CN102226377A - Drill string installed with downhole blowout preventer and working method thereof - Google Patents

Abstract

The invention discloses a downhole blowout prevention technology and belongs to the technical field of downhole blowout prevention. The invention relates to a drill string equipped with a downhole blowout preventer, and the drill string comprises a drill string body, wherein a drill bit is arranged at the bottom of the drill string body. The drill string is characterized in that the downhole blowout preventer is mounted on the drill string body, at least one pressure monitoring and signal generating device is arranged at one end, adjacent to the drill bit, of the drill string body, a signal receiving and alarm generating device is arranged at the upper part of the top of the drill string body, and the signal receiving and alarm generating device is matched with the pressure monitoring and signal generating device. By adopting the drill string equipped with the downhole blowout preventer, downhole well kick or blowout can be effectively monitored; and furthermore, the alarm signal transfer speed is fast, measures can be timely and effectively adopted for implementing well sealing, the blowout preventer is positioned above a neutralization point, the blowout preventer is in a tension state, the purposes of placing a pipe column downwards for setting and lifting the pipe column upwards for unsealing can be realized, and the well kick or the blowout can be effectively prevented.

Description

Drill string installed with downhole blowout preventer and working method thereof

technical field

The invention relates to a blowout prevention technology when well kick and blowout occur in the drilling process of oil and gas fields.

Background technique

Drilling plays a very important role in various tasks of oil exploration and oil field development, such as finding and confirming oil and gas structures, obtaining industrial oil flows, ascertaining the oil and gas bearing areas and reserves of proven oil and gas structures, and obtaining relevant The geological data and development data of the oil field, and finally the crude oil is taken from the ground to the ground, etc. are all completed by drilling. Drilling is an important link in the exploration and exploitation of oil and natural gas resources, and an important means of oil exploration and development. .

During the drilling process, when drilling into oil and gas layers, if the bottom hole pressure is lower than the formation pressure, the formation fluid will enter the wellbore. After a large amount of formation fluid enters the wellbore, well kicks, blowouts, and even fires may occur. lead to major accidents. Therefore, in the drilling process, taking effective measures to control oil and gas well pressure is an extremely important part of drilling safety. However, because the pressure of high-pressure oil and gas formations is difficult to predict accurately, especially when drilling exploratory wells in new blocks, high-pressure oil and gas from formations enter the wellbore from time to time during drilling. Kick and blowout accidents may occur in the following three situations: during drilling, during tripping of the drill pipe, and in the state of an empty well. The probability of blowout in an empty well is very low. If the tripping speed can be well controlled to prevent excessive suction force during tripping, the probability of blowout accidents can be effectively reduced. The high pressure of oil and gas reservoirs has the highest probability of blowout.

When signs of well kick and blowout are found, fast and efficient well shut-in and well killing operations are an important guarantee to effectively reduce blowout accidents. However, the traditional way of judging well kick by observing overflow at the wellhead has the disadvantages of poor accuracy and serious lag in judgment. Well operation is difficult. The PWD system (Pressure While Drilling pressure while drilling monitoring system) can monitor the annular pressure in real time, and can upload the pressure signal to the ground, but the system is expensive, it is difficult to popularize and popularize, and it uses the mud pulse method For data transmission, the signal transmission speed is slow, error codes are prone to occur, and there is also a certain degree of signal transmission delay, especially when the formation high-pressure fluid (especially gas) has begun to invade the well, it will affect the transmission channel of this signal, resulting in a bit error rate. Elevation doesn't even allow for signal transmission.

When signs of well kick and blowout are found, fast and efficient well shut-in and well killing operations are an important guarantee to effectively reduce blowout accidents. The traditional shut-in operation (soft shut-in is often used in China) is: after a well kick is found, the throttle valve is opened first, and then the blowout preventer is closed. , the amount of formation fluid intrusion is large, and the additional formation fluid will also have additional pressure on the wellhead device and the formation, which will bring difficulties in killing the well.

At present, the blowout preventers used in the drilling process of oil and gas fields are mostly installed at the wellhead. During the drilling process, an arrow-shaped check valve will be installed near the drill During drilling, it is mostly used to seal off the annular space, and only when it is necessary to cut the drill pipe, the full wellbore sealing is carried out. When the operator finds a possible blowout downhole on the well, the control system is turned on to complete the shut-in operation of the wellhead blowout preventer to prevent blowout accidents. The action of this type of blowout preventer must rely on the experience and sense of responsibility of the operator to prevent blowout accidents. If the operator's inexperience or negligence during work fails to detect well kick or blowout signs in time, serious accidents will occur. Moreover, the traditional wellhead blowout preventer takes a long time to replace the mud and kill the well after the well shut-in operation, which will cause more bottom fluid to invade the wellbore, increase the downhole annular pressure difference, and thus increase the control of blowout. difficulty, at the same time, the traditional signal transmission is realized by mud pulse, which is mainly to add a mud pulse generator in the middle of the mud circulation pipeline for two-way communication, so whether it is the acquisition of downhole signals or the control of subsequent blowout prevention, the other The transmission speed of the signal is relatively slow and takes a long time, so it cannot play the effect of early warning and blowout prevention at all. Therefore, it is necessary to design a new drill string structure. In this new drill string structure, a downhole pressure monitoring and signal generating device is installed. Monitoring, when it is found that the annular pressure changes, it can be judged. If it is judged that the high-pressure fluid in the formation is invading, that is, when the signs of well kick and blowout may occur, the well kick and blowout signal will be sent through the drilling in the form of sound waves or electromagnetic waves in the shortest time. The rod is transmitted to the ground, so that the ground personnel can respond to the well kick and blowout in the first time. The drill string structure also needs to be installed with a downhole annular blowout preventer. The annular blowout preventer is placed downhole. When the ground receives the bottom well blowout signal, the downhole annular blowout preventer is operated to seal the annular space. , and the check valve near the drill bit can effectively isolate the inside of the drill string, and after isolation, it can connect the inside of the drill string and the annulus above the annulus packer, so as to facilitate subsequent heavy mud killing The downhole annular blowout preventer used in operation, and the use of this downhole annular packer in conjunction with the near-bit check valve (one-way valve) and early well kick overflow warning system can achieve early detection and early treatment of well control guidance principle, and is easier to perform than conventional well control operations.

Contents of the invention

The purpose of the present invention is to: aim at the above existing problems, to provide a simple structure, very convenient to use, very simple to operate, capable of monitoring well kicks or blowouts in time, and quickly sealing wells to effectively prevent blowout accidents. A drill string with a downhole blowout preventer and its working method, the drill string with the downhole blowout preventer can effectively monitor well kicks or blowouts in the well, and has one-way signal transmission, and the transmission speed of the alarm signal is fast and can be timely Measures are taken to seal the well. The blowout preventer is located above the neutralization point. The blowout preventer is in a tensioned state, which can realize the setting of the lowering string and unsealing of the lifting string. The blowout preventer works while drilling, and can realize the actions of blowout preventer setting and unsealing many times in the downhole, without pulling out the drill string to replace the blowout preventer, which can be reused and reduces the overall cost; the drill installed with downhole blowout preventer The working method of the column is simple and feasible, easy to operate, quick in response, and the positioning of each component is accurate. It can effectively monitor the well kick or blowout in the well, quickly realize the sealing and unsealing of the well, prevent the occurrence of blowout accidents, and ensure Safe to use during drilling.

The technical scheme that the present invention adopts is as follows:

The drill string equipped with downhole blowout preventer of the present invention comprises a drill string body, a drill bit is arranged at the bottom of the drill string body, a downhole blowout preventer is installed on the drill string body, and an end of the drill string body adjacent to the drill bit is arranged There is at least one pressure monitoring and signal generating device, and a signal receiving and alarm generating device is arranged on the top of the drill string body, and the signal receiving and alarm generating device is matched with the pressure monitoring and signal generating device.

Due to the adoption of the above structure, a pressure monitoring and signal generating device is provided at the bottom of the drill string body, that is, the end of the drill string adjacent to the drill bit, for monitoring the downhole pressure value during the drilling process. Once the downhole pressure value is found suddenly When changing, the pressure monitoring and signal generating device compares the set program. When the pressure signal is abnormal pressure, it will send out a signal quickly. The signal is set at the upper end of the kelly at the top of the drill string or the signal set at the lower end of the top drive. The receiver accepts the signal, and the signal receiver immediately sends out an alarm signal through the signal receiving and alarm generating device. At this time, the control personnel can respond quickly to deal with the sudden situation in the downhole, lower the drill string body for setting, and realize the ring in the well. The air is closed to achieve the effect of controlling well kick and blowout. When the blowout is under control, lift the drill string to release the seal, which is easy to operate and has a good blowout prevention effect. The drill string installed with the downhole blowout preventer of the present invention can detect the pressure situation in the downhole in time, and can complete the alarm operation of abnormal downhole pressure. At the same time, the drill string installed with the downhole blowout preventer of the present invention adopts one-way signal transmission Judging the downhole phenomenon breaks the technical prejudice of those skilled in the art. Existing technicians use two-way communication to detect downhole blowouts or well kicks. Because two-way communication takes a long time, Moreover, the signal will continue to attenuate during the transmission process. After multiple signal comparisons between the downhole and the uphole, and then send out an alarm signal, the signal delay is longer and the response is too slow, so the dangerous situation cannot be eliminated in time. However, the present invention uses a one-way The signal transmission can realize rapid underground response and send out signals, quickly transmit alarm information, and can eliminate dangerous situations in real time to ensure safe use. The signal can be transmitted by a variety of signals, such as sound waves, electromagnetic waves, etc., so that the distance that can be transmitted by the signal is increased, and the well kick and blowout can be effectively detected. The drill string installed with the downhole blowout preventer of the present invention forms a complete set of early warning and processing system, which can effectively prevent well kick and blowout.

In the drill string installed with downhole blowout preventer of the present invention, the pressure monitoring and signal generating device mainly detects the downhole pressure value and judges the pressure value. If it is an abnormal value, it will send a signal; if it is a normal value, it will not deal with.

Due to the adoption of the above structure, the pressure monitoring and signal generating device can quickly compare the preset program after detecting the downhole pressure value, and then make a judgment. If the pressure value is abnormal, it will immediately send out Signal, if the pressure value is a pressure fluctuation within the normal range, it will not be processed. The pressure monitoring and signal generating device can automatically compare and judge the pressure in the well, and has the function of automatic correction. On the one hand, it can effectively eliminate interference signals, and on the other hand, it can effectively compare dangerous pressures and send out signals quickly. , is convenient for follow-up operations, responds quickly, and can instantly convey the danger in the well to the ground, which is easy to control.

In the drill string installed with the downhole blowout preventer of the present invention, the signal sent by the pressure monitoring and signal generating device is an acoustic wave signal or an electromagnetic wave signal.

Due to the above-mentioned drill string, the transmission signal adopts acoustic wave signal or electromagnetic wave signal, and the propagation speed of the signal is very fast in the downhole or in the drill string, and can quickly transmit the downhole danger signal to the ground, so that the ground staff can quickly know the downhole situation, and can take timely measures to implement well closure to avoid dangerous situations.

In the drill string installed with the downhole blowout preventer of the present invention, the signal receiving and alarm generating device mainly receives the signal from the pressure monitoring and signal generating device, and sends out an alarm electromagnetic wave signal.

Due to the adoption of the above structure, the signal receiving and alarm generating device is installed on the upper end of the kelly or the lower end of the top drive at the top of the drill string body, and can receive downhole signals through the drill pipe, and quickly send out an alarm electromagnetic wave signal to give Surface operators sounded the alarm, which facilitated the organization of blowout containment. The drill string can quickly convert downhole signals into uphole alarm signals, and the transmission speed is fast. The drill string installed with the downhole blowout preventer of the present invention forms a whole set of early warning and processing system, which can effectively prevent well kick and blowout.

In the drill string installed with the downhole blowout preventer of the present invention, the downhole blowout preventer can be set by lowering the drill string body, and can be unsealed by lifting the drill string body.

Due to the adoption of the above structure, the drill string installed with the downhole blowout preventer can be set by lowering the drill string body, and unsealed by lifting the drill string body, so that the isolation operation of the downhole annular space is very convenient and quick , The well sealing and unsealing can be realized in an instant, and the well sealing takes less time, which can effectively control the phenomenon of well kick and blowout, and ensure the safety of drilling operation.

In the drill string installed with the downhole blowout preventer of the present invention, the downhole blowout preventer can seal off the annular space outside the drill string, and the downhole blowout preventer can connect the inside of the drill string and the annular space during the process of sealing off the annulus.

Due to the adoption of the above-mentioned structure, during the isolation process of the annulus, the downhole blowout preventer can connect the inside of the drill string and the annulus, allowing the drilling fluid in the drill pipe to enter the annulus, which is used for the subsequent heavy mud killing The operation provides a channel, which is beneficial to eliminate phenomena such as blowout or kick.

In the drill string installed with the downhole blowout preventer of the present invention, the downhole blowout preventer is arranged at the neutral point of the drill string body and above, so that the downhole blowout preventer is in a tensioned state when the drill string is working.

Due to the adoption of the above structure, the neutral point of the drill string body is the dividing point between tension and pressure. The downhole blowout preventer is installed above the neutral point of the drill string, so that the downhole blowout preventer is in In the state of tension, due to the special structure of the blowout preventer, the blowout preventer is in the state of tension during the normal drilling process, and the downhole blowout preventer at this time has the function of transmitting torque.

In the drill string installed with the downhole blowout preventer of the present invention, the downhole blowout preventer is mainly composed of an annular blowout preventer and a check valve, the check valve is arranged below the annular blowout preventer, and the annular blowout preventer The blowout preventer is provided with a packer rubber barrel and a blowout preventer opening, and the blowout preventer opening is arranged above the packer rubber barrel.

Due to the adoption of the above structure, the annular blowout preventer on the drill string is used to seal off the annular space outside the drill string, and the drill string internal blowout preventer on the drill string, that is, the check valve, is used to prevent the internal blowout of the drill string. When the mud returns upward, the check valve and the downhole annulus blowout preventer work together to seal off the inside of the drill string and the annulus at the same time, so as to control the occurrence of blowout and eliminate the danger. The annulus blowout preventer is mainly used to seal off the casing or the well wall through the packer rubber tube to ensure that the annulus is well sealed, and the blowout preventer opening is mainly used to conduct the internal drilling of the drill string. The annulus provides a channel for subsequent heavy mud killing operations.

In the drill string for installing downhole blowout preventer of the present invention, the annular blowout preventer includes an upper joint, an upper and outer sleeve, an inner sleeve, a lower joint, a central cylinder and a packer rubber sleeve, and the upper joint and the upper The outer sleeve and the inner sleeve are fixedly connected, and the central sleeve is placed outside the upper joint, the upper outer sleeve, the inner sleeve and the lower joint, and the lower end of the central sleeve is fixedly connected with the lower joint; the inner sleeve The lower end of the inner sleeve is set on the inner side of the upper end of the lower joint, and the inner sleeve and the lower joint are splined. The lower end of the inner sleeve can move freely relative to the lower joint along the spline pair. The outer side of the inner sleeve The packer rubber sleeve is set, and the packer rubber sleeve can be squeezed and expanded by the upper outer sleeve and the lower joint. When shifting, the blowout preventer conduction port is conducted.

In the drill string of the present invention, the downhole blowout preventer used is a component installed at the neutral point of the drill string, and it must firstly be able to fulfill its role as a component of the drill string, that is, it must be able to withstand a certain amount of pressure during normal drilling. Pulling force, it must be able to withstand a certain pressure when dealing with accidents (well kick blowout prevention), and it must be able to transmit sufficient torque during drilling. Therefore, with the above structure, the inner sleeve and the lower joint are splined, and the upper joint is fixedly connected with the upper outer sleeve and the inner sleeve. Use the transmission torque; the lower end of the inner sleeve can move freely relative to the lower joint along the spline pair, that is, the pipe string can be lowered to move the upper joint down to realize setting and prevent blowout or well kick; The lower joint is fixedly connected, so after the upper joint moves down, the rubber sleeve is squeezed and expanded by the upper outer sleeve and the lower joint, thereby closing the annular space between the drill string and the well wall or the drill string and the casing, and the upper outer sleeve and the center There is a blowout preventer conduction port on the sleeve. When the upper and outer sleeves move down, the blowout preventer conduction port is conducted. At this time, the surrounding area of the blowout preventer conduction port is sealed, so that the slurry in the annular space can enter the Inside the center barrel, a channel is provided for the subsequent heavy mud killing operation; effectively avoiding blowout and kick. The drill string installed with downhole blowout preventer of the present invention can ensure the continuous, safe and reliable drilling process, not only can be used to prevent well kick and blowout, but also can transmit torque to ensure the orderly progress of the drilling process, and the concept is ingenious, suitable for popularization , can be installed in different well depths, work while drilling, can realize blowout setting and unsealing actions downhole for many times, no need to lift the drill string to replace the blowout preventer, ensure the continuation of drilling work, and can be reused, reducing cost.

The working method of the drill string with downhole blowout preventer in the present invention is characterized in that: in the drilling process, when encountering high-pressure oil reservoirs or gas reservoirs, the blowout preventer is required to implement isolation, and its working method is as follows:

101. The pressure monitoring and signal generating device detects the downhole pressure value, and compares the value with the set program. If the pressure value is abnormal pressure, immediately start the signal excitation device on the pressure monitoring and signal generating device , the signal excitation device sends out a pressure abnormal signal, and the signal propagates upward along the drill string body, and is received by the signal receiving and alarm generating device installed on the upper part of the drill string, and the signal receiving and alarm generating device sends out an alarm electromagnetic wave signal; if the pressure value is normal pressure, it will not be dealt with;

102. After the ground receives the signal, the emergency response is activated, and the drill string body is lowered actively or automatically. The packer rubber tube in the annular blowout preventer is squeezed and expanded, and the packer rubber tube seals the drill string and the well wall or drill string. The annulus between the column and the casing realizes setting;

103. During the downhole blowout preventer moving down and setting, the blowout preventer guide port in the annular blowout preventer is turned on, connecting the inside of the drill pipe with the annular space, and performing heavy mud killing operations;

104. When the blowout is under control, the drill string body is lifted up, the packer rubber tube in the annular blowout preventer is automatically retracted, the annular blowout preventer is unsealed, and the conduction port of the blowout preventer is closed at the same time.

Due to the adoption of the above method, it is possible to effectively monitor well kicks or blowouts downhole. During the drilling process, when encountering high-pressure oil or gas reservoirs and needing to implement isolation, it can respond quickly to set the drill string and the well wall or the drill string. The annulus between the string and the casing can quickly realize sealing and unsealing, prevent blowout accidents, and ensure the safety of use during drilling. The method is simple and feasible, easy to operate, quick in response and precise in positioning between parts. The signal used in the alarm process is one-way communication, and various signals can be used for transmission, so that the distance that can be transmitted by the signal is increased, and the well kick and blowout can be effectively detected.

In summary, owing to adopting above-mentioned technical scheme, the beneficial effect of the present invention is:

1. The drill string installed with downhole blowout preventer of the present invention can effectively monitor well kick or blowout downhole, and the alarm signal transmission speed is fast, and effective measures can be taken to implement well closure. The blowout preventer is located at the neutralization point In the above position, the blowout preventer is in a tensioned state, which can realize the setting of the lowering string and unsealing of the lifting string, effectively preventing well kick or blowout;

2. The drill string installed with the downhole blowout preventer of the present invention adopts one-way signal transmission, and can use multiple signals for transmission, with fast transmission speed, less time-consuming, quick response to dangerous situations, and a complete set of early warning and The treatment system can effectively prevent well kick and blowout, etc.;

3. The working method of the drill string installed with the downhole blowout prevention of the present invention is simple and feasible, easy to operate, quick in response, and can effectively monitor well kicks or blowouts downhole, quickly realize well sealing and unsealing, and prevent blowout accidents occurrence, to ensure the safety of use during drilling.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Fig. 1 is the structural representation of the drill string that downhole blowout preventer is installed among the present invention;

Fig. 2 is the structural representation of annular blowout preventer among the present invention;

Fig. 3 is the B-B view among Fig. 2;

Fig. 4 is a working flow chart of the drill string installed with the downhole blowout preventer of the present invention.

Marks in the figure: 1-drill bit, 2-pressure monitoring and signal generating device, 2-1-first pressure monitoring and signal generating device, 2-2-second pressure monitoring and signal generating device, 3-downhole blowout preventer, 3-1-Check valve, 3-2-Annular blowout preventer, 3-2a-Packer rubber cartridge, 3-2b-Blowout preventer guide port, 3-2c-Upper connector, 3-2d -Upper and outer sleeve, 3-2e-inner sleeve, 3-2f-lower joint, 3-2g-central sleeve, 4-casing, 5-drill pipe, 6-signal receiving and alarm generating device.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless expressly stated otherwise, may be replaced by alternative features which are equivalent or serve a similar purpose. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

The drill string with downhole blowout preventer of the present invention is installed, as shown in Fig. 1, Fig. 2 and Fig. 3, is provided with drill bit 1 on the drill string body, and is provided with downhole blowout preventer 3 on the drill string body, will The downhole blowout preventer 3 is installed at a position above the neutral point of the drill string body, of course, it can also be selected not to be installed at a position above the neutral point according to actual needs. Moreover, the drill string body is located in the casing or the borehole wall. Two pressure monitoring and signal generating devices 2 are arranged at one end of the drill string body adjacent to the drill bit 1. Of course, multiple pressure monitoring and signal generating devices 2 can also be set according to actual needs, respectively the first pressure The monitoring and signal generating device 2-1 and the second pressure monitoring and signal generating device 2-2 are provided with a pressure acquisition device, a pressure value analysis system and a signal sending device in the two pressure monitoring and signal generating devices. When the downhole pressure value is detected, the pressure value can be transmitted to the pressure value analysis system. The pressure value analysis system will compare the collected pressure value with the set program to make a judgment. If the pressure value is an abnormal pressure value, Then the signal sending device can be quickly excited to make it send out a signal rapidly, including an acoustic wave signal or an electromagnetic wave signal, and the signal is transmitted along the drill string to the ground. Since the acoustic wave signal or electromagnetic wave signal is in a limited space underground, its propagation speed is very high. The signal is fast and the signal attenuation is quite small. A signal receiving and alarm generating device 6 is installed on the top of the drill string body. This device matches the pressure monitoring and signal generating device 2 and can quickly receive the signal sent downhole The signal is converted into an alarm electromagnetic wave signal, which notifies the ground staff to carry out the blowout prevention operation. The entire alarm process is completed within a few seconds, which greatly improves the response time of the existing early warning and alarm system, making the response quite sensitive, and providing a good solution for underground mines. Detection provides a strong guarantee. The drill string with the downhole blowout preventer of the present invention is installed with the downhole blowout preventer 3 above the two pressure detection devices, and is positioned at the position above the neutralization point of the drill string, so that when the drill string works, the downhole blowout preventer (3) In a tensioned state, the downhole blowout preventer 3 is mainly composed of a check valve 3-1 and an annular blowout preventer 3-2, and the check valve 3-1 is set at the annular blowout preventer 3- 1, the annular blowout preventer 3-1 is provided with a packer rubber cylinder 3-2a and a blowout preventer opening 3-2b, and the blowout preventer opening 3-2b is set on the seal Above the spacer rubber cylinder 3-2a, above the blowout preventer 16 in the drill string. The annular blowout preventer 3-2 includes an upper connection head 3-2c, an upper and outer sleeve 3-2d, an inner sleeve 3-2e, a lower joint 3-2f, a central cylinder 3-2g and a packer rubber sleeve 3-2a, the upper connecting head 3-2c is fixedly connected with the upper outer sleeve 3-2d and the inner sleeve 3-2e, and the central sleeve 3-2g is covered with the upper connecting head 3-2c, the upper outer sleeve 3- 2d, inside the inner sleeve 3-2e and the lower joint 3-2f, and the lower end of the central cylinder 3-2g is fixedly connected with the lower joint 3-2f; the lower end of the inner sleeve 3-2e is set on the lower joint 3-2f The inner side of the upper end of 2f, and the inner sleeve 3-2e and the lower joint 3-2f are splined, and the lower end of the inner sleeve 3-2e can move freely relative to the lower joint 3-2f along the spline pair, The outer side of the inner sleeve 3-2e is fitted with a packer rubber sleeve 3-2a, and the packer rubber sleeve 3-2a can be squeezed and expanded by the upper and outer sleeves 3-2d and the lower joint 3-2f, The upper and outer sleeves 3-2d and the central sleeve 3-2g are provided with a blowout preventer conducting port 3-2b, and when the upper and outer sleeve 3-2d moves down, the blowout preventer conducting port 3-2b is conducted. Make the drill string with downhole BOP installed in the present invention, the annular blowout preventer on the drill string is used to seal off the annular space outside the drill string, and the drill string internal blowout preventer on the drill string is the check valve It is used to prevent the mud in the drill string from returning upwards. The check valve works together with the downhole annular blowout preventer to isolate the drill string and the annular space at the same time, so as to control the occurrence of blowout and eliminate the danger. The blowout preventer opening 3-2b is connected to connect the inside of the drill pipe and the annular space, and the drilling fluid in the drill pipe can be discharged into the annular space through the blowout preventer opening 3-2b to replace the heavy mud Well killing operations. The annular blowout preventer is mainly through the packer rubber sleeve, which is made of rubber and other materials, which can achieve effective isolation from the casing or the well wall and ensure that the annulus is well sealed. The lead-through port of the blowout preventer is mainly used to connect the inside of the drill string and the annular space, providing a channel for the subsequent heavy mud killing operation, and helping to eliminate blowout or kick. During the blowout prevention operation, the drill string can be set by lowering the drill string body, and unsealed by lifting the drill string body. Subsequent heavy mud killing operations. In the annular blowout preventer 3-2 of the present invention, the upper joint 3-2c, the upper outer sleeve 3-2d and the inner sleeve 3-2e can be an integral structure, and the lower joint 3-2f It is also possible to adopt a two-stage structure, including a splined section and a non-splined section, which is convenient for cost saving.

The downhole blowout preventer adopted in the present invention has a simple structure, is convenient to use, and is easy to operate. It can monitor well kicks or blowouts in time, adopts one-way signal transmission, and realizes downhole data judgment, which can greatly shorten the early warning of dangerous situations. The time guarantees rapid early warning and safe use, and the lowering of the string to set the seal and the lifting of the string to unseal the well ensures rapid well closure, effectively prevents blowout accidents, and ensures continuous, safe, reliable and preventive drilling. After spraying, there is no need to lift the drill string to replace the blowout preventer, which can be reused to reduce costs.

The working method of the drill string of the downhole blowout preventer of the present invention is installed, as shown in Figure 4, in drilling process, when encountering high-pressure oil reservoir or gas reservoir, needs to implement packing, and its operation method adopts the following steps to complete:

101. The pressure monitoring and signal generating device 2 detects the downhole pressure value, and compares the value with the set program. If the pressure value is abnormal, immediately start the signal on the pressure monitoring and signal generating device 2 The excitation device, the signal excitation device sends out a pressure abnormal signal, and the signal propagates upward along the drill string body, and is received by the signal receiving and alarm generating device 6 installed on the upper part of the drill string, and the signal receiving and alarm generating device 6 sends out an alarm electromagnetic wave signal; if the If the pressure value is normal pressure, it will not be processed;

102. After the ground receives the signal, the emergency response is activated, and the drill string body is lowered actively or automatically. The packer rubber tube 3-2a in the annular blowout preventer 3-2 is squeezed and expanded, and the packer rubber tube 3- 2a Close the annulus between the drill string and the well wall or between the drill string and the casing to realize setting;

103. During the downhole BOP 3 moving down and setting, the BOP conduction port 3-2b in the annular BOP 3-2 is turned on, connecting the inside of the drill pipe with the annulus, and replacing Heavy mud killing operations;

104. When the blowout is under control, the drill string body is lifted up, the packer rubber tube 3-2a in the annular BOP 3-2 retracts automatically, and the annular BOP 3-2 is unsealed, and the blowout preventer The device conduction port 3-2b is closed, and continues to drill or other actions.

The working method of the drill string equipped with the downhole blowout preventer of the present invention can effectively monitor the downhole kick or blowout, and can respond quickly when encountering high pressure oil or gas reservoirs and needing to implement isolation during the drilling process , setting and sealing the annular space between the drill string and the well wall or between the drill string and the casing, quickly realizing the sealing and unsealing of the well, preventing the occurrence of blowout accidents, and ensuring the safety of the drilling process. The method is simple and feasible, easy to operate, quick in response and precise in positioning between parts. The signal used in the alarm process is one-way communication, and various signals can be used for transmission, so that the distance that can be transmitted by the signal is increased, and the well kick and blowout can be effectively detected.

The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims (10)

1. A drill string installed with a downhole blowout preventer, including a drill string body, a drill bit (1) is arranged at the bottom of the drill string body, and it is characterized in that: a downhole blowout preventer (3) is installed on the drill string body , at least one pressure monitoring and signal generating device (2) is provided at one end of the drill string body adjacent to the drill bit (1), and a signal receiving and alarm generating device (6) is provided at the top of the drill string body, the signal receiving And the alarm generating device (6) is matched with the pressure monitoring and signal generating device (2). 2. The drill string with downhole blowout preventer as claimed in claim 1, characterized in that: said pressure monitoring and signal generating device (2) mainly detects the downhole pressure value and judges the pressure value, if it is Outliers are signaled; normal values are ignored. 3. The drill string installed with downhole blowout preventer according to claim 2, characterized in that the signal sent by the pressure monitoring and signal generating device (2) is an acoustic wave signal or an electromagnetic wave signal. 4. The drill string with downhole BOP installed according to claim 1, 2 or 3, characterized in that: the signal receiving and alarm generating device (6) mainly receives the signal from the pressure monitoring and signal generating device (2) signal and send out an alarm electromagnetic wave signal. 5. The drill string with downhole blowout preventer installed according to claim 1, 2 or 3, characterized in that: the downhole blowout preventer (3) can be set by lowering the drill string body, and by lifting the drill string Ontology realizes unblocking. 6. The drill string with downhole blowout preventer installed as claimed in claim 5, characterized in that: the downhole blowout preventer (3) can seal off the annular space outside the drill string, during the process of annulus isolation, the downhole preventer The injector (3) can connect the inside of the drill string and the annular space. 7. The drill string with downhole blowout preventer installed according to claim 1 or 2 or 3 or 6, characterized in that: the downhole blowout preventer (3) is set at the neutral point of the drill string body and above position, so that when the drill string is working, the downhole blowout preventer (3) is under tension. 8. The drill string with downhole blowout preventer as claimed in claim 1 or 2 or 3 or 6, characterized in that: the downhole blowout preventer (3) is mainly composed of annular blowout preventer (3-2) and Check valve (3-1), the check valve (3-1) is set under the annular blowout preventer (3-2), and the annular blowout preventer (3-2) is equipped with A packer rubber cylinder (3-2a) and a blowout preventer opening (3-2b), the blowout preventer opening (3-2b) is arranged above the packer rubber cylinder (3-2a). 9. The drill string with downhole blowout preventer installed according to claim 8, characterized in that: the annular blowout preventer (3-2) includes an upper joint (3-2c), an upper outer sleeve (3 -2d), inner sleeve (3-2e), lower joint (3-2f), center cylinder (3-2g) and packer rubber sleeve (3-2a), upper joint (3-2c) and upper The outer sleeve (3-2d) and the inner sleeve (3-2e) are fixedly connected, and the central sleeve (3-2g) is set on the upper connector (3-2c), the upper outer sleeve (3-2d), The inside of the inner sleeve (3-2e) and the lower joint (3-2f), and the lower end of the central cylinder (3-2g) is fixedly connected with the lower joint (3-2f); the inner sleeve (3-2e) The lower end of the lower joint (3-2f) is fitted inside the upper end of the lower joint (3-2f), and the inner sleeve (3-2e) is splined with the lower joint (3-2f). The inner sleeve (3-2e) The lower end can move freely relative to the lower joint (3-2f) along the spline pair, and the outer side of the inner sleeve (3-2e) is fitted with a packer rubber cartridge (3-2a), and the packer rubber cartridge (3-2a) can be squeezed and expanded by the upper outer sleeve (3-2d) and the lower joint (3-2f), and the upper outer sleeve (3-2d) and the central sleeve (3-2g) are provided with blowout prevention The blowout preventer conduction port (3-2b), when the upper and outer sleeves (3-2d) move down, the blowout preventer conduction port (3-2b) is conducted. 10. A working method of a drill string with a downhole blowout preventer as described in any one of claims 1 to 9, characterized in that: in the drilling process, when encountering a high-pressure oil reservoir or a gas reservoir, it is necessary to The blowout preventer implements isolation, and its working method is as follows: The pressure monitoring and signal generating device (2) detects the downhole pressure value and compares the value with the set program. If the pressure value is abnormal, the pressure monitoring and signal generating device (2) is activated immediately The signal excitation device, the signal excitation device sends a pressure abnormal signal, the signal propagates upward along the drill string body, is received by the signal receiving and alarm generating device (6) installed on the upper part of the drill string, and the signal receiving and alarm generating device (6) sends out Alarm electromagnetic wave signal; if the pressure value is normal pressure, it will not be processed; After the ground receives the signal, the emergency response is activated, the drill string body is lowered actively or automatically, the packer rubber tube (3-2a) in the annular blowout preventer (3-2) is squeezed and expanded, and the packer rubber tube (3-2a) Close the annulus between the drill string and the well wall or between the drill string and the casing to realize setting; 103. During the setting process of the downhole blowout preventer (3), the blowout preventer opening (3-2b) in the annular blowout preventer (3-2) is connected to connect the inside of the drill pipe with the annular space , and carry out heavy mud killing operations; 104. When the blowout is controlled, the drill string body is lifted up, the packer rubber tube (3-2a) in the annular BOP (3-2) retracts automatically, and the annular BOP (3-2) is Unsealing, at the same time the blowout preventer conduction port (3-2b) is closed.

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