than 5m, the amount of thermosetting agent is 75-90m 3 When the oil layer thickness is greater than 5m and less than 10m, the amount of thermosetting agent is 90~105m 3 When the oil layer thickness is greater than 10m and less than 15m, the dosage of thermosetting agent is 105~120m 3 .

[0119] In summary, if Figure 14 As shown, a thermosetting + gel combination method is used on the plane to block large water outlet channels with high water content and close distance to the edge water. A gel + foam combination method is used to block the distal water outlet channels. Vertically, nitrogen foam is used to block the upper water outlet channels, and gel is used to block the lower water outlet channels. This patent optimizes the use limits of plugging agents. When the edge water distance is less than 100m, the thermosetting + gel combination method is used first. When the edge water distance is greater than 100m and less than 300m, the gel + foam combination method is used first. When the edge water distance is greater than 300m, foam is used first, thereby achieving a three-dimensional combination and graded plugging effect of multiple combinations of thermosetting + gel + foam.

[0120] Furthermore, in step S24, after the plugging agent is injected, the steam injection temperature field is used to heat and enhance the plugging strength of the plugging agent, and a balanced steam injection string is used to inject steam into the unpropelled layer to improve the steam injection effect.

[0121] Furthermore, in step S24, the requirements for steam injection are: the bottom hole dryness is greater than 40%, and the wellhead dryness is greater than 75% in the east and greater than 70% in the west.

[0122] Furthermore, in step S24, the amount of steam injected is: the initial steam injection intensity is 5 to 10 t / m, and increases with each cycle, with a cycle increase of about 5%.

[0123] Furthermore, in step S3, after the steam injection is completed, the well is shut down and the oil production effect after the well is opened is tracked in real time.

[0124] Example 3:

[0125] A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, the other steps are similar to those of Example 2, such as Figure 5As shown, the target well is a vertical well, and a thermal recovery vertical well three-dimensional graded plugging and adjustment integrated process string is used to prefabricate the optical fiber on the outside of the insulated oil pipe. The process string is connected in sequence with a bell mouth, a thermal-sensitive seal, a compensator, an insulated oil pipe, a casing, a magnet, an optical fiber, and a signal processor. Before going down the well, the optical fiber is prefabricated on the outside of the oil pipe through a magnet and lowered into the oil layer. The production profile is tested by optical fiber in the early stage. The test results are processed by the signal processor to determine the water outlet position of the oil layer and calculate the amount of plugging agent. Then nitrogen foam is injected. The over-covering effect of the foam and the selectivity of oil and water are used to suppress steam over-covering, reduce inter-layer differences, and slow down the intrusion of edge and bottom water. Since the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high-permeability water space. After the nitrogen foam occupies the upper space, the heat-resistant foam is injected. Gel, since the nitrogen foam has occupied the upper space, the heat-resistant gel relies on the characteristics of high permeability of the water outlet pores and low permeability of the oil outlet pores. The heat-resistant gel preferentially enters the lower space of the high-permeability water outlet large pores and replaces the nitrogen foam to the upper layer. Then the thermosetting plugging agent is injected. The thermosetting plugging agent pushes the gel to move deep into the water outlet pores and seals the gel, realizing water blocking by the proximal thermosetting plugging agent and the distal heat-resistant gel on the plane, water blocking by the upper nitrogen foam and the lower heat-resistant gel in the vertical direction, and finally steam is injected to further enhance the blocking effect, so as to achieve the purpose of three-dimensional combination and graded blocking.

[0126] Furthermore, nitrogen foam is injected in a plug-type manner, with the first plug injecting a room-temperature foaming agent, the second plug injecting a medium-temperature foaming agent, and the third plug injecting a high-temperature foaming agent. The injection of nitrogen foam mainly blocks the upper water outlet channel and forms a gas cap to prevent gas channeling during steam injection. On the other hand, the nitrogen foam serves to pressurize water and drive hot steam into the unused oil layer section.

[0127] Furthermore, after steam injection, the reservoir temperature is further increased, the steam contacts the thermosetting plugging agent, and heat is transferred to the gel and nitrogen foam injected at the far end through the thermosetting plugging agent. The steam temperature is greatly reduced due to long-distance heat transfer, and the remaining heat is heated through the steam injection temperature field and strengthens the plugging strength of the gel plugging agent and nitrogen foam.

[0128] Example 4:

[0129] A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, the other steps are similar to those of Example 2, such as Figure 6As shown, the target well is a horizontal well. A thermal recovery horizontal well three-dimensional combined graded plugging and adjustment integrated process string is used. Nitrogen foam, gel and thermosetting plugging agents are constructed. Optical fibers are prefabricated on the outside of the tubing. The process string is connected in sequence with magnets, optical fibers, packers, tubing, casing and signal displays. Before going down the well, the optical fiber is prefabricated on the outside of the oil pipe through a magnet and lowered into the oil layer. In the early stage, the production profile is tested by optical fiber. The test results are processed by a signal processor to determine the water outlet position of the oil layer and calculate the amount of plugging agent. Then the packer is lowered to isolate the water outlet area of ​​the oil well, and then nitrogen foam is injected. The over-covering effect of the foam and the selectivity of oil and water are used to inhibit steam over-covering, reduce interlayer differences, and slow down the intrusion of edge and bottom water. Since the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high-permeability water outlet space. After the nitrogen foam occupies the upper space, the heat-resistant gel is injected. Since the nitrogen foam has occupied the upper space, the heat-resistant gel relies on the characteristics of high permeability of the water outlet pore and low permeability of the oil outlet pore. The heat-resistant gel preferentially enters the lower space of the high-permeability water outlet large pore, thereby achieving the purpose of nitrogen foam water blocking in the upper part and heat-resistant gel water blocking in the lower part, and the purpose of three-dimensional combined graded plugging and adjustment.

[0130] Furthermore, the optical fiber is fixed by a magnet through magnetic force to achieve a close fit with the oil pipe.

[0131] Example 5:

[0132] A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, the other steps are similar to those of Example 2, such as Figure 6 As shown in the figure, the target well is a horizontal well, and a thermal recovery horizontal well three-dimensional combined staged plugging and adjustment integrated process string is used. Figure 7 As shown, steam injection is targeted at unproduced zones to improve injection effectiveness. A balanced steam injection string is employed. The process string consists of casing, downhole compensators, insulated tubing, thermal packers, injectors, inter-zone packers, and anti-sticking stabilizers. The injectors are installed on the insulated tubing to control the steam injection pressure differential. Steam is injected evenly at a pressure not exceeding the reservoir's fracture pressure. Based on the production profile measured by optical fiber, injectors are strategically placed within the producing zones to maximize steam flow into unproduced zones with low water production. Inter-zone packers are used to isolate different horizontal zones. During steam injection, the injectors are positioned to target unproduced zones, allowing steam to displace the unproduced oil. Steam is injected from the insulated tubing, enters the horizontal tubing, flows through the injectors, and then enters the annulus through the injector orifices, achieving efficient production of the oil zones and improving recovery.

[0133] Example 6:

[0134] A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in any of embodiments 1-5, a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs, including a thermal recovery vertical well three-dimensional graded plugging and regulating integrated process string, which includes a casing 5 arranged in the vertical well, two insulated oil pipes 4 vertically arranged in the casing 5, the two insulated oil pipes 4 are connected by a compensator 3, the lower end of the lower insulated oil pipe 4 is provided with a bell mouth 1, the outer side of the lower insulated oil pipe 4 is provided with a thermal sensitive seal 2 and a magnet 6, the outer side of the insulated oil pipe 4 is provided with an optical fiber 7, the optical fiber 7 is fixed by the magnet 6, and the upper end of the optical fiber 7 is connected to a signal processor 8.

[0135] Example 7:

[0136] A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in any of embodiments 1-5, includes a three-dimensional combined graded plugging and regulating integrated process string for thermal recovery horizontal wells, which includes a three-dimensional combined graded plugging and regulating integrated process string for thermal recovery vertical wells, which includes a casing 5 and an oil pipe 10 inside, an optical fiber 7 is provided on the outside of the oil pipe 10 through a magnet 6, a signal processor 8 is connected to the upper end of the optical fiber 7, and a packer 9 is provided on the outside of the horizontal section of the oil pipe 10.

[0137] Example 8:

[0138] A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in any of Examples 1-5, comprises a balanced steam injection string, which includes an insulated oil pipe 4, the vertical section of the insulated oil pipe 4 is connected to the sucker rod 15 through a thickening pump 14, and the outer side of the horizontal section of the insulated oil pipe 4 is sequentially provided with a thermal packer 2, an anti-sticking centralizer 13, an interlayer packer 12, and an injector 11 from left to right.

[0139] Example 9:

[0140] like Figure 5As shown, it is a three-dimensional graded plugging and adjustment integrated process string for thermal recovery vertical wells. This implementation method is mainly an implementation method of prefabricating optical fibers on the outside of the insulated oil pipe. The process string is connected in sequence to 1 bell mouth, 2 thermal packers, 3 compensators, 4 insulated oil pipes, 5 casings, 6 magnets, 7 optical fibers, and 8 signal processors. Before going down the well, 7 optical fibers are prefabricated on the outside of 4 insulated oil pipes through 6 magnets and lowered into the oil layer. The production profile is tested in the early stage through 7 optical fibers. The test results are processed by 8 signal processors to determine the water outlet position of the oil layer and calculate the amount of plugging agent. Then nitrogen foam is injected. The over-covering effect of the foam and the selectivity of oil and water are used to suppress steam over-covering, reduce inter-layer differences, and slow down the intrusion of edge and bottom water. Since the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high-permeability water space. After the nitrogen foam occupies the upper space, Then, the heat-resistant gel is injected. Since the nitrogen foam has occupied the upper space, the heat-resistant gel relies on the characteristics of high permeability of the water outlet pores and low permeability of the oil outlet pores. The heat-resistant gel preferentially enters the lower space of the high-permeability water outlet large pores and replaces the nitrogen foam to the upper layer. Then, the thermosetting plugging agent is injected. The thermosetting plugging agent pushes the gel to move deep into the water outlet pores and seals the gel, realizing water blocking by the proximal thermosetting plugging agent and the distal heat-resistant gel on the plane, water blocking by the upper nitrogen foam and the lower heat-resistant gel in the vertical direction, and finally steam is injected to further enhance the blocking effect and achieve the purpose of three-dimensional combination and graded blocking.

[0141] Taking a vertical well in a certain block as an example, the plugging and adjustment process and tubing string described in Example 9 are used for development, including the following steps:

[0142] (1) Determine the target reservoir: The oil well in a certain block is a heavy oil reservoir with edge-bottom water, and the oil-bearing area is 1.8 km 2 The viscosity of ground degassed crude oil at 50°C is 8760 mPa·s, the reservoir is buried at a depth of 1401 m, the oil layer thickness is 5 m, the average porosity is 38%, the permeability is 1954 mD, the formation static pressure is 5.32 MPa, the original formation pressure is 12.53 MPa, the pressure coefficient is 0.999, the formation temperature is 70°C, and the measured geothermal gradient is 3.6°C / 100 m. The reservoir meets the implementation requirements of this plugging and adjustment process.

[0143] (2) Optimization of three-dimensional combined graded plugging and regulating string: Arrange the three-dimensional graded plugging and regulating integrated process string for thermal recovery vertical wells along the middle and lower part of the bottom water reservoir. Figure 5 ;

[0144] (3) Calculation of plugging agent dosage and displacement:

[0145] Since the formation static pressure is 5.32MPa, the amount of nitrogen foam used is 100,000 standard cubic meters. Since the volume ratio of normal temperature foaming agent, medium temperature foaming agent and high temperature foaming agent is 3:4:3, the amount of each foaming agent is calculated based on the ratio.

[0146]

[0147] Through optical fiber detection, there is one water outlet at a well depth of 1331m. The liquid production profile is detected by optical fiber and substituted into the formula to calculate the amount of liquid production plugging agent;

[0148] L1 is the length of the vertical well water-producing layer, 23.6 m; r1 is the width of the bottom water contact layer, 11.3 m; H1 is the height of the bottom water contact layer, 4.3 m; φ is the reservoir porosity, 0.38; α is the bottom water layer volume integrity coefficient, 0.82.

[0149] The amount of liquid plugging agent used is calculated to be 357m 3 , permeability 1954mD, ground degassed crude oil viscosity 8760mPa·s at 50℃, due to the relatively high formation permeability and relatively low viscosity of heavy oil, there is no need to worry about the risk of formation blockage. In order to make the plugging agent have a good water blocking effect, the on-site design recommends injecting the plugging agent at 350-450m 3 Since the oil layer thickness is 5m, the recommended amount of thermosetting agent is 75-90m 3 .

[0150] The plugging agent displacement is calculated by the following formula

[0151]

[0152] K is 1954*10 -3 μm 2 ; h is 5m; p2 is the water plugging agent injection pressure 7MPa; 5.32MPa; γ o The radius of the oil layer is 2.5m; γ a The radius of the water layer is 0.8m; μ m 3mPa.S; μ w 1mPa.S;

[0153] The calculated plugging agent displacement is 153.4m 3 / d, average plugging agent displacement 6.37m 3 / h, combined Figure 8 Chart, recommended plugging agent displacement is 5-7m 3 / h.

[0154] (4) Optimization of the plugging agent injection sequence: Inject nitrogen foam to seal the upper area of ​​the water outlet channel. The nitrogen foam is injected in a segmented plug manner. First, inject the normal temperature foaming agent, then the medium temperature foaming agent, and finally the high temperature foaming agent. After the nitrogen foam fills the upper water outlet area, inject the temperature-resistant gel to seal the lower area of ​​the water outlet channel, and then inject the thermosetting plugging agent to seal it, thereby achieving the purpose of three-dimensional combined graded plugging and adjustment.

[0155] (5) Steam injection: Steam injection is used to enhance the plugging effect of the plugging agent. The oil layer thickness is 5m. Since the first cycle of this well is 2000m 3 , the cycle increases by about 5%, and the second cycle steam injection is 2100m 3 The above processes all use tubing positive injection.

[0156] (6) Well sealing and effect tracking: After the injection is completed, the well is sealed for 7-10 days.

[0157] The development effect of the plugging and adjusting process and the tubing string described in Example 9: After normal well opening, the daily oil production reached a maximum of 15.3 tons / day, with an average daily oil production of 10.8 tons / day. Compared with the well before the measures, the average daily oil production increased by 7.8 tons / day, the water content decreased by 31%, and the stage oil production was 593.1 tons. The effective period is expected to be more than half a year. The on-site implementation of the oil increase curve is shown in Figure 16 .

[0158] Example 10:

[0159] like Figure 6 The figure shows a three-dimensional, integrated, staged plugging and adjustment process string for thermal recovery horizontal wells. It applies nitrogen foam, gel, and thermosetting plugging agents. This implementation primarily involves prefabricating optical fibers on the exterior of the tubing. The process string is connected in sequence to magnets (6), optical fibers (7), packers (9), tubing (10), casing (5), and a signal display (8). Before going down the well, 7 optical fibers are prefabricated on the outside of the oil pipe through 6 magnets and lowered into the oil layer. In the early stage, the 7 optical fibers are used to test the liquid production profile. The test results are processed by 8 signal processors to determine the water outlet position of the oil layer and calculate the amount of plugging agent. Then the packer is lowered to isolate the water outlet area of ​​the oil well. Then nitrogen foam is injected. The overlapping effect of the foam and the selectivity of oil and water are used to inhibit steam overlapping, reduce interlayer differences, and slow down the intrusion of edge and bottom water. Since the relative molecular mass of nitrogen is lower than that of air, after the nitrogen foam is injected, the nitrogen foam moves to the upper layer and occupies the upper high-permeability water outlet space. After the nitrogen foam occupies the upper space, the heat-resistant gel is injected. Since the nitrogen foam has occupied the upper space, the heat-resistant gel relies on the characteristics of high permeability of the water outlet pore and low permeability of the oil outlet pore. The heat-resistant gel preferentially enters the lower space of the high-permeability water outlet large pore, achieving the purpose of nitrogen foam water blocking in the upper part and heat-resistant gel water blocking in the lower part, and the purpose of three-dimensional combined graded plugging and adjustment.

[0160] like Figure 7Figure 1 shows a balanced steam injection string for a horizontal well. This string improves steam injection efficiency by injecting steam into unproduced zones. The string consists of an injector 11, an interlayer packer 12, an anti-sticking centralizer 13, two thermal packers, four insulated tubings, a thickening pump 14, and a sucker rod 15. The injector 11 is installed on the insulated tubing 4 to control the steam injection pressure differential. Steam is injected evenly at a pressure not exceeding the reservoir's fracture pressure. Based on the production profile measured by optical fiber, the injectors 11 are strategically placed within the producing zones to maximize steam delivery to unproduced zones with low water production. Interlayer packers 12 are used to isolate different horizontal zones. When injecting steam, the 11th injector is adjusted to the unproduced layer, so that steam can displace the unproduced oil layer. Steam is injected from the 4th insulated oil pipe, enters the horizontal section of the tubing, flows through the 11th injector, and enters the annulus through the orifice of the 11th injector, thereby realizing efficient production of the oil layer and improving the recovery rate.

[0161] Taking a horizontal oil well in a certain block as an example, the plugging and adjustment process and tubing string described in Example 10 are used for development, including the following steps:

[0162] (1) Determination of the target reservoir: The oil well in a certain block is a bottom water heavy oil reservoir with an oil-bearing area of ​​2.5 km2, a ground degassed crude oil viscosity of 967,000 mPa·s at 50°C, a reservoir burial depth of 1,862 m, an oil layer thickness of 10.8 m, an average porosity of 36%, a permeability of 314 mD, a reservoir pressure of 12.09 MPa, a pressure coefficient of 0.999, a formation temperature of 80°C, a calculated geothermal gradient of 3.7°C / 100 m, and a horizontal section length of 231 m. The reservoir meets the implementation requirements of this plugging and adjustment process.

[0163] (2) Optimization of three-dimensional combined graded plugging and regulating pipe string: Horizontal wells are arranged along the middle and lower parts of the bottom water reservoir. Figure 13 ;

[0164] (3) Calculation of plugging agent dosage and displacement:

[0165] Since the reservoir pressure is 12.09 MPa, the amount of nitrogen foam is 50,000 standard cubic meters. Since the volume ratio of normal temperature foaming agent, medium temperature foaming agent and high temperature foaming agent is 3:4:3, the amount of each foaming agent is calculated based on the ratio.

[0166]

[0167] Through optical fiber detection, there are two water outlets, 54m and 86m away from the root of the horizontal section respectively. The liquid production profile is detected by optical fiber and substituted into the formula to calculate the amount of liquid production plugging agent;

[0168] L1 is the length of the horizontal section water-producing layer, 7.6 m; L2 is the length of the horizontal section water-producing layer, 4.3 m; r1 is the width of the bottom water contact layer, 5.8 m; r2 is the width of the bottom water contact layer, 4.9 m; H1 is the height of the bottom water contact layer, 6.2 m; H2 is the height of the bottom water contact layer, 7.1 m; φ is the reservoir porosity, 0.36; α is the bottom water layer volume integrity coefficient, 0.75.

[0169] The amount of liquid plugging agent used is calculated to be 422.8m 3 , permeability 917mD, ground degassed crude oil viscosity at 50℃ 967000mPa·s, due to the relatively low formation permeability and relatively high viscosity of heavy oil, in order not to block the oil outlet channel, the on-site design recommends injecting 400-450m 3 Since the oil layer thickness is 10.8m, the recommended thermal solid plugging agent is 105-120m 3 .

[0170] The plugging agent displacement is calculated by the following formula

[0171]

[0172] K is 314*10 -3 μm 2 ; h is 10.8m; p2 is the water plugging agent injection pressure 14MPa; is 12.09MPa; γ o The radius of the oil layer is 5.4m; γ a The radius of the water layer is 1m; μ m 3mPa.S; μ w 1mPa.S;

[0173] The calculated plugging agent displacement is 165m 3 / d, average plugging agent discharge volume 6.9m 3 / h, combined Figure 8 Plate, gel plugging agent displacement is 6-8m 3 / h.

[0174] (4) Optimization of the plugging agent injection sequence: lower the packer to isolate the water outlet area of ​​the oil well, then inject nitrogen foam to seal the upper area of ​​the water outlet channel. The nitrogen foam is injected in a segmented plug manner, first injecting the normal temperature foaming agent, then the medium temperature foaming agent, and finally the high temperature foaming agent. After the nitrogen foam fills the upper water outlet area, inject the temperature-resistant gel to seal the lower area of ​​the water outlet channel, and then inject the thermosetting plugging agent to seal it, thereby achieving the purpose of three-dimensional combined graded plugging and adjustment.

[0175] (5) Steam injection: Then take out the thermal recovery horizontal well three-dimensional combined graded plugging and adjustment integrated process string, put it into the horizontal well balanced steam injection string, inject steam, the horizontal section length is 231m and the oil layer thickness is 10.8, through Figure 11The steam injection intensity is 13t / m, as shown in the chart. 3 , the cycle increases by about 5%, and the steam injection in the 18th cycle is 3000m 3 The above processes all use tubing positive injection.

[0176] (6) Well sealing and effect tracking: After the injection is completed, the well is sealed for 7-10 days.

[0177] The development effect of the plugging and adjusting process and the tubing string described in Example 10 is as follows: after normal well opening, the daily oil production is up to 12.9 tons / day, and the average daily oil production is 10.5 tons / day. Compared with the pre-measures, the average daily oil production is increased by 6.86 tons / day, the water content is reduced by 20%, and the stage oil production is 598.5 tons. The effective period is expected to be more than half a year. The on-site implementation of the oil increase curve is shown in Figure 17 .

[0178] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A three-dimensional combined graded plugging and adjustment method for heavy oil reservoirs, characterized in that: The following steps are involved: S1 Target reservoir determination; S2 three-dimensional combined graded plugging regulation; S3 well stewing and effect tracking.

2. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 1, characterized in that: In step S1, the target reservoir is determined, specifically including: Collect basic physical property data of oil wells and determine whether they meet the requirements for the implementation of three-dimensional combined graded plugging and regulation based on the activity of edge and bottom water and the viscosity of heavy oil.

3. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 1, characterized in that: In step S2, the three-dimensional combined graded plugging control specifically includes: S21 three-dimensional combined graded plugging control string optimization; S22 plugging agent dosage and displacement calculation; S23 plugging agent injection sequence optimization; S24 injects steam.

4. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 3, characterized in that: In step S21, a vertical well adopts a thermal recovery vertical well three-dimensional graded plugging and regulation integrated process string; a horizontal well adopts a thermal recovery horizontal well three-dimensional combined graded plugging and regulation integrated process string; and a balanced steam injection string is used for steam injection into unpropelled intervals.

5. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 3, characterized in that: In step S22, the calculation of the plugging agent dosage and displacement specifically includes: The production profile test of optical fiber is used to determine the water-producing area of ​​the oil well and calculate its water-producing range to guide the determination of the plugging agent dosage and displacement.

6. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 5, characterized in that: In step S22, the calculation formula for the amount of water plugging agent is: Where: V is the amount of water plugging agent, m 3 ; L1 is the length of the horizontal section water-producing layer, m; r is the width of the bottom water contact layer, m; H is the height of the bottom water contact layer, m; φ is the reservoir porosity, %; α is the bottom water layer volume integrity coefficient; Among them, L1 and α are calculated through the optical fiber liquid production profile.

7. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 5, characterized in that: In step S22, the water plugging agent displacement calculation formula is: Where: q is the water plugging agent displacement, m 3 / d; K is permeability, 10 -3 μm 2 ;h is the oil layer thickness, m; is the average pressure of the oil layer, MPa; S h is the skin coefficient; γ o is the radius of the oil layer, m; γ a is the radius of the water layer, m; μ w is the viscosity of water, mPa.S; μ m is the viscosity of the water plugging agent, mPa.S; K rw relative permeability of water; Among them, p1 is the bottom hole injection pressure, MPa; p2 is the surface injection pressure, p2 = p1-ρgh.

8. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 5, characterized in that: In step S23, the blocking agent injection sequence includes: First inject nitrogen foam, then inject temperature-resistant gel, then inject thermosetting plugging agent, and finally inject high-temperature steam.

9. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, the selection conditions of the nitrogen foam are: the foam volume under the test conditions of 300°C and 10MPa is greater than 150ml, the foam half-life is greater than 250s, the foaming agent is kept at a constant temperature at the steam injection temperature for 24 hours, and the foam volume, foam half-life, and resistance factor are all maintained at more than 90% of the original.

10. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, the nitrogen foam displacement range is 600m 3 / h~1200m 3 / h.

11. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, the injection amount of nitrogen foam is determined according to the formation pressure. When the formation pressure is less than 5 MPa, 120,000 standard cubic meters are injected; when the formation pressure is 5-6 MPa, 100,000 standard cubic meters are injected; when the formation pressure is 6-8 MPa, 80,000 standard cubic meters are injected; when the formation pressure is greater than 8 MPa and less than 15 MPa, 50,000 standard cubic meters are injected.

12. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In the step S23, during the process of injecting nitrogen foam, the volume ratio of the normal temperature foaming agent, the medium temperature foaming agent and the high temperature foaming agent is 3:4:

3.

13. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, the conditions for selecting the heat-resistant gel are that the water plugging rate of the target block core is at least greater than 80%, and the gel strength is at strength level D or above after being subjected to a high temperature of 200° C. for 24 consecutive hours.

14. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, the conditions for selecting the thermosetting plugging agent are: initial viscosity less than 30 mPa.s, curing temperature greater than 80°C, plugging pressure greater than 3 MPa / m, plugging rate greater than 98%, temperature resistance greater than 300°C, and erosion resistance greater than 70PV.

15. The three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, when the oil layer thickness is less than 5m, the amount of thermosetting agent is 75-90m 3 When the oil layer thickness is greater than 5m and less than 10m, the amount of thermosetting agent is 90~105m 3 When the oil layer thickness is greater than 10m and less than 15m, the dosage of thermosetting agent is 105~120m 3 .

16. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 8, characterized in that: In step S23, when the edge water distance is less than 100m, the combination of thermosetting plugging agent + temperature-resistant gel is preferentially used; when the edge water distance is greater than 100m and less than 300m, the combination of temperature-resistant gel + nitrogen foam is preferentially used; when the edge water distance is greater than 300m, nitrogen foam is preferentially used.

17. A three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 3, characterized in that: In step S24, after the plugging agent is injected, the steam injection temperature field is used to heat and enhance the plugging strength of the plugging agent, and a balanced steam injection string is used to inject steam into the unpropelled layer.

18. The three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 3, characterized in that: In step S24, the steam injection requirement is: the bottom hole dryness is greater than 40%, and the wellhead dryness is greater than 75% in the east and greater than 70% in the west.

19. The three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 3, characterized in that: In step S24, the amount of steam injected is: the initial steam injection intensity is 5-10 t / m, and increases with each cycle, with a cycle increase of about 5%.

20. The three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to claim 1, characterized in that: In step S3, after the steam injection is completed, the well is shut down and the oil production effect after the well is opened is tracked in real time.

21. A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to any one of claims 1 to 20, characterized in that: The invention comprises a three-dimensional graded plugging and regulating integrated process string for thermal recovery vertical wells, comprising a casing (5) arranged in the vertical well, two thermal insulation oil pipes (4) vertically arranged in the casing (5), the two thermal insulation oil pipes (4) being connected via a compensator (3), a bell mouth (1) being provided at the lower end of the lower thermal insulation oil pipe (4), a heat-sensitive packer (2) and a magnet (6) being provided on the outer side of the lower thermal insulation oil pipe (4), an optical fiber (7) being provided on the outer side of the thermal insulation oil pipe (4), the optical fiber (7) being fixed by the magnet (6), and a signal processor (8) being connected to the upper end of the optical fiber (7).

22. A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to any one of claims 1 to 20, characterized in that: The invention comprises a three-dimensional combined graded plugging and regulating integrated process string for thermal recovery horizontal wells, which comprises a three-dimensional graded plugging and regulating integrated process string for thermal recovery vertical wells, comprising a casing (5) and an oil pipe (10) therein, an optical fiber (7) being provided on the outside of the oil pipe (10) via a magnet (6), a signal processor (8) being connected to the upper end of the optical fiber (7), and a packer (9) being sleeved on the outside of the horizontal section of the oil pipe (10).

23. A three-dimensional combined graded plugging and regulating string for heavy oil reservoirs, used in a three-dimensional combined graded plugging and regulating method for heavy oil reservoirs according to any one of claims 1 to 20, characterized in that: The invention comprises a balanced steam injection pipe string, which comprises an insulated oil pipe (4). The vertical section of the insulated oil pipe (4) is connected to a sucker rod (15) through a thickening pump (14). The outer side of the horizontal section of the insulated oil pipe (4) is sequentially sleeved with a heat-sensitive packer (2), an anti-sticking centralizer (13), an interlayer packer (12), and an injector (11) from left to right.

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