CN108716396A - A kind of development approach of coal bed gas multiple-limb distal end connected well - Google Patents

Abstract

The present invention relates to the technical field of coalbed methane exploitation, and relates to a development method of multi-branched remote connected wells of coalbed methane, which specifically includes the following steps: 1) Firstly, a Φ311.1mm drill bit is used to drill to the designed surface casing depth, and then drilled into a Φ244. 5mm casing is used to seal the upper part which is unstable, easy to leak and easy to collapse; 2) In the second opening, a Φ215.9mm drill bit is used to drill to the design target point, the inclination angle reaches 84°, and the Φ177.8mm technical casing is run in for cementing and isolation Leakage-prone formations; 3) The three deviated well sections were drilled to the design target point with a Φ155.6mm drill bit; 4) Each branch well section was drilled to the corresponding design target point with a Φ155.69mm drill bit in turn. Compared with vertical wells and horizontal wells, the multi-branch horizontal well of the present invention has improved conductivity, increased sweep area, and greatly increased single well production; the present invention adopts drilling along the downdip direction of the reservoir, which is beneficial to the control of wellbore trajectory , is conducive to the water in the coal seam to flow into the bottom of the production well under the action of gravity, and improves the drainage and gas recovery efficiency of the production well.

Description

A method for developing coalbed methane multi-branch remote connected wells

technical field

The invention relates to the technical field of coalbed methane exploitation, in particular to a development method for multi-branched remote connected wells of coalbed methane.

Background technique

In the process of coalbed methane exploitation, there are mainly problems of low drilling rate and low recovery rate, and the development efficiency of simple structure wells is lower. Therefore, it is necessary to design production wells that can be developed efficiently through drilling engineering according to the geological characteristics of coalbed methane.

The existing technology adopts the vertical well development scheme, and arranges multiple wells in the coalbed methane block to form a development well pattern, which greatly increases the number of wells, high operating costs, and low development efficiency; another scheme uses horizontal wells and vertical wells connected, considering The problem of water drainage and gas recovery is an improvement to the original scheme, but the oil and gas recovery has a small spread area, and the recovery factor still needs to be improved. Generally speaking, the existing technology is not high for single well production of coalbed methane exploitation.

Contents of the invention

Aiming at the problems existing in the prior art, the object of the present invention is to provide a method for developing coalbed methane multi-branch remote connected wells.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for developing multi-branched remote connected wells of coalbed methane, specifically comprising the following steps:

1) Drill with a Φ311.1mm drill bit to the designed depth of the casing at the surface layer, and run a Φ244.5mm casing to seal the upper unstable, easy to leak, and easy-to-collapse layer, and use the inner pipe cementing process to return the cement slurry to the surface , establish the wellhead and install the blowout preventer;

2) In the second opening, the Φ215.9mm drill bit was used to drill to the design target point, the inclination angle reached 84°, and the Φ177.8mm technical casing was put into the well for cementing to seal the leaky formation;

3) The Φ155.6mm drill bit is used to drill to the design target point in the third deviated well section;

4) Each branch well section is drilled to the corresponding design target with Φ155.69mm drill bit in turn;

5) The casing depth of each layer shall be corrected according to the actual drilling depth according to the design principle.

Engineering wells are multi-lateral wells, production wells are cave vertical wells, and multi-lateral horizontal wells are drilled along the downdip direction of the reservoir.

Further optimization of the technical solution, the multi-branched distal communicating well is a communicating well in which a multi-branched horizontal well communicates with a vertical well in a distal cave.

Further optimization of the technical solution, the communication process between the multi-branch well and the cave vertical well is:

1) When the drilling of the circular horizontal well is 50-60m away from the vertical cave well, a strong magnetic ranging instrument is run in the vertical well of the cave, and a strong magnetic joint of the tracing nipple is run in the horizontal well;

2) Adjust the trajectory according to the data given by the instrument, so that the actual drilling trajectory collides with the connected point;

3) Trajectory measurement is carried out every 3 to 5 meters of drilling, and the tool face is adjusted in time to control the wellbore trajectory;

4) Use non-magnetic short joints to minimize the distance from the bottom of the well to the MWD measurement point;

5) When the horizontal well is drilled to the vicinity of the cave, the vertical depth of the trajectory should be in the middle or upper middle of the cave. If the connection fails, further sidetracking can be used to find the cave.

Further optimization of this technical solution, the control method for the communication between the multi-branch well and the cave vertical well is:

1) After the third opening, run the electromagnetic generating device in the vertical well of the cave, and run the MWD into the tracking sub in the horizontal well;

2) The electromagnetic generating device sends out strong and sometimes weak signals, which are sent to the MWD after being received by the tracking sub, and then sent to the drilling fluid by the MWD;

3) The receiving device on the ground receives the pulse signal from the upward drilling fluid and then converts it into an electrical signal, which is displayed in the computer of the ground staff to form a certain electromagnetic sensing line, thereby judging the orientation between the drilling tool and the cave well ;

4) Trajectory measurement is carried out every 3-5m, and the tool face is adjusted in time to control the wellbore trajectory;

5) It is estimated that the drilling of the horizontal well 2-3m away from the vertical well cave will stop. The vertical well will pull out the instrument, the wellhead gate will be slightly opened, and the main wellbore will continue to drill. During the drilling process, the pump pressure will drop, the wellhead will not return mud, and there will be liquid at the wellhead of the vertical well. The discharge phenomenon indicates that the connection is successful.

Further optimization of this technical solution, the main components of the drill tool assembly used in step 1) of the communication process are: drill bit + motor + MWD + non-magnetic drill collar + drill pipe.

Further optimization of the technical solution, in the step 5) of the control method, after the connection is successful, continue to drill about 10 meters, and pull out the drill to get rid of the strong magnetic joint.

Further optimization of the technical solution, the main wellbore of the connected well is drilled along the downdip direction of the reservoir.

Further optimization of the technical solution, the connected wells are drawn according to the design parameters for three-dimensional wellbore trajectory, and the number of branch wellbores can be increased or decreased according to the reservoir conditions.

The beneficial effects of the present invention are:

(1) Compared with vertical wells and horizontal wells, the multi-branch horizontal well of the present invention has improved the flow conductivity, increased the swept area, and greatly improved the single well production;

(2) The present invention adopts drilling along the downdip direction of the reservoir, which is beneficial to the control of the wellbore trajectory and the water in the coal seam to flow into the bottom of the production well under the action of gravity, so as to improve the drainage and gas recovery efficiency of the production well.

(3) The characteristic multi-branch well of the present invention can greatly improve the output of a single well for the exploitation of coalbed methane, and has reference significance for the exploitation of coalbed methane in the whole country. to meet domestic demand.

Description of drawings

Fig. 1 is a process diagram of the present invention;

Fig. 2 is the structural diagram of multi-branch horizontal well and far-end vertical well shaft in the simulated block of the present invention;

Fig. 3 is the design data drawing of the communicating well that multi-branch horizontal well of the present invention is communicated with far-end vertical well;

Among them, a is the main wellbore of the horizontal well and the cave vertical well connected at the far end, and b is each branch wellbore.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1, a method for developing multi-branched remote connected wells of coalbed methane specifically includes the following steps:

(1) Drill with a Φ311.1mm drill bit to the designed surface casing depth at the first opening, seal the upper unstable, easy to leak, and easy-to-collapse layer with a Φ244.5mm casing, and use the inner pipe cementing process to return the cement slurry to the surface , establish the wellhead, and install blowout preventers to ensure the second well control requirements and smooth construction.

(2) The 215.9mm drill bit was used to drill to the design target point in the second opening, and the inclination angle reached 84°, and the Φ177.8mm technical casing cementing was run in to seal the leakage-prone formation, which provided favorable conditions for the safe construction of the third opening horizontal well section. construction risk.

(3) The Φ155.6mm drill bit is used to drill to the design target point in the third deviated well section.

(4) Each branch well segment is sequentially drilled to the corresponding design target point with a Φ155.69mm drill bit.

(5) The casing depth of each layer is corrected according to the actual drilling depth according to the design principle.

Engineering wells are multi-lateral wells, production wells are cave vertical wells, and multi-lateral horizontal wells are drilled along the downdip direction of the reservoir.

The multi-branch distal communicating well of the present invention is a communicating well in which a multi-branch horizontal well communicates with a vertical well in a distal cave.

As shown in Figures 1-2, the communication process between the multi-branch well and the vertical cave well is as follows:

(1) When the circular horizontal well is drilled at a distance of 50-60m from the cave vertical well, a strong magnetic ranging instrument is run in the cave vertical well, and a tracking nipple strong magnetic joint is run in the horizontal well. The main components of the drilling tool assembly are: drill bit + Motor+MWD+non-magnetic drill collar+drill pipe;

(2) Adjust the trajectory according to the data given by the instrument, so that the actual drilling trajectory collides with the connected point;

(3) Trajectory measurement is carried out every 3 to 5 meters of drilling, and the tool face is adjusted in time to control the wellbore trajectory;

(4) Use non-magnetic short joints to minimize the distance from the bottom of the well to the MWD measurement point;

(5) When the horizontal well is drilled to the vicinity of the cave, the vertical depth of the trajectory should not be located in the lower part of the cave, but should be located in the middle or upper middle of the cave. If the connection fails, you can drill further to find the cave. If it is located in the lower part, it is difficult to increase the slope and sidetrack, which is not conducive to taking follow-up measures.

As shown in Figures 1-2, the control method for the communication between the multi-branch well and the cave vertical well is as follows:

(1) After three openings, the electromagnetic generating device is installed in the cave well, and the MWD is installed in the tracking joint in the horizontal well;

(2) The electromagnetic generating device sends out strong and sometimes weak signals, which are sent to the MWD after being received by the tracking sub, and then sent to the drilling fluid by the MWD;

(3) The receiving device on the ground receives the pulse signal from the upward drilling fluid and then converts it into an electrical signal, which shows that a certain electromagnetic sensing line is formed in the computer of the ground staff, thereby judging the distance between the drilling tool and the cave well. position;

(4) Trajectory measurement is carried out every 3 to 5 meters of drilling, and the tool face is adjusted in time to control the wellbore trajectory;

(5) It is estimated that the drilling of the horizontal well 2 to 3 meters away from the vertical well cave will stop. The vertical well will pull out the instrument, the wellhead gate will be slightly opened, and the main wellbore will continue to drill. During the drilling process, the pump pressure will drop and the wellhead will not return mud. Fluid discharge indicates successful connection. After connecting, continue to drill for about 10 meters, pull out the drill and get rid of the strong magnetic joint.

The main wellbore of the communication well of the present invention is drilled along the downdip direction of the reservoir.

As shown in Figure 3, the design data drawing of the connected well with the multi-branch horizontal well and the remote vertical well is connected, and the vertical depth, N coordinate, E Coordinates, well inclination angle, well inclination azimuth, etc.), and draw the visualization graph of three-dimensional wellbore trajectory. The interconnected well of the present invention draws the three-dimensional wellbore trajectory according to the design parameters, and can increase or decrease the number of branch wellbores according to the conditions of the reservoir.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand the foregoing embodiments Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention. Inside.

Claims (8)

1. a development method of multi-branch far-end connected well of coalbed methane, is characterized in that, specifically comprises the following steps: 1) Drill with a Φ311.1mm drill bit to the designed depth of the casing at the surface layer, and run a Φ244.5mm casing to seal the upper unstable, easy to leak, and easy-to-collapse layer, and use the inner pipe cementing process to return the cement slurry to the surface , establish the wellhead and install the blowout preventer; 2) In the second opening, the Φ215.9mm drill bit was used to drill to the design target point, the inclination angle reached 84°, and the Φ177.8mm technical casing was put into the well for cementing to seal the leaky formation; 3) The Φ155.6mm drill bit is used to drill to the design target point in the third deviated well section; 4) Each branch well section is drilled to the corresponding design target with Φ155.69mm drill bit in turn; 5) The casing depth of each layer shall be corrected according to the actual drilling depth according to the design principle. 2. The development method of a multi-branched remote connected well of coalbed methane according to claim 1, wherein the multi-branched remote connected well is a connected well in which a multi-branched horizontal well communicates with a distal cave vertical well. 3. the development method of a kind of coalbed methane multi-branch far-end communicating well according to claim 2, is characterized in that, the communication technology of described multi-branch well and cave vertical well is: 1) When the drilling of the circular horizontal well is 50-60m away from the vertical cave well, a strong magnetic ranging instrument is run in the vertical well of the cave, and a strong magnetic joint of the tracing nipple is run in the horizontal well; 2) Adjust the trajectory according to the data given by the instrument, so that the actual drilling trajectory collides with the connected point; 3) Trajectory measurement is carried out every 3 to 5 meters of drilling, and the tool face is adjusted in time to control the wellbore trajectory; 4) Use non-magnetic short joints to minimize the distance from the bottom of the well to the MWD measurement point; 5) When the horizontal well is drilled to the vicinity of the cave, the vertical depth of the trajectory should be in the middle or upper middle of the cave. If the connection fails, further sidetracking can be used to find the cave. 4. the development method of a kind of coalbed methane multi-branch far-end communicating well according to claim 3, is characterized in that, the control method that described multi-branch well communicates with cave vertical well is: 1) After the third opening, run the electromagnetic generating device in the vertical well of the cave, and run the MWD into the tracking sub in the horizontal well; 2) The electromagnetic generating device sends out strong and sometimes weak signals, which are sent to the MWD after being received by the tracking sub, and then sent to the drilling fluid by the MWD; 3) The receiving device on the ground receives the pulse signal from the upward drilling fluid and then converts it into an electrical signal, which is displayed in the computer of the ground staff to form a certain electromagnetic sensing line, thereby judging the orientation between the drilling tool and the cave well ; 4) Trajectory measurement is carried out every 3-5m, and the tool face is adjusted in time to control the wellbore trajectory; 5) It is estimated that the drilling of the horizontal well 2-3m away from the vertical well cave will stop. The vertical well will pull out the instrument, the wellhead gate will be slightly opened, and the main wellbore will continue to drill. During the drilling process, the pump pressure will drop, the wellhead will not return mud, and there will be liquid at the wellhead of the vertical well. The discharge phenomenon indicates that the connection is successful. 5. The development method of a kind of coalbed methane multi-branch remote connected well according to claim 3, characterized in that, the main components of the drilling tool assembly used in the step 1) of the connected process are: drill bit+motor+MWD+ Non-magnetic drill collar + drill pipe. 6. the development method of a kind of coalbed methane multi-branch far-end communicating well according to claim 4, it is characterized in that, in the step 5) of described control method, continue to drill about 10 meters after being communicated successfully, pull out and get rid of Strong magnetic connector. 7. The method for developing multi-branched remote connected wells of coalbed methane according to any one of claims 1 to 6, characterized in that the main borehole of the connected wells is drilled along the downdip direction of the reservoir. 8. The development method of a kind of coalbed methane multi-branch remote connected well according to claim 1 or 2, characterized in that, the connected well carries out three-dimensional borehole trajectory drawing according to the design parameters, which can be carried out according to the situation of the reservoir Increase or decrease in the number of lateral wellbores.