Overflow detection device and method based on underground injection flow and return flow monitoring

Abstract

The invention relates to an overflow detection device and method based on underground injection flow and return flow monitoring, the device comprises a shaft, an instrument, an underground injection flow monitoring module and a return flow monitoring module, a hollow channel is arranged in the instrument, the instrument is arranged in the shaft, and the hollow channel is communicated with the hollow channel. A space is reserved between the inner wall of the shaft and the outer wall of the instrument to form an annular space; the underground injection flow monitoring module comprises a shaft heat source fixing point and a shaft temperature thermocouple, and the shaft heat source fixing point and the shaft temperature thermocouple are arranged on the instrument outer wall of the annular space; the return flow monitoring module comprises a backflow heat source fixing point and a backflow temperature thermocouple, and the backflow heat source fixing point and the backflow temperature thermocouple are arranged on the inner wall of the hollow channel of the instrument. According to the overflow detection method based on underground injection flow and return flow monitoring, overflow is judged according to the correlation between underground injection flow information and return flow information, and therefore early overflow monitoring is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling construction, and in particular to an overflow detection device and method based on downhole injection flow and return flow monitoring. Background Art

[0002] During oil drilling, blowout accidents can cause great environmental damage and economic losses, but there are still many technical limitations for the prediction and monitoring of blowouts. Blowout is a phenomenon in which the pressure of formation fluids (oil, natural gas and water) is greater than the pressure in the well and flows into the wellbore in large quantities and gushes out from the wellhead during drilling. Blowout is extremely harmful, and the earlier the tendency of blowout is discovered, the greater the loss will be. Overflow is a precursor to blowout. It is a phenomenon in which formation fluids invade the well when the bottom hole pressure cannot balance the formation pressure during drilling. The most intuitive manifestation of overflow is a sharp increase in the flow rate of drilling fluid in the outlet pipe, which is much greater than the flow rate injected into the wellbore. Therefore, real-time monitoring of flow plays an important role in predicting the occurrence of overflow. If overflow is not discovered in time, it will cause drilling fluid pollution and drilling tool corrosion, and in severe cases, it will cause major accidents. Therefore, early monitoring of overflow is an important means to prevent blowouts.

[0003] Overflow is one of the most serious drilling complexities that affect drilling construction safety. Overflow not only seriously hinders the normal progress of drilling operations and reduces drilling efficiency, but also may cause other underground complex accidents such as well collapse, stuck drill, blowout, and may even cause wellbore scrapping and cause a large number of casualties. Late discovery of overflow will lose precious primary well control time and increase the difficulty of accident elimination and secondary well control. Therefore, intelligent detection and early warning of overflow have great practical significance for drilling efficiency, avoiding accidents and ensuring the safety of drilling workers. Early monitoring of overflow is actually monitoring the change of flow rate. The commonly used measurement method is to judge the overflow flow rate by measuring the drilling fluid level height in the ground mud pool. Although this can also observe the occurrence of overflow more intuitively, there is a serious lag. Although the current popular underground overflow detection technology is more effective than the traditional ground monitoring method, it is based on the measurement of indirect parameters and has certain limitations in monitoring accuracy. However, the current downhole flow measurement in drilling is usually aimed at the measurement of the downhole annular flow, and the overflow is judged by comparing the annular flow measured downhole with the mud pump injection flow on the ground. This judgment is based on two premises. First, the injected drilling fluid flow needs to be kept relatively stable at all times; second, the high temperature and high pressure and working conditions downhole have no effect on the drilling fluid flow through the measurement system. However, it is difficult to meet these two premises in practice. But if the injected drilling fluid flow and the drilling fluid flow returned from the annular can be measured downhole at the same time, through direct comparison and analysis of downhole data, it will be conducive to the early, rapid and accurate detection and early warning of overflow.

[0004] In summary, the existing technology currently has the following shortcomings:

[0005] (1) The existing downhole flow monitoring only monitors the flow of the one-way flow channel near the drill bit downhole, but does not monitor the downhole injection flow and return flow near the drill bit downhole, and does not judge whether there is overflow based on the relationship between the two flow rates.

[0006] (2) The flow correlation between the downhole injection flow and the return flow near the drill bit has not been established.

[0007] (3) Since only a single flow channel is monitored, the overflow monitoring lacks contrast, has a certain lag, and the accuracy of judging the overflow type is not high. Summary of the invention

[0008] The object of the present invention is to provide an overflow detection device and method based on downhole injection flow and return flow monitoring to solve the above-mentioned problem.

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

[0010] In a first aspect, the present invention discloses an overflow detection device based on downhole injection flow and return flow monitoring, comprising a wellbore, an instrument, a downhole injection flow monitoring module and a return flow monitoring module.

[0011] A hollow channel is provided inside the instrument, the instrument is arranged inside the wellbore, and a space is reserved between the inner wall of the wellbore and the outer wall of the instrument to form an annular space;

[0012] The downhole injection flow monitoring module includes a wellbore heat source fixing point and a wellbore temperature measuring thermocouple, and the wellbore heat source fixing point and the wellbore temperature measuring thermocouple are arranged on the outer wall of the instrument in the annular space;

[0013] The return flow monitoring module includes a return heat source fixing point and a return temperature measuring thermocouple, and the return heat source fixing point and the return temperature measuring thermocouple are arranged on the inner wall of the hollow channel of the instrument;

[0014] Among them, the downhole injection flow monitoring module and the return flow monitoring module are used to monitor the changes in downhole temperature data in real time; the downhole injection flow is obtained according to the temperature difference between the wellbore heat source fixed point and the wellbore temperature measuring thermocouple, and the return flow is obtained according to the temperature difference between the return flow heat source fixed point and the return flow temperature measuring thermocouple; finally, based on the correlation between the downhole injection flow and the return flow, it is judged whether there is overflow and an overflow conclusion is drawn.

[0015] Preferably, the temperatures of the wellbore heat source fixed point and the return heat source fixed point are both higher than the downhole temperature.

[0016] Preferably, the instrument is provided with a data acquisition module and a data processing module.

[0017] The wellbore heat source fixed point and wellbore temperature measuring thermocouple of the downhole injection flow monitoring module and the return flow heat source fixed point and return flow temperature measuring thermocouple of the return flow monitoring module are respectively connected to the input end of the data acquisition module, and the output end of the data acquisition module is connected to the data processing module;

[0018] The data acquisition module is used to collect the temperature data changes of the wellbore heat source fixed point and the wellbore temperature measuring thermocouple of the downhole injection flow monitoring module and the return flow heat source fixed point and the return flow temperature measuring thermocouple of the return flow monitoring module in real time;

[0019] The data processing module is used to calculate the downhole injection flow rate in real time according to the temperature difference between the wellbore heat source fixed point and the wellbore temperature measuring thermocouple, and to calculate the return flow rate in real time according to the temperature difference between the return flow heat source fixed point and the return flow temperature measuring thermocouple; finally, based on the correlation between the downhole injection flow rate and the return flow rate, it is judged whether there is overflow and an overflow conclusion is drawn.

[0020] Preferably, a data communication module is also provided in the instrument, and the data communication module is connected to the data processing module.

[0021] Preferably, a power supply module is also provided in the instrument, and the power supply module is respectively connected to the wellbore heat source fixed point of the downhole injection flow monitoring module, the wellbore temperature measuring thermocouple, the return flow heat source fixed point and the return flow temperature measuring thermocouple of the return flow monitoring module, the data acquisition module, the data processing module and the data communication module through wires.

[0022] In a second aspect, the present invention also discloses an overflow detection method based on downhole injection flow and return flow monitoring, using the above-mentioned overflow detection device, characterized in that it includes:

[0023] Step 1: The downhole injection flow monitoring module and the return flow monitoring module monitor the downhole temperature data changes in real time;

[0024] Step 2: The data acquisition module collects the temperature data changes of the wellbore heat source fixed point and the wellbore temperature measuring thermocouple of the downhole injection flow monitoring module and the return flow heat source fixed point and the return flow temperature measuring thermocouple of the return flow monitoring module in real time, and transmits these temperature data changes to the data processing module in real time;

[0025] Step 3: The data processing module calculates the downhole injection flow rate in real time according to the temperature difference between the wellbore heat source fixed point and the wellbore temperature measuring thermocouple, and calculates the return flow rate in real time according to the temperature difference between the return flow heat source fixed point and the return flow temperature measuring thermocouple, and finally determines whether overflow occurs according to the correlation between the downhole injection flow rate and the return flow rate, and draws an overflow conclusion;

[0026] Step 4: Once the overflow conclusion is that there is overflow, the data processing module transmits the overflow conclusion to the data communication module, and the data communication module transmits the early warning signal to the ground.

[0027] Preferably, the method for judging overflow according to the correlation between downhole injection flow information and return flow information is:

[0028] If the downhole injection flow rate information is well correlated with the return flow rate information, there is no overflow;

[0029] If the correlation between the downhole injection flow information and the return flow information becomes weak, there is overflow.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (I) The present invention discloses an overflow detection device based on downhole injection flow and return flow monitoring, comprising a wellbore, an instrument, a downhole injection flow monitoring module and a return flow monitoring module, wherein a hollow channel is arranged inside the instrument, the instrument is arranged inside the wellbore, and a space is reserved between the inner wall of the wellbore and the outer wall of the instrument to form an annular space; the downhole injection flow monitoring module comprises a wellbore heat source fixing point and a wellbore temperature measuring thermocouple, and the wellbore heat source fixing point and the wellbore temperature measuring thermocouple are arranged on the outer wall of the instrument in the annular space; the return flow monitoring module comprises a reflux heat source fixing point and a reflux temperature measuring thermocouple, and the reflux heat source fixing point and the reflux temperature measuring thermocouple are arranged on the inner wall of the hollow channel of the instrument. Among them, the downhole injection flow monitoring module and the return flow monitoring module are used to monitor the changes in downhole temperature data in real time; the downhole injection flow is obtained according to the temperature difference between the wellbore heat source fixed point and the wellbore temperature measuring thermocouple, and the return flow is obtained according to the temperature difference between the return heat source fixed point and the return temperature measuring thermocouple; finally, based on the correlation between the downhole injection flow and the return flow, it is judged whether there is overflow and the overflow conclusion is drawn.

[0032] (ii) The present invention discloses an overflow detection method based on downhole injection flow and return flow monitoring, comprising the following steps: a downhole injection flow monitoring module and a return flow monitoring module monitor downhole temperature data changes in real time; a data acquisition module acquires temperature data changes of a wellbore heat source fixed point and a wellbore temperature measuring thermocouple of the downhole injection flow monitoring module and a return flow heat source fixed point and a return flow temperature measuring thermocouple of the return flow monitoring module in real time, and transmits these temperature data changes to a data processing module in real time; the data processing module obtains the downhole injection flow according to the temperature difference between the wellbore heat source fixed point and the wellbore temperature measuring thermocouple, obtains the return flow according to the temperature difference between the return flow heat source fixed point and the return flow temperature measuring thermocouple, and finally determines whether overflow occurs according to the correlation between the downhole injection flow and the return flow, and draws an overflow conclusion.

[0033] In addition, the present invention also has the following advantages:

[0034] 1. Establish the flow correlation between the downhole injection flow and the return flow near the drill bit, use the thermocouple temperature sensor for downhole flow monitoring, and calculate the downhole injection flow and return flow by measuring the temperature difference between the wellbore injection flow channel and the annular return flow channel, which can more accurately reflect the downhole situation and play an effect in a variety of complex downhole conditions;

[0035] 2. The parameters can be processed directly underground and the warning results can be transmitted to the surface in a timely manner, which can reflect the changes in the underground situation more quickly, reduce the lag of overflow detection, and provide more timely warning results. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of an overflow detection device based on downhole injection flow and return flow monitoring provided in Example 1 of the present invention.

[0037] Description of reference numerals:

[0038] 1-wellbore, 10-annular space,

[0039] 2-Instrument, 20-Hollow Channel,

[0040] 31-Fixed point of heat source in wellbore, 32-Thermocouple for measuring temperature in wellbore,

[0041] 41- reflux heat source fixed point, 42- reflux temperature measurement thermocouple,

[0042] 5-Data acquisition module;

[0043] 6-Data processing module;

[0044] 7-Data communication module;

[0045] 8- Power module. DETAILED DESCRIPTION

[0046] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0047] In view of the above problems, the present invention applies thermocouples to downhole overflow detection, sets a fixed temperature heat source point, and calculates the downhole injection flow and return flow according to the temperature difference between the thermocouple and the heat source point. Two sets of flow monitoring devices simultaneously measure the flow information of the wellbore domain and the return flow domain, and at the same time, the flow information of the two is processed and analyzed using the Apriori correlation algorithm. When there is no overflow, the downhole injection flow information and the return flow information are well correlated; when there is overflow, the correlation becomes weak, thereby judging the overflow, and based on the correlation between the two flows, extremely early overflow monitoring is achieved.

[0048] Example 1: An overflow detection device based on downhole injection flow and return flow monitoring

[0049] Embodiment 1 provides an overflow detection device based on downhole injection flow and return flow monitoring, and its structure is described in detail below in conjunction with the accompanying drawings.

[0050] refer to Figure 1 The overflow detection device based on downhole injection flow and return flow monitoring includes a wellbore 1, an instrument 2, a downhole injection flow monitoring module and a return flow monitoring module.

[0051] A hollow channel 20 is provided inside the instrument 2, the instrument 2 is arranged inside the wellbore 1, and a space is reserved between the inner wall of the wellbore 1 and the outer wall of the instrument 2 to form an annular space 10;

[0052] A hollow channel 20 is provided inside the instrument 2, the instrument 2 is arranged inside the wellbore 1, and a space is reserved between the inner wall of the wellbore 1 and the outer wall of the instrument 2 to form an annular space 10;

[0053] The downhole injection flow monitoring module includes a wellbore heat source fixed point 31 and a wellbore temperature measuring thermocouple 32, and the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32 are arranged on the outer wall of the instrument 2 in the annular space 10;

[0054] The return flow monitoring module includes a return heat source fixed point 41 and a return temperature measuring thermocouple 42, and the return heat source fixed point 41 and the return temperature measuring thermocouple 42 are arranged on the inner wall of the hollow channel 20 of the instrument 2;

[0055] Among them, the downhole injection flow is obtained according to the temperature difference between the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32, and the return flow is obtained according to the temperature difference between the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42. Finally, whether overflow occurs is determined based on the correlation between the downhole injection flow and the return flow, and an overflow conclusion is drawn.

[0056] Specifically, the temperature of the wellbore heat source fixed point 31 and the return heat source fixed point 41 are both higher than the downhole temperature.

[0057] In order to collect and process data and obtain overflow conclusions, a data acquisition module 5 and a data processing module 6 are provided in the instrument 2. The wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32 of the downhole injection flow monitoring module and the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42 of the return flow monitoring module are respectively connected to the input end of the data acquisition module 5, and the output end of the data acquisition module 5 is connected to the data processing module 6.

[0058] The data acquisition module 5 is used to collect the temperature data changes of the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32 of the downhole injection flow monitoring module and the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42 of the return flow monitoring module in real time;

[0059] The data processing module 6 is used to obtain the downhole injection flow rate according to the temperature difference between the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32, and to obtain the return flow rate according to the temperature difference between the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42, and finally determine the overflow situation according to the correlation between the downhole injection flow rate and the return flow rate.

[0060] The data processing module 6 has a built-in Apriori correlation algorithm, which can analyze and calculate the correlation between the downhole injection flow and the return flow.

[0061] In order to transmit the overflow result to the outside in real time, a data communication module 7 is further provided in the instrument 2 , and the data communication module 7 is connected to the data processing module 6 .

[0062] In order to power the entire equipment, a power supply module 8 is also provided in the instrument 2, and the power supply module 8 is respectively connected to the wellbore heat source fixed point 31 of the downhole injection flow monitoring module, the wellbore temperature measuring thermocouple 32, the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42 of the return flow monitoring module, the data acquisition module 5, the data processing module 6 and the data communication module 7 through wires.

[0063] Example 2: An overflow detection method based on downhole injection flow and return flow monitoring

[0064] Embodiment 2 provides an overflow detection method based on downhole injection flow and return flow monitoring, using the device of embodiment 1, and the detection method includes the following steps:

[0065] Step 1: The downhole injection flow monitoring module and the return flow monitoring module monitor the downhole temperature data changes in real time;

[0066] Step 2: The data acquisition module 5 collects the temperature data changes of the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32 of the downhole injection flow monitoring module and the temperature data changes of the return flow heat source fixed point 41 and the return flow temperature measuring thermocouple 42 of the return flow monitoring module in real time, and transmits these temperature data changes to the data processing module 6 in real time;

[0067] Step three: The data processing module 6 calculates the downhole injection flow rate in real time according to the temperature difference between the wellbore heat source fixed point 31 and the wellbore temperature measuring thermocouple 32, and calculates the return flow rate in real time according to the temperature difference between the return heat source fixed point 41 and the return temperature measuring thermocouple 42. Finally, it determines whether there is overflow based on the correlation between the downhole injection flow rate and the return flow rate, and draws an overflow conclusion.

[0068] Wherein, the method for judging overflow according to the correlation between downhole injection flow information and return flow information is:

[0069] If the downhole injection flow rate information is well correlated with the return flow rate information, there is no overflow;

[0070] If the correlation between the downhole injection flow information and the return flow information becomes weak, there is overflow.

[0071] Step 4: Once the overflow conclusion is that there is overflow, the data processing module 6 transmits the overflow conclusion to the data communication module 7, and the data communication module 7 transmits the early warning signal to the ground.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An overflow detection device based on downhole injection flow and return flow monitoring, characterized in that: It comprises a wellbore (1), an instrument (2), a downhole injection flow monitoring module and a return flow monitoring module. The instrument (2) is provided with a hollow channel (20) inside, the instrument (2) is arranged inside the wellbore (1), and a space is reserved between the inner wall of the wellbore (1) and the outer wall of the instrument (2) to form an annular space (10); The downhole injection flow monitoring module comprises a wellbore heat source fixing point (31) and a wellbore temperature measuring thermocouple (32), and the wellbore heat source fixing point (31) and the wellbore temperature measuring thermocouple (32) are arranged on the outer wall of the instrument (2) in the annular space (10); The return flow monitoring module comprises a return heat source fixing point (41) and a return temperature measuring thermocouple (42), and the return heat source fixing point (41) and the return temperature measuring thermocouple (42) are arranged on the inner wall of the hollow channel (20) of the instrument (2); The downhole injection flow monitoring module and the return flow monitoring module are used to monitor the change of downhole temperature data in real time; the downhole injection flow is obtained according to the temperature difference between the wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32); the return flow is obtained according to the temperature difference between the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42); finally, whether overflow occurs is determined according to the correlation between the downhole injection flow and the return flow, and an overflow conclusion is drawn.

2. The overflow detection device according to claim 1, characterized in that: The temperatures of the wellbore heat source fixed point (31) and the return heat source fixed point (41) are both higher than the downhole temperature.

3. The overflow detection device according to claim 1, characterized in that: The instrument (2) is provided with a data acquisition module (5) and a data processing module (6). The wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32) of the downhole injection flow monitoring module and the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42) of the return flow monitoring module are respectively connected to the input end of the data acquisition module (5), and the output end of the data acquisition module (5) is connected to the data processing module (6); The data acquisition module (5) is used to collect in real time the temperature data changes of the wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32) of the downhole injection flow monitoring module and the temperature data changes of the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42) of the return flow monitoring module; The data processing module (6) is used to respectively calculate the downhole injection flow rate in real time according to the temperature difference between the wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32), and to calculate the return flow rate in real time according to the temperature difference between the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42); finally, based on the correlation between the downhole injection flow rate and the return flow rate, it is determined whether overflow occurs, and an overflow conclusion is obtained.

4. The overflow detection device according to claim 3, characterized in that: The instrument (2) is also provided with a data communication module (7), and the data communication module (7) is connected to the data processing module (6).

5. The overflow detection device according to claim 4, characterized in that: The instrument (2) is also provided with a power supply module (8). The power module (8) is respectively connected to the wellbore heat source fixed point (31) of the downhole injection flow monitoring module, the wellbore temperature measuring thermocouple (32), the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42) of the return flow monitoring module, the data acquisition module (5), the data processing module (6) and the data communication module (7) through wires.

6. An overflow detection method based on downhole injection flow and return flow monitoring, using the overflow detection device according to claim 5, characterized in that: include Step 1: The downhole injection flow monitoring module and the return flow monitoring module monitor the downhole temperature data changes in real time; Step 2: The data acquisition module (5) collects in real time the temperature data changes of the wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32) of the downhole injection flow monitoring module and the temperature data changes of the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42) of the return flow monitoring module, and transmits these temperature data changes to the data processing module (6) in real time; Step 3: The data processing module (6) calculates the downhole injection flow rate in real time according to the temperature difference between the wellbore heat source fixed point (31) and the wellbore temperature measuring thermocouple (32), and calculates the return flow rate in real time according to the temperature difference between the return flow heat source fixed point (41) and the return flow temperature measuring thermocouple (42), and finally determines whether overflow occurs according to the correlation between the downhole injection flow rate and the return flow rate, and draws an overflow conclusion; Step 4: Once the overflow conclusion is that there is overflow, the data processing module (6) transmits the overflow conclusion to the data communication module (7), and the data communication module (7) transmits the early warning signal to the ground.

7. The overflow detection method according to claim 6, characterized in that: The method for judging overflow according to the correlation between downhole injection flow information and return flow information is: If the downhole injection flow rate information is well correlated with the return flow rate information, there is no overflow; If the correlation between the downhole injection flow information and the return flow information becomes weak, there is overflow.

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