A method for preventing and controlling sand and mud of silty fine sand by adopting three-level stereoscopic type

Abstract

The present application relates to the technical field of oil and gas well exploitation engineering, and particularly relates to a method for preventing and controlling silt and fine sand sanding mud in a three-level stereoscopic manner and application. The sand and mud of the wellbore accessory are flushed out through a foam swallowing negative pressure mixed discharge mode, a space channel is formed in the near wellbore zone, then a reticular resin is filled to form a isolation layer, a proppant is filled again to form a fixed layer, and finally a filter sand layer with a crosslinking agent is filled with 4-6 times of the median particle size of the stratum. The method is suitable for both vertical wells and horizontal wells. A sand control and mud removal barrier of more than three levels is formed to form a spatial stereoscopic filter barrier, while ensuring the smooth discharge of fine particle size sand and mud, ensuring the economic productivity of the oil and gas well, improving the efficiency of sand control and mud removal, prolonging the production cycle of the oil and gas well, preventing the plugging of the oil and gas layer, and after a certain period of production, the permeability is reduced to affect normal production. The plugging can be removed through the positive and negative circulation well washing mode to improve the permeability of the stratum and ensure the productivity of the oil and gas well.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas well exploitation engineering, in particular to a method for controlling and removing mud and fine sand of marine natural gas hydrate reservoir by adopting three-dimensional prevention and control of mud and fine sand. BACKGROUND

[0002] In the process of oil and gas well exploitation, sand production phenomenon occurs from time to time. The sand production phenomenon includes formation sand production, water injection and gas development process. In the process of gas development, the cementing material of the formation swells and becomes loose, the cementing strength decreases, and the free sand particles increase to cause sand production.

[0003] Because the hydrate reservoir usually belongs to unconsolidated, weakly consolidated or fractured formation, sand production phenomenon of the reservoir is inevitable in the process of hydrate production. In particular, the hydrate reservoir in the South China Sea is an unconsolidated ultra-fine sand reservoir, and the sand production problem becomes a key factor restricting the effective development of hydrate resources. The mechanical sand control method cannot prevent and control the fine sand, mud and clay materials with small particle size; the sand control screen pipe is easily blocked by fine sand and mud, resulting in production reduction or shutdown of the oil and gas well.

[0004] For the natural gas hydrate exploitation reservoir with poor cementing strength of mud and fine sand formation and the characteristics of reservoir heterogeneity and ultra-low permeability, the conventional hydraulic packing and sand control technology applied to the hydrate reservoir reconstruction and sand control effect is not ideal, and there is no effective process method suitable for the exploitation and sand control of natural gas hydrate reservoir geological fluid characteristics. The sand production amount and capacity in the process of natural gas hydrate exploitation are not only closely related to the sand control method and sand blocking precision, but also related to a series of factors such as sand particle size, mud content, clay mineral components in mud, fluid viscosity, flow rate, production pressure difference, change degree of pressure difference, etc., so it is a very complex process. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art, and provide a method for preventing and controlling mud and fine sand sand production by adopting three-dimensional method and application, and the technical scheme is as follows:

[0006] A method for preventing and controlling mud and fine sand sand production by adopting three-dimensional method, comprising the following steps:

[0007] Step one, lowering the hydraulic sand blasting and sand carrying and filling pipe column in the wellbore;

[0008] Step two, washing the wellbore, washing the well with washing fluid before sand carrying, so that the water quality of the inlet and outlet is the same; the sand and mud near the wellbore are flushed out by the foam swallowing negative pressure mixed discharge method, and a space channel is formed in the near wellbore zone;

[0009] Step three, lower layer hydraulic sand-carrying primary packing: injecting sand-carrying liquid from the oil pipe, and the sand-carrying liquid returns from the oil jacket annulus until the sand-carrying of the lower layer casing and the formation is completed, and after the micro near wellbore zone is generated, the casing or screen cock is closed, the sand-carrying liquid is injected from the oil jacket annulus; at the same time, the sand-carrying liquid is injected from the oil pipe to carry out the primary packing operation;

[0010] Step four, lower layer sand-preventing medium main packing: the micro near wellbore zone is pressed open and extended by using the end sand-removing packing technology, and after the near wellbore zone length reaches the requirement by injecting the preflush to form a fracture, the sand-preventing medium is pumped by using a large displacement and low sand ratio, so that the sand-preventing medium is not deposited at the bottom of the near wellbore zone and is carried to the front end of the near wellbore zone to be deposited after sand removal, the near wellbore zone length direction extension is forced to slow down or stop, and the near wellbore zone width direction is increased, and finally a plurality of short and wide high conductivity packing fracture zones are formed in the low permeability reservoir;

[0011] Step five, sand-preventing medium packing operation: after the lower layer packing is completed, the reverse circulation is carried out; after the washing is completed, the pipe string is lifted, the hydraulic jet is lifted to the position of the upper layer needing sand-carrying; then the sand-preventing medium is packed from the oil jacket annulus at a displacement smaller than that in the packing operation, and the packing surface is at least higher than the sand-carrying position of the lower layer, and the packing surface of the horizontal well is between the two sand-carrying layers; after the packing is completed, the packing surface is detected by using the hydraulic sand-carrying and packing pipe string until the packing is completed to the position required by the design;

[0012] Step six, upper layer hydraulic sand-carrying and packing: after the sand surface is detected, the hydraulic sand-carrying and packing pipe string is lifted, the hydraulic jet is lifted to the position of the upper layer needing sand-carrying, and the upper layer hydraulic sand-carrying and packing are carried out;

[0013] Step seven, sand washing operation: after the upper layer packing is completed, the reverse circulation is carried out; then the sand washing operation is carried out by using the hydraulic sand-carrying and packing pipe string, or the pipe string is lifted and the sand washing drill pipe is used to carry out the sand washing and detect the packing surface until the sand washing is completed to the lowermost layer of the packing modification, and finally the sand washing pipe string is lifted.

[0014] Further, the method specifically comprises the following steps:

[0015] Step one, lowering the hydraulic sand-carrying and packing process pipe string: making the hydraulic jet tool reach the reservoir position needing sand-carrying;

[0016] Step two, normal washing: washing the well by using the washing fluid at the displacement required by the design before sand-carrying, so as to make the water quality of the inlet and outlet the same; the washing displacement is between 0.5-1 m3 / min;

[0017] Step three, lower layer hydraulic sand blasting sand-carrying primary filling: sand-carrying fluid is injected from the tubing, and the sand-carrying construction discharge and the wellhead pressure are determined by the nozzle number, aperture and nozzle and casing distance of the hydraulic jetting tool, when sand-carrying, the sand-carrying fluid is returned from the tubing-casing annulus until the sand-carrying of the lowermost layer casing and the formation is completed, and the micro near wellbore zone is generated; the cock is closed, sand-carrying fluid is injected from the tubing-casing annulus, the injection discharge of the sand-carrying fluid is executed according to the design, and the injection pressure range of the sand-carrying fluid cannot exceed the pressure bearing limit of the casing and the wellhead device; at the same time, sand-carrying fluid is injected from the tubing to carry out primary filling construction, and the injection discharge is in a certain proportion with the injection discharge of the tubing-casing annulus; the nozzle number of the hydraulic jetting tool is 6-8, the aperture is 8-6mm, and the nozzles are symmetrically arranged; the sand-carrying fluid is mainly based on salt water-based clean sand-carrying fluid; the discharge of the sand-carrying fluid and the injection pressure range of the sand-carrying fluid are designed and calculated according to the underwater burial depth of the natural gas hydrate reservoir to be filled and transformed in the sea area, and the rock and soil mechanics parameters of the reservoir;

[0018] Step four, lower layer sand control medium main filling: the micro near wellbore zone is opened and extended by using the end sand shedding filling technology, after the near wellbore zone length reaches the requirement by injecting the preflush fluid, the sand control medium is not deposited at the bottom of the near wellbore zone and is carried to the front end of the near wellbore zone after sand shedding deposition by using the large discharge low sand ratio pump injection, so that the extension of the near wellbore zone length direction is slowed down or stopped, the near wellbore zone mainly grows in the width direction, and finally a plurality of short and wide high conductivity filling sand fracture zones are formed in the low permeability reservoir; the sand control medium filter body in the near wellbore zone plays the sand control effect of gravel packing;

[0019] Step five, sand control medium filling operation: after the lower layer filling is completed, reverse circulation well flushing is carried out; after the well flushing is completed, the pipe string is lifted, the hydraulic jet 5 is lifted to the upper layer position where sand-carrying is required; then the sand control medium is filled from the tubing-casing annulus at a discharge smaller than that in the filling construction, and the filling surface is at least higher than the lower sand-carrying position by a certain height, after the filling is completed, the filling surface is measured and explored by using the hydraulic sand blasting sand-carrying filling pipe string, until the filling is completed to the required position; the first three-dimensional layer of the sand control medium adopts the grid-shaped resin, fiber and calcium powder composed isolation layer; the second three-dimensional layer adopts the sawtooth-shaped proppant composed fixed layer; the third three-dimensional layer adopts the filter layer composed of coated sand; the migration of fine particles is prevented, and a certain sand stabilizing and sand consolidating effect is achieved;

[0020] Step six, upper layer hydraulic sand blasting sand-carrying and filling: after the filling surface is measured and explored, the hydraulic sand blasting sand-carrying filling pipe string is lifted, the hydraulic jet 5 is lifted to the upper layer position where sand-carrying is required, and the upper layer hydraulic sand blasting sand-carrying and filling is carried out;

[0021] Step seven, sand washing operation: after the upper layer filling is completed, reverse circulation well flushing is carried out; then sand washing operation is carried out by using the pipe string, or the pipe string is lifted, sand washing drill tools are used, sand washing is carried out while the filling surface is explored, until the sand washing is completed to the lowermost layer of the filling and transformation, and finally the sand washing pipe string is lifted.

[0022] Further, the sand control medium is multilayered, including a tertiary stereoscopic layer, a secondary stereoscopic layer and a primary stereoscopic layer.

[0023] The primary stereoscopic layer adopts a grid-shaped resin, a fiber and a calcium powder to form an isolation layer; the secondary stereoscopic layer adopts a sawtooth-shaped proppant to form a fixed layer; and the tertiary stereoscopic layer adopts a coated sand to form a filter layer.

[0024] The proportion of the glass fiber and the calcium powder is 1:1.

[0025] The component of the proppant at least includes bauxite, which is sintered by ceramic.

[0026] The coated sand is prepared by adding plastic phenolic resin and reticular crosslinking agent to natural quartz sand.

[0027] The present application is applicable to vertical wells and horizontal wells.

[0028] The present application has the following beneficial effects:

[0029] The present application is a process method for low-permeability reservoir natural gas hydrate reservoir reconstruction, yield increase and sand control, which can realize the following: ① reservoir reconstruction, yield increase and sand control are combined. The near-wellbore zone sand and mud are flushed back and extended by using the positive and reverse flushing well technology, the filling and filtering space is greatly increased, and meanwhile, the sand control medium is filled in the low-permeability argillaceous reservoir to form a plurality of short and wide high-conductivity fracture zones, so as to improve the seepage condition and increase the production capacity; the sand control medium filter of the filled material plays the effect of gravel packing and three-dimensional layer sand control. The water jet filling and positive and reverse circulation well flushing technology are combined. The jet water hammer effect can effectively clean the near-wellbore formation sand and mud, accurately form a three-dimensional layer sand control space, ensure the reservoir reconstruction of the low-permeability argillaceous fine sand layer, and does not need mechanical isolation, and can be used for the reservoir reconstruction of the open hole, casing and sand control screen pipe completion of the marine hydrate; the water jet filling and positive and reverse circulation well flushing technology realizes the artificial reconstruction of the near-wellbore zone reservoir, improves the seepage condition, achieves the sand control and mud removal, and achieves the purpose of economically exploiting the natural gas hydrate. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a vertical well application schematic diagram;

[0031] Figure 2 is a horizontal well application schematic diagram;

[0032] Figure 3 is a water jet sand filling and carrying pipe column structure schematic diagram;

[0033] In the drawings:

[0034] 1, diameter wellhead, 2, production layer, 3, isolation layer, 4, filter layer, 5, fixed layer, 6, oil pipe, 7, safety joint, 8, centralizer, 9, jet, 10, packer, 11, horizontal wellhead, 12, check valve, 13, coupling, 14, screen pipe, 15, pilot head. DETAILED DESCRIPTION

[0035] Example one:

[0036] A method for preventing and controlling the sand of muddy fine sand by adopting three-dimensional type, comprising:

[0037] Lowering the hydraulic sand jetting and sand carrying and filling pipe column: taking the production layer as a low permeability reservoir of natural gas hydrate, in the production layer, the hydraulic jet is lowered through the casing, so that the hydraulic jet reaches the lower position needing to carry sand; the pipe column comprises an oil pipe and a safety joint, a hydraulic jet, a check valve and an inclined tip installed on the oil pipe from top to bottom.

[0038] Positive washing: the well is washed with a washing fluid before sand carrying, so as to achieve the same water quality at the inlet and outlet; the sand and mud near the wellbore are flushed out by the foam swallowing negative pressure mixing and discharging mode, and a space channel is formed in the near wellbore zone.

[0039] Lower hydraulic sand jetting and sand carrying and preliminary filling: the sand carrying fluid is injected from the oil pipe, the sand carrying fluid returns from the oil casing annulus during sand carrying, until the lower casing and the formation are carried with sand, and a micro near wellbore zone is generated; then, the casing or screen pipe cock is closed, the sand carrying fluid is injected from the oil casing annulus; at the same time, the sand carrying fluid is injected from the oil pipe, and the preliminary filling construction is carried out; lower sand prevention medium main filling: the micro near wellbore zone is pressed open and extended by using the end sand shedding filling technology, after the seam is created by injecting the preflush and the near wellbore zone length reaches the requirement, the large displacement low sand ratio is used for pumping, so that the sand prevention medium is not deposited at the bottom of the near wellbore zone and is carried to the front end of the near wellbore zone after sand shedding deposition, the extension of the near wellbore zone length direction is forced to slow down or stop, the near wellbore zone mainly grows in the width direction, and finally a plurality of short and wide high conductivity filling sand seam belts are formed in the low permeability reservoir, and the three-stage sand prevention medium filter in the near wellbore zone plays the sand prevention effect of gravel packing.

[0040] Sand prevention medium filling operation: after the lower filling is completed, reverse circulation washing is carried out; after the washing is completed, the pipe column is lifted, the hydraulic jet is lifted to the upper layer position needing to carry sand; then, the sand prevention medium is filled from the oil casing annulus at a displacement smaller than that in the filling construction, and the filling surface is at least higher than the lower sand carrying position, and the filling surface of the horizontal well is between the two sand carrying layers; after the filling is completed, the filling surface is measured by the hydraulic sand jetting and sand carrying and filling pipe column, until the filling is completed to the position required by the design.

[0041] Upper layer hydraulic sand blasting carrying sand and filling: after the completion of the exploration sand surface, the upper layer hydraulic sand blasting carrying sand and filling pipe column is lifted, the hydraulic jet is lifted to the upper layer position where sand carrying is needed, and upper layer hydraulic sand blasting carrying sand and filling is carried out.

[0042] Sand washing operation: after the completion of the upper layer filling, reverse circulation well washing is carried out; then the sand washing operation is carried out by using the hydraulic sand blasting carrying sand and filling pipe column, or the pipe column is lifted and a sand washing drill is used to wash sand and explore the filling surface until the sand is washed to the lowermost layer of the filling modification, and finally the sand washing pipe column is lifted.

[0043] Example two:

[0044] A method for preventing and controlling muddy fine sand and silt sand by using three-dimensional layers, applied to the hydraulic sand blasting carrying sand and filling and sand control reverse circulation well washing process method of low permeability reservoir natural gas hydrate exploitation reservoir, combining the technical characteristics of hydraulic sand blasting carrying sand and filling gravel packing process, using the hydraulic jet tool installed on the construction pipe column, forming one or more sand blasting channels in the reservoir through water hammer, thereby generating a micro near wellbore zone in the near wellbore zone, and then using the end sand removal and filling technology to press open and extend the micro near wellbore zone, and filling the sand control medium therein and realizing end sand removal, forming multiple short and wide high conductivity fracture zones in the low permeability reservoir, and the sand control medium filter in the near wellbore zone plays the sand control effect of gravel packing.

[0045] The hydraulic sand blasting carrying sand and filling pipe column of the application is composed of a safety joint, a centralizer, a jet, a packer, a centralizer, a check valve, a coupling, a screen pipe and a guide head connected in sequence from top to bottom through the oil pipe.

[0046] The specific process steps are as follows:

[0047] (1) Lower the hydraulic sand blasting carrying sand and filling process pipe column: make the hydraulic jet tool reach the reservoir position where sand carrying is needed;

[0048] (2) Positive washing: before sand carrying, wash the well with the designed required displacement of the well washing fluid to make the inlet and outlet water quality the same; the washing displacement is between 0.5-1 m 3 / min;

[0049] (3) Lower layer hydraulic sand-carrying and primary filling: sand-carrying fluid is injected from the tubing, and the sand-carrying construction discharge and the wellhead pressure are determined by the number of nozzles, the aperture and the distance between the nozzle and the casing of the hydraulic jetting tool. When sand-carrying, the sand-carrying fluid is returned through the oil-casing annulus until the sand-carrying of the lowermost casing and the formation is completed, and a micro near wellbore zone is generated in the near wellbore zone. The cock is closed, sand-carrying fluid is injected from the oil-casing annulus, the injection discharge of the sand-carrying fluid is executed according to the design, and the injection pressure range of the sand-carrying fluid cannot exceed the pressure bearing limit of the casing and the wellhead device. At the same time, sand-carrying fluid is injected from the tubing to perform primary filling construction, and the injection discharge is in a certain proportion to the injection discharge of the oil-casing annulus. The number of nozzles of the hydraulic jetting tool is 6-8, the aperture is 8-6 mm, and the nozzles are symmetrically arranged. The sand-carrying fluid is mainly based on salt water-based clean sand-carrying fluid. The discharge of the sand-carrying fluid and the injection pressure range of the sand-carrying fluid are designed and calculated according to the underwater burial depth of the natural gas hydrate reservoir to be filled and transformed in the sea area, and the rock and soil mechanics parameters of the reservoir.

[0050] (4) Lower layer sand control medium main filling: the micro near wellbore zone is opened and extended by using the end sand-shedding filling technology. After the near wellbore zone length reaches the requirement by injecting preflush fluid, a large discharge low sand ratio pump is used to make the sand control medium not deposited at the bottom of the near wellbore zone and carried to the front end of the near wellbore zone after sand shedding and deposition, so as to force the extension of the near wellbore zone in the length direction to slow down or stop, and the near wellbore zone mainly grows in the width direction. Finally, a plurality of short and wide high conductivity filling sand fracture zones are formed in the low permeability reservoir. The sand control medium filter in the near wellbore zone plays the sand control effect of gravel packing;

[0051] (5) Sand control medium filling operation: after the lower layer filling is completed, reverse circulation well flushing is performed; after the well flushing is completed, the pipe string is lifted, the hydraulic jetting device 5 is lifted to the upper layer position where sand-carrying is required; then the sand control medium is filled from the oil-casing annulus at a discharge smaller than that in the filling construction, and the filling surface is at least higher than the lower sand-carrying position by a certain height. After the filling is completed, the filling surface is detected by the hydraulic sand-carrying and filling pipe string until the filling is completed to the required position. The first three-dimensional layer of the sand control medium adopts a grid-shaped isolation layer composed of resin, fiber and calcium powder; the second three-dimensional layer adopts a fixed layer composed of a sawtooth-shaped proppant; and the third three-dimensional layer adopts a filter layer composed of a coated sand. The migration of fine particles is prevented, and a certain sand stabilizing and sand fixing effect is achieved;

[0052] (6) Upper layer hydraulic sand-carrying and filling: after the detection of the filling surface is completed, the hydraulic sand-carrying and filling pipe string is lifted, the hydraulic jetting device 5 is lifted to the upper layer position where sand-carrying is required, and the upper layer hydraulic sand-carrying and filling is performed;

[0053] (7) Sand washing operation: after the upper layer filling is completed, reverse circulation well flushing is performed; then the sand washing operation is performed by using the pipe string, or the pipe string is lifted and a sand washing drill is used to wash sand while detecting the filling surface until the sand is washed to the lowermost layer of the filling and transformation, and then the sand washing pipe string is lifted.

[0054] The hydraulic sand jetting sand carrying packing and sand prevention positive and reverse circulation well washing process method of the present application realizes hydraulic jetting packing of lower layers, generates a micro near wellbore zone in the formation and extends the micro near wellbore zone, forms multiple short and wide high conductivity fracture zones in the low permeability reservoir, at the same time, the sand prevention medium filter body is packed in the space of the extended near wellbore zone and achieves the sand prevention effect of gravel packing, and the sand packing fracture forms a double linear flow pattern in the low permeability reservoir; then, the sand prevention medium packing and sealing of lower layers and the hydraulic jetting packing and sand prevention medium packing of upper layers are carried out, which ensures the effective transformation and sand prevention of lower layers and can implement multi-section drag packing of horizontal wells in low permeability reservoirs with strong heterogeneity and large physical property difference, improves the seepage condition and achieves the purpose of yield increase and sand control.

[0055] Example Three

[0056] The sand and mud near the wellbore are flushed out by foam feeding and negative pressure mixed discharge, a space channel is formed in the near wellbore zone, then a reticular resin is filled to form an isolation layer, proppants are filled again to form a fixed layer, and finally a filter sand layer with a crosslinking agent is filled with 4-6 times the median particle size in the formation. This method is suitable for both vertical wells and horizontal wells. A three-level or more sand control and mud removal barrier is formed to form a spatial three-dimensional filter barrier, while ensuring the smooth discharge of fine particle size sand and mud, ensuring the economic productivity of oil and gas wells, improving the efficiency of sand control and mud removal, prolonging the production cycle of oil and gas wells, preventing oil layer plugging, and after a certain period of production, the permeability decreases to affect normal production. The plugging can be removed by positive and reverse circulation well washing to improve the permeability of the formation and ensure the productivity of the oil and gas well.

[0057] The first three-dimensional layer is an isolation layer composed of grid-shaped resin, fiber and calcium powder; the second three-dimensional layer is a fixed layer composed of sawtooth-shaped proppants; and the third three-dimensional layer is a filter layer composed of coated sand.

[0058] The isolation layer composed of grid-shaped resin, fiber and calcium powder has a glass fiber and calcium powder ratio of 1:1.

[0059] The second three-dimensional layer is a fixed layer composed of sawtooth-shaped proppants; and the components are made of bauxite and other raw materials and sintered by ceramics.

[0060] The third three-dimensional layer is a filter layer composed of coated sand, and the coated sand of the filter layer is prepared from natural quartz sand as raw sand, heated plastic phenolic resin, and reticular crosslinking agent.

[0061] A method for preventing and controlling the outflow of muddy fine sand by using a three-dimensional barrier is suitable for both vertical wells and horizontal wells.

[0062] The straight well bottom shedding heavy material is used, the horizontal well uses the end shedding technology to press open and extend the micro near wellbore zone, and fills the sand control medium in it and realizes the bottom end shedding heavy material, and a plurality of short wide high conductivity fracture zones are formed in the low permeability reservoir. Ensure the effective transformation of the lower layer to increase production and control sand and mud, and implement the straight well horizontal well multi-layer multi-section drag filling in the low permeability reservoir, realize the transformation of the reservoir with strong heterogeneity and large physical property difference, improve the seepage condition, achieve the purpose of controlling sand and mud, and economically exploit the natural gas hydrate.

[0063] The low permeability reservoir natural gas hydrate reservoir transformation and sand control combined process method of the application is combined with the reservoir transformation and sand control, and the near wellbore zone sand mud is washed out and extended by using the positive and reverse washing well technology, the filtration space is greatly increased, the sand control medium is filled in it to form a plurality of short wide high conductivity fracture zones in the low permeability mud reservoir, the seepage condition is improved, and the production capacity is improved; the sand control medium filter of the filled material plays the effect of preventing and controlling sand and mud of the three-dimensional layer of gravel packing. The water jet filling positive and reverse circulation well washing technology is combined. The jet water hammer effect can effectively clean the near wellbore formation sand and mud, accurately form a three-dimensional layer of prevention and control space, ensure the reservoir transformation of the low permeability mud fine sand layer, and does not need mechanical isolation, and can be used for the reservoir transformation of the open hole, casing and sand control screen pipe completion of the ocean hydrate; the water jet filling positive and reverse circulation well washing realizes the artificial transformation of the near wellbore zone reservoir, improves the seepage condition, achieves the purpose of controlling sand and mud, and economically exploits the natural gas hydrate.

[0064] (1) The micro near wellbore zone is pressed open and extended, the sand control medium is filled in the formation near wellbore zone by the sand carrying fluid to form a plurality of short wide high conductivity fracture zones, and the sand control medium filter in the near wellbore zone can meet the requirements of reservoir transformation and sand control. The application can meet the requirements of the low permeability reservoir natural gas hydrate exploitation water jet filling positive and reverse circulation well washing sand control integrated operation, improve the seepage condition, increase the gas production, and reduce the sand carrying speed, so as to achieve the dual purposes of increasing production and preventing the formation from sanding. The technical principle of the low permeability reservoir natural gas hydrate of the application is as follows: the water hammer effect of the downhole water jet tool is combined with the characteristics of the water jet filling positive and reverse circulation well washing process technology, one or more sand carrying channels are formed in the reservoir, the micro near wellbore zone is generated in the near wellbore zone, the space of the near wellbore zone is filled by using the end sanding technology, a three-dimensional prevention and control space is formed: the first three-dimensional layer is composed of a grid-shaped resin, a fiber and calcium powder; the second three-dimensional layer is composed of a sawtooth-shaped proppant; and the third three-dimensional layer is composed of a filter layer of coated sand. The sand control medium is filled in it and the end sanding is realized, a plurality of short wide high conductivity fracture zones are formed in the low permeability reservoir, and the sand control medium filter in the fracture plays the sand control effect of gravel packing.

[0065] The above examples are only used to illustrate but not to limit the technical solutions of the present application. Although the present application is described in detail above, those skilled in the art should understand that the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification and partial replacement without departing from the spirit and scope of the present application should be covered in the scope of claims of the present application.

Claims

1. A method for preventing and controlling the sand and mud of silty fine sand by adopting three-dimensional type, characterized in that, It comprises the following steps: step one, lowering a hydraulic sand jetting and carrying and filling pipe string into a wellbore: making a hydraulic jetting tool reach a reservoir position requiring sand carrying; step two, positively washing the wellbore, washing the wellbore with a well washing fluid before sand carrying, so as to make the water quality at the inlet and outlet the same; flushing out the sand and mud near the wellbore through a foam swallowing negative pressure mixed discharge mode, forming a space channel in the near wellbore zone, and the well washing displacement is between 0.5-1m 3 / min; step three, lower hydraulic sand jetting and carrying and preliminary filling: injecting a sand carrying fluid from a tubing, and the sand carrying displacement and wellhead pressure are determined by the number of nozzles of the hydraulic jetting tool, the aperture and the distance between the nozzle and the casing, during sand carrying, the sand carrying fluid returns through the oil casing annulus, until the lower casing and the formation sand carrying is completed, after the micro near wellbore zone is formed, closing the casing or screen plug, injecting the sand carrying fluid from the oil casing annulus, the injection displacement of the sand carrying fluid is executed according to the design, and the injection pressure range of the sand carrying fluid cannot exceed the pressure bearing limit of the casing and the wellhead device; at the same time, injecting the sand carrying fluid from the tubing to carry out preliminary filling construction; the injection displacement and the injection displacement of the oil casing annulus are in a certain proportion; the number of nozzles of the hydraulic jetting tool is 6-8, the aperture is 6-8mm, and the nozzles are symmetrically arranged; the sand carrying fluid mainly uses a salt water based clean sand carrying fluid; the displacement of the sand carrying fluid and the pressure range of the injected sand carrying fluid are designed and calculated according to the underwater burial depth of the natural gas hydrate reservoir to be filled in the sea area and the rock and soil mechanics parameters of the reservoir; step four, lower sand control medium main filling: using an end sand shedding filling technology to press open and extend the micro near wellbore zone, after forming a seam through injecting a preflush and making the near wellbore zone length meet the requirements, using a large displacement and low sand ratio to pump, so that the sand control medium is not deposited at the bottom of the near wellbore zone and is carried to the front end of the near wellbore zone after sand shedding deposition, forcing the extension of the near wellbore zone length direction to slow down or stop, and the near wellbore zone grows in the width direction, finally forming multiple short and wide high conductivity filling sand fracture zones in the low permeability reservoir, and the sand control medium filter body in the near wellbore zone plays the sand control effect of gravel packing; step five, sand control medium filling operation: after the lower filling is completed, carrying out reverse circulation well washing; after the well washing is completed, lifting the pipe string, and lifting the hydraulic jetting tool to the upper layer position requiring sand carrying; then filling the sand control medium from the oil casing annulus at a displacement smaller than that during the filling construction, and the filling surface is at least higher than the lower sand carrying position, and the filling surface of the horizontal well is between the two sand carrying layers; after the filling is completed, using the hydraulic sand jetting and carrying and filling pipe string to detect the filling surface, until the filling reaches the required position; the sand control medium is multi-layered, including a three-dimensional layer, a two-dimensional layer and a one-dimensional layer, and the one-dimensional layer of the sand control medium adopts a grid-shaped isolation layer composed of resin, fiber and calcium powder; The secondary stereoscopic layer uses jagged proppant to form a fixed layer; the tertiary stereoscopic layer uses a filter layer formed by coated sand; migration of fine particles is prevented, and a certain sand stabilizing and sand consolidating effect is achieved; step six, upper layer hydraulic sand blasting sand carrying and filling: after the sand face is measured and probed, an upper layer hydraulic sand blasting sand carrying and filling pipe column is lifted, the hydraulic jetting tool is lifted to a position where sand carrying is required, and upper layer hydraulic sand blasting sand carrying and filling is performed; step seven, sand washing operation: after the upper layer section is filled, reverse circulation well washing is performed; then sand washing is performed using the hydraulic sand blasting sand carrying and filling pipe column, or the pipe column is lifted, a sand washing drill is used, sand washing is performed while the filled surface is probed, until the sand washing reaches the lowermost layer of the filling modification, and finally the sand washing pipe column is lifted; the proportion of glass fiber and calcium powder is 1:1, the coated sand is prepared by adding plastic phenolic resin and reticular crosslinking agent to natural quartz sand.

2. The method for preventing and controlling the sand production and the mud of the silty fine sand by adopting the three-level stereoscopic type according to claim 1, characterized in that, The proppant is made of at least bauxite sintered with ceramic.

3. The method for preventing and controlling the sand production and the mud of the silty fine sand by adopting the three-level stereoscopic type according to claim 1, characterized in that, It is suitable for vertical wells and horizontal wells.

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