A process method for integrating plug filling hydraulic fracturing and well wall sand prevention

Abstract

The present application provides a kind of process method of slug filling hydraulic fracturing and well wall sand prevention integration, belong to oil and gas exploitation technical field.The process method is to combine hydraulic fracturing technology and oil well sand prevention technology, adopt the technology of fracturing reconstruction first, sand sealing later, through the change of fracturing truck group displacement, the displacement of each stage is lower than the previous stage, but the sand ratio of each stage is higher than the previous stage, realize stage drop, stage high sand ratio filling, slug filling, form wide and thick artificial well wall around wellbore, thereby complete formation far end fracturing reconstruction, wellbore near end consolidation well wall sand prevention.The process method uses existing pipe column, realizes one-time pipe column continuous construction, has the advantages such as simple operation, low measure cost, effectively improves fracturing sand prevention effect, effectively improves construction success rate.

Description

Technical Field

[0001] This invention relates to a process method that integrates slug filling hydraulic fracturing with wellbore sand control, belonging to the field of oil and gas extraction technology. Background Technology

[0002] In oil extraction, hydraulic fracturing is an important method for enhancing oil and gas production. However, in the development of some loose sandstone reservoirs, problems such as proppant backflow and increased formation sand production occur after hydraulic fracturing. Proppant backflow and sand production after fracturing both necessitate pump inspections and the re-implementation of sand control measures, increasing production and operating costs and reducing the production enhancement effect within the post-fracturing cycle. In particular, the Liaohe Oilfield reservoirs, due to their shallow burial and the fact that most blocks are composed of sandstone formations, experience severe sand production problems in light oil wells, heavy oil wells, steam-pumped heavy oil wells, and natural gas wells. Despite the adoption of various sand control measures, such as sand-fixing agents, gravel-filled wire-wound screens, high-pressure filling, and various screen technologies within the wellbore, the effectiveness of these measures has been unsatisfactory, specifically manifested in short-lived sand control effectiveness and decreased well production. Therefore, developing a new oil and gas extraction method is crucial to meeting production needs. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, this invention discloses an integrated process for hydraulic fracturing and wellbore sand control using slug packing. This method combines hydraulic fracturing technology with oil well sand control technology, employing a technique of fracturing first and then sealing with sand control. By varying the displacement of the fracturing truck, with each stage having a lower displacement than the previous stage but a higher sand ratio, it achieves staged reduction in displacement, staged high-sand-ratio filling, and slug packing, forming a wide and thick artificial wellbore wall around the wellbore. This completes the fracturing and sand control at the far end of the formation and the consolidation of the wellbore wall near the wellbore. This method utilizes existing tubing strings, enabling continuous construction with a single tubing string, and has advantages such as simple operation, low cost, and effectively improves the fracturing and sand control effect, significantly increasing the success rate of construction.

[0004] The technical solution adopted in this invention is: a process method integrating slug filling hydraulic fracturing and wellbore sand control, the specific steps of which are as follows:

[0005] Before construction, the casing string is lowered. The sand-filled casing string is lowered into the casing using a fracturing truck. The lower end of the sand-filled casing string is connected to the external thickened fracturing tubing via threads. The external thickened fracturing tubing is then connected in sequence to the reverse circulation valve, hydraulic anchor, fracturing packer, setting ball seat, ball basket, and guide head via threads. The sand-filled casing string is lowered to a position 10m to 50m above the top of the target oil layer using a fracturing truck; or the sand-filled casing string is lowered to a position 10m to 50m above the top of the uppermost oil layer in a multi-layer system using a fracturing truck.

[0006] During construction:

[0007] Step 1: In the initial stage of on-site implementation, the instantaneous displacement of the fracturing truck is 5.0–5.5 m³ / h. 3 At a high pressure and high flow rate, pre-fracturing fluid is continuously injected into the well to extend the fracture. Pre-fracturing fluid is pumped to clean the near-wellbore formation and create fractures. Once the oil layer fractures are formed and the pump pressure and flow rate are stable, proppant can be added. Then, fracturing-grade quartz sand proppant is added at a 20% proppant ratio. After proppant addition, the displacement bypass process of the proppant mixing truck is activated, and displacement fluid is injected into the well to displace 10–20 m³ of the surface. 3 The sand-carrying liquid forms a slub filling to prevent the quartz sand proppant interface from directly contacting the subsequent resin-coated sand proppant, thereby affecting the bonding and curing effect of the resin-coated sand.

[0008] Step 2: The instantaneous displacement of the fracturing truck is 3.5–4.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 20%, and control the amount of resin-coated sand filled in this step to be 2-4t;

[0009] Step 3: The instantaneous displacement of the fracturing truck is 2.5–3.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 30%, and control the amount of resin-coated sand filled in this step to be 3-5t;

[0010] Step 4: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 40%, and control the amount of resin-coated sand filled in this step to be 10-13t;

[0011] Step 5: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 50%, and control the amount of resin-coated sand filled in this step to be 3-5t;

[0012] Step Six: The instantaneous displacement of the fracturing truck is 1.5–2.0 m³ / h. 3 / min, reduce displacement to form a sufficiently high sand ratio in the formation in the final stage, form a certain sand removal pressure difference, and establish a sand barrier of sufficient thickness;

[0013] If layered fracturing is adopted, steps 1 to 6 above are repeated for each layer. The only difference is that the displacement fluid should be designed to displace an excessive amount to avoid sand jamming of the tubing when the sand ratio is too high.

[0014] Step 7: After completing the above steps, close the well and diffuse the pressure for 72 hours; after using the fracturing truck to pull out the sand-filled tubing string, lower the sand-flushing tubing string to a position 5m to 10m above the top boundary of the oil layer. The sand-flushing tubing string consists of tubing and sand-flushing tools; the tubing and sand-flushing tools are connected by threads.

[0015] Step 8: Inject well-washing fluid into the sand-flushing tubing via positive circulation; the well-washing fluid is 90℃ hot oilfield wastewater; the well-washing fluid returns to the surface through the annular space of the tubing and casing; the well-washing sand-flushing discharge rate is 0.8m³. 3 / min~1.0m 3 / min; flush out the resin sand plugs pre-installed in the wellbore; until the bottom of the artificial well is reached; stop when the fluid returning from the wellhead is clear water.

[0016] Step 9: Lower the sand flushing string to probe the sand level inside the wellbore; if obstruction is encountered, continue flushing sand to the bottom of the artificial well; if flushing sand does not work, lower the screw drill string and drill plug to the bottom of the artificial well.

[0017] The sand ratio is the concentration ratio of fracturing fluid to proppant.

[0018] In step 1, the viscosity and dosage of the pretreatment fluid are set based on the premise that the crack length does not exceed 100m.

[0019] In step 1, the quartz sand particle size is selected to be 0.3-0.6 mm.

[0020] In step 1, the amount of quartz sand proppant used is one-third of the amount of resin-coated sand proppant used.

[0021] The particle size of the resin-coated sand is selected to be 0.45-0.85 mm.

[0022] In step six, the sand ratio is 40-50%, and the sand removal pressure difference is greater than 3 MPa.

[0023] The resin-coated sand is classified into normal-temperature resin sand, high-temperature resistant resin sand, and long-lasting high-temperature resistant resin sand. All three types of resin sand can be used for sand control in light oil wells. Among them, high-temperature resistant resin sand and long-lasting high-temperature resistant resin sand can be used for sand control in high-temperature 350℃ steam injection wells, while long-lasting high-temperature resistant resin sand can be used for sand control in steam-driven wells.

[0024] The technological principle of this invention is as follows:

[0025] Hydraulic fracturing involves using a high-pressure pump on the surface to inject a high-viscosity fracturing fluid into the oil reservoir through the wellbore. When the injection rate of the fracturing fluid exceeds the reservoir's absorption capacity, a very high pressure is created at the bottom of the well. When this pressure exceeds the fracturing pressure of the rock near the bottom of the well, the reservoir is forced open, creating fractures. Continuing to inject fracturing fluid further propagates the fractures into the reservoir. To keep the fractures open, proppant-carrying fluid is injected. This proppant-carrying fluid, once inside the fractures, both allows the fractures to extend further and supports the opened fractures, preventing them from closing. Next, displacement fluid is injected to displace all the proppant-carrying fluid from the wellbore into the fractures, which are then supported by silica sand. Finally, the injected high-viscosity fracturing fluid automatically degrades and is discharged from the wellbore, leaving one or more fractures of varying lengths, widths, and heights within the reservoir, establishing a new fluid channel between the reservoir and the wellbore. After fracturing, the production of oil and gas wells generally increases significantly.

[0026] Fracturing and sand control technology utilizes the relatively loose nature of sand-producing formations, combining fracturing with sand control. It employs a fracturing truck to pump fracturing fluid into the formation at pressures higher than the formation fracturing pressure. Filler sand is then injected into the opened formation at different sand ratios (10%, 15%, 20%, 30%). After the filler sand reaches the design requirements, resin-coated sand is injected. Under the influence of formation temperature and a curing agent, the resin-coated sand cements and solidifies, forming a sand barrier near the wellbore. Because of its high permeability, it does not impede fluid flow into the wellbore. While achieving sand control, this method also significantly alters the flow pattern of fluids in the formation, changing the flow near the wellbore from radial to linear, reducing flow resistance. Compared to other sand control methods, its entire filler layer acts as a high-permeability filter zone, increasing the filtration area for formation fluids. This is particularly beneficial for wells producing fine sands, reducing filter clogging and significantly extending the effective period of sand control.

[0027] The beneficial effects of the above-mentioned technical solution adopted in this invention are as follows:

[0028] (1) This invention expands the high permeability range of the near-well formation by pressing open the sand layer and filling it with a larger amount of quartz sand and resin-coated sand, which is beneficial to improving the sand control effect and extending the sand control period.

[0029] (2) This technology combines fracturing and sand control, and utilizes existing tubing to achieve continuous construction of tubing in one operation. It has the advantages of simple operation and low cost, effectively improving the fracturing and sand control effect and increasing the success rate of construction.

[0030] (3) This invention can help to unblock the near-wellbore zone of the oil-bearing layer and even modify the oil layer, thereby increasing the production of the oil well. This technology also has the function of protecting and reinforcing the casing, which can effectively prevent casing deformation and breakage. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To further understand the invention, the following detailed description is provided in conjunction with the embodiments:

[0033] Example 1:

[0034] A process for integrating slug-filled hydraulic fracturing with wellbore sand control, the specific steps of which are as follows:

[0035] Before construction, the casing string is lowered. The sand-filled casing string is lowered into the casing using a fracturing truck. The lower end of the sand-filled casing string is connected to the external thickened fracturing tubing via threads. The external thickened fracturing tubing is then connected in sequence to the reverse circulation valve, hydraulic anchor, fracturing packer, setting ball seat, ball basket, and guide head via threads. The sand-filled casing string is lowered to a position 10m to 50m above the top of the target oil layer using a fracturing truck; or the sand-filled casing string is lowered to a position 10m to 50m above the top of the uppermost oil layer in a multi-layer system using a fracturing truck.

[0036] During construction:

[0037] Step 1: In the initial stage of on-site implementation, the instantaneous displacement of the fracturing truck is 5.0–5.5 m³ / h. 3 At a high pressure and high flow rate, pre-fracturing fluid is continuously injected into the well to extend the fracture. Pre-fracturing fluid is pumped to clean the near-wellbore formation and create fractures. Once the oil layer fractures are formed and the pump pressure and flow rate are stable, proppant can be added. Then, fracturing-grade quartz sand proppant is added at a 20% proppant ratio. After proppant addition, the displacement bypass process of the proppant mixing truck is activated, and displacement fluid is injected into the well to displace 10-20m³ of the surface. 3 The sand-carrying liquid forms a slub filling to prevent the quartz sand proppant interface from directly contacting the subsequent resin-coated sand proppant, thereby affecting the bonding and curing effect of the resin-coated sand.

[0038] Step 2: The instantaneous displacement of the fracturing truck is 3.5–4.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 20%, and control the amount of resin-coated sand filled in this step to be 2-4t;

[0039] Step 3: The instantaneous displacement of the fracturing truck is 2.5–3.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 30%, and control the amount of resin-coated sand filled in this step to be 3-5t;

[0040] Step 4: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 40%, and control the amount of resin-coated sand filled in this step to be 10-13t;

[0041] Step 5: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 50%, and control the amount of resin-coated sand filled in this step to be 3-5t;

[0042] Step Six: The instantaneous displacement of the fracturing truck is 1.5–2.0 m³ / h. 3 / min, reduce displacement to form a sufficiently high sand ratio in the formation in the final stage, form a certain sand removal pressure difference, and establish a sand barrier of sufficient thickness;

[0043] If layered fracturing is adopted, steps 1 to 6 above are repeated for each layer. The only difference is that the displacement fluid should be designed to displace an excessive amount to avoid sand jamming of the tubing when the sand ratio is too high.

[0044] Step 7: After completing the above steps, close the well and diffuse the pressure for 72 hours; after using the fracturing truck to pull out the sand-filled tubing string, lower the sand-flushing tubing string to a position 5m to 10m above the top boundary of the oil layer. The sand-flushing tubing string consists of tubing and sand-flushing tools; the tubing and sand-flushing tools are connected by threads.

[0045] Step 8: Inject well-washing fluid into the sand-flushing tubing via positive circulation; the well-washing fluid is 90℃ hot oilfield wastewater; the well-washing fluid returns to the surface through the annular space of the tubing and casing; the well-washing sand-flushing discharge rate is 0.8m³. 3 / min~1.0m 3 / min; flush out the resin sand plugs pre-installed in the wellbore; until the bottom of the artificial well is reached; stop when the fluid returning from the wellhead is clear water.

[0046] Step 9: Lower the sand flushing string to probe the sand level inside the wellbore; if obstruction is encountered, continue flushing sand to the bottom of the artificial well; if flushing sand does not work, lower the screw drill string and drill plug to the bottom of the artificial well.

[0047] The sand ratio is the concentration ratio of fracturing fluid to proppant.

[0048] In step one, the viscosity and dosage of the pretreatment fluid are set based on the premise that the crack length does not exceed 100m.

[0049] In step one, the quartz sand particle size is selected to be 0.3-0.6 mm.

[0050] In step one, the amount of quartz sand proppant used is one-third of the amount of resin-coated sand proppant used.

[0051] The particle size of the resin-coated sand is selected to be 0.45-0.85 mm.

[0052] In step six, the sand ratio is 40-50%, and the sand removal pressure difference is greater than 3 MPa.

[0053] The resin-coated sand is classified into normal-temperature resin sand, high-temperature resistant resin sand, and long-lasting high-temperature resistant resin sand. All three types of resin sand can be used for sand control in light oil wells. Among them, high-temperature resistant resin sand and long-lasting high-temperature resistant resin sand can be used for sand control in high-temperature 350℃ steam injection wells, while long-lasting high-temperature resistant resin sand can be used for sand control in steam-driven wells.

[0054] Example 2:

[0055] Taking the Shusan Block of Liaohe Oilfield as an example, the target development layer in Shusan Block is the Dujiatai oil layer of the fourth member of the Shahejie Formation of the Lower Tertiary, with a burial depth of 950–1700 m and an oil-bearing area of ​​19.0 km². 2 The geological reserves are 2244×104t, the recoverable reserves are 758×104t, and the average effective thickness of the oil layer is 12.7m.

[0056] The oil wells being produced are experiencing widespread sand production; over 90% of the oil and water wells have a history of sand or mud production, severely hindering normal production. The cumulative sand production exceeds 2 cubic meters per second. 3 The number of wells reached 149, accounting for 55.8% of the total number of oil and water wells, with a cumulative sand production of 0.5m³. 3 ~2m 3 Of the 81 wells, 30.3% were affected. In terms of sand particle size, the sand produced by oil and water wells is mostly fine sand and mud, with a median particle size generally between 0.07 and 0.16 mm.

[0057] To address the sand production problem in oil and water wells in the Shusan District, various sand control methods were employed. One method involved using metal wire-wound screens, implemented in 31 wells with a sand control effectiveness rate exceeding 65%. However, due to subsequent blockages leading to low production, most wells with potential for sand control underwent major repairs and were subsequently removed. Low-temperature sand-fixing technology was implemented in 21 wells, showing generally good results with an effectiveness rate of 71.4%, but its effective period was relatively short.

[0058] The Shu 3-10-5c well has a producing layer at 1152.6–1201.6 m, with an effective thickness of 23.1 m and 10 layers. Due to severe sand production, the well could not produce normally. Artificial wellbore sand control measures were previously implemented, but production dropped significantly afterward, forcing the well to be shut down. Subsequently, the construction process of this invention was adopted, with the specific steps as follows:

[0059] Step 1: At the initial stage of on-site implementation, the instantaneous displacement of the fracturing truck is 5.0 m³ / h. 3At a high pressure and high flow rate, pre-fracturing fluid is continuously injected into the well to extend the fracture. Pre-fracturing fluid is pumped to clean the near-wellbore formation and create fractures. Once the oil layer fractures are formed and the pump pressure and flow rate are stable, proppant can be added. Then, fracturing-grade quartz sand proppant is added at a 20% proppant ratio. After proppant addition, the displacement bypass process of the proppant mixing truck is activated, and displacement fluid is injected into the well to displace 10m³ of the proppant. 3 The sand-carrying liquid forms a slub filling to prevent the quartz sand proppant interface from directly contacting the subsequent resin-coated sand proppant, thereby affecting the bonding and curing effect of the resin-coated sand.

[0060] Step 2: The instantaneous displacement of the fracturing truck is 3.5m³. 3 / min, fill resin-coated sand proppant with a sand ratio of 20%, and control the amount of resin-coated sand filled in this step to 2t;

[0061] Step 3: The instantaneous displacement of the fracturing truck is 2.5m³. 3 / min, fill resin-coated sand proppant with a sand ratio of 30%, and control the amount of resin-coated sand filled in this step to 4t;

[0062] Step 4: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 40%, and control the amount of resin-coated sand filled in this step to 10t;

[0063] Step 5: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 50%, and control the amount of resin-coated sand filled in this step to 3t;

[0064] Step Six: The instantaneous displacement of the fracturing truck is 1.5m³. 3 / min, reduce displacement to form a sufficiently high sand ratio in the formation in the final stage, form a certain sand removal pressure difference, and establish a sand barrier of sufficient thickness;

[0065] Step 7: After completing the above steps, close the well and diffuse the pressure for 72 hours; after using the fracturing truck to pull out the sand-filled tubing string, lower the sand-flushing tubing string to a position 5m to 10m above the top boundary of the oil layer. The sand-flushing tubing string consists of tubing and sand-flushing tools; the tubing and sand-flushing tools are connected by threads.

[0066] Step 8: Inject well-washing fluid into the sand-flushing tubing via positive circulation; the well-washing fluid is 90℃ hot oilfield wastewater; the well-washing fluid returns to the surface through the annular space of the tubing and casing; the well-washing sand-flushing discharge rate is 0.8m³. 3 / min; flush out the resin sand plugs pre-installed in the wellbore; until the bottom of the artificial well is reached; stop when the fluid returning from the wellhead is clear water.

[0067] Step 9: Lower the sand flushing string to probe the sand level inside the wellbore; if obstruction is encountered, continue flushing sand to the bottom of the artificial well; if flushing sand does not work, lower the screw drill string and drill plug to the bottom of the artificial well.

[0068] After construction using the construction process of this invention, the filling sand breaks through the artificial well wall filter layer, removes the sand blockage, and forms a high-permeability zone near the bottom of the well, greatly enhancing the sand control and flow guiding capabilities. After construction, the oil well produces more than 8 tons of oil per day, with remarkable results.

[0069] The process method of this invention has been applied to 124 wells in this block, with a 100% success rate and an effectiveness rate of 88.7%. It has a long sand control period, with an average sand control period of 180 days, and has achieved good economic benefits.

[0070] Example 3:

[0071] A field test of the method of this invention was conducted at well Lei 21-05, with 20m³ of quartz sand designed for use. 3 15m resin-coated sand 3 The specific steps of the process method of this invention are as follows:

[0072] Before construction, the casing string is lowered. The sand-filled casing string is lowered into the casing using a fracturing truck. The lower end of the sand-filled casing string is connected to the external thickened fracturing tubing via threads. The external thickened fracturing tubing is then connected in sequence to the reverse circulation valve, hydraulic anchor, fracturing packer, setting ball seat, ball basket, and guide head via threads. The sand-filled casing string is lowered to a position 10m to 50m above the top of the target oil layer using a fracturing truck; or the sand-filled casing string is lowered to a position 10m to 50m above the top of the uppermost oil layer in a multi-layer system using a fracturing truck.

[0073] During construction:

[0074] Step 1: At the initial stage of on-site implementation, the instantaneous displacement of the fracturing truck is 5.1 m³ / s. 3 At a high pressure and high flow rate, pre-fracturing fluid is continuously injected into the well to extend the fracture. Pre-fracturing fluid is pumped to clean the near-wellbore formation and create fractures. Once the oil layer fractures are formed and the pump pressure and flow rate are stable, proppant can be added. Then, fracturing-grade quartz sand proppant is added at a 20% proppant ratio. After proppant addition, the displacement bypass process of the proppant mixing truck is activated to inject displacement fluid into the well, displacing the proppant-carrying fluid and forming a slug filler. This prevents the quartz sand proppant interface from directly contacting the subsequent resin-coated sand proppant, which could affect the bonding and curing effect of the resin-coated sand.

[0075] Step 2: The instantaneous displacement of the fracturing truck is 3.8m³. 3 / min, fill resin-coated sand proppant with a sand ratio of 20%, and control the amount of resin-coated sand filled in this step to be 3.4t;

[0076] Step 3: The instantaneous displacement of the fracturing truck is 3.0 m³ / h.3 / min, fill resin-coated sand proppant with a sand ratio of 30%, and control the amount of resin-coated sand filled in this step to be 4.5t;

[0077] Step 4: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 40%, and control the amount of resin-coated sand filled in this step to 13t;

[0078] Step 5: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 50%, and control the amount of resin-coated sand filled in this step to 5t;

[0079] Step Six: The instantaneous displacement of the fracturing truck is 1.7m³. 3 / min, reduce displacement to form a sufficiently high sand ratio in the formation in the final stage, form a certain sand removal pressure difference, and establish a sand barrier of sufficient thickness;

[0080] Step 7: After completing the above steps, close the well and diffuse the pressure for 72 hours; after using the fracturing truck to pull out the sand-filled tubing string, lower the sand-flushing tubing string to a position 5m to 10m above the top boundary of the oil layer. The sand-flushing tubing string consists of tubing and sand-flushing tools; the tubing and sand-flushing tools are connected by threads.

[0081] Step 8: Inject well-washing fluid into the sand-flushing tubing string via positive circulation; the well-washing fluid is 90℃ hot oilfield wastewater; the well-washing fluid returns to the surface through the annular space of the tubing and casing; the well-washing sand-flushing discharge rate is 0.9m³. 3 / min; flush out the resin sand plugs pre-installed in the wellbore; until the bottom of the artificial well is reached; stop when the fluid returning from the wellhead is clear water.

[0082] Step 9: Lower the sand flushing string to probe the sand level inside the wellbore; if obstruction is encountered, continue flushing sand to the bottom of the artificial well; if flushing sand does not work, lower the screw drill string and drill plug to the bottom of the artificial well.

[0083] Observations from the on-site construction process indicate that the formation was completely fractured during the early high-flow-rate fracturing stage, and the filling pressure differential increased by 13 MPa during the later low-flow-rate resin-coated sand sealing stage, forming a relatively good artificial wellbore. The well was pumped after 304 days of self-flowing production, with a cumulative oil production of 1575.8 tons.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process method integrating slug-filled hydraulic fracturing with wellbore sand control, characterized in that, The specific steps are as follows: Before construction, the casing string is lowered. The sand-filled casing string is lowered into the casing using a fracturing truck. The lower end of the sand-filled casing string is connected to the external thickened fracturing tubing via threads. The external thickened fracturing tubing is then connected in sequence to the reverse circulation valve, hydraulic anchor, fracturing packer, setting ball seat, ball basket, and guide head via threads. The sand-filled casing string is lowered to a position 10m to 50m above the top of the target oil layer using a fracturing truck; or the sand-filled casing string is lowered to a position 10m to 50m above the top of the uppermost oil layer in a multi-layer system using a fracturing truck. During construction: Step 1: In the initial stage of on-site implementation, the instantaneous displacement of the fracturing truck is 5.0–5.5 m³ / h. 3 At a high pressure and high flow rate, pre-fracturing fluid is continuously injected into the well to extend the fracture. Pre-fracturing fluid is then pumped to clean the near-wellbore formation and create fractures. Once the oil layer fractures are formed and the pump pressure and flow rate are stable, proppant can be added. Then, fracturing-grade quartz sand proppant is added at a 20% proppant ratio. After proppant addition, the displacement bypass process of the proppant truck is activated, and displacement fluid is injected into the well to displace 10–20 m³ of the surface. 3 The sand-carrying liquid forms a slub filling to prevent the quartz sand proppant interface from directly contacting the subsequent resin-coated sand proppant, thereby affecting the bonding and curing effect of the resin-coated sand. Step 2: The instantaneous displacement of the fracturing truck is 3.5–4.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 20%, and control the amount of resin-coated sand filled in this step to be 2-4t; Step 3: The instantaneous displacement of the fracturing truck is 2.5–3.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 30%, and control the amount of resin-coated sand filled in this step to be 3-5t; Step 4: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 40%, and control the amount of resin-coated sand filled in this step to be 10-13t; Step 5: The instantaneous displacement of the fracturing truck is 2.0 m³ / h. 3 / min, fill resin-coated sand proppant with a sand ratio of 50%, and control the amount of resin-coated sand filled in this step to be 3-5t; Step Six: The instantaneous displacement of the fracturing truck is 1.5–2.0 m³ / h. 3 / min, reduce displacement to form a sufficiently high sand ratio in the formation in the final stage, form a certain sand removal pressure difference, and establish a sand barrier of sufficient thickness; If layered fracturing is adopted, steps one to six above are repeated for each layer. When repeating step one, an excessive amount of displacement fluid is injected into the well to avoid sand jamming the tubing when the sand ratio is too high. Step 7: After completing the above steps, close the well and diffuse the pressure for 72 hours; after using the fracturing truck to pull out the sand-filled tubing string, lower the sand-flushing tubing string to a position 5m to 10m above the top boundary of the oil layer. The sand-flushing tubing string consists of tubing and sand-flushing tools; the tubing and sand-flushing tools are connected by threads. Step 8: Inject well-washing fluid into the sand-flushing tubing via positive circulation; the well-washing fluid is 90℃ hot oilfield wastewater; the well-washing fluid returns to the surface through the annular space of the tubing and casing; the well-washing sand-flushing discharge rate is 0.8m³. 3 / min~1.0m 3 / min; flush out the resin sand plug pre-installed in the wellbore; until the bottom of the artificial well is reached; stop when the fluid returning from the wellhead is clear water; Step 9: Lower the sand flushing string to probe the sand level inside the wellbore; if obstruction is encountered, continue flushing sand to the bottom of the artificial well; if flushing sand does not work, lower the screw drill string and drill plug to the bottom of the artificial well.

2. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, The viscosity and dosage of the pre-treatment fluid are set based on the premise that the crack length does not exceed 100m.

3. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, The quartz sand particle size is selected to be 0.3-0.6 mm.

4. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, The amount of the quartz sand proppant used is one-third of the amount of the resin-coated sand proppant used.

5. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, The particle size of the resin-coated sand is selected to be 0.45-0.85 mm.

6. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, In step six, the sand ratio is 40-50%, and the sand removal pressure difference is greater than 3 MPa.

7. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, In step six, the sand ratio is 50%.

8. The integrated hydraulic fracturing and wellbore sand control process according to claim 1, characterized in that, The resin-coated sand is of the following types: room temperature resin sand, high temperature resistant resin sand, or long-lasting high temperature resistant resin sand.