JP2018066117A - Natural gas recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering natural gas capable of efficiently recovering the natural gas while preventing subsidence of ground when recovering the natural gas from a plurality of natural gas formations with one well in the natural gas field having the plurality of natural gas formations.SOLUTION: A method for recovering natural gas of this invention, comprises burying a double pipe 20 in the ground by penetrated through a plurality of natural gas formations 11 to 13, and attaching respective valves 31 to 36 to two portion of upper and a lower of each natural gas formation, and pumping up brine absorbed the natural gas through an inner pipe 21 via the upper valve attached to one of the plurality of natural gas formations 11 to 13, and then recovering the natural gas from the brine absorbed the natural gas, after its separation treatment, and adjusting reused brine by mixing a specific-gravity agent and an additive agent into the brine which having already removed natural gas, and returning the reused brine into said gas collecting formation through the outer pipe 22 and the under valve.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a natural gas collection method for collecting natural gas dissolved in brine in the ground.

  In Patent Document 1, the brine containing the natural gas is pumped from the underground gas layer, the natural gas is collected from the pumped brine, and the brine collected from the natural gas is the same as the gas layer from which the brine is pumped. A natural gas sampling method is disclosed in which ground subsidence is prevented by reduction to a gas layer. Further, in Patent Document 1, in order to avoid mixing of the brine that has been reduced in the gas layer and the brine before pumping, a brine inlet and a reduced water outlet are provided at different height positions of the underground pipe. Is disclosed.

JP 2014-218806 A

  However, in the natural gas sampling method disclosed in Patent Document 1, although the brine intake port and the reduced water discharge port are provided at different height positions of the underground buried pipe, the reduced brine and the brine before pumping There is a problem that the reduced brine is gradually mixed with the brine before being pumped over time. In addition, if the reduced brine is mixed with the brine before pumping, the natural gas concentration of the pumped brine will be lowered, and the efficiency of collecting natural gas will deteriorate.

  Furthermore, the natural gas collection method disclosed in Patent Document 1 is a natural gas collection method on the premise that natural gas is collected from one gas layer, and one well is provided in a gas field in which a plurality of gas layers exist. Therefore, it cannot be applied as it is when natural gas is collected from a plurality of gas layers.

  Accordingly, the first object of the present invention is to provide a natural gas sampling method capable of efficiently collecting natural gas while preventing ground subsidence in a gas field having a plurality of gas layers. A natural gas sampling method capable of collecting and reducing irrigation water for a plurality of gas layers in a single well in a gas field having multiple layers, and efficiently collecting natural gas while preventing land subsidence. The second object is to provide the above.

  In order to achieve the first object, the invention described in claim 1 pumps up brine water in which natural gas is dissolved from the underground gas layer, collects natural gas from the pumped brine, and collects natural gas. In the natural gas sampling method for reducing the finished brine into the same gas layer as the one that pumped up the brine, the collection pipe and the reduction pipe are buried in the ground so as to penetrate multiple gas layers. A plurality of gas layers, wherein valves are installed at two upper and lower portions in each layer, an upper valve in each gas layer is connected to the collection pipe, a lower valve in each gas layer is connected to the reduction pipe, Select one sampling layer to collect natural gas from, and pump the brine collected from the upper valve sampling port in the selected sampling layer using the sampling tube, increasing the specific gravity of the brine collected from the natural gas Agent Mixed as additives, natural gas sampling method which comprises reducing the collection layer is discharged from the discharge port of the lower valve in the collection layer with the brine back using the reducing pipe.

  In order to achieve the second object, the invention described in claim 2 is the invention described in claim 1, wherein a double pipe having an inner pipe and an outer pipe is passed through a plurality of gas layers. It is embedded in the ground, and one of the inner tube and the outer tube is used as the collecting tube, and the other is used as the reducing tube.

  The invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2, the marker is added as an additive to the brine which has been sampled for natural gas.

  The invention described in claim 4 is the invention described in claim 3, wherein the brine is sampled from the natural gas and the brine is pumped from the sampling layer when the marker is detected. It is characterized by terminating.

  According to the first aspect of the present invention, since the brine that has been collected from the natural gas is reduced to the same gas layer as the gas layer from which the brine is pumped, ground subsidence can be prevented. Further, the brine in which the natural gas is dissolved is collected from the upper valve in the sampling layer, and the specific gravity increasing agent is further added as an additive to the brine having a higher specific gravity after the sampling of the natural gas, and the brine is mixed in the sampling layer. Since it is discharged from the lower valve, the reduced brine is accumulated in the lower part of the sampling layer, so that the reduced brine and the brine before pumping cannot be mixed. Thus, according to the present invention, it is possible to provide a natural gas sampling method that can efficiently extract natural gas while preventing land subsidence in a gas field in which a plurality of gas layers exist.

  According to the invention described in claim 2, a double pipe having an inner pipe and an outer pipe is buried in the ground so as to penetrate a plurality of gas layers, and one of the inner pipe and the outer pipe is collected. In addition to the effect of claim 1, the brine can be collected and reduced for a plurality of gas layers in one well by using the reduction pipe as the other pipe. As described above, according to the present invention, in a gas field where a plurality of gas layers exist, it is possible to collect and reduce brine in a plurality of gas layers in one well, and to prevent land subsidence while improving efficiency. It is possible to provide a natural gas collection method that can collect natural gas well.

  According to the invention described in claim 4, since the brine is collected from the natural gas, and when the marker is detected, the pumping of the brine from the collection layer is completed. Can be collected.

It is the schematic explaining the natural gas sampling method concerning the 1st Embodiment of this invention. It is explanatory drawing explaining operation | movement of each valve | bulb in case natural gas is extract | collected from the uppermost layer among the three gas layers of FIG. It is explanatory drawing explaining operation | movement of each valve | bulb when extract | collecting natural gas from an intermediate | middle layer among the three gas layers of FIG. It is explanatory drawing explaining operation | movement of each valve | bulb in case natural gas is extract | collected from the lowest layer among the three gas layers of FIG. It is a top view of the valve body which constitutes the upper valve in each gas layer of FIG. It is sectional drawing along the AA line in FIG. It is sectional drawing along the BB line in FIG. It is a top view of the disk assembled | attached to the valve body of FIG. It is sectional drawing along CC line in FIG. It is a top view of the valve body which constitutes the lower valve in each gas layer of FIG. It is sectional drawing along the DD line | wire in FIG. It is sectional drawing along the EE line in FIG. It is a top view of the disk assembled | attached to the valve body of FIG. It is sectional drawing along the FF line in FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 31 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 31 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 31 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 31 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 32 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 32 of FIG. It is explanatory drawing explaining operation | movement of the valve | bulb 32 of FIG. It is the schematic explaining the natural gas sampling method concerning the 2nd Embodiment of this invention.

(First embodiment)
A “natural gas sampling method” according to the first embodiment of the present invention will be described with reference to FIGS. The natural gas collection method of the present embodiment is a natural gas collection method using the natural gas collection system shown in FIG. 1, and a plurality of gas layers 11 in one well in a gas field in which a plurality of gas layers 11 to 13 exist. This is a natural gas collection method for collecting and reducing brine for ˜13. The natural gas collection system shown in FIG. 1 includes a double pipe 20, valves 31 to 36, a gas lift compressor 41, a gas lift pipe 40, a compressor 48, a gas storage tank 42, an iodine recovery factory 45, a brine adjustment unit 46, and a flow meter 44. , 47, etc.

  The double pipe 20 has an inner pipe (corresponding to “collecting pipe” in the claims) 21 disposed in an outer pipe (corresponding to “reducing pipe” in the claims) 22. And the outer tube | pipe 22 and the inner tube | pipe 21 are arrange | positioned coaxially. The double pipe 20 is embedded in the ground so as to penetrate the plurality of gas layers 11 to 13. The gas layers 11 to 13 contain brine water in which natural gas is dissolved. The valves 31 to 36 are connected to the inner tube 21 and the outer tube 22, and are installed at two upper and lower positions in each gas layer 11 to 13. The gas lift compressor 41 is installed on the ground surface 10 and sends high-pressure gas to the inner pipe 21 via the gas lift pipe 40.

  In the gas storage tank 42, natural gas collected from the brine pumped up from the gas layers 11 to 13 is stored. The brackish water pumped up from the gas layers 11 to 13 rises in the inner pipe 21 as shown by an arrow K1 in FIG. The separated natural gas is compressed by the compressor 48 and stored in the gas storage tank 42 as indicated by an arrow K2 in FIG. The natural gas stored in the gas storage tank 42 is sent to a supply destination such as the power generation facility 43. On the other hand, the brine after the natural gas has been collected is sent to the iodine recovery factory 45 where the iodine is recovered and sent to the brine adjustment unit 46.

  In addition, when pumping the brine from the gas layers 11 to 13, the brine is not pumped from the gas layers 11 to 13 at the same time, and the brine is pumped from one gas layer 11 to 13 selected in advance as a collection layer.

  In the irrigation adjustment unit 46, a specific gravity increasing agent and a marker are mixed as an additive to the irrigation, and water is further added. In this embodiment, cerium hydroxide that is harmless to the environment is used as the specific gravity increasing agent. In this embodiment, a colorant that is harmless to the environment is used as the marker. In the present invention, as the specific gravity increasing agent, in addition to the cerium hydroxide described above, a substance that is harmless to the environment and that can increase the specific gravity of brine can be used. In the present invention, in addition to the above-mentioned colorants, a marker that is harmless to the environment and that can be identified as added by the irrigation adjusting unit 46 can be used as the marker.

  The brine in which the additive and water are added in the brine adjustment unit 46 in this manner is lowered in the outer tube 22 as shown by an arrow K3 in FIG. 1, and is the same as the gas layers 11 to 13 pumping up the brine. It is reduced to gas layers 11-13. Further, when returning the irrigation water from the irrigation adjusting unit 46 into the outer tube 22, the adjustment is performed so that the amount of the irrigation water pumped up from the inner tube 21 is the same. The flow meters 44 and 47 are for performing this adjustment. By these things, ground subsidence can be prevented.

  Further, the irrigation adjusting unit 46 analyzes whether or not the marker is detected from the irrigation. When the marker is detected, the remaining amount of natural gas in the brine collection layer has bottomed out, so the pumping of brine from the collection layer ends and other gases in which the natural gas is present are collected. Change to layers 11-13. By these things, natural gas can be extract | collected efficiently.

  Further, in the natural gas sampling method of the present invention, the brine water in which the natural gas is dissolved is collected from the upper valve in the collection layer, and the brine after the natural gas is collected is discharged from the lower valve in the collection layer. Reduce to the collection layer. For example, when natural gas is collected from the uppermost layer 11 of the three gas layers 11 to 13 in FIG. 1, brine water in which natural gas is dissolved is collected from the upper valve 31 in the gas layer 11 as shown in FIG. 2. Then, the brine which has been collected natural gas is discharged from the lower valve 32 in the gas layer 11.

  Further, when natural gas is collected from the intermediate layer 12 among the three gas layers 11 to 13 in FIG. 1, brine water in which natural gas is dissolved is collected from the upper valve 33 in the gas layer 12 as shown in FIG. 3. The brine that has been sampled for natural gas is discharged from the lower valve 34 in the gas layer 12. At this time, the valves 31 and 32 of the uppermost layer 11 operate so that the inner pipe 21 and the outer pipe 22 pass the brine.

  Further, when natural gas is collected from the lowermost layer 13 of the three gas layers 11 to 13 in FIG. 1, brine water in which the natural gas is dissolved is collected from the upper valve 35 in the gas layer 13 as shown in FIG. 4. Then, the brine which has been collected natural gas is discharged from the lower valve 36 in the gas layer 13. At this time, the valves 31 and 32 of the uppermost layer 11 and the valves 33 and 34 of the intermediate layer 12 operate so that the inner pipe 21 and the outer pipe 22 pass through the brine.

  The upper valves 31, 33, and 35 in each gas layer described above have the same configuration. As shown in FIGS. 2 to 4, the upper valves 31, 33, and 35 in these gas layers have two functions, that is, brine collection and passage through the outer tube 22, and passage through the outer tube 22 and the inner tube 21. . The lower valves 32, 34, and 36 in each gas layer have the same configuration. As shown in FIGS. 2 to 4, the lower valves 32, 34, and 36 in these gas layers function as drainage (return water) discharge and closing of the inner pipe 21, and pass through both the outer pipe 22 and the inner pipe 21. There are two ways. These valves 31 to 36 are switched by an air cylinder (not shown).

  As described above, in the natural gas sampling method of the present invention, the brine in which the natural gas is dissolved is collected from the upper valve in the collection layer, and the specific gravity increasing agent is further added to the brine having a higher specific gravity after the collection of the natural gas. Is added as an additive, and the brine is discharged from the lower valve in the collection layer, so that the reduced brine is accumulated in the lower part of the collection layer so that the reduced brine and the brine before pumping are not mixed. Can do. By these things, natural gas can be extract | collected efficiently.

  In the natural gas sampling method of the present invention, the double pipe 20 having the inner pipe 21 and the outer pipe 22 is buried in the ground so as to penetrate the plurality of gas layers 11 to 13, and the gas layers 11 to 13 are buried. Natural gas can be collected from the desired gas layers 11 to 13 by installing valves 31 to 36 connected to the inner tube 21 and the outer tube 22 at two locations above and below. As described above, according to the natural gas collection method of the present invention, it is possible to collect and reduce brine in a plurality of gas layers in one well in a gas field having a plurality of gas layers, and subsidize the ground. Natural gas can be collected efficiently while preventing the above.

  Next, specific structures and operations of the above-described valves 31 to 36 will be described with reference to FIGS. Since the valves 31, 33, and 35 have the same configuration, the valve 31 will be described as a representative, and the other description will be omitted. Further, since the valves 32, 34, and 36 have the same configuration, the valve 32 will be described as a representative, and other description will be omitted.

  The valve 31 is a rotary disk valve in which the disk 7 shown in FIGS. 8 to 9 is assembled to the valve body 6 shown in FIGS. The valve body 6 has a cylindrical outer shape, and has a center hole 61 penetratingly formed at the center thereof, a pair of outer holes 63 penetratingly formed outside the center hole 61, and penetratingly formed outside the center hole 61. A pair of outer holes 64, a pair of recesses 62 that are recessed from the inner surface of the center hole 61, and a pair of lateral holes 65 that open to the inner surface of the center hole 61 and the outer peripheral surface of the valve body 6. doing.

  As shown in FIG. 7, a partition plate 66 is attached in the horizontal hole 65, and the horizontal hole 65 is partitioned into a sampling port 67 and a gas pressure inlet 68 by the partition plate 66. Brine is passed through the sampling port 67, and high-pressure gas sent from the gas lift pipe 40 is passed through the gas pressure inlet 68. One end portion 68b of the gas pressure inlet 68 on the center hole 61 side has a smaller cross-sectional area than the other end portion 68a of the gas pressure inlet 68 on the gas lift pipe 40 side. The one end 68 b merges with the sampling port 67. Thus, the valve 31 is formed so that a venturi effect is produced at the sampling port 67. That is, the valve 31 is formed to increase the suction efficiency of the brine passing through the sampling port 67 by increasing the gas flow rate at the one end 68b to lower the pressure at the one end 68b.

  The disk 7 includes a bottomed cylindrical tube portion 72, a flange portion 71 extending outward from the upper end of the tube portion 72, a pair of openings 73 formed through the outer peripheral surface of the tube portion 72, and the tube portion 72. A pair of openings 74 formed in a different position from the pair of openings 73, and a pair of outer holes 75 formed through the flange 71.

  When the pair of outer holes 75 overlap the pair of outer holes 64, the valve 31 overlaps the pair of lateral holes 65 with the pair of openings 73 as shown in FIG. The inner pipe 21 communicates with the inside of the section 72, and brine is collected from the gas layer 11 to the inner pipe 21. When the pair of outer holes 75 overlap the pair of outer holes 64, as shown in FIG. 16, the outer tube 22 (upper side of the valve 31), the outer hole 75, the outer hole 64, and the outer tube 22 (below the valve 31). Side) communicates, and brine (return water) passes through the outer tube 22.

  On the other hand, in the valve 31, when the pair of outer holes 75 overlap the pair of outer holes 63, the pair of recesses 62 overlaps the pair of openings 74 as shown in FIG. Side), the center hole 61, the recess 62, the opening 74, the inside of the cylindrical portion 72, and the inner pipe 21 (upper side of the valve 31) communicate with each other, and brine passes through the inner pipe 21. When the pair of outer holes 75 overlap with the pair of outer holes 63, as shown in FIG. 18, the outer tube 22 (upper side of the valve 31), the outer hole 75, the outer hole 63, and the outer tube 22 (below the valve 31). Side) communicates, and brine (return water) passes through the outer tube 22.

  The valve 32 is a rotary disk valve in which the disk 9 shown in FIGS. 13 to 14 is assembled to the valve body 8 shown in FIGS. The valve body 8 has a cylindrical outer shape, a center hole 81 formed through the center of the valve body 8, a pair of discharge ports 83 opened on the upper surface of the valve body 8 and the outer peripheral surface of the valve body 8, and the center hole 81. It has a pair of outer holes 84 penetrating to the outside and a pair of recesses 82 recessed from the inner surface of the center hole 81.

  The disk 9 includes a bottomed cylindrical tube portion 92, a flange portion 91 extending outward from the upper end of the tube portion 92, a pair of openings 93 formed through the outer peripheral surface of the tube portion 92, and a flange portion 91. A pair of outer holes 94 penetratingly formed.

  In the valve 32, when the pair of outer holes 94 overlap with the pair of discharge ports 83, as shown in FIG. 19, the outer tube 22 (upper side of the valve 32), the outer hole 94, and the discharge port 83 communicate with each other. The brine (return water) is discharged from the gas layer 11. When the pair of outer holes 94 overlap with the pair of discharge ports 83, the inner tube 21 is closed as shown in FIG.

  On the other hand, in the valve 32, when the pair of outer holes 94 overlap the pair of outer holes 84, the pair of recesses 82 overlap the pair of openings 93 as shown in FIG. Side), the center hole 81, the recess 82, the opening 93, the inside of the cylindrical portion 92, and the inner pipe 21 (upper side of the valve 32) communicate with each other, and brine passes through the inner pipe 21.

  When the pair of outer holes 94 overlap with the pair of outer holes 84, as shown in FIG. 21, the outer tube 22 (upper side of the valve 32), the outer hole 94, the outer hole 84, and the outer tube 22 (below the valve 32). Side) communicates, and brine (return water) passes through the outer tube 22.

  In the above-described first embodiment, the inner pipe 21 is used to pump up the brine and the outer pipe 22 is used to return the brine (return water) to the collection layer. A configuration may be used in which the brine is pumped up and the brine (returned water) is returned to the collection layer using the inner tube.

(Second Embodiment)
The “natural gas collection method” according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 22, the same components as those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  The natural gas sampling method of the present embodiment is a natural gas sampling method using the natural gas sampling system shown in FIG. 22, and has three sampling wells and three reduction wells in a gas field having a plurality of gas layers 11 to 13. Is a natural gas collection method for collecting and reducing brine to a plurality of gas layers 11 to 13. In each sampling well, a sampling pipe 121 is buried in the ground so as to penetrate the plurality of gas layers 11 to 13, and each sampling pipe 121 collects brine from the plurality of gas layers 11 to 13. In addition, each reduction well has a reduction pipe 122 embedded in the ground so as to penetrate the plurality of gas layers 11 to 13, and each reduction pipe 122 reduces brine into the plurality of gas layers 11 to 13. .

  Valves 131, 133, and 135 are installed in portions of the collection pipe 121 located above the gas layers 11 to 13. These valves 131, 133, and 135 have two kinds of functions of collecting brine or passing through the collection pipe 121.

  Valves 132, 134, and 136 are installed in portions of the reduction pipe 122 located below the gas layers 11 to 13. These valves 132, 134, and 136 have two kinds of functions of discharging brine (return water) or passing through the reduction pipe 122.

  In addition, when pumping the brine from the gas layers 11 to 13, the brine is not pumped from the gas layers 11 to 13 at the same time, and the brine is pumped from one gas layer 11 to 13 selected in advance as a collection layer. Furthermore, when pumping brine from the selected collection layer, the three collection tubes 121 may be used simultaneously, or one or two pipes may be used.

  Then, the natural water is collected as in the first embodiment, and the brackish water to which the additive and water are added by the bracking water adjusting unit 46 descends in the reduction pipe 122 and the gas layer 11 pumped up the brackish water. To the same gas layers 11 to 13 as ˜13, that is, the collection layers. Further, when the brine is returned from the brine adjustment unit 46 into the reduction tube 122, the adjustment is performed so that the amount is equal to the amount of the brine pumped up from the collection tube 121. During this adjustment, surplus brine may be drained to a place other than the reduction well. Furthermore, when reducing the brine to the collection layer, the three reduction pipes 122 may be used simultaneously, or one or two pipes may be used.

  As described above, by using a plurality of pairs of sampling pipes 121 and reduction pipes 122, natural gas can be efficiently sampled while preventing ground subsidence in a gas field having a plurality of gas layers.

  In the second embodiment described above, an example in which three pairs of the collection pipe 121 and the reduction pipe 122 are used has been described. However, at least one pair of the collection pipe 121 and the reduction pipe 122 may be provided. . Further, the number of collection tubes 121 and the number of reduction tubes 122 may not be the same. For example, two collecting pipes 121 may be provided, and one reducing pipe 122 may be provided. Also in these cases, the valves 131, 133, and 135 are respectively installed at portions located above the gas layers of the collection pipe 121, and the valves 132, 134, and 136 are located below the gas layers of the reduction pipe 122. It is installed in the part located in each.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

10 Ground surface 11-13 Gas layer 20 Double pipe 21 Inner pipe (pipe for collection)
22 Outer pipe (reduction pipe)
31-36 Valve 40 Gas lift pipe 41 Gas lift compressor 42 Gas storage tank 43 Power generation facility 45 Iodine recovery factory 46 Brine adjustment section 44, 47 Flow meter 48 Compressor 121 Collection pipe 122 Reduction pipe 131-136 Valve

Claims (4)

Pumping the brine containing natural gas from the underground gas layer, collecting the natural gas from the pumped brine, and reducing the brine that has been sampled to the same gas layer that pumped the brine In the natural gas collection method,
The collection tube and the reduction tube are buried in the ground so as to penetrate through multiple gas layers, and valves are installed at two locations above and below each gas layer, and the upper valve in each gas layer is connected to the collection tube. And connecting a lower valve in each gas layer to the reduction pipe,
Select one sampling layer to extract natural gas from the plurality of gas layers, pump up brine collected from the sampling port of the upper valve in the selected sampling layer using the sampling tube, and finish sampling natural gas A specific gravity increasing agent is added as an additive to the brine, and the brine is returned using the reduction pipe and discharged from the outlet of the lower valve in the collection layer to be reduced to the collection layer. Natural gas sampling method. A double pipe having an inner pipe and an outer pipe is buried in the ground so as to penetrate a plurality of gas layers, and one of the inner pipe and the outer pipe is used as the sampling pipe, and the other is used as the reducing pipe. The natural gas collection method according to claim 1, wherein The natural gas collection method according to claim 1 or 2, wherein a marker is mixed as an additive in the brine after collection of natural gas. 4. The method for collecting natural gas according to claim 3, wherein the brine is analyzed after the collection of natural gas, and pumping of brine from the collection layer is terminated when the marker is detected.

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