Casing sliding sleeve separate layer fracturing pipe column and fracturing method for free-calibration deep well completion

Abstract

The casing sliding sleeve layered fracturing pipe column for free calibration deep well completion comprises a plurality of layers of pipe column units connected in sequence, each pipe column unit comprises a casing, the top end of the casing is coaxially connected with a sliding sleeve, the sliding sleeve is slidably connected with an inner core barrel, the side wall of the sliding sleeve is provided with a fracturing channel corresponding to the inner core barrel, and the bottom end of the casing is coaxially connected with a secondary connection ball barrel with an inner diameter smaller than that of the inner core barrel. The application further discloses a casing sliding sleeve layered fracturing method for free calibration deep well completion. The casing sliding sleeve layered fracturing pipe column and the fracturing method for free calibration deep well completion adopt the operation mode of the casing sliding sleeve and the secondary connection ball barrel, so that the later operation process is simpler and safer, the well is directly cemented and completed after drilling without calibration deep well, the operation efficiency of the casing sliding sleeve completion can be greatly improved, and the sticking caused by calibration deep well can be effectively avoided.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to a casing sliding sleeve layered fracturing string for deep well completion without calibration. This invention also relates to a casing sliding sleeve layered fracturing method for deep well completion without calibration. Background Technology

[0002] With the continuous exploitation of global oil resources, oil and gas resources with good reservoir properties are becoming increasingly scarce; low-grade oil and gas resources with poor reservoir properties are becoming the main source of oil and natural gas production. Improving the production of single wells is key, and large-volume fracturing has become an effective means of increasing gas well production. The casing sliding sleeve pressure distribution technology has the outstanding advantages of high construction efficiency and low construction cost.

[0003] The casing-sleeve fracturing process involves running the casing-sleeve tool along with the casing into the well after drilling is completed, followed by cementing. Later, ball-dropping at the wellhead enables rapid, layered fracturing. This process boasts significant advantages such as high efficiency, low operating costs, and minimal equipment usage. However, after the casing-sleeve tool is in the well, cable depth adjustment and repositioning of the casing-sleeve tool are required before cementing and completion. This necessitates multi-party coordination, impacting the process's progress and posing a certain risk of stuck pipe. Summary of the Invention

[0004] The purpose of this invention is to provide a casing sliding sleeve layered fracturing string for well completion without depth correction, which solves the problem of waiting for logging equipment to correct the depth of the casing sliding sleeve after the casing sliding sleeve tool is inserted into the well.

[0005] Another objective of this invention is to provide a casing sliding sleeve layered fracturing method for well completion without depth correction.

[0006] The first technical solution adopted in this invention is: a casing-sliding sleeve layered fracturing string for depth-free well completion, comprising several layers of string units connected end to end in sequence, each string unit including a casing, a sliding sleeve coaxially connected to the top of the casing, an inner core cylinder slidingly fitted inside the sliding sleeve, fracturing channels opened on the side wall of the sliding sleeve corresponding to the inner core cylinder, and a secondary ball receiving cylinder with an inner diameter smaller than the inner diameter of the inner core cylinder coaxially connected to the bottom of the casing.

[0007] The first technical solution of the present invention is further characterized in that,

[0008] The inner core is fitted with a sliding sleeve soluble ball.

[0009] The secondary ball receiving tube is equipped with a ball receiving tube that can dissolve balls.

[0010] The inner diameter of the secondary ball receiving cylinder in the upper-level column unit is larger than the inner diameter of the inner core cylinder in the adjacent lower-level column unit.

[0011] The inner diameter of the sleeve in each tubular unit is not less than the inner diameter of the inner core cylinder.

[0012] The second technical solution adopted in this invention is: a casing sliding sleeve layered fracturing method for well completion without depth correction. The method uses the aforementioned casing sliding sleeve layered fracturing string for well completion without depth correction, and includes the following steps:

[0013] Step 1: Determine the number of tubing units according to the number of layers to be fractured, and connect the tubing units on the surface so that the distance between two adjacent sliding sleeves is the same as the reservoir distance. After the tubing is connected, insert it into the well and cement it directly after it is inserted into the well.

[0014] Step 2: When measuring the cementing quality after cementing, re-measure the sliding sleeve position. If the sliding sleeve position is not deviated from the reservoir, directly drop the soluble ball from the sliding sleeve in the lowest tubing unit to open the fracturing channel and complete the first-stage fracturing. Then drop the soluble ball from the sliding sleeve in the tubing unit above the lowest one to complete the second-stage fracturing. Repeat this process to complete the fracturing of all segments. If the sliding sleeve position deviates from the reservoir when re-measuring the sliding sleeve position, proceed directly to Step 3.

[0015] Step 3: Connect the perforation gun to the ground cable working equipment to perforate the sidewall of the tubing corresponding to the lowest reservoir layer. After perforation, directly carry out the first layer fracturing. After fracturing, perforate the sidewall of the tubing corresponding to the next lower reservoir layer. After perforation, drop the soluble ball in the ball receiving tube of the next lower tubing unit to seal the lowest reservoir layer and carry out the second layer fracturing. Repeat this process to complete the fracturing of all layers.

[0016] The second technical solution of the present invention is further characterized in that,

[0017] In step 2, a magnetic locator is used to re-determine the position of the sliding sleeve.

[0018] The beneficial effects of the present invention are as follows: The casing sliding sleeve layered fracturing string and fracturing method of the present invention for depth-free well completion adopts the operation mode of casing sliding sleeve and secondary ball receiving tube, which makes the subsequent operation process simpler and safer. It realizes direct cementing completion without depth correction after drilling, which can significantly improve the operation efficiency of casing sliding sleeve well completion and effectively avoid stuck drill bit situation caused by equal depth correction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the casing sliding sleeve layered fracturing string for deep well completion without calibration according to the present invention;

[0020] Figure 2 This is a schematic diagram of the sliding sleeve structure in the casing sliding sleeve layered fracturing string of the present invention, which eliminates the need for deep well completion calibration.

[0021] Figure 3 This is a schematic diagram of the secondary ball receiving tube in the casing sliding sleeve layered fracturing string of the present invention, which is a deep well completion without calibration.

[0022] In the figure, 1. casing, 2. sliding sleeve, 3. inner core cylinder, 4. fracturing channel, 5. secondary ball receiving tube, 6. soluble ball of sliding sleeve, 7. soluble ball of ball receiving tube, 8. reservoir. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a casing sliding sleeve layered fracturing string for well completion without depth correction, such as... Figure 1 As shown, the system comprises several layers of tubular units connected end-to-end by sequential threads. Each tubular unit includes a sleeve 1, and a sliding sleeve 2 is coaxially connected to the top end of the sleeve 1. Figure 2 As shown, an inner core cylinder 3 is slidably fitted inside the sliding sleeve 2, and a soluble ball 6 is fitted inside the inner core cylinder 3. A fracturing channel 4 is formed on the side wall of the sliding sleeve 2 corresponding to the inner core cylinder 3. A secondary ball receiving cylinder 5 with an inner diameter smaller than the inner diameter of the inner core cylinder 3 is coaxially connected to the bottom end of the casing 1. Figure 3 As shown, the secondary ball receiving tube 5 is equipped with a soluble ball 7. Furthermore, the inner diameter of the secondary ball receiving tube 5 located in the upper-level tube unit is larger than the inner diameter of the inner core tube 3 in the adjacent lower-level tube unit, and the inner diameter of the sleeve 1 in each tube unit is not smaller than the inner diameter of the inner core tube 3, thereby ensuring that the soluble ball can pass through the upper-level tube unit and fall into the required inner core tube 3 or secondary ball receiving tube 5.

[0025] Through the above methods, the casing sliding sleeve layered fracturing string and fracturing method of the present invention, which achieves well completion without depth correction, adopts the operation mode of casing sliding sleeve and secondary ball receiving tube, which makes the subsequent operation process simpler and safer. It realizes direct cementing completion without depth correction after drilling, which can significantly improve the operation efficiency of casing sliding sleeve well completion and effectively avoid stuck drill situation caused by equal depth correction.

[0026] Example 1

[0027] Based on the above-mentioned fracturing method for casing sliding sleeve layered fracturing string without calibration for deep well completion, such as Figure 1 As shown, it includes the following steps:

[0028] Step 1: Determine the use of two tubing units for the two reservoirs 8 that need to be fractured, and connect the tubing units on the surface so that the distance between the two sliding sleeves 2 is the same as the distance between the reservoirs 8. After the tubing is connected, it is inserted into the well and cemented directly after it is inserted into the well.

[0029] Step 2: When measuring the cementing quality after cementing, the position of the sliding sleeve 2 is re-determined using a magnetic locator. If the position of the sliding sleeve 2 does not deviate from the reservoir 8, the soluble ball 6 of the sliding sleeve in the lower tubing unit is directly deployed. Then, liquid is injected into the tubing string, and the inner core cylinder 3 is pushed down by pushing the soluble ball 6 of the sliding sleeve, thereby opening the fracturing channel 4. Fracturing fluid is injected into the reservoir 8 through the fracturing channel 4 to complete the first-stage fracturing. Then, the soluble ball 6 of the sliding sleeve in the upper tubing unit is deployed to complete the second-stage fracturing.

[0030] Example 2

[0031] Based on the above-mentioned fracturing method for casing sliding sleeve layered fracturing string without calibration for deep well completion, such as Figure 1 As shown, it includes the following steps:

[0032] Step 1: Determine the use of two tubing units for the two reservoirs 8 that need to be fractured, and connect the tubing units on the surface so that the distance between the two sliding sleeves 2 is the same as the distance between the reservoirs 8. After the tubing is connected, it is inserted into the well and cemented directly after it is inserted into the well.

[0033] Step 2: When measuring the cementing quality after cementing, the position of the sliding sleeve 2 is re-determined using a magnetic locator. If the position of the sliding sleeve 2 deviates from the reservoir 8, the perforation gun is connected to the surface cable working equipment to perforate the sidewall of the tubing corresponding to the lower reservoir 8. After perforation, fracturing fluid is injected directly into the reservoir 8 through the perforation to perform the first-stage fracturing. After fracturing, the sidewall of the tubing corresponding to the upper reservoir 8 is perforated. After perforation, the soluble ball 7 in the ball receiving tube of the upper tubing unit is inserted to seal the lower reservoir 8 and perform the second-stage fracturing.

[0034] Example 3

[0035] The fracturing method based on the above-mentioned casing sliding sleeve layered fracturing string for depth-free well completion includes the following steps:

[0036] Step 1: Determine the number of tubing units required for the multi-layer reservoir 8 to be fractured, and connect the tubing units on the surface so that the distance between two adjacent sliding sleeves 2 is the same as the distance between reservoir 8. After the tubing is connected, insert it into the well and cement it directly after it is inserted into the well.

[0037] Step 2: When measuring the cementing quality after cementing, the position of the sliding sleeve 2 is re-determined using a magnetic locator. If the position of the sliding sleeve 2 is not deviated from the reservoir 8, the soluble ball 6 of the sliding sleeve in the lowest tubing unit is directly deployed. Then, fluid is injected into the tubing, and the inner core cylinder 3 is pushed down by pushing the soluble ball 6 of the sliding sleeve, thereby opening the fracturing channel 4. Fracturing fluid is injected into the reservoir 8 through the fracturing channel 4 to complete the first-stage fracturing. Then, the soluble ball 6 of the sliding sleeve in the tubing unit above the lowest layer is deployed to complete the second-stage fracturing. This process is repeated to complete the fracturing of all stages.

[0038] Example 4

[0039] The fracturing method based on the above-mentioned casing sliding sleeve layered fracturing string for depth-free well completion includes the following steps:

[0040] Step 1: Determine the number of tubing units required for the multi-layer reservoir 8 to be fractured, and connect the tubing units on the surface so that the distance between two adjacent sliding sleeves 2 is the same as the distance between reservoir 8. After the tubing is connected, insert it into the well and cement it directly after it is inserted into the well.

[0041] Step 2: When measuring the cementing quality after cementing, the position of the sliding sleeve 2 is re-determined using a magnetic locator. If the position of the sliding sleeve 2 deviates from the reservoir 8, the perforation gun is connected to the surface cable working equipment to perforate the sidewall of the tubing corresponding to the lowest reservoir 8. After perforation, fracturing fluid is injected directly into the reservoir 8 through the perforation to perform the first-stage fracturing. After fracturing, the sidewall of the tubing corresponding to the next lower reservoir 8 is perforated. After perforation, the soluble ball 7 in the ball receiving tube of the next lower tubing unit is dropped to seal the lowest reservoir 8 and perform the second-stage fracturing. This process is repeated to complete the fracturing of all segments.

Claims

1. A casing-sliding sleeve layered fracturing string for well completion without depth correction, characterized in that, The system comprises several layers of tubing units connected end to end. Each tubing unit includes a sleeve (1). The top of the sleeve (1) is coaxially connected to a sliding sleeve (2). The inner core cylinder (3) is slidably fitted inside the sliding sleeve (2). The inner core cylinder (3) is fitted with a sliding sleeve soluble ball (6). The side wall of the sliding sleeve (2) is provided with a fracturing channel (4) corresponding to the inner core cylinder (3). The bottom end of the sleeve (1) is coaxially connected to a secondary ball receiving cylinder (5) with an inner diameter smaller than that of the inner core cylinder (3). The secondary ball receiving cylinder (5) is fitted with a ball receiving cylinder soluble ball (7). The inner diameter of the secondary ball receiving cylinder (5) in the upper layer of tubing unit is larger than that of the inner core cylinder (3) in the adjacent lower layer of tubing unit. The inner diameter of the sleeve (1) in each tubing unit is not smaller than that of the inner core cylinder (3).

2. A casing-sliding sleeve layered fracturing method for well completion without depth correction, characterized in that, The casing sliding sleeve layered fracturing string for well completion without depth correction as described in claim 1 includes the following steps: Step 1: Determine the number of tubing units according to the number of layers to be fractured, and connect the tubing units on the ground so that the distance between two adjacent sliding sleeves (2) is the same as the distance between the reservoir (8). After the tubing is connected, it is inserted into the well and cemented directly after it is inserted into the well. Step 2: When measuring the cementing quality after cementing, re-measure the position of the sliding sleeve (2). If the position of the sliding sleeve (2) is not deviated from the reservoir (8), directly inject the soluble ball (6) of the sliding sleeve in the lowest tubing unit to open the fracturing channel (4) and complete the first layer fracturing. Then inject the soluble ball (6) of the sliding sleeve in the tubing unit above the lowest layer to complete the second layer fracturing. Repeat this process to complete the fracturing of all segments. If the position of the sliding sleeve (2) deviates from the reservoir (8) when re-measuring the position of the sliding sleeve, proceed directly to step 3. Step 3: Connect the perforation gun to the ground cable operation equipment to perforate the sidewall of the tubing corresponding to the lowest reservoir (8). After perforation, perform first-stage fracturing directly. After fracturing, perforate the sidewall of the tubing corresponding to the next lower reservoir (8). After perforation, insert the soluble ball (7) in the ball receiving tube of the next lower tubing unit to seal the lowest reservoir (8) and perform second-stage fracturing. Repeat this process to complete the fracturing of all segments.

3. The casing sliding sleeve layered fracturing method for depth-free well completion as described in claim 2, characterized in that, In step 2, the position of the sliding sleeve (2) is re-determined using a magnetic locator.

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