CN107795303B - Gravel pack simulation system and method in hydrate exploitation well pipe - Google Patents
Gravel pack simulation system and method in hydrate exploitation well pipe Download PDFInfo
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- 238000004088 simulation Methods 0.000 title claims abstract description 134
- 238000000034 method Methods 0.000 title claims abstract description 71
- 238000011049 filling Methods 0.000 claims abstract description 175
- 238000012856 packing Methods 0.000 claims abstract description 93
- 230000008569 process Effects 0.000 claims abstract description 52
- NMJORVOYSJLJGU-UHFFFAOYSA-N methane clathrate Chemical compound C.C.C.C.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O NMJORVOYSJLJGU-UHFFFAOYSA-N 0.000 claims abstract description 45
- 238000010276 construction Methods 0.000 claims abstract description 42
- 230000000694 effects Effects 0.000 claims abstract description 40
- 238000012360 testing method Methods 0.000 claims abstract description 27
- 238000005429 filling process Methods 0.000 claims abstract description 24
- 238000001514 detection method Methods 0.000 claims abstract description 21
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- 238000012544 monitoring process Methods 0.000 claims abstract description 18
- 238000013461 design Methods 0.000 claims abstract description 16
- 239000004576 sand Substances 0.000 claims description 110
- 239000007789 gas Substances 0.000 claims description 73
- 239000007924 injection Substances 0.000 claims description 51
- 238000002347 injection Methods 0.000 claims description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 50
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- 239000012530 fluid Substances 0.000 claims description 35
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Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/02—Subsoil filtering
- E21B43/04—Gravelling of wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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Abstract
The invention discloses a simulation system and a method for gravel packing in a hydrate exploitation well pipe, wherein the simulation system comprises a test well subsystem, a simulated packing subsystem and a packing quality detection subsystem; according to the method, a well pipe column is installed according to an actual well structure, filling operation simulation and filling quality detection are carried out, full-size simulation can be carried out on the characteristics of an actual natural gas hydrate exploitation well reservoir and in-pipe gravel filling operation under the limitation of the well structure, whole-course monitoring and evaluation can be carried out on the construction quality of filling operation and filling operation adaptability under the long-term hydrate generation condition, so that the purposes of optimizing construction parameters and process design parameters are achieved, a radial flow diverter, a fixed-point pressure gauge and an acoustic imaging logging system are combined, the measuring effect is real and reliable, simulation results are closer to phase difference construction, the referenceis strong, the method is suitable for in-pipe gravel filling processes of different well structures and effect monitoring simulation thereof, a new idea is provided for the gravel filling operation adaptability evaluation of the marine shallow natural gas hydrate exploitation well, and a basis is provided for the best construction scheme and the best process parameters of gravel filling operation.
Description
Technical Field
The invention relates to the technical field of marine natural gas hydrate resource development engineering, in particular to an integrated simulation system and an integrated simulation method capable of simulating a gravel packing process in a hydrate exploitation well pipe and evaluating the effect of the gravel packing process.
Background
The natural gas hydrate resource is an unconventional natural gas resource with wide distribution and high energy density, and is a strategic high point of future global energy development, and the research and development plans of the natural gas hydrate are sequentially developed in the United states, japan, germany, india, canada and Korea. The successful trial production in south China certainly goes the front of the world in competition of the exploration and development of the global natural gas hydrate resources. At present, the industrialized exploitation pace of the natural gas hydrate is accelerated in China, and the method is striving to take advantage of the international natural gas hydrate competition.
In general, the natural gas hydrate resource reservoir is buried deep and shallow, the cementation is poor, the cementation strength of the stratum is further reduced due to the decomposition of the hydrate, and the original weakly consolidated reservoir can be even completely converted into a quicksand stratum, so that sand can not be generated inevitably in the process of exploiting the natural gas hydrate, and in order to maintain the continuous production, stratum sand can not be strictly blocked completely according to the sand prevention view of the conventional natural gas petroleum industry. For the silt powder sand natural gas reservoir in the south China sea, the sand prevention mode firstly needs to ensure that a large amount of silt particles of a stratum can be smoothly discharged to a shaft, and the silt fine particles discharged into the shaft are carried to a wellhead through the shaft fluid supplementing mode, so that a bottom hole sand prevention medium is a bridge for connecting the sand production process of the stratum and the sand carrying process of the shaft. Therefore, simulation research of the construction operation process of the sand control medium and evaluation of the construction operation effect are important to the design of the sand control operation of the actual natural gas hydrate exploitation well.
Gravel packing is a typical downhole sand control means and mainly includes both in-pipe gravel packing and out-of-pipe gravel packing. The natural gas hydrate test production project of Nankai Trough 2013 in Japan adopts the gravel packing operation outside the open-hole pipe, and the test production results of 6d and 12 ten thousand of test production are obtained. The biggest problems with open hole extra-tubular gravel packing are: in the original formation, the hydrate exists as a cement and occupies a large volume of space. With the decomposition of the hydrate, the volume occupied by the hydrate is gradually lost, and the lost foam gradually extends to the inside of the stratum through the open hole well wall. Under the condition, the filling gravel layer at the joint of the sand control screen and the open hole well wall can generate certain peristaltic and sedimentation processes, and along with the continuous sedimentation processes, large filling defects can appear at the upper part of the stratum at the filling section, so that the sand control screen is directly exposed in the gas, liquid and sand flowing space, and screen erosion can quickly occur, thereby causing sand control failure. In summary, how to prevent the creep of gravel pack particles is one of the key to solve the above problems, wherein gravel pack in a pipe, pre-pack screen or coated sand cement screen (for example, geonorm) is one of the means to solve the creep settlement of gravel.
However, the gravel packing in the pipe has no example successfully applied in the natural gas hydrate test production engineering at present, and only the pre-packed sieve pipe or the sand-glued sieve pipe is partially tested and produced. One typical feature of natural gas hydrate reservoirs, compared to conventional hydrocarbon reservoirs, is the depth of burial, extremely low formation fracture pressure, and the gravel packing operation necessarily faces different challenges than conventional deep hydrocarbon reservoirs. The final use effect of the gravel packing operation depends on two major key data of technological parameters and construction operation parameters, in order to verify the adaptability of the in-pipe gravel packing construction operation in the natural gas hydrate exploitation process, it is necessary to simulate the large-scale in-pipe gravel packing process, and verify the gravel packing effect (including both the construction quality and the sand control effect under the long-term production condition) through a certain experimental means, so that a support is provided for solving the serious challenges in the aspect of the shallow natural gas sand production management in the sea area.
Therefore, in order to meet the development requirements of natural gas hydrate resources of sandy reservoirs in China and provide a certain support for sand production management of natural gas hydrate test production engineering in sea areas in China, the invention provides a simulation system capable of simulating the construction process of in-pipe gravel packing sand prevention operation, and simultaneously provides a method capable of monitoring the gravel packing effect.
Disclosure of Invention
Aiming at the urgent need of the existing natural gas hydrate exploitation for controlling the sand production of a shaft, the invention provides a simulation system and a simulation method for gravel packing in a hydrate exploitation well pipe, which can simulate the whole-size in-pipe gravel packing operation process and monitor the effect of the simulation, provide a new thought for the adaptability evaluation of the gravel packing operation of the marine shallow natural gas hydrate exploitation well, and provide a basis for the optimal construction scheme and the optimal technological parameters of the gravel packing operation.
The invention is realized by adopting the following technical scheme:
the simulation system for gravel packing in the hydrate exploitation well pipe has a 1:1 correspondence with an actual gravel packing tool, meets the conditions of full-size gravel packing tool running and natural gas hydrate reservoir depth, has high simulation result reliability and strong engineering practicability, and comprises a test well subsystem, a simulation packing subsystem and a packing quality detection subsystem;
the test well subsystem comprises a simulated well bore, a simulated sleeve, a simulated oil pipe, a three-phase injection pipeline and a mechanical screen pipe, and a wellhead blowout prevention flashboard is arranged at the wellhead of the simulated well bore; a three-phase injection pipeline interface, a gas output pipeline interface, a water sand output/injection pipeline interface and a slurry return pipeline interface are arranged on the wellhead blowout prevention flashboard, and each pipeline interface is provided with a corresponding gate valve; the simulation sleeve is arranged in the simulation shaft, an oil pipe penetrating packer is further arranged in an annulus between the simulation shaft and the simulation sleeve, the simulation sleeve has an oil pipe penetrating function, and a three-phase injection pipeline penetrates through the oil pipe penetrating packer and is connected with a radial flow diverter fixedly arranged at the bottom of the simulation shaft; the simulated oil pipe and the mechanical sieve tube are arranged in the simulated sleeve; the simulated oil pipe is connected with the mechanical sieve tube and is positioned at the upper part of the mechanical sieve tube, simulated perforation holes are preset in the production layer section of the simulated sleeve according to actual well bottom perforation parameters, and the length of the simulated perforation hole section is consistent with that of the mechanical sieve tube; an oil sleeve annulus packer is arranged in the annulus between the simulation sleeve and the simulation oil pipe, and the oil sleeve annulus packer is positioned above the simulation perforation holes; the space formed between the outer protective cover of the mechanical sieve tube and the inner wall of the simulated casing, the oil sleeve annular packer and the bottom of the well is the gravel filling space in the tube; in the gravel packing process simulation stage, a three-phase injection pipeline penetrates through an oil pipe and penetrates through a packer to inject a three-phase mixture of gas, water and silt into a well, and in the packing effect monitoring stage, a valve of the three-phase injection pipeline is in a closed state;
The simulated filling subsystem comprises a filling pipe column combination arranged in a simulated shaft, a high-pressure gas cylinder group, a water tank, a gravel mixing box, a three-phase mixer and a slurry recycling tank which are arranged on the ground, wherein the filling pipe column combination comprises a filling pipeline, a filling packer and a filling spray nozzle, the filling pipeline is arranged in a simulated oil pipe, the filling spray nozzle is arranged at the lower end of the filling pipeline, the filling packer is arranged between the upper part of the filling spray nozzle and the inner wall of a mechanical screen pipe, the gravel mixing box is a key part for simulating the gravel filling process and comprises gravel, a sand-carrying liquid mixing stirrer and an injection pump, the gravel mixing box is connected with a water sand output/injection pipeline interface, and in the actual gravel filling process simulation, the purpose of the filling process simulation under different construction parameters can be realized through the control of the sand ratio in the gravel mixing box, the pump discharge capacity and the pump outlet pressure; the inlet end of the high-pressure gas cylinder group is connected with an oil sleeve annular gas output loop through a pipeline, the outlet end of the high-pressure gas cylinder group is connected with the inlet end of the three-phase mixer through a pipeline, and the oil sleeve annular gas output loop is an annular space formed between a simulation sleeve and a simulation oil pipe and is used for supplementing gas to the three-phase mixer and recovering gas produced by bottom hole separation; the inlet end of the water tank is connected with a lifting pipe column in the simulated oil pipe through a pipeline, and the outlet end of the water tank is connected with the inlet end of the three-phase mixer through a pipeline and is used for supplementing water and silt mixed liquid into the three-phase mixer and recovering water and silt mixed liquid produced from the bottom of the well, and the gas and water supply amount is consistent with the gas-water ratio produced by the actual natural gas hydrate reservoir; the three-phase mixer comprises a gas-water-silt mixing stirrer and a three-phase injection pump, is a sealed high-pressure device, and is characterized in that the outlet end of the three-phase mixer is connected with a three-phase injection pipeline interface through a pipeline, so that three-phase real-time rapid mixing and injection can be realized, and the change condition of a well bottom gravel filling layer under different sand production conditions can be simulated by controlling the discharge capacity of the three-phase injection pump, the proportion of silt and the particle size in the actual gravel filling effect simulation process; the slurry recovery tank is connected with a shaft sand-carrying fluid return annulus through a pipeline, the shaft sand-carrying fluid return annulus is an annulus between a filling pipeline and a simulated oil pipe, and a sand-carrying fluid filtering device is arranged in the slurry recovery tank to filter and store the filled sand-carrying fluid;
The filling quality detection subsystem comprises a gas separator, a lifting pipe column, a fixed-point pressure gauge and an acoustic imaging logging system; the gas separator is only used in the gravel packing effect simulation monitoring process, the gas separator and the lifting pipe column are both arranged in the simulated oil pipe, the outlet of the gas separator is communicated with an oil sleeve annular gas production loop and is consistent with an actual natural gas hydrate exploitation well, the gas separator mainly aims at separating gas from gas, water and silt three-phase mixed fluid produced by a reservoir, and the separated water and silt mixture is lifted to the ground through the lifting pipe column in the simulated oil pipe; the fixed-point pressure gauge comprises a fixed-point pressure gauge P3 and a fixed-point pressure gauge P2 which are arranged at the upper end and the lower end of the inner wall of the mechanical screen pipe, and a fixed-point pressure gauge P4 and a fixed-point pressure gauge P1 which are arranged at the upper end and the lower end of the outer pipe of the filling part of the simulation sleeve; the filling quality detection subsystem is a conventional underground acoustic imaging logging system, can measure the gray value of a filling layer outside the screen pipe, and judges whether the gravel filling construction in the pipe is successful or not according to the continuity and the absolute value of the gray value.
Furthermore, the inside entrance of radial flow shunt is provided with the whirl guide vane, and the lower extreme of whirl guide vane links up annular perforated plate, and annular perforated plate is located between radial flow shunt inner wall and the outer wall, still is provided with the wedge hole on the inner wall of radial flow shunt, and the design of whirl guide vane can make the gas of injection, liquid, silt particle spout in radial flow shunt's annular space, combines the design of annular perforated plate and wedge hole to make the simulation more be close to actual shaft's flow condition.
Furthermore, the simulated well bore meets the conditions of full-size gravel packing tool running and natural gas hydrate reservoir depth, the depth is 200m, and the simulation result is high in reliability and engineering practicability.
Further, a sand-carrying fluid filtering device is arranged in the slurry recovery tank, so that the filtering and storage of filled sand-carrying fluid are realized.
Furthermore, the wellhead blowout prevention flashboard is a bridge connected between the test well subsystem and the simulation filling subsystem, is a main component of a test well maintenance high-pressure system, and resists 15Mpa.
Based on the simulation system, the invention further provides a simulation method for gravel packing in the hydrate exploitation well pipe, which comprises the following steps:
A. installing a shaft pipe column according to an actual well structure, checking the tightness of each sealing position, and setting a filling simulation subsystem and performing filling operation simulation;
B. the lower filling quality detection subsystem monitors the filling quality and judges whether the filling quality is qualified or not, and if the filling quality is not qualified, the filling operation simulation is conducted again; if the sand is qualified, mixing and injecting gas, liquid and mud sand to simulate the production process, and monitoring the sand condition in real time;
C. judging whether the sand control effect is qualified or not, if the sand control effect is not qualified, adjusting filling process parameters, and carrying out filling operation simulation again; if the sand control effect is qualified, obtaining optimal filling process parameters and filling construction parameters, and finishing simulation;
The filling construction parameters comprise sand ratio, pump displacement, pump outlet pressure, sand-carrying fluid type and related hydrodynamic parameters controlled by a gravel mixing box; the filling process parameters comprise particle size of a filling gravel layer, filling layer thickness, gravel type (ceramsite, quartz sand, walnut shell and the like) and the like and the mutual combination thereof.
Further, the step a specifically includes:
a1, checking connection of a wellhead blowout prevention flashboard and a simulated shaft and self-sealing of a three-phase mixer; obtaining the fracture pressure gradient of the stratum in the actual natural gas hydrate exploitation process through simulation calculation;
a2, combining an actual well structure of the natural gas hydrate test production well, and putting a simulation sleeve with preset perforation holes into the simulation well, and enabling a seat oil pipe to penetrate through the packer; installing a simulated oil pipe, a mechanical screen pipe and an oil sleeve annular packer, and putting the simulated oil pipe, the mechanical screen pipe and the oil sleeve annular packer into a well bottom appointed position, wherein the oil sleeve annular packer is set; setting a filling packer by setting a filling pipe column combination;
a3, connecting a ground pipeline, setting the sand ratio and the discharge capacity in the gravel mixing box, starting an injection pump in the gravel mixing box, circularly filling, and collecting the discharge capacity, the pressure and the sand ratio data of the injection pump, the basic properties of sand-carrying fluid and the pressure data detected by a fixed-point pressure gauge in real time; the reading of the fixed-point pressure gauge P1 outside the simulated casing is ensured to be smaller than the formation fracture pressure gradient in the filling process; observing the pump pressure change of the injection pump, and the sudden pump pressure rise indicates the filling end.
Further, the step B specifically includes:
b1, unsealing the filling packer, lifting out a filling pipe column combination, lowering a filling quality detection subsystem to the bottom of the well, and then slowly lifting up and measuring the acoustic imaging condition of the bottom of the well; if the acoustic imaging continuity of the bottom of the well is poor, obvious gray value mutation or interruption appears, which indicates that the filling is uneven or some parts do not reach the filling effect at all, the filling construction parameters are readjusted, a filling quality detection subsystem is started, and the step A3 is returned to carry out filling operation simulation again; if the acoustic imaging continuity of the bottom hole is good, recording current filling construction parameters, and entering a step B2;
b2, installing a gas separator, feeding a lifting pipe column, adjusting a bottom hole gas circuit manifold, and connecting a ground high-pressure gas cylinder group, a water tank and a three-phase mixer; adding stratum sand samples or simulated hydrate stratum sand samples obtained from a hydrate reservoir according to a specific proportion into a water tank, and uniformly stirring; pumping the cement-sand mixture and gas into a three-phase mixer according to a fixed proportion according to a numerical simulation result or a gas-water ratio condition obtained by field test sampling;
and B3, adjusting a shaft flow, starting a lifting pipe column and a gas separator, pumping the gas-water-silt mixture into the bottom of the well through a three-phase injection pipeline by utilizing a three-phase mixer, forming radial flow through a radial flow diverter, entering a preset perforation hole and a gravel filling layer, continuously and stably operating a water tank and a high-pressure gas cylinder group to supply the three-phase mixer in the process, recording the numerical value of a fixed-point pressure gauge in the well in real time, calculating the internal and external pressure difference of the filling layer, evaluating the blocking condition of the gravel filling layer in the long-term production process by the change condition of the internal and external pressure difference of the gravel filling layer, evaluating the blocking condition of the gravel filling layer on the silt by using the condition of produced sand, visually and reliably observing the sand concentration in water produced at the wellhead of the lifting pipe column, evaluating the adaptability of the gravel filling operation of a given filling process parameter to a specific stratum and optimizing the optimal gravel filling process parameter.
In step B1, the gray value and the uniformity of the acoustic imaging logging are used to determine whether the gravel packing quality is qualified, so as to achieve the purpose of optimizing the gravel packing construction parameters.
Further, in the step B3, whether the design of the current filling process parameters is reasonable or not is judged by using the change rule of the pressure difference between the inside and the outside of the filling layer along with time and the sand concentration and the sand containing diameter in the wellhead produced liquid, so that the purpose of optimizing the design of the gravel filling process parameters is achieved.
Compared with the prior art, the invention has the advantages and positive effects that:
the test well subsystem, the simulated filling subsystem and the filling quality detection subsystem are all full-size parameter simulation, the depth range of the test well can cover the basic depth range of the marine natural gas hydrate reservoir in China at present, the simulation result is closer to phase difference construction, and the simulation referenceis strong; the rotational flow guide vane is designed at the inlet of the radial flow diverter, so that injected gas, liquid and silt can be sprayed into the annular space of the radial flow diverter in a rotational mode, the wedge-shaped design of the inner porous plate is combined, the three-phase mixed fluid is guaranteed to flow into the bottom of a well in a radial flow mode, the simulation process is closer to the radial flow process of the actual stratum production process, and the accumulation and blockage of the silt on the porous plate are prevented;
In addition, fixed-point pressure gauges are respectively arranged at the upper end and the lower end of the inner wall of the mechanical screen pipe and the outer wall of the simulation sleeve, pressure measurement parameters are detected in real time, and in the filling simulation stage, the bottom hole pressure is ensured to be smaller than the fracture pressure of the natural gas hydrate stratum in the filling simulation process through data real-time transmission, so that the aim of optimizing construction parameters is fulfilled; in the gravel packing effect monitoring stage, the blocking or peristaltic deformation process of the gravel layer in the simulated production process can be described in real time, the effective period of the gravel packing is judged, the gravel size of the gravel packing layer is optimized, and in addition, an acoustic imaging logging system actually used on site is introduced into the gravel packing effect measurement, so that the measuring effect is real and reliable;
the construction parameter result obtained by simulation optimization and the site construction parameter are in a corresponding relation of 1:1, the simulation result can be directly used for gravel packing construction of a shallow natural gas hydrate reservoir, the quality of the gravel packing construction per se and the blocking process possibly occurring in a gravel layer under the long-term production condition can be synchronously detected through simulation, and the pipe inner pipe column combination can be adjusted according to actual conditions, so that the method is suitable for monitoring and simulating the gravel packing process and the effect of the gravel packing process in diameter pipes of different well structures.
Drawings
FIG. 1 is a schematic diagram of a filling process of a simulation system according to an embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a filling effect monitoring process of the simulation system in embodiment 1 of the present invention;
FIG. 3 is a schematic view of a radial flow splitter according to example 1 of the present invention;
FIG. 4 is a schematic cross-sectional view of the inner wall of the radial flow splitter of FIG. 3;
FIG. 5 is a flow chart of a simulation method according to embodiment 2 of the present invention;
1, simulating a shaft; 2. simulating a sleeve; 3. simulating an oil pipe; 4. a radial flow diverter; 5. wellhead blowout prevention flashboard; 6. a high pressure gas cylinder group; 7. a gas separator; 8. a three-phase injection line; 9. a three-phase mixer; 10. a water tank; 11. the oil pipe passes through the packer; 12. an oil casing annulus packer; 13. filling a packer; 14. filling a spray head; 15. gravel sand mixing box; 16. a slurry recovery tank; 17. a gravel pack; 18. a mechanical screen; 19. simulating perforation holes; 20. filling a pipeline; 21. a radial flow diverter outer wall; 22. a radial flow diverter inner wall; 23. a wall wedge aperture; 24. swirl flow deflector; 25. an annular porous plate; F1-F7: a high pressure valve; P1-P4: a fixed-point pressure gauge.
Detailed Description
In order that the above objects, features and advantages of the invention will be more readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.
The embodiment 1, a gravel pack simulation system in a hydrate exploitation well pipe, which has a 1:1 correspondence with an actual gravel pack tool, meets the conditions of full-size gravel pack tool running and natural gas hydrate reservoir depth, has high simulation result reliability and strong engineering practicability, and comprises a test well subsystem, a simulated packing subsystem and a packing quality detection subsystem.
Referring to fig. 1, the test well subsystem comprises a simulated well bore 1, a simulated sleeve 2, a simulated oil pipe 3, a three-phase injection pipeline 8 and a mechanical screen 18, wherein a wellhead blowout prevention flashboard 5 is arranged at the wellhead of the simulated well bore 1; the depth of the simulated shaft is 200m, the wellhead blowout prevention flashboard is a bridge for connecting the test well subsystem and the simulated filling subsystem, and is a main component of the test well maintaining high-pressure system, the withstand voltage is 15Mpa, a three-phase injection pipeline interface, a gas output pipeline interface, a water sand output/injection pipeline interface and a slurry return pipeline interface are arranged on the wellhead blowout prevention flashboard 5, and corresponding gate valves (F2, F4, F3 and F7) are arranged on the pipeline interfaces, and are high-pressure ball valves; the simulated casing 2 is arranged in the simulated wellbore 1, an oil pipe penetrating packer 11 is further arranged in an annulus between the simulated wellbore 1 and the simulated casing 2, the oil pipe penetrating packer 11 is provided with an oil pipe penetrating function, and a three-phase injection pipeline 8 penetrates through the oil pipe penetrating packer 11 and is connected with a radial flow diverter 4 fixedly arranged at the bottom of the simulated wellbore 1, as shown in fig. 3, a swirl deflector 24 is arranged at an inlet inside the radial flow diverter 4, the lower end of the swirl deflector 24 is connected with an annular porous plate 25, and the annular porous plate 25 is positioned between an inner wall 22 and an outer wall 21 of the radial flow diverter so as to fully mix gas and liquid; referring to fig. 4, the inner wall 22 of the radial flow diverter is provided with a wedge-shaped hole 23 with a small outside and a large inside, the design of the rotational flow guide vane 24 can enable injected gas, liquid and silt to be rotationally sprayed into the annular space of the radial flow diverter, and the design of the inner annular porous plate 25 and the wedge-shaped hole 23 of the rotational flow diverter ensures that three-phase mixed fluid flows into the bottom of a well in a radial flow mode, so that the flow condition of an actual shaft is more similar to the simulation; and can prevent the accumulation and blockage of mud and sand on the perforated plate, can adjust the simulation tubular column combination according to the well body structure of the actual natural gas hydrate exploitation well, and realize the conversion of the injection mixture from unidirectional flow to radial flow through the radial flow diverter at the bottom of the well.
The simulated oil pipe 3 and the mechanical screen 18 are arranged in the simulated casing 2; the simulated oil pipe 3 is connected with the mechanical screen pipe 18 and is positioned at the upper part of the mechanical screen pipe 18, the simulated oil pipe 3 and the mechanical screen pipe 18 can be adjusted according to the well depth structure of an actual natural gas hydrate production test well, and the mechanical screen pipe 18 is a screen pipe sample used by the actual natural gas hydrate production test well; in addition, the production interval of the simulation sleeve 2 is preset with simulation perforation holes 19 according to actual well bottom perforation parameters (aperture and hole density), and the length of the simulation perforation holes is consistent with that of the mechanical screen pipe 18; an oil sleeve annulus packer 12 is arranged in the annulus between the simulated casing 2 and the simulated oil pipe 3, and the oil sleeve annulus packer 12 is positioned above the simulated perforation 19 (namely at the connection position of the simulated oil pipe 3 and the mechanical screen 18); the space formed between the outer protective cover of the mechanical screen 18 and the inner wall of the simulated casing 2, the oil sleeve annulus packer 12 and the bottom of the well is an in-pipe gravel packing space, and the in-pipe gravel packing space is filled with a gravel packing layer 17; in the gravel packing process simulation stage, the three-phase injection pipeline 8 penetrates through the oil pipe and passes through the packer 11 to inject the three-phase mixture of gas, water and silt into the well, and in the packing effect monitoring stage, the valve (F2) of the three-phase injection pipeline 8 is in a closed state.
In addition, with continued reference to fig. 1 and 2, the simulated filling subsystem includes a filling pipe column combination disposed in the simulated wellbore 1, and a high-pressure gas cylinder group 6, a water tank 10, a gravel mixing flask 15, a three-phase mixer 9 and a slurry recovery tank 16 disposed on the ground, wherein the filling pipe column combination includes a filling pipe 20, a filling packer 13 and a filling nozzle 14, the filling pipe 20 is disposed in the simulated oil pipe 3, the filling nozzle 14 is disposed at the lower end of the filling pipe 20, the filling nozzle 14 can be a different type of downhole gravel filling tool, the filling packer 13 is installed between the upper side of the filling nozzle 14 and the inner wall of the mechanical screen 18, and the main functions of the filling packer 13 are as follows: forming a fluid loop in the process of simulating gravel packing, wherein the fluid carries the gravel to be packed into the gravel packing space, and liquid returns to an annular space formed by a packing string and a simulated oil pipe through a mechanical screen pipe and is discharged out of the ground; the gravel mixing box 15 is a key component for simulating a gravel packing process, comprises a gravel, a sand-carrying fluid mixing stirrer and an injection pump, is connected with a water sand output/injection pipeline interface, and can realize the purpose of simulating the packing process under different construction parameters by controlling the sand ratio, the pump discharge capacity and the pump outlet pressure in the gravel mixing box 15 in the actual gravel packing process simulation; the inlet end of the high-pressure gas cylinder group 6 is connected with an oil sleeve annular gas output loop through a pipeline, the outlet end of the high-pressure gas cylinder group 6 is connected with the inlet end of the three-phase mixer through a pipeline, and the oil sleeve annular gas output loop is an annular space formed between the simulation sleeve 2 and the simulation oil pipe 3 and is used for supplementing gas to the three-phase mixer 9 and recovering gas produced by bottom hole separation; the inlet end of the water tank 10 is connected with a lifting pipe column in the simulated oil pipe 3 through a pipeline, and the outlet end of the water tank 10 is connected with the inlet end of the three-phase mixer 9 through a pipeline and is used for supplementing water and silt mixed liquid into the three-phase mixer 9 and recovering water and silt mixed liquid produced from the bottom of a well, wherein the gas and water supply amount is consistent with the gas-water ratio produced by an actual natural gas hydrate reservoir; the three-phase mixer 9 comprises a gas-water-silt mixing stirrer and a three-phase injection pump, and is a sealed high-pressure device, the outlet end of the three-phase mixer 9 is connected with a three-phase injection pipeline interface through a pipeline, so that three-phase real-time rapid mixing and injection can be realized, and in the actual gravel packing effect simulation process, the change condition of a bottom gravel packing layer under different sand production conditions is simulated by controlling the discharge capacity of the three-phase injection pump, the proportion of silt and the particle size; the slurry recovery tank 16 is connected with a shaft sand-carrying fluid return annulus through a pipeline, the shaft sand-carrying fluid return annulus is an annulus between the filling pipeline 20 and the simulated oil pipe 3, and a sand-carrying fluid filtering device is arranged in the slurry recovery tank 16 to realize filtering and storage of filling sand-carrying fluid.
The filling quality detection subsystem comprises a gas separator 7, a lifting pipe column, a fixed-point pressure gauge and an acoustic imaging logging system; as shown in fig. 2, the gas separator 7 is only used in the gravel packing effect simulation monitoring process, the gas separator 7 and the lifting pipe column are arranged in the simulated oil pipe 3, the outlet (above the oil sleeve annular packer 12) of the gas separator 7 is communicated with an oil sleeve annular gas production loop, and is consistent with an actual natural gas hydrate exploitation well, the main function of the gas separator 7 is to separate gas from gas, water and silt three-phase mixed fluid produced by a reservoir, and the separated water and silt mixture is lifted to the ground through the lifting pipe column in the simulated oil pipe; the fixed-point pressure gauge comprises a fixed-point pressure gauge P3 and a fixed-point pressure gauge P2 which are arranged at the upper end and the lower end of the inner wall of the mechanical screen pipe 18, and a fixed-point pressure gauge P4 and a fixed-point pressure gauge P1 which are arranged at the upper end and the lower end of the outside of the pipe at the filling part of the simulation sleeve 2; the filling quality detection subsystem is a conventional underground acoustic imaging logging system, can measure the gray value of a filling layer outside the screen pipe, and judges whether the gravel filling construction in the pipe is successful or not according to the continuity and the absolute value of the gray value.
The simulation systems are full-size parameter simulation, the depth range of the test well can cover the basic depth range of the marine natural gas hydrate reservoir in China at present, the simulation results are closer to phase difference construction, and the simulation referenceis strong; the rotational flow guide vane is designed at the inlet of the radial flow diverter, so that injected gas, liquid and silt can be sprayed into the annular space of the radial flow diverter in a rotational mode, and the simulation process is closer to the radial flow process of the actual stratum production process by combining the design of the inner porous plate and the wedge-shaped holes; in addition, by respectively installing fixed-point pressure gauges on the upper end and the lower end of the inner wall of the mechanical screen pipe and the outer wall of the simulation sleeve, the pressure measurement parameters are detected in real time, and in the filling simulation stage, the bottom hole pressure can be ensured to be smaller than the fracture pressure of the natural gas hydrate stratum in the filling simulation process through data real-time transmission, so that the aim of optimizing the construction parameters is fulfilled; in the gravel packing effect monitoring stage, the plugging or peristaltic deformation process of the gravel layer in the simulated production process can be described in real time, the effective period of the gravel packing is judged, the gravel size of the gravel packing layer is optimized, and in addition, the acoustic imaging logging system actually used on site is introduced into the gravel packing effect measurement, so that the real and reliable measurement effect is ensured.
Embodiment 2, based on the simulation system of embodiment 1, the present embodiment further provides a simulation method for gravel packing in a hydrate production well pipe, referring to fig. 5, including the following steps:
A. installing a shaft pipe column according to an actual well structure, checking the tightness of each sealing position, and setting a filling simulation subsystem and performing filling operation simulation;
B. the lower filling quality detection subsystem monitors the filling quality and judges whether the filling quality is qualified or not, and if the filling quality is not qualified, the filling operation simulation is conducted again; if the sand is qualified, mixing and injecting gas, liquid and mud sand to simulate the production process, and monitoring the sand condition in real time;
C. judging whether the sand control effect is qualified or not, if the sand control effect is not qualified, adjusting filling process parameters, and carrying out filling operation simulation again; if the sand control effect is qualified, obtaining optimal filling process parameters and filling construction parameters, and finishing simulation;
the filling construction parameters comprise sand ratio, pump displacement, pump outlet pressure, sand-carrying fluid type and related hydrodynamic parameters controlled by a gravel mixing box; the filling process parameters comprise particle size of a filling gravel layer, filling layer thickness, gravel type (ceramsite, quartz sand, walnut shell and the like) and the like and the mutual combination thereof.
For example, taking the breaking pressure of a certain natural gas hydrate basic stratum in south China as an example, taking the sand grain size distribution and the clay composition of an actual natural gas hydrate stratum as basic simulation media, respectively selecting quartz sand with 40 meshes to 70 meshes, quartz sand with 30 meshes to 50 meshes and quartz sand with 70 meshes to 100 meshes for simulation and filling effect monitoring, and specifically comprising the following steps of:
(1) Disconnecting a connecting pipeline between the simulation filling subsystem and the wellhead blowout prevention flashboard, injecting 15MPa into a well, verifying sealing between the wellhead blowout prevention flashboard 5 and the simulation shaft 1, sealing between the wellhead blowout prevention flashboard 5 and the three-phase injection pipeline 8, sealing between the wellhead blowout prevention flashboard 5 and the filling injection pipeline 20, sealing between the wellhead blowout prevention flashboard 5 and the simulation sleeve 2 and sealing between the wellhead blowout prevention flashboard 5 and the simulation oil pipe 3;
(2) The simulated calculation shows that the stratum fracture pressure gradient of a certain natural gas hydrate reservoir stratum in the south China sea is 1.1ppg, so that the sand-carrying fluid is selected as the light sand-carrying fluid containing the scraping additive, and quartz sand with 40-70 meshes is selected for the first time;
(3) According to the exploitation well pipe column combination to be adopted by certain natural gas hydrate in south China sea, the dimension of the simulation sleeve 2 is 13 1 / 2 ", the dimensions of the simulated tubing 3 and the mechanical screen 18 are 8 3 / 4 The thickness of the production layer is 26m, the size of the mechanical screen joint is 9m, and 3 screens are added in total; gravel pack 17, the ideal filling layer thickness is 27m, and the radial filling layer thickness is the difference between the inner diameter of the simulated casing and the outer diameter of the mechanical screen pipe; respectively installing fixed-point pressure gauges P4 and P1 at the outer side of the simulation sleeve 2 close to the upper end and the lower end of a production layer, and putting the simulation sleeve 2 and an oil pipe into the simulation sleeve to pass through a packer 11 and sealing; respectively installing fixed-point pressure gauges P3 and P2 on the inner wall of the mechanical sieve tube 18 near the upper and lower ends of a production layer, connecting the mechanical sieve tube 18 with the simulated oil tube 3, and setting the pipe column combination and the oil sleeve annular packer 12;
(4) The gravel packing pipeline 20 and the packing nozzle 14 are put in, the packing packer 13 is set, the valves F2 and F4 connected with the wellhead blowout prevention flashboard 5 are closed, the valves F3 and F7 are connected, the gravel mixing sand box 15 and the slurry recovery tank 16 are respectively connected, the sand ratio in the gravel mixing sand box is set to be 20%, and the pump discharge capacity is set to be 10m 3 /h；
(5) Starting an injection pump in the gravel mixing box 15, filling in a circulating way, and enabling sand-carrying fluid between a filling pipe column and a simulated oil pipe to flow into the slurry tank 16 for subsequent treatment. Collecting displacement, pressure and sand ratio data of an injection pump and back pressure data of bottom hole fixed-point pressure gauges P1 and P4 in real time, and ensuring that P1 is smaller than formation fracture pressure calculated according to a formation fracture pressure gradient; if the change condition of the pump pressure is observed in the filling process, if P1 continuously rises, the pump displacement is reduced, otherwise, the pump displacement is slightly increased; observing the pumping pressure of a filling pump in the gravel mixing box 15 in real time, if the pumping pressure suddenly rises under the condition that the displacement is continuously reduced, indicating that filling is finished, and switching to the step (6);
(6) Stopping filling simulation, unsealing the filling packer 13, lifting the gravel filling pipe column 20 and the filling nozzle 14, lowering the filling quality detection subsystem to the artificial well bottom, slowly lifting, testing the acoustic imaging data of the filling layer section in the lifting process and performing inversion treatment, wherein if the measured gray values of the acoustic imaging system are uniformly distributed, the gray is stronger, the filling compactness is high, the filling is uniform, and the filling quality is qualified. Otherwise, the oil jacket annular packer 12 is unsealed, clear water or sand-carrying fluid is injected through the three-phase injection pipeline 8, the gravel filling layer 17 is flushed out, the step (4) is returned, the sand ratio or the pump displacement is adjusted, the refilling is carried out until the filling quality is qualified, and the obtained construction parameter combination is the optimal gravel filling construction parameter combination required by the actual natural gas hydrate exploitation well;
(7) The filling quality detection subsystem is started, a gas separator 7 and a shaft lifting pipe column are put in, a gravel mixing sand box 15 and a slurry recovery tank 16 are disassembled, a high-pressure gas cylinder group 6, a water tank 10 and a three-phase mixer 9 are installed, valves F1, F2, F3, F4, F5 and F6 are connected, water sand mixed fluid with the concentration of 5% of muddy sand is generated in the water tank through stirring and is conveyed to the three-phase mixer 9, a three-phase injection pump in the three-phase mixer 9 is started, and gas-water-muddy sand is conveyed to a three-phase injection pipeline 8 in a shaft;
(8) The mixture flowing through the three-phase injection pipeline 8 changes the flow direction and the flow pattern into radial flow through the action of the radial flow diverter 4, and enters the simulated perforation 19, the gravel packing layer 17 and the mechanical screen 18, and blocked stratum sand is accumulated in an annular space formed by the radial flow diverter 4 and the simulated casing 2; after the gas-water-cement sand mixture flows into the mechanical sieve tube 18, the gas flows upwards through an annulus formed by the simulation sleeve 2 and the simulation production oil tube 3 and flows into the high-pressure gas cylinder group 6 for recovery under the action of the gas separator 7, and the water-cement sand mixture flows back to the water tank 10 under the lifting action of a lifting pipe column in the production oil tube 3 and is subjected to solid-liquid separation;
(9) In the steps (7) and (8), the feedback data of the fixed-point pressure gauges P1, P2, P3 and P4 are recorded in real time, the position of the bottom of the gravel pack is evaluated according to the change rule of the difference value of the P1 and the P2 along with time, and the accumulation rule of stratum sand in the gravel layer at the position of the bottom of the gravel pack is reversely pushed due to the additional skin coefficient caused by the gravel pack; and evaluating the accumulation rule of stratum sand in the gravel layer at the top position of the gravel pack according to the change rule of the difference value of P3 and P4 with time due to the additional skin coefficient caused by the gravel pack. Comparing and researching the position where the blockage occurs first or the position where the peristaltic damage occurs first to cause sand prevention failure in the gravel packing operation of the hydrate exploitation well;
(10) In the steps (7) to (9), observing the sand concentration and the sand grain size in the cement sand mixture passing through the valve F3 in real time, if the sand concentration in the produced liquid is not different from the sand concentration mixed and injected in the water tank, and the sand grain size in the produced liquid is consistent with the stratum sand grain size distribution mixed and injected in the water tank, indicating that the current gravel filling process parameters are not suitable for the current hydrate exploitation reservoir, properly reducing the size of gravel in the filling layer, adopting quartz sand with 70 meshes to 100 meshes, and returning to the step (3); otherwise, the design of the gravel packing process parameters is conservative, and if the differential pressure of the fixed-point pressure gauge rises too fast under the condition, the gravel size is too small or the packing thickness is too large, although the sand prevention is beneficial, and when the production capacity of the hydrate exploitation well is not beneficial to be maintained, the quartz sand with the size of 30 meshes to 50 meshes is needed to be adjusted, and the step (3) is returned.
For ease of understanding, it is to be noted that:
the basic monitoring principle of the accumulation and blockage process of the stratum silt in the filled gravel layer based on the reading difference value of the fixed-point pressure gauges inside and outside the filling layer is as follows: as fine-grained silt is accumulated in the gravel layer, the permeability of the gravel packing layer is gradually reduced, and the reduction reaction of the permeability is that the pressure difference between the inside and the outside of the packed gravel layer is gradually increased on the measurement data. Under the same formation air outlet and water outlet conditions, the faster the pressure difference between the inside and the outside of the gravel layer rises, which indicates that the gravel layer is easier to block, and vice versa. If two or more sets of parallel tests are compared in which the gravel packing process parameters are different, the preferred gravel packing process parameters can be selected by the time the gravel pack becomes plugged or the rate of increase of the internal and external differential pressure.
The specific evaluation parameters for evaluating the gravel packing effect by utilizing the sand outlet condition in the wellhead produced liquid are the sand concentration in the produced liquid and the sand grain size in the produced liquid, and the basic principle for evaluating the gravel layer packing effect by utilizing the sand outlet condition in the wellhead produced liquid is as follows: if the gravel layer filling process parameters are not matched with the formation sand parameters, the filling layer may not have a sand blocking effect, and a large amount of injected formation sand is produced at the moment, and the performance in wellhead production fluid is as follows: the sand concentration in the produced liquid is not much different from the mud sand concentration mixed and injected in the water tank, and the sand particle size in the produced liquid is consistent with the particle size distribution of stratum sand mixed and injected in the water tank; on the contrary, if the design of the gravel packing process parameters is conservative, the sand concentration in the wellhead produced fluid is very small or the stratum sand particle size in the produced fluid is very small, and in this case, although the sand prevention is beneficial, the maintenance of stratum productivity is not beneficial, and at the moment, the optimum gravel packing process parameters are optimized by combining the difference value of the fixed-point pressure gauge and comprehensively considering the productivity condition.
By implementing the above-described gravel pack effect monitoring method of the present embodiment, the most fundamental purpose is: the concentration and the grain size distribution of the silt in the wellhead produced liquid are in a controllable interval, the formation silt is properly blocked, and the normal production of the formation is maintained, namely, the sand production management effect of 'anti-discharge combination, mainly discharge' is achieved. The final in-pipe gravel packing quality of different gravel packing construction parameters can be verified, and the optimal packing construction parameter combination is optimized; optimizing gravel packing process parameters, preferably optimizing the size, thickness and other process parameters of a packed gravel layer; evaluating the accumulation and penetration process of the argillaceous silt hydrate reservoir products in the gravels under the condition of long-term exploitation; simulating the adaptability of the in-pipe gravel pack to the hydrate production well under the fracture pressure condition of the hydrate reservoir; and verifying the adaptive sand concentration range of certain gravel packing process parameters, and providing a basis for controlling the depressurization scheme of the hydrate exploitation well.
Through the steps, the optimal gravel packing construction parameters and the process design parameters of the hydrate exploitation well can be preferably obtained, and the foundation is provided for the sand prevention completion design of natural gas hydrate exploitation in the sea area of China. It should be noted that the process parameters and filling parameters designed in the above embodiments are not actual construction data, and the scope of protection of the present patent is not limited by the list of the above data, which is only for the convenience of case analysis and description, but is not limited to other forms of the present invention, and any equivalent embodiments that can be changed or modified to equivalent changes by those skilled in the art using the above disclosed technical matters are applicable to other fields, but any simple modification, equivalent changes and modification made to the above embodiments according to the technical matters of the present invention still fall within the scope of protection of the technical matters of the present invention.
Claims (7)
1. The simulation system for gravel packing in the hydrate exploitation well pipe is characterized by being in a 1:1 corresponding relation with an actual construction tool on site, and comprising a test well subsystem, a simulated packing subsystem and a packing quality detection subsystem;
the test well subsystem comprises a simulated well bore, a simulated sleeve, a simulated oil pipe, a three-phase injection pipeline and a mechanical screen pipe, wherein the simulated well bore meets the depth conditions of the full-size gravel packing tool in a natural gas hydrate reservoir, the depth is 200m, a wellhead blowout prevention flashboard is arranged at the wellhead of the simulated well bore, and the wellhead blowout prevention flashboard is withstand 15Mpa; a three-phase injection pipeline interface, a gas output pipeline interface, a water sand output/injection pipeline interface and a slurry return pipeline interface are arranged on the wellhead blowout prevention flashboard, corresponding gate valves are arranged at the pipeline interfaces, and the gate valves are high-pressure ball valves; the simulation sleeve is arranged in the simulation shaft, an oil pipe penetrating packer is further arranged in an annulus between the simulation shaft and the simulation sleeve, a three-phase injection pipeline penetrates through the oil pipe penetrating packer and is connected with a radial flow diverter fixedly arranged at the bottom of the simulation shaft, and a wedge-shaped hole with a small outside and a large inside is formed in the inner wall of the radial flow diverter; the simulated oil pipe and the mechanical screen pipe are arranged in the simulated sleeve, and the simulated oil pipe is connected with the mechanical screen pipe and is positioned at the upper part of the mechanical screen pipe; the production interval of the simulated casing is pre-provided with simulated perforation holes according to actual well bottom perforation parameters, and the length of the simulated perforation holes is consistent with that of the mechanical screen pipe; an oil sleeve annulus packer is also arranged in the annulus between the simulation sleeve and the simulation oil pipe, and the oil sleeve annulus packer is positioned above the simulation perforation holes; the space formed between the outer protective cover of the mechanical sieve tube and the inner wall of the simulated casing, the oil sleeve annular packer and the bottom of the well is the gravel filling space in the tube;
The simulated filling subsystem comprises a filling pipe column combination arranged in a simulated shaft, a high-pressure gas cylinder group, a water tank, a gravel mixing box, a three-phase mixer and a slurry recycling tank which are arranged on the ground, wherein the filling pipe column combination comprises a filling pipeline, a filling packer and a filling spray nozzle, the filling pipeline is arranged in a simulated oil pipe, the filling spray nozzle is arranged at the lower end of the filling pipeline, and the filling packer is arranged between the upper part of the filling spray nozzle and the inner wall of a mechanical screen pipe; the gravel sand mixing box comprises a mixing stirrer and an injection pump, and is connected with a water sand output/injection pipeline interface; the inlet end of the high-pressure gas cylinder group is connected with an oil sleeve annular gas output loop through a pipeline, the outlet end of the high-pressure gas cylinder group is connected with the inlet end of the three-phase mixer through a pipeline, and the oil sleeve annular gas output loop is an annular space formed between a simulation sleeve and a simulation oil pipe; the inlet end of the water tank is connected with a lifting pipe column in the simulated oil pipe through a pipeline, and the outlet end of the water tank is connected with the inlet end of the three-phase mixer through a pipeline; the three-phase mixer comprises a gas-water-silt mixing stirrer and a three-phase injection pump, and the outlet end of the three-phase mixer is connected with the three-phase injection pipeline interface through a pipeline; the slurry recovery tank is connected with a shaft sand-carrying fluid return annulus through a pipeline, the shaft sand-carrying fluid return annulus is an annulus between a filling pipeline and a simulated oil pipe, and a sand-carrying fluid filtering device is arranged in the slurry recovery tank;
The filling quality detection subsystem comprises a gas separator, a lifting pipe column, a fixed-point pressure gauge and an acoustic imaging logging system; the gas separator is only used in the gravel packing effect simulation monitoring process, the gas separator and the lifting pipe column are both arranged in the simulated oil pipe, and the outlet of the gas separator is communicated with the annular gas production loop of the oil sleeve; the fixed-point pressure gauge comprises fixed-point pressure gauges P3 and P2 which are arranged at the upper end and the lower end of the inner wall of the mechanical sieve tube, and fixed-point pressure gauges P4 and P1 which are arranged at the upper end and the lower end of the outer pipe of the filling part of the simulation sleeve; the filling quality detection subsystem is a conventional downhole acoustic imaging logging system.
2. The system of claim 1, wherein the radial flow diverter has a swirl deflector disposed at an inner inlet thereof, the swirl deflector having a lower end engaging an annular perforated plate disposed between an inner wall and an outer wall of the radial flow diverter.
3. A simulation method based on a gravel pack simulation system in a hydrate production well pipe according to any one of claims 1-2, comprising the steps of:
A. installing a shaft pipe column according to an actual well structure, checking the tightness of each sealing position, and setting a filling simulation subsystem and performing filling operation simulation;
B. The lower filling quality detection subsystem monitors the filling quality and judges whether the filling quality is qualified or not, and if the filling quality is not qualified, the filling operation simulation is conducted again; if the sand is qualified, mixing and injecting gas, liquid and mud sand to simulate the production process, and monitoring the sand condition in real time;
C. judging whether the sand control effect is qualified or not, if the sand control effect is not qualified, adjusting filling process parameters, and carrying out filling operation simulation again; if the sand control effect is qualified, obtaining optimal filling process parameters and filling construction parameters, and finishing simulation;
the filling construction parameters comprise sand ratio, pump displacement, pump outlet pressure, sand-carrying fluid type and related hydrodynamic parameters controlled by a gravel mixing box; the packing process parameters include the particle size of the packed gravel layer, the packed layer thickness, and the gravel type.
4. The method of simulating a gravel pack simulation system in a hydrate production well pipe according to claim 3, wherein the step a specifically comprises:
a1, checking connection of a wellhead blowout prevention flashboard and a simulated shaft and self-sealing of a three-phase mixer; obtaining a fracture pressure gradient of the stratum in the actual natural gas hydrate exploitation process;
a2, combining an actual well structure of the natural gas hydrate test production well, and putting a simulation sleeve with preset perforation holes into the simulation well, and enabling a seat oil pipe to penetrate through the packer; installing a simulated oil pipe, a mechanical screen pipe and an oil sleeve annular packer, and putting the simulated oil pipe, the mechanical screen pipe and the oil sleeve annular packer into a well bottom appointed position, wherein the oil sleeve annular packer is set; setting a filling packer by setting a filling pipe column combination;
A3, connecting a ground pipeline, setting the sand ratio and the discharge capacity in the gravel mixing box, starting an injection pump in the gravel mixing box, circularly filling, and collecting the discharge capacity, the pressure and the sand ratio data of the injection pump, the basic properties of sand-carrying fluid and the pressure data detected by a fixed-point pressure gauge in real time; the reading of the fixed-point pressure gauge P1 outside the simulated casing is ensured to be smaller than the formation fracture pressure gradient in the filling process; observing the pump pressure change of the injection pump, and the sudden pump pressure rise indicates the filling end.
5. The method of simulating a gravel pack system in a hydrate production well according to claim 4, wherein step B specifically comprises:
b1, unsealing the filling packer, lifting out a filling pipe column combination, lowering a filling quality detection subsystem to the bottom of the well, and then slowly lifting up and measuring the acoustic imaging condition of the bottom of the well; if the acoustic imaging continuity of the bottom of the well is poor, obvious gray value mutation or interruption appears, which indicates that the filling is uneven or some parts do not reach the filling effect at all, the filling construction parameters are readjusted, a filling quality detection subsystem is started, and the step A3 is returned to carry out filling operation simulation again; if the acoustic imaging continuity of the bottom hole is good, recording current filling construction parameters, and entering a step B2;
B2, installing a gas separator, feeding a lifting pipe column, adjusting a bottom hole gas circuit manifold, and connecting a ground high-pressure gas cylinder group, a water tank and a three-phase mixer; adding stratum sand samples or simulated hydrate stratum sand samples obtained from a hydrate reservoir according to a specific proportion into a water tank, and uniformly stirring; pumping the cement-sand mixture and gas into a three-phase mixer according to a fixed proportion according to a numerical simulation result or a gas-water ratio condition obtained by field test sampling;
and B3, adjusting a shaft flow, starting a lifting pipe column and a gas separator, pumping the gas-water-silt mixture into the bottom of a well through a three-phase injection pipeline by using a three-phase mixer, forming radial flow through a radial flow diverter, entering a preset perforation hole and a gravel filling layer, continuously and stably operating a water tank and a high-pressure gas cylinder group to supply the three-phase mixer in the process, recording the numerical value of a fixed-point pressure gauge in the well in real time, calculating the pressure difference between the inside and the outside of the filling layer, observing the sand concentration in water produced by the wellhead of the lifting pipe column, and evaluating the adaptability of the gravel filling operation of given filling process parameters to a specific stratum and optimizing the optimal gravel filling process parameters.
6. The simulation method of a gravel pack simulation system in a hydrate production well pipe according to claim 5, wherein in the step B1, the purpose of optimizing the gravel pack construction parameters is achieved by judging whether the gravel pack quality is qualified or not by using the gray value of acoustic imaging logging and the uniformity thereof.
7. The simulation method of the gravel packing simulation system in the hydrate production well pipe according to claim 6, wherein in the step B3, whether the design of the current packing process parameters is reasonable or not is judged by utilizing the change rule of the pressure difference between the inside and the outside of the packing layer along with time and the sand concentration and the sand containing diameter in the produced fluid of the well mouth, so as to achieve the purpose of optimizing the design and optimization of the gravel packing process parameters.
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| CN109488259B (en) * | 2018-12-12 | 2019-08-06 | 青岛海洋地质研究所 | It is handled up the method for replacement exploitation I class hydrate system based on warm seawater-gravel |
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| CN115522920B (en) * | 2022-11-24 | 2023-02-10 | 西南石油大学 | Test device for measuring gas-water double-layer perforation exploitation of tight sandstone gas reservoir |
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