Synchronous staged fracturing acidizing process

Abstract

The invention provides a synchronous staged fracturing acidizing process which comprises the following steps: adopting a sliding sleeve arranged at the joint of each section of reservoir and an oil pipe or a sleeve, and controlling the opening of the sliding sleeve to control the flow of a liquid outlet of the sliding sleeve, so as to control the liquid inlet amount of each section of reservoir and realize uniform transformation of each section; the sliding sleeve can conduct multi-stage adjustment on the area of a fluid outlet of the sliding sleeve. The sliding sleeves or the flow sensors connected with the sliding sleeves can obtain flow data passing through the sliding sleeves in real time, and the flow data are shared among the multiple sliding sleeves. The sliding sleeve can carry out remote communication, when the ground equipment monitors that the actually measured flow of a liquid outlet of the sliding sleeve is inconsistent with the preset flow of the liquid outlet, the sliding sleeve is in remote communication with the ground equipment, the ground equipment sends a control instruction to the sliding sleeve, the flow value needing to enter each section of reservoir stratum is modified, and the flow value is adjusted by adjusting the opening degree of the sliding sleeve. And the redistribution of the inlet flow of each section of reservoir is realized. The method has the beneficial effect that synchronous staged fracturing without layer transfer can be realized.

Description

Technical Field

[0001] This invention relates to the field of fracturing construction technology, specifically to a simultaneous segmented fracturing and acidizing process. Background Technology

[0002] The current mainstream demand for fracturing and acidizing is staged fracturing and acidizing technology, which can achieve precise staged stimulation of reservoirs and increase production. Various staged fracturing technologies exist, including ball-drop sliding sleeve staged fracturing, bridge plug staged fracturing, and temporary plugging ball / plugging agent staged fracturing. When evaluating the merits of each staged fracturing technology, layer transition efficiency is a crucial indicator; higher efficiency leads to improved operational efficiency and reduced costs. However, layer transition time is an unavoidable cost factor that impacts the construction schedule to some extent. Therefore, providing a simultaneous staged fracturing and acidizing process that eliminates the need for layer transition is of significant importance.

[0003] Chinese patent application number CN201510078639.6, entitled "Segmented Fracturing Method for Horizontal Wells," discloses a segmented fracturing method for horizontal wells. The method includes: setting a fixing seat on the inner wall of the casing along the central axis of the casing according to the number of fracturing stages in the casing; lowering the casing into a predetermined position within the horizontal well; and sequentially performing the following operations on the second to Nth fracturing stages: placing a soluble ball seat at the lower end of the perforation tool string; and pumping the perforation tool string and the soluble ball seat to... In the corresponding fracturing segment; the soluble ball seat is controlled to form a closed soluble ball seat, the outer diameter of which is larger than the through diameter of the fixed seat. The perforation tool string is controlled to separate from the closed soluble ball seat so that the closed soluble ball seat abuts against the fixed seat in the corresponding fracturing segment. The perforation tool string is controlled to perforate at a first preset position in the corresponding fracturing segment. The perforation tool string is then removed, and the corresponding fracturing segment is fracturing. Soluble balls are inserted into the through hole of the closed soluble ball seat to seal the corresponding fracturing segment. However, this method differs from the process described in this application. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to solve one or more of the problems existing in the prior art. For example, one objective of this invention is to provide a simultaneous segmented fracturing and acidizing process that does not require layer transfer.

[0005] To achieve the above objectives, the present invention provides a synchronous segmented fracturing and acidizing process. This process may include using sliding sleeves installed at the connections between each reservoir segment and the tubing or casing. By controlling the opening of the sliding sleeves, the flow rate at the sleeve outlet is controlled, thereby controlling the fluid inflow to each reservoir segment and achieving uniform fracturing of each segment. The sliding sleeves can perform multi-level adjustment of the fluid outlet area. The sliding sleeves themselves, or through a flow sensor connected to them, can acquire real-time flow data through the sliding sleeves, and this flow data is shared among several sliding sleeves. The sliding sleeves can perform remote communication. When the ground equipment detects a discrepancy between the measured flow rate at the sliding sleeve outlet and the preset flow rate, the sliding sleeves communicate remotely with the ground equipment. The ground equipment sends control commands to the sliding sleeves to modify the flow rate values ​​required to enter each reservoir segment. By adjusting the opening of the sliding sleeves, the flow rate entering each reservoir segment is redistributed.

[0006] According to one or more exemplary embodiments of one aspect of the present invention, one or more sliding sleeves may be provided at each segment of the reservoir.

[0007] According to one or more exemplary embodiments of one aspect of the present invention, the remote communication may include wired, wireless and fiber optic communication.

[0008] According to one or more exemplary embodiments of one aspect of the present invention, the flow sensor may be disposed on the upper side of the liquid outlet of the sliding sleeve, and the flow sensor is capable of transmitting the measured flow data to the sliding sleeve, which then transmits the data to other sliding sleeves via remote communication.

[0009] According to one or more exemplary embodiments of one aspect of the present invention, the number of stages of the reservoir may include a first stage to an nth stage according to the flow direction; the flow rate entering the first stage reservoir is equal to the flow rate passing through the sliding sleeve at the first stage, and the flow rate entering the nth stage reservoir is equal to the flow rate passing through the sliding sleeve at the nth stage minus the flow rate passing through the sliding sleeve at the (n-1)th stage.

[0010] Furthermore, n can be 2 to 10000.

[0011] According to one or more exemplary embodiments of one aspect of the present invention, the pumping time of each reservoir segment is the same, and the scale of the modification of each reservoir segment can be proportional to the flow rate entering each reservoir segment.

[0012] According to one or more exemplary embodiments of one aspect of the present invention, the opening adjustment of the sliding sleeve may employ closed-loop control or open-loop control.

[0013] According to one or more exemplary embodiments of one aspect of the present invention, the closed-loop control may include: when the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate at the outlet, the ground equipment sends a control command to the sliding sleeve to modify the flow rate value required to enter each reservoir segment, and the sliding sleeve automatically adjusts its opening to realize the redistribution of the flow rate entering each reservoir segment; the open-loop control may include: when the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate at the outlet, the sliding sleeve automatically adjusts its opening according to the change in the discharge rate through the body based on the preset flow rate value required for each reservoir segment.

[0014] According to one or more exemplary embodiments of one aspect of the present invention, each reservoir segment may be provided with a pressure sensor and a temperature sensor to assist the sliding sleeve in adjusting the opening degree.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0016] (1) The synchronous segmented fracturing acidizing process proposed in this invention can realize segmented fracturing without stopping the pump, saving the transition time, greatly improving construction efficiency and saving costs.

[0017] (2) The synchronous segmented fracturing and acidizing process proposed in this invention can dynamically realize the uniform transformation of each reservoir segment, and can also be adjusted according to different flow rates to realize the synchronous transformation of different segments at different scales.

[0018] (3) The synchronous segmented fracturing and acidizing process proposed in this invention can achieve adaptive adjustment under different reservoir conditions in different segments, ensuring that the scale of each segment modification is consistent with the design. Attached Figure Description

[0019] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram of the fracturing tubing structure in the synchronous segmented fracturing acidizing process of the present invention is shown;

[0021] Figure 2 A schematic diagram of the three-stage flow distribution in the synchronous staged fracturing and acidizing process of the present invention is shown.

[0022] Figure 3A This diagram illustrates the closed-loop control principle of the sliding sleeve opening control in the synchronous segmented fracturing and acidizing process of the present invention.

[0023] Figure 3B The diagram illustrates the open-loop control principle of the sliding sleeve opening control in the synchronous segmented fracturing and acidizing process of the present invention.

[0024] Explanation of key figure labels:

[0025] 1-oil pipe, 2-third sliding sleeve, 3-second sliding sleeve, 4-first sliding sleeve. Detailed Implementation

[0026] In the following, a simultaneous segmented fracturing acidizing process of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0027] In the description of this application, it should be understood that the terms "center," "upper," "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "first," "second," "third," etc., are only for the convenience of description and distinction, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality" or "several" means two or more. In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Exemplary Example 1

[0029] This exemplary embodiment provides a simultaneous segmented fracturing acidizing process.

[0030] Figure 1 A schematic diagram of the fracturing tubing structure in the simultaneous segmented fracturing and acidizing process of the present invention is shown. The following is in conjunction with... Figure 1 To describe the simultaneous segmented fracturing acidizing process of this exemplary embodiment.

[0031] The synchronous segmented fracturing and acidizing in this exemplary embodiment mainly relies on the downhole intelligent sliding sleeve to autonomously adjust its own opening degree through changes in its own wellbore displacement. By autonomously adjusting its own opening degree, the sliding sleeve ensures that the actual fluid injection volume of each segment meets the design requirements.

[0032] Because the geological characteristics (formation fracture pressure, porosity, etc.) of each reservoir segment differ, when the sliding sleeve opening is completely uniform across all segments, the fluid inflow will vary significantly, making it impossible to achieve uniform stimulation across all segments. Therefore, to achieve uniform stimulation across all segments, it is necessary to adjust the opening of the sliding sleeve in each segment to change the throttling pressure differential at the fluid outlet of each segment. This balances the differences in geological characteristics across segments and ensures uniform stimulation across all segments.

[0033] Specifically, the process described in this application may include the use of sliding sleeves installed at the connections between each reservoir section and the tubing or casing. By controlling the opening of the sliding sleeve, the flow rate at the sleeve outlet is controlled, thereby controlling the fluid inflow into each reservoir section and achieving uniform stimulation of each section. The sliding sleeve must at least have the functions of remote communication, in-tubing flow measurement, and automatic multi-stage opening adjustment. The sliding sleeve is run into the well along with the tubing / casing, and is initially in a closed state. It is activated before fracturing, putting the sliding sleeve into a standby state. When fracturing begins, the flow rate in the wellbore changes, and each sliding sleeve needs to automatically adjust its opening according to the change in the flow rate through the wellbore. Furthermore, the sliding sleeve can perform multi-stage adjustment of the fluid outlet area (e.g., five stages). The sliding sleeve itself can acquire flow rate data in real time, and the sliding sleeve itself has a flow measurement function; the flow rate data is shared among several sliding sleeves (the sliding sleeve can transmit data to other sliding sleeves via remote communication). The sliding sleeve is capable of remote communication. When the ground equipment detects that the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate, the sliding sleeve communicates remotely with the ground equipment. The ground equipment sends control commands to the sliding sleeve to modify the flow rate value that needs to enter each reservoir segment. By adjusting the opening of the sliding sleeve, the flow rate entering each reservoir segment is redistributed.

[0034] In this exemplary embodiment, one or more sliding sleeves may be provided at the corresponding location of each reservoir segment.

[0035] In this exemplary embodiment, remote communication may include wired, wireless, and fiber optic communication.

[0036] In this exemplary embodiment, the reservoir is segmented into stages from the first stage to the nth stage, in the opposite direction of flow. The flow rate entering the first stage reservoir is equal to the flow rate through the sliding sleeve at the first stage, and the flow rate entering the nth stage reservoir is equal to the flow rate through the sliding sleeve at the nth stage minus the flow rate through the sliding sleeve at the (n-1)th stage. For example, when there are three stages of reservoir, such as... Figure 1 As shown, a sliding sleeve can be provided at each connection point between the tubing 1 (or casing) and the first to third reservoir sections. A first sliding sleeve 4 is provided at the first reservoir section, a second sliding sleeve 3 is provided at the second reservoir section, and a third sliding sleeve 2 is provided at the third reservoir section.

[0037] Furthermore, in actual construction, the number of segmented levels is not limited to... Figure 1The level 3 in the text can be a segment from level 2 to level 10,000, such as level 5, level 5, 5,000 or level 9,500.

[0038] In this exemplary embodiment, the pumping time for each reservoir segment is the same, and the scale of modification of each reservoir segment can be proportional to the flow rate entering each reservoir segment.

[0039] In this exemplary embodiment, the opening adjustment of the sliding sleeve can be achieved using closed-loop control or open-loop control.

[0040] Furthermore, closed-loop control may include: when the measured flow rate at the sliding sleeve outlet is inconsistent with the preset flow rate, the surface equipment sends a control command to the sliding sleeve to modify the flow rate value required to enter each reservoir segment. The sliding sleeve automatically adjusts its opening to redistribute the flow rate entering each reservoir segment. In other words, the surface can actively adjust the flow rate based on real-time downhole flow monitoring.

[0041] Furthermore, open-loop control may include: when the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate at the outlet, the sliding sleeve automatically adjusts its opening according to the preset flow rate value required for each reservoir segment, based on the change in the discharge volume through the main body. That is, it relies on the sliding sleeve itself for automatic adjustment.

[0042] In this exemplary embodiment, each reservoir section may also be equipped with a pressure sensor and / or a temperature sensor to assist the sliding sleeve in adjusting the opening degree.

[0043] Exemplary Example 2

[0044] This exemplary embodiment provides another simultaneous segmented fracturing acidizing process.

[0045] Figure 2 A schematic diagram of the three-stage flow distribution in the synchronous staged fracturing and acidizing process of the present invention is shown. Figure 3A This diagram illustrates the closed-loop control principle of the sliding sleeve opening control in the synchronous segmented fracturing and acidizing process of the present invention. Figure 3B This diagram illustrates the open-loop control principle of the sliding sleeve opening control in the synchronous segmented fracturing and acidizing process of the present invention. The following is in conjunction with... Figures 2 to 3B To describe the simultaneous segmented fracturing acidizing process of this exemplary embodiment.

[0046] The process of this exemplary embodiment is largely the same as the synchronous segmented fracturing and acidizing process of Exemplary Embodiment 1. The main difference is that the sliding sleeve does not rely on itself to obtain the flow data passing through it, but rather obtains the flow data in real time through a flow sensor connected to it. For example, the flow sensor can be located on the upper side of the liquid outlet of the sliding sleeve. The flow sensor can transmit the measured flow data to the sliding sleeve, and the sliding sleeve can then transmit the data to other sliding sleeves through remote communication to achieve data sharing.

[0047] Furthermore, for flow measurement, a separate flow sensor can be installed at the upper end of each sliding sleeve (on the side above the fluid outlet of the sliding sleeve body, that is, closer to the wellhead). The flow sensor can transmit the measured data to the corresponding sliding sleeve, and the sliding sleeve can then transmit the data to other sliding sleeves via remote communication. Here, the flow sensor can refer to a sensor manufactured using various fluid measurement methods that can realize the flow measurement function.

[0048] In this exemplary embodiment, on the surface, the control program of the electrical control system built into each sliding sleeve can pre-set the flow rate value required to enter each reservoir segment according to the required modification scale of each segment. Later, control commands can also be sent from the surface equipment to each sliding sleeve downhole to modify the flow rate value required to enter each reservoir segment.

[0049] In this exemplary embodiment, the sliding sleeve must at least have the functions of remote communication and automatic multi-level adjustment of opening.

[0050] The remote communication function of the sliding sleeves ensures that each sliding sleeve can obtain real-time flow parameters measured by itself and every other sliding sleeve. Flow rate refers to the flow rate inside the casing or the tubing. The remote communication function refers to various wired, wireless, or fiber optic communication methods. Simultaneously, control commands can be sent from surface equipment to each sliding sleeve downhole to modify the flow rate values ​​entering each reservoir segment, and the sliding sleeves can automatically adjust their opening to redistribute the flow rate entering each reservoir segment.

[0051] The automatic multi-stage opening adjustment function refers to the ability of the sliding sleeve itself, driven by an electro-hydraulic drive system or a motor system, to adjust the fluid outlet area of ​​the sliding sleeve in multiple stages (five stages). This function requires no manual operation; each sliding sleeve automatically adjusts its fluid outlet area based on the difference between the pre-set required inlet flow rate and the actual measured flow rate, ensuring that the required inlet flow rate and the actual inlet flow rate are the same for each sliding sleeve.

[0052] In this exemplary embodiment, when three reservoirs exist, such as Figure 2 As shown in the diagram, Q1 represents the wellbore flow rate through the first reservoir flow sensor, Q2 represents the wellbore flow rate through the second reservoir flow sensor, and Q3 represents the wellbore flow rate through the third reservoir flow sensor; Q1' represents the flow rate entering the first reservoir, Q2' represents the flow rate entering the second reservoir, and Q3' represents the flow rate entering the third reservoir.

[0053] Where Q1' = Q1; Q2' = Q2 - Q1; Q3' = Q3 - Q2.

[0054] In this exemplary embodiment, the process of this application belongs to synchronous staged fracturing, with the same pumping time for each stage of the reservoir, and the scale of the stimulation of each stage of the reservoir (the volume of fracturing fluid entering each stage of the reservoir) can be proportional to the flow rate entering each stage of the reservoir.

[0055] In this exemplary embodiment, as Figures 3A-3B As shown, the opening adjustment of each sliding sleeve can be achieved using either closed-loop or open-loop control. In closed-loop control: the sliding sleeve control system that controls the opening can determine whether the measured flow rate at the sliding sleeve outlet matches the program-set flow rate. If they match, the sliding sleeve opening remains unchanged; if they do not match, the sliding sleeve opening is adjusted, and the measured flow rate at the sliding sleeve outlet is measured again. This flow rate information is then transmitted to the sliding sleeve control system for a new round of judgment. In open-loop control: the sliding sleeve control system that controls the opening can determine whether the measured flow rate at the sliding sleeve outlet matches the program-set flow rate. If they match, the sliding sleeve opening remains unchanged; if they do not match, the sliding sleeve opening is adjusted according to the program-set value (the flow rate value required for each reservoir segment preset in the sliding sleeve's own program). Specifically, the program settings here are to determine the fluid flow rate of each section of the reservoir before the sliding sleeve is lowered, and write this flow rate parameter into the program of each section using the circuit board of the sliding sleeve; the real-time flow rate measurement value of each section needs to be compared with this setting value in the program to determine how the sliding sleeve should act next.

[0056] In summary, the advantages proposed by this invention include at least one of the following:

[0057] (1) The synchronous segmented fracturing acidizing process proposed in this invention does not require layer transfer, which can help improve operational efficiency and reduce costs.

[0058] (2) The synchronous segmented fracturing and acidizing process proposed in this invention can be achieved by the sliding sleeve in the wellbore adjusting its own opening through the change of its own wellbore discharge. The sliding sleeve adjusts its own opening to ensure that the actual fluid intake of each segment meets the design requirements.

[0059] (3) Since the geological characteristics (formation fracture pressure, porosity, etc.) of each reservoir segment are different, when the opening of the sliding sleeve of each segment is completely consistent, the liquid inflow of each segment will be significantly different, making it impossible to achieve the goal of uniform modification of each segment. Therefore, in order to achieve uniform modification of each segment, the synchronous segmented fracturing and acidizing process proposed in this invention can be used to autonomously adjust the opening of the sliding sleeve of each segment to change the throttling pressure difference at the liquid outlet of each sliding sleeve, thereby balancing the differences in geological characteristics of each segment and ensuring that uniform modification of each segment is achieved.

[0060] Although a simultaneous segmented fracturing acidizing process of the present invention has been described above in conjunction with exemplary embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A simultaneous staged fracturing acidizing process, characterized in that, The process includes using sliding sleeves installed at the connections between each reservoir section and the tubing or casing. By controlling the opening of the sliding sleeves, the flow rate at the outlet of the sliding sleeve is controlled, thereby controlling the amount of fluid entering each reservoir section and achieving uniform modification of each section. The sliding sleeves can adjust the fluid outlet area in multiple stages. The sliding sleeves themselves or through a flow sensor connected to them can acquire flow data through the sliding sleeves in real time, and the flow data is shared among several sliding sleeves. The sliding sleeves can perform remote communication. When the ground equipment detects that the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate, the sliding sleeves communicate remotely with the ground equipment. The ground equipment sends control commands to the sliding sleeves to modify the flow rate value that needs to enter each reservoir section. By adjusting the opening of the sliding sleeves, the flow rate entering each reservoir section is redistributed.

2. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, One or more sliding sleeves are provided at each of the reservoir sections.

3. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, The remote communication includes wired, wireless, and fiber optic communication.

4. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, The flow sensor is located on the upper side of the liquid outlet of the sliding sleeve. The flow sensor can transmit the measured flow data to the sliding sleeve, and the sliding sleeve can then transmit the data to other sliding sleeves via remote communication.

5. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, The reservoir is divided into segments from the first segment to the nth segment according to the flow direction; the flow rate entering the first segment of the reservoir is equal to the flow rate passing through the sliding sleeve at the first segment, and the flow rate entering the nth segment of the reservoir is equal to the flow rate passing through the sliding sleeve at the nth segment minus the flow rate passing through the sliding sleeve at the (n-1)th segment.

6. The simultaneous staged fracturing and acidizing process according to claim 5, characterized in that, The value of n is 2 to 10000.

7. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, The pumping time for each reservoir segment is the same, and the scale of the modification of each reservoir segment is proportional to the flow rate entering each reservoir segment.

8. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, The opening degree of the sliding sleeve is adjusted by closed-loop control or open-loop control.

9. The simultaneous staged fracturing and acidizing process according to claim 8, characterized in that, The closed-loop control includes: when the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate at the outlet, the ground equipment sends a control command to the sliding sleeve to modify the flow rate value required to enter each reservoir segment, and the sliding sleeve automatically adjusts its opening to achieve a redistribution of the flow rate entering each reservoir segment; the open-loop control includes: when the measured flow rate at the outlet of the sliding sleeve is inconsistent with the preset flow rate value required for each reservoir segment, the sliding sleeve automatically adjusts its opening according to the change in the discharge rate through the main body based on the preset flow rate value.

10. The simultaneous staged fracturing and acidizing process according to claim 1, characterized in that, Each section of the reservoir is equipped with a pressure sensor and a temperature sensor to assist the sliding sleeve in adjusting the opening.

Images