Wellhead backflow system and method for oil field water injection well
Technical Field
The invention relates to the field of oil field backflow, in particular to a wellhead backflow system and method for an oil field water injection well.
Background
According to the statistical analysis of OPEC organization, the global daily consumed oil amount in 2015 is 86.5 multiplied by 106 barrels per day, the global daily consumed oil amount in 2040 reaches 100.7 multiplied by 106 barrels per day, the water content of the current oil field generally exceeds 75%, and the water content of a part of old oil fields even exceeds 95%. In China, according to the analysis of Han big rack academicians and Li Yang academicians, the reserves and the yield of the water injection exploitation oil field in China all account for more than 80% of the total amount, and the water content of the oil field averagely exceeds 86.0%. Therefore, a large amount of byproduct, produced water, is produced during the oilfield exploitation.
In order to avoid the influence of produced water on the environment and keep the pressure balance of the oil reservoir, according to the recommendation index and analysis method for water injection quality of clastic rock oil reservoir (SY/T5329-2012), the oil field treats the impurities such as floating oil, emulsified oil, solid suspended matters and the like in the produced water at a united station or a sewage treatment station, so that the produced water meets the reinjection requirement and is reinjected to the stratum. However, in the long-time outward transportation process from the combined station to the water injection well, the solid suspended matters in the reinjection water are subjected to collision coalescence reaction continuously to form large-particle solid suspended matters, so that the content and the median particle size of the large-particle solid suspended matters cannot meet the reinjection requirement at the well mouth.
When an oil field is to be reinjected into the formation, the daily reinjection water volume of a cogeneration station is typically about equal to the production water volume (Q)Reinjection water≈QProduced water) The daily water injection amount of the water injection well is also fixed, and the flow rate of water in a water injection pipeline needs to be kept stable. Therefore, in the existing reinjection water process flow, if the outlet flow rate of the reinjection water is directly increased to shorten the conveying time of the reinjection water, the daily reinjection water amount required by the combined station is larger than the produced water amount (Q)Reinjection water>QProduced water) And the problem of insufficient daily reinjection water required by the combined station occurs. The shortage of daily water injection amount of the water source allocation combined station from other places can lead to excessive exploitation of the oil reservoir and influence the life cycle of the oil reservoir.
Therefore, it is necessary to provide a wellhead backflow system and method for an oilfield injection well to solve the above technical problems.
Disclosure of Invention
The invention provides a wellhead backflow system and method for an oil field water injection well, which solve the problem that the daily reinjection water quantity required by a combined station is insufficient after the reinjection water flow rate.
In order to solve the technical problem, the wellhead backflow system of the oilfield water injection well provided by the invention comprises:
a wellhead circulation adjusting device and a wellhead backflow device;
the wellhead circulation adjusting device comprises a first gate valve, a second gate valve, a third gate valve, a fourth gate valve, a fifth gate valve, a sixth gate valve and a seventh gate valve, the first gate valve is connected with a reinjection water incoming pipeline, the first gate valve is respectively connected with the fourth gate valve and the seventh gate valve in series through pipelines, and the fourth gate valve and the seventh gate valve are respectively connected with a reinjection water return pipeline and a reinjection water return pipeline;
the wellhead backflow device comprises a backflow mechanism, a pendulum mechanism, a motion conversion mechanism and a timing mechanism;
the backflow mechanism comprises a cylinder body, a first inner cavity and a second inner cavity are formed in the cylinder body, a first cylindrical cock and a second cylindrical cock are arranged at the top of the cylinder body respectively, a third cylindrical cock and a fourth cylindrical cock are arranged between the first inner cavity and the second inner cavity respectively, and a fifth cylindrical cock and a sixth cylindrical cock are arranged on two sides of the bottom of the cylinder body respectively;
an upper piston is arranged in the first inner cavity, an upper shaft is arranged on the left side of the upper piston, a lower piston is arranged in the second inner cavity, and a lower shaft is arranged on the left side of the lower piston;
the pendulum mechanism comprises a pendulum bob, the top of the pendulum bob is provided with a swing rod, the top of the front surface of the swing rod is provided with an upper slide block through an upper guide rail, the front surface of the swing rod is provided with a support, and the bottom end of the front surface of the swing rod is provided with a lower slide block through a lower guide rail;
the motion transformation mechanism comprises a seat body, a driving rod and a driven rod, wherein an upper rack is arranged at the top of the seat body, a lower rack is arranged at the bottom of the seat body, a gear is arranged at the right side of the seat body, a first spring is arranged at the top of the seat body through a traction seat, the driven rod is arranged at the left end of the first spring through a lifting lug, a second spring is arranged at the bottom of the seat body through the traction seat, and the left end of the second spring is connected with the lower rack through the lifting lug; the driven rod is connected with a timing connecting rod of a timing mechanism;
the timing mechanism comprises a timing connecting rod, a timing upright rod, a timing upper rack, a timing middle rack, a timing lower rack, a first timing ratchet wheel, a second timing ratchet wheel, a third timing ratchet wheel, a fourth timing ratchet wheel, a fifth timing ratchet wheel and a sixth timing ratchet wheel, wherein the first timing ratchet wheel, the second timing ratchet wheel, the third timing ratchet wheel, the fourth timing ratchet wheel, the fifth timing ratchet wheel and the sixth timing ratchet wheel are all connected with the cylindrical cocks with corresponding serial numbers, the second gate valve and the third gate valve are respectively connected with a first inlet and a second inlet of a wellhead backflow device, and the fifth gate valve and the sixth gate valve are respectively connected with a first outlet and a second outlet of the wellhead backflow device;
through the reinjection water adjusting device, the running processes of full backflow, partial backflow and full reinjection can be selected by adjusting the switch of a valve according to the difference of reinjection water reinjection schemes. When a partial backflow operation scheme is adopted, the backflow amount with different proportions can be set through the stroke sliding block according to different requirements of the backflow amount of the reinjection water.
Compared with the existing oilfield reinjection water treatment process, the method realizes the regulation of the external flow rate of reinjection water between the combined station and the water injection well, solves the problem that the water quality at the wellhead of the oilfield water injection well does not reach the standard, and has the technical characteristics of no external power source, pure mechanical structure and flexible flow rate regulation.
Preferably, the top of the first and second cylindrical taps are provided as first and second inlets, respectively, and the bottom of the fifth and sixth cylindrical taps are provided as first and second outlets, respectively.
Preferably, a first emptying valve is arranged on one side of the second inner cavity, and a second emptying valve is arranged on the other side of the second inner cavity.
Preferably, the upper sliding block of the pendulum mechanism is connected with the upper shaft of the backflow mechanism, and the lower sliding block is connected with the lower shaft of the backflow mechanism.
Preferably, a stroke slide block is arranged on the left side of the driving rod of the motion conversion mechanism through a stroke guide rail.
Preferably, the driving rod is connected with the left end of the upper shaft of the backflow mechanism, and the upper rack and the lower rack are both meshed with the gear.
Preferably, the driven rod of the motion conversion mechanism is connected with the timing connecting rod of the timing mechanism.
Preferably, the timing connecting rod is connected with the timing vertical rod, and the timing vertical rod is connected with the timing upper rack, the timing middle rack and the timing lower rack; the timing upper rack is connected with the first timing ratchet wheel and the second timing ratchet wheel, the timing middle rack is connected with the third timing ratchet wheel and the fourth timing ratchet wheel, and the timing lower rack is connected with the fifth timing ratchet wheel and the sixth timing ratchet wheel.
Preferably, the first timing ratchet, the second timing ratchet, the third timing ratchet, the fourth timing ratchet, the fifth timing ratchet and the sixth timing ratchet are respectively connected with the first cylindrical tap, the second cylindrical tap, the third cylindrical tap, the fourth cylindrical tap, the fifth cylindrical tap and the sixth cylindrical tap.
An operation method of a wellhead backflow system of an oil field water injection well comprises the following steps:
s1, opening a first emptying valve and a second emptying valve of the reflux device, closing a fourth gate valve and a seventh gate valve, and opening a fifth gate valve, a sixth gate valve, a second gate valve and a third gate valve to enable the reflux device to be in a standby working state;
s2, adjusting the stroke slide block of the motion conversion mechanism to a preset reflux ratio position;
s3, slowly opening the first gate valve, and closing the first emptying valve and the second emptying valve to enable the reflux device to be in a working state after water is stably discharged from the first emptying valve and the second emptying valve;
the method also comprises the following movement processes:
s1, when the first cylindrical cock is opened and the second cylindrical cock is closed, the reinjection water enters the left half part of the first inner cavity through the second gate valve and pushes the upper piston to move rightwards under the pressure of the reinjection water; the reinjection water on the right half part of the first inner cavity enters the right half part of the second inner cavity; the movement process also drives the swing rod of the pendulum mechanism and the stroke slide block of the movement conversion mechanism to move through the upper shaft; the oscillating bar moves to drive the lower piston to move leftwards, and the reinjection water in the left half part of the second inner cavity is pushed to flow out; when the stroke slider moves rightwards to a trigger point position, the upper rack of the motion conversion mechanism is pushed to move, the motion enables the driven rod to move leftwards, after the stroke meets 1/4 weeks of a driving gear of the timing ratchet wheel, the first cylindrical cock is in a closed state, the second cylindrical cock is in an open state, and the backflow device is in another motion state;
s2, when the first cylindrical cock is closed and the second cylindrical cock is opened, the reinjection water enters the right half part of the first inner cavity through the third gate valve and pushes the upper piston to move leftwards; the reinjection water of the left half part of the first inner cavity enters the left half part of the second inner cavity; the motion also drives the oscillating bar and the stroke slide block to move through the upper shaft; the swing rod drives the lower piston to move rightwards to push the reinjection water on the right half part of the second inner cavity to flow out; when the stroke slider moves leftwards to the trigger point, the driven rod is pushed to move leftwards, and after the stroke meets 1/4 weeks of the gear, the first cylindrical cock is in an open state, and the second cylindrical cock is in a closed state;
and S3, completing one complete reciprocating motion by the backflow device, and repeating the motion process by the backflow device to realize backflow of the reinjection water to the united station and reinjection of the stratum.
Compared with the related technology, the wellhead backflow system and method for the oilfield water injection well provided by the invention have the following beneficial effects:
the invention provides a wellhead backflow system and method for an oil field water injection well.
Compared with the existing oilfield reinjection water treatment process, the method realizes the regulation of the external delivery flow rate of the reinjection water between the combined station and the water injection well, solves the problem that the water quality at the wellhead of the oilfield water injection well does not reach the standard, and has the technical characteristics of flexible working condition regulation and simple process flow.
Drawings
FIG. 1 is a schematic structural diagram of a preferred embodiment of a wellhead return system and method for an oilfield injection well according to the present invention;
FIG. 2 is a schematic cross-sectional view of a wellhead flow back device;
FIG. 3 is a schematic cross-sectional view of a pendulum mechanism of the wellhead flow back device;
FIG. 4 is a schematic cross-sectional view of a motion transfer mechanism of the wellhead return device;
FIG. 5 is a schematic cross-sectional view of a timing mechanism of the wellhead return device;
FIG. 6 is a schematic diagram of a timing ratchet of the timing mechanism.
Reference numbers in the figures: 1. wellhead flow regulating device, 11, first gate valve, 12, second gate valve, 13, third gate valve, 14, fourth gate valve, 15, fifth gate valve, 16, sixth gate valve, 17, seventh gate valve, 2, wellhead backflow device, 21, backflow mechanism, 211, cylinder, 212, first lumen, 213, second lumen, 214, first cylindrical plug, 215, second cylindrical plug, 216, third cylindrical plug, 217, fourth cylindrical plug, 218, fifth cylindrical plug, 219, sixth cylindrical plug, 2120, upper piston, 2121, upper shaft, 2122, lower piston, 2123, lower shaft, 2124, first inlet, 2125, second inlet, 2126, first outlet, 2127, second outlet, 2128, first vent valve, 2129, second vent valve, 22, pendulum mechanism, pendulum, 222, pendulum, 223, upper slider, 224, support, 225, lower slider, 221, 23, motion converting mechanism, 231. the timing ratchet wheel comprises a seat body, 232, a driving rod, 233, an upper rack, 234, a lower rack, 235, a gear, 236, a first spring, 237, a driven rod, 238, a second spring, 239, a stroke slider, 24, a timing mechanism, 241, a timing connecting rod, 242, a timing vertical rod, 243, a timing upper rack, 244, a timing middle rack, 245, a timing lower rack, 246, a first timing ratchet wheel, 247, a second timing ratchet wheel, 248, a third timing ratchet wheel, 249, a fourth timing ratchet wheel, 2410, a fifth timing ratchet wheel, 2411 and a sixth timing ratchet wheel.
Detailed Description
The invention is further described with reference to the following figures and embodiments.
Referring to fig. 1, fig. 2, fig. 3, fig. 4, fig. 5 and fig. 6, wherein fig. 1 is a schematic structural diagram of a wellhead backflow system and method for an oilfield injection well according to a preferred embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of a wellhead flow back device; FIG. 3 is a schematic cross-sectional view of a pendulum mechanism of the wellhead flow back device; FIG. 4 is a schematic cross-sectional view of a motion transfer mechanism of the wellhead return device; FIG. 5 is a schematic cross-sectional view of a timing mechanism of the wellhead return device; FIG. 6 is a schematic diagram of a timing ratchet of the timing mechanism. The wellhead backflow system and method for the oil field water injection well comprise the following steps:
a wellhead circulation adjusting device 1 and a wellhead backflow device 2;
the wellhead circulation adjusting device 1 comprises a first gate valve 11, a second gate valve 12, a third gate valve 13, a fourth gate valve 14, a fifth gate valve 15, a sixth gate valve 16 and a seventh gate valve 17, wherein the first gate valve 11 is connected with a reinjection water supply pipeline, the first gate valve 11 is respectively connected with the fourth gate valve 14 and the seventh gate valve 17 in series through pipelines, and the fourth gate valve 14 and the seventh gate valve 17 are respectively connected with a reinjection water return pipeline and a reinjection water return pipeline;
the wellhead backflow device 2 comprises a backflow mechanism 21, a pendulum mechanism 22, a movement conversion mechanism 23 and a timing mechanism 24;
the backflow mechanism 21 comprises a cylinder body 211, a first inner cavity 212 and a second inner cavity 213 are formed in the cylinder body 211, a first cylindrical cock 214 and a second cylindrical cock 215 are respectively arranged at the top of the cylinder body 211, a third cylindrical cock 216 and a fourth cylindrical cock 217 are respectively arranged between the first inner cavity 212 and the second inner cavity 213, and a fifth cylindrical cock 218 and a sixth cylindrical cock 219 are respectively arranged on two sides of the bottom of the cylinder body 211;
an upper piston 2120 is arranged inside the first inner cavity 212, an upper shaft 2121 is arranged on the left side of the upper piston 2120, a lower piston 2122 is arranged inside the second inner cavity 213, and a lower shaft 2123 is arranged on the left side of the lower piston 2122;
the pendulum mechanism 22 comprises a pendulum bob 221, the top of the pendulum bob 221 is provided with a pendulum rod 222, the top of the pendulum rod 222 is provided with an upper slider 223 through an upper guide rail, the middle upper part of the pendulum rod 222 is provided with a support 224, and the bottom end of the pendulum rod 222 is provided with a lower slider 225 through a lower guide rail;
the motion conversion mechanism 23 includes a seat body 231, a driving rod 232, and a driven rod 237, wherein an upper rack 233 is disposed at the top of the seat body 231, a lower rack 234 is disposed at the bottom of the seat body 231, a gear 235 is disposed at the right side of the seat body 231, a first spring 236 is disposed at the top of the seat body 231 through a linking seat, the left end of the first spring 236 is connected to the driven rod 237 through a lifting lug, a second spring 238 is disposed at the bottom of the seat body 231 through a linking seat, and the left end of the second spring 238 is connected to the lower rack 234 through a lifting lug; the right end of the driven rod 237 is connected with a timing connecting rod 241;
the timing mechanism 24 comprises a timing connecting rod 241, a timing vertical rod 242, a timing upper rack 243, a timing middle rack 244, a timing lower rack 245, a first timing ratchet wheel 246, a second timing ratchet wheel 247, a third timing ratchet wheel 248, a fourth timing ratchet wheel 249, a fifth timing ratchet wheel 2410 and a sixth timing ratchet wheel 2411, wherein the first timing ratchet wheel 246, the second timing ratchet wheel 247, the third timing ratchet wheel 248, the fourth timing ratchet wheel 249, the fifth timing ratchet wheel 2410 and the sixth timing ratchet wheel 2411 are respectively connected with the cylindrical cock 214-cock cylinder 219;
through reinjection water adjusting device, can be according to the difference of reinjection water reinjection scheme, through the switch of governing valve, select the operation technology of whole backward flow, partial backward flow, whole reinjection, when adopting partial backward flow operation scheme, according to the difference that the reinjection water reflux requires, the accessible stroke slider sets up the reflux of different proportions.
Compared with the existing oilfield reinjection water treatment process, the method realizes the regulation of the external delivery flow rate of reinjection water between the combined station and the water injection well, solves the problem that the water quality at the wellhead of the oilfield water injection well does not reach the standard, and has the technical characteristics of no external power source, pure mechanical structure and flexible flow rate regulation.
The second gate valve 12 and the third gate valve 13 are respectively connected with a first inlet 2124 and a second inlet 2125 of the wellhead backflow device 2, and the fifth gate valve 15 and the sixth gate valve 16 are respectively connected with a first outlet 2126 and a second outlet 2127 of the wellhead backflow device 2;
the tops of the first 214 and second 215 cylindrical taps are provided as first 2124 and second 2125 inlets, respectively, and the bottoms of the fifth 218 and sixth 219 cylindrical taps are provided as first 2126 and second 2127 outlets, respectively.
A first venting valve 2128 is disposed on the left side of the second inner cavity 213, and a second venting valve 2129 is disposed on the right side of the second inner cavity 213.
The upper slider 223 is connected to an upper shaft 2121 of the return mechanism 21, and the lower slider 225 is connected to a lower shaft 2123 of the return mechanism 21.
The left side of the active rod 232 is provided with a stroke slider 239 through a stroke guide rail.
The right end of the driving rod 232 is connected to the left end of the upper shaft 2121 of the reflux mechanism, and the upper rack 233 and the lower rack 234 are both engaged with the gear 235.
The right end of the driven rod 237 is connected to the left end of the timing connecting rod 241.
The right end of the timing connecting rod 241 is connected with the timing vertical rod 242, and the timing vertical rod 242 is connected with the timing upper rack 243, the timing middle rack 244 and the timing lower rack 245; the timing upper rack 243 is connected with a first timing ratchet wheel 246 and a second timing ratchet wheel 247, the timing middle rack 244 is connected with a third timing ratchet wheel 248 and a fourth timing ratchet wheel 249, and the timing lower rack 245 is connected with a fifth timing ratchet wheel 2410 and a sixth timing ratchet wheel 2411.
The first, second, third, fourth, fifth and sixth timing ratchet wheels 246, 247, 248, 249, 2410 and 2411 are connected to the first, second, third, fourth, fifth and sixth cylindrical taps 214, 215, 216, 217, 218 and 219, respectively.
An operation method of a wellhead backflow system of an oil field water injection well comprises the following steps:
s1, opening a first emptying valve 2128 and a second emptying valve 2129 of the reflux device, closing a fourth gate valve 14 and a seventh gate valve 17, and opening a fifth gate valve 15, a sixth gate valve 16, a second gate valve 12 and a third gate valve 13 to enable the reflux device to be in a standby working state;
s2, adjusting the stroke slide block 239 of the motion conversion mechanism 23 to reach the preset reflux ratio position;
s3, slowly opening the first gate valve 11, and closing the first and second vent valves 2128 and 2129 to make the reflux unit in working state after the water output from the first and second vent valves 2128 and 2129 is stable;
the method also comprises the following movement processes:
s1, when the first cylindrical cock 214 is opened and the second cylindrical cock 215 is closed, the refill water enters the left half of the first chamber 212 through the second gate valve 12, and pushes the upper piston 2120 to move to the right by the pressure of the refill water; the reinjection water in the right half of the first lumen 212 enters the right half of the second lumen 213; in the motion process, the upper shaft 2121 drives the swing rod 222 of the pendulum mechanism 22 and the stroke slide block 239 of the motion conversion mechanism 23 to move; the swing rod 222 moves to drive the lower piston 2122 to move leftwards, and pushes the return water in the left half part of the second inner cavity 213 to flow out; when the stroke slider 239 moves to the right to the triggering position, the upper rack 233 of the movement conversion mechanism 23 is pushed to move, and the movement will make the driven rod 237 move to the left, and after the stroke meets 1/4 cycles of the driving gear 235 of the timing ratchet, the first cylindrical plug 214 is in the closed state, the second cylindrical plug 215 is in the open state, and the backflow device is in another movement state;
s2, when the first cylindrical cock 214 is closed and the second cylindrical cock 215 is opened, the refill water enters the right half of the first chamber 212 through the third gate valve 13 and pushes the upper piston 2120 to move leftward; the reinjection water of the left half of the first lumen 212 enters the left half of the second lumen 213; the movement also drives the swing rod 222 and the stroke slider 239 to move through the upper shaft 2121; the swing rod 222 drives the lower piston 2122 to move rightwards, so as to push the reinjection water in the right half part of the second inner cavity 213 to flow out; when the stroke slider 239 moves leftwards to the triggering point, the driven rod 237 is pushed leftwards, and after the stroke meets 1/4 weeks of the gear 235, the first cylindrical plug 214 is in an opening state, and the second cylindrical plug 215 is in a closing state;
and S3, completing one complete reciprocating motion by the backflow device, and repeating the motion process by the backflow device to realize backflow of the reinjection water to the united station and reinjection of the stratum.
Compared with the related technology, the wellhead backflow system and method for the oilfield water injection well provided by the invention have the following beneficial effects:
through reinjection water adjusting device, can be according to the difference of reinjection water reinjection scheme, through the switch of governing valve, select the operation technology of whole backward flow, partial backward flow, whole reinjection, when adopting partial backward flow operation scheme, according to the difference that the reinjection water reflux requires, the accessible stroke slider sets up the reflux of different proportions.
Compared with the existing oilfield reinjection water treatment process, the method realizes the regulation of the external delivery flow rate of reinjection water between the combined station and the water injection well, solves the problem that the water quality at the wellhead of the oilfield water injection well does not reach the standard, and has the technical characteristics of no external power source, pure mechanical structure and flexible flow rate regulation.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.