A kind of high temperature low-density water shutoff agent and preparation method thereof and onsite application methodTechnical field
The present invention relates to a kind of high temperature low-density water shutoff agent and preparation method thereof and onsite application method, belong to oil workJourney technical field.
Background technology
China's viscous crude resource reserve enriches, and about 250 × 108t, accounts for the 28% of total petroleum resources.Heavy crude producing and super-viscous oilThe best way of resource is oil recovery by heating, including steam soak and steam drive.But due to steam and viscous crude mobility difference and steamingThe factors such as the gravity segregation of vapour, in actual production, easily cause steam and fingering and channeling occur in high permeability formation, so as to reduceSteam swept volume, has influence on steam utilization, and it is poor to ultimately result in thermal recovery effect, reduces heavy crude heat extraction yield and increase energyConsumption.Channeling, water breakthrough, side bottom water coning etc. have turned into heavy oil development the most in stubborn problem, and thickened oil recovery urgentlyThe difficulty of solution.In the technical measures for solving these problems, water-plugging technique is that oil field improves waterflooding development effect, realizes oil reservoirThe effective means of stable yields.
Water blockoff is exactly to control water-oil factor or water production control, its essence is the flow behavior of water in the earth formation is changed, that is, is changedThe Percolation Law of water in the earth formation, prevent current by or change the direction of a stream of water.Water-blocking operation divides according to the difference of construction objectFor oil well (producing well) water blockoff and the class of well (injection well) profile control two.The blocking agent type that the country mainly uses at present includes：It is inorganicSalt blocking agent, Ploymer Gel Plugging Agent, resinae blocking agent, foam class profile-controlling and plugging agent etc..In the oil reservoir for high salinityIn water plugging profile control agent system, cross-linked polymeric species blocking agent due to its salt is quick, the flocculation of temperature-sensitive and multivalent ion etc. and make its applicationScope is restricted；Inorganic solid particles class envelope, which alters agent, has extraordinary heat resistance, but injection is poor, it is impossible to enters groundLayer depth portion, block apart from short, steam continues coning after streaming；After particle plugging action, still there is fine gap, steam can still alterStream；Caused closure is non-selective permanent closure, oil reservoir is injured big.Its shortcoming of foam type blocking agent be shut-off capacity compared withIt is low；Foam stability is poor, to obtain preferable plugging effect, it is necessary to which implantation dosage is big, to maintain foam stabilization and processing weekPhase；Domestic alternative foaming agent is less, and foaming agent cost is higher.Resin type blocking agent be using phenolic resin, epoxy resin,The materials such as Lauxite, by being formulated adjustment and setting, resin blocking agent is set to solidify within the default period of underground, formation hasHigh intensity and good heatproof, salt tolerant, the induration of ageing-resistant performance.The most of field application are thermosetting resins.Heat curing-typeChemical change, gradual hardened forming are produced after resin heating, then is heated and does not also soften, can not be dissolved.Thermosetting resin shortcomingIt is that mechanical performance is poor.For microbial polysaccharide polymer profile-controlling and plugging agent system, the formula used at present has microbial polysaccharideCurdlan is compounded with hydrogen bonding power accelerator or microbial polysaccharide curdlan and flocculation aid compound system.
The content of the invention
In order to solve the problems, such as water breakthrough, channeling present in heavy crude heat extraction production, carried by research and many experiments, the present inventionGoing out a kind of there are raw material sources extensively to send out, simple production process, easy for construction, safety and environmental protection, meet heavy oil thermal recovery fleeing proof water blockoffThe high temperature of construction requirement low-density water shutoff agent, the high temperature low-density water shutoff agent fluid system viscosity prepared using water shutoff agentIt is low, good fluidity, deep plugging adjustment can be carried out；Salt tolerant, heatproof, effective time length, voltage endurance capability are strong；With selective water plugging work(Can, the not stifled oil of water blockoff；More than 98% is reached to current permeable formation, channeling permeable formation sealing ratiod；Heavy oil production more than 50% is improved,Aquifer yield is reduced, improves recovery ratio, reduces development cost.
In being produced the present invention relates to a kind of high temperature oil gas well, thick oil thermal extraction, for blocking high-temperature oil reservoir channeling layer, water breakthroughLayer, water-yielding stratum；For adjusting the high-temperature steam swept volume of steam injection well；Adjust the intake profile of water injection well, oil-producing wellThe water-plugging technique that water blockoff and oily edge water, bottom water, current are altered.
A kind of high temperature low-density water shutoff agent and preparation method thereof is provided, to solve water present in heavy crude heat extraction productionThe problem of altering channeling.
The present invention is achieved by the following technical solution：A kind of high temperature low-density water shutoff agent, including following components：Agstone, 100 parts by weight；Cotton fiber, 5~15 parts by weight；Oxide, 10~50 parts by weight；Oil-soluble resin, 5~15 weightsMeasure part；High-temperature cross-linking agent, 1~3 parts by weight；The grain diameter of above each component is less than 47 microns, carbonic acid in the agstoneThe content of calcium is more than 95%wt, and the content of fiber is more than 85%wt in the cotton fiber, and the content of the oxide is more than 95%wt。
Further, the oil-soluble resin is natural resin and/or synthetic resin, and softening point is 100~300 CelsiusDegree, the dissolution rate in anhydrous kerosene are more than 90%wt；
Further, the oxide is calcium oxide, magnesia, barium monoxide, calcium hydroxide, magnesium hydroxide and barium hydroxideAt least one of；
A kind of preparation method present invention also offers high temperature with low-density water shutoff agent, comprises the following steps：
(1) appropriate agstone is taken, ultra-fine grinding to particle diameter is less than 47 microns；
(2) oxide is taken to be mixed with high-temperature cross-linking agent, ultra-fine grinding to particle diameter is less than 47 microns；
(3) cotton fiber is prepared：Cotton linter is taken, cotton linter is immersed in the acid solution of concentration 5~10%, it is warming up to 80~90 degrees Celsius, soak 6~8 hours, by acid-treated cotton linter after high speed centrifugation dries, with the alkali that concentration is 15~30%Solution is neutralized between pH value reaches 7~9, is dried；
(4) after dried cotton fiber is well mixed with oil-soluble resin by design flow, ultra-fine grinding to particle diameter is less than47 microns；
(5) material made from the step of above-mentioned (1)-(4) is well mixed with design quantity, you can obtain high temperature low-densityWater shutoff agent；
(6) finally weigh, pack.
Further, after high-temperature cross-linking agent and oil-soluble resin cross-linking reaction, liquid volume increase by more than 5%, and 120Occur fast chemical reaction more than degree Celsius, more than 360 degrees Celsius of the cross-linking agent heatproof of high-temperature cross-linking agent and oil-soluble resin.
Further, agstone：100 parts by weight, cotton fiber：13 parts by weight, oxide：40 parts by weight, oil-soluble treeFat：13 parts by weight, high-temperature cross-linking agent：2 parts by weight.
Further, the acid solution at least selects following one kind：Hydrochloric acid, phosphoric acid, hydrofluoric acid, acetic acid；Aqueous slkali is at leastSelection is following a kind of：Sodium hydroxide solution, sodium carbonate liquor, potassium hydroxide solution, magnesium hydroxide solution.
High temperature of the present invention with low-density water shutoff agent it is specific the advantages of it is as follows：
(1) high temperature prepared by the present invention is strong with low-density water shutoff agent heat-resisting ability, and water plugging effect is good, can effectively adjustSteam injection profile, expand high-temperature steam swept volume, improve heavy oil production and thick oil recovery ratio, reduce heavy oil development cost.
(2) for the high temperature prepared by the present invention with low-density water shutoff agent in sour environment, most of material is acidified de-plugging, rawInto soluble inorganic salt, preferable permeability is kept；
(3) present invention prepared by high temperature with low-density water shutoff agent in underground crude oil oil reservoir environment, high-temperature cross-linking agent etc.Coated by crude oil, lather collapse, form " Water-In-Oil " reversed-phase emulsion, blocked high temperature low-density water shutoff agent to be chemically crosslinkedThe approach of reaction, phase transformation will not be produced, not block oil flow channel, ground city is discharged during production of hydrocarbons, be advantageous to protection storageLayer, has selective water plugging function；
(4) high temperature prepared by the present invention adds part oil-soluble resin with low-density water shutoff agent, and oil-soluble resin can be withDissolved in crude oil, do not block oil reservoir；
(5) the high temperature low-density water shutoff agent prepared by the present invention is detained and undergone phase transition in water breakthrough passage, is turned by liquidBecome solid, permanent plugging action is played to water stream channel；
(6) the high temperature low-density water shutoff agent prepared by the present invention can give full play to low density advantage, make it in oil reservoirSeparation layer is formed with water layer interface, effectively blocks the quick coning of bottom water.
(7) high temperature prepared by the present invention is simple with low-density water shutoff agent preparation technology, and Costco Wholesale is cheap.
Construction technology of the high temperature of the present invention with low-density water shutoff agent at the scene is as follows：
(a) industrial water of design flow is injected in 20~40 side's agitator tanks；
(b) under 100~500 revs/min of stirring, 20%wt~35%wt high temperature low-density water blockoff is addedAgent, charging rate are 25~50kg/ minutes；
(c) after high temperature has been added with low-density water shutoff agent, the performance such as stirring 30 minutes, measurement apparent viscosity, density is continued；It is required that apparent viscosity 15mpa.s~80mpa.s；Density is less than 0.95g/cm3Adjusting performance；
(d) apparent viscosity increases high temperature low-density water shutoff agent dosage, wanted until reaching design if less than 15mpa.sAsk；Apparent viscosity increases industrial water consumption, until reaching design requirement if greater than 80mpa.s；Density is more than 0.95g/cm3,Increase mixing speed；
(e) and then according to tune deblocking technology, drilling leakage blockage construction is required.
In summary, after high temperature proposed by the present invention is stirred with low-density water shutoff agent in water, high temperature is formed with lowDensity water shutoff agent fluid system, the system have preferable suspension stability, and density is low, can be stood for a long time under room temperature environmentOccur without obvious layering within more than two weeks, can meet that site operation blocking agent injection link and later stage long-acting closure link are noted to blocking agentEnter the long-time stability requirement of fluid.
Fluid system of the high temperature proposed by the present invention after the preparation of low-density water shutoff agent, starts to be thickened more than 120 DEG C, withThe rising of temperature, thickening time shorten, are finally reached and are transformed into solid by liquid, play good plugging function.In high temperature barUnder part, undergoing phase transition the time can adjust between 10 hours to 72 hours, can meet that the long-time closure of deep-well and ultradeep well is madeIndustry construction requirement.Site operation safety, is widely used, economic benefit, social benefit are notable.
High temperature low-density water shutoff agent proposed by the present invention can be high by adjusting according to specific plugging construction job requirementsThe temperature effective content of low-density water shutoff agent component, change the performances such as plugging agent bodying temperature, thickening time, thickening intensity and refer toMark.
Described heavy crude heat extraction high temperature after the completion of preparation, is injected into viscous crude steam with low-density water shutoff agent fluid systemDrive thermal production well and carry out water plugging and profile controlling, heavy crude heat extraction high temperature proposed by the present invention with low-density water shutoff agent fluid system at the sceneUsing.
Described heavy crude heat extraction high temperature has preferable mobility, viscosity at normal temperatures with low-density water shutoff agent fluid system15mPa.s-80mPa.s, 0.85~0.95g/cm3 of density, it is easy to prepare, is easy to infusion, is easy to construct, is easy to deep plugging adjustment.
For described heavy crude heat extraction high temperature with low-density water shutoff agent fluid system because viscosity is relatively low, density is low, can quickly noteEnter into thick oil steam drive thermal production well, because the viscosity differences of viscous crude and stratum water are big, blocking agent fluid selectivity enters oilWater breakthrough passage in well, under the promotion of rear injection fluid, water shutoff agent fluid enters the deep of water breakthrough passage, small in formation temperatureIn the environment of 100 DEG C, the long-term retention property of blocking agent fluid is stable.After injecting steam, formation temperature rise, with oil well productionProcess continues several cycles, and edge-bottom water starts to coning around producing well, promotes blocking agent fluid to be flowed to the higher environment of temperature.Blocking agent crosslinks reaction, viscosity rapid increase, forms induration, block the generation of water breakthrough under the exciting of high temperature, so as to riseTo the effect blocked for a long time.
Site operation can select industry water, stratum sewage, high-salinity brine etc. with liquid water.Stratum sewage is nextFrom the oil-polluted water during oil development.The total salinity of high-salinity brine is less than 200,000 mg/L, wherein calcium and magnesium ore depositChange degree is less than 10,000 mg/L.Adjust stifled slurry performance unaffected with low-density high temperature using the heavy crude heat extraction of above liquid dosage, adjust stifledPerformance indications can meet construction operation requirement.Therefore, described heavy crude heat extraction high temperature low-density water shutoff agent fluid system pairRequirement with liquid stream body is relatively low, and the profile control and water plugging construction operation and drilling well that can be widely applied to the region such as ocean, desert oil well block upLeakage.Described heavy crude heat extraction high temperature is low with low-density water shutoff agent fluid system density, can be widely applied to low pressure reservoir, bottom waterThe plug water constructions such as oil reservoir.Described heavy crude heat extraction high temperature low-density water shutoff agent fluid system does not have any poison secondary to human bodyEffect, so as to ensure that the requirement of the health and safety of construction worker.
Embodiment
Below by non-limiting embodiment, the present invention is further illustrated：
Test data when being each component different content in high temperature low-density water shutoff agent of the present invention below.
(1) embodiment 1
1) preparing high-temp low-density water shutoff agent is matched somebody with somebody according to following different component content：Agstone, 100 parts by weight；Cotton is fine(the two 1 with oil-soluble resin for dimension：1)：20 parts by weight；(the two 40 with high-temperature cross-linking agent for calcium oxide：2)：42 parts by weight；Will be above-mentionedMaterial mixing, stir, obtain high temperature low-density water shutoff agent.
2) high temperature is prepared with low-density water shutoff agent water blockoff system：In the water of metering, be separately added into 10%, 13%, 15%,18%th, 20%, 25%, 30%, 35%, 40% high temperature low-density water shutoff agent.
3) high temperature low-density water shutoff agent is added in water, 100-500 revs/min of rotating speed, is persistently stirred 2 hours, to each groupDivide dispersed, measurement performance.
4) gained high temperature is measured into apparent viscosity, density with low-density water blockoff system at room temperature, is shown in Table 1；
The different dosage viscosity/density values at room temperature of table 1
Middle gained high temperature is stood, after constant temperature 48 hours under confined conditions with low-density water blockoff system at 80 DEG C.Its is coldBut to room temperature, stir 2 hours respectively, measure apparent viscosity/density, be shown in Table 2；
Different dosage viscosity/density values under the conditions of 2 80 DEG C of table
The dosage of high temperature low-density water shutoff agent is can be seen that from table 1, the data of table 2 to be controlled below 30%, make itPreferable mobility is kept, reaches the purpose of deep plugging adjustment.
5) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 150 DEG C, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 3；
Different dosage viscosity/density values under the conditions of 3 150 DEG C of table
As can be seen from Table 3, the dosage of high temperature low-density water shutoff agent, formation temperature is under the conditions of 150 DEG C, it shouldControl makes it keep preferable mobility below 25%, reaches the purpose of deep plugging adjustment.
6) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 250 degree, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 4；
Different dosage viscosity/density values under the conditions of 4 250 DEG C of table
As can be seen from Table 4, the dosage of high temperature low-density water shutoff agent, should under the conditions of formation temperature is 250 DEG CThe control makes it keep preferable mobility below 20%, reaches the purpose of deep plugging adjustment.
7) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 360 degree, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 5；
Different dosage viscosity/density values under the conditions of 5 360 DEG C of table
As can be seen from Table 5, the dosage of high temperature low-density water shutoff agent, should under the conditions of formation temperature is 360 DEG CThe control makes it keep preferable mobility below 15%, reaches the purpose of deep plugging adjustment.
8) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 400 DEG C, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 6；
Different dosage viscosity/density values under the conditions of 6 400 DEG C of table
As can be seen from Table 6, the dosage of high temperature low-density water shutoff agent, should under the conditions of formation temperature is 400 DEG CThe control makes it keep preferable mobility below 13%, reaches the purpose of deep plugging adjustment.
9) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 360 DEG C, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 7；
Solidify situation under the conditions of 7 360 DEG C of table
As can be seen from Table 7, the dosage of high temperature low-density water shutoff agent reaches 20%, is 360 DEG C in formation temperatureUnder the conditions of, there is very strong solidification intensity, fully meet high temperature water blockoff envelope and alter requirement.
(2) embodiment 2
1) high temperature low-density water shutoff agent is produced according to following different component content：Agstone, 100 parts by weight；Cotton is fine(the two 1 with oil-soluble resin for dimension：1), 10 parts by weight；(the two 40 with high-temperature cross-linking agent for calcium oxide：2), 21 parts by weight；Will be above-mentionedMaterial mixing, stir, obtain high temperature low-density water shutoff agent.
2) high temperature is prepared with low-density water shutoff agent system：In the water of metering, be separately added into 10%, 13%, 15%,18%th, 20%, 25%, 30%, 35%, 40% high temperature low-density water shutoff agent.
3) high temperature low-density water shutoff agent is added in water, 100-500 revs/min of rotating speed, is persistently stirred 2 hours, to each groupDivide dispersed, measurement performance.
4) gained high temperature is measured into apparent viscosity/density with low-density water blockoff system at room temperature, is shown in Table 8；
The different dosage viscosity/density values at room temperature of table 8
4) gained high temperature is being stood, after constant temperature 48 hours under confined conditions with low-density water blockoff system at 80 DEG C, respectivelyStirring 2 hours, is cooled to room temperature, observes respectively, measures the high temperature solidification situation of low-density water blockoff system, is shown in Table 9；
Different dosage viscosity/density values under the conditions of 9 80 DEG C of table
The dosage of high temperature low-density water shutoff agent is can be seen that from table 8, the data of table 9 to be controlled below 35%, make itPreferable mobility is kept, reaches the purpose of deep plugging adjustment.
5) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 150 DEG C, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 10；
Different dosage viscosity/density values under the conditions of 10 150 DEG C of table
As can be seen from Table 10, the dosage of high temperature low-density water shutoff agent, formation temperature, should under the conditions of 150 DEG CThe control makes it keep preferable mobility below 35%, reaches the purpose of deep plugging adjustment.
6) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 250 degree, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 11；
Different dosage viscosity/density values under the conditions of 11 250 DEG C of table
The dosage of high temperature low-density water shutoff agent is can be seen that from the data of table 11, under the conditions of formation temperature is 250 DEG C,It should control below 25%, it is kept preferable mobility, reach the purpose of deep plugging adjustment.
7) gained high temperature is being stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 360 degree, by itRoom temperature is cooled to, observes respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 12；
Different dosage viscosity/density values under the conditions of 12 360 DEG C of table
The dosage of high temperature low-density water shutoff agent is can be seen that from the data of table 12, under the conditions of formation temperature is 360 DEG C,It should control below 20%, it is kept preferable mobility, reach the purpose of deep plugging adjustment.
8) gained high temperature is stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 400 DEG C, its is coldBut to room temperature, observe respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 13；
Different dosage viscosity/density values under the conditions of 13 400 DEG C of table
The dosage of high temperature low-density water shutoff agent is can be seen that from the data of table 13, under the conditions of formation temperature is 400 DEG C,It should control below 15%, it is kept preferable mobility, reach the purpose of deep plugging adjustment.
9) gained high temperature is stood, after constant temperature 24 hours under confined conditions with low-density water blockoff system at 360 DEG C, its is coldBut to room temperature, observe respectively, measure the high temperature solidification situation of low-density water blockoff system, be shown in Table 14；
Solidify situation under the conditions of 14 360 DEG C of table
The dosage that high temperature low-density water shutoff agent is can be seen that from the data of table 14 reaches 30%, is 360 DEG C in formation temperatureUnder the conditions of, there is very strong solidification intensity, fully meet high temperature water blockoff envelope and alter requirement.
Analyzed from embodiment 1 and the correction data of embodiment 2, embodiment 1, dosage is few, and water plugging effect is good；
Embodiment 2, dosage is big, and cost is high.
(3) field test situation is as follows：
(1) the water blockoff experiment of side water water logging dead well
C puts down 17 wells：Development layer position shop one, net horizontal section perforating length 150m, the horizontal well are in side waterside edge.
Well steam injection in July, 2005, for opening well and making production after 153 days, water content rises to 100% by 56%, is forced to stop production.Stop production day before yesterday liquid 83.1t/d, day oil 0t/d, and aqueous 100%.Through analyzing the well influenceed by the block south water coning, it is horizontalSection multi-stage outlet.
On December 1st, 2015,17 wells are put down to C and carry out suppressing side water plug water construction, inject water shutoff agent system 280m3, row altogether10-20m3/h is measured, injection pressure is increased to 6.5MPa from 4MPa.
On December 20th, 2015, after steam injection is gone into operation, day at initial stage 10.2 tons of oil-producing, current 5.0 tons or so of day oil-producing, water contentLess than 70%, continuous production nearly two year, water layer are effectively blocked.
(2) oil reservoir bottom water water logging oilwell water shutoff is tested
Qinghe M-X16 wells are gone into operation for 2009,1700 tons of oil-producing are tired out in December, 2010, because oil reservoir bottom water coning, aqueousAmount is quickly increased to 100%, is forced long-term shutdowns by the 22% of producing initial stage.In July, 2016 uses high temperature low-density water blockoffSystem implementation bottom water plugging is constructed, and the well injects high temperature low-density water blockoff system 150m3 altogether, after operation, produces liquid peak period daily36.2t/d, day oil 18.4t/d, aqueous 49.2%.To in June, 2017, well day oil-producing 7.6t/d, aqueous 78%.
(3) oil well channeling passage plugging is tested
41 meters of B509-X100 wells and B509-X51 well target spots distance, occur channeling during heat extraction by steam injection, 2016 3The moon in September, 2016, is influenceed, B509-X51 wells stop production 200 days, influence 450 tons of crude output by B509-X100 channelings.2017January in year is constructed using high temperature with low-density water blockoff system implementation bottom water plugging, and the well injects high temperature low-density water blockoff system altogether80m3, B509-X100 well steam injection pressures grow steadily in steam injection process, 16.3 MPas are risen to by 15 MPas, by channeling wellB509-X51 wells are normally produced, and do not influence yield, end in August, 2017, and still normal production, channeling passage is effectively blocked.
Therefore, high temperature low-density water shutoff agent system can be extensively using the plug water construction under following complex situations：(1) side waterIt is quick-fried to flood water exit interval water blockoff；(2) the quick-fried waterflooding of bottom water section water blockoff layer by layer；(3) macropore water layer section water blockoff；(4) heavy crude heat extraction is taken turns moreHandle up well water exit interval water blockoff；(5) steam drives the closure of section has channeling layer；(6) high, middle infiltration water-yielding stratum water blockoff；(7) casing damage leaksLose the closure of layer position；(7) sleeve pipe has channeling passage plugging etc..
The embodiment of the present invention is the foregoing is only, is not intended to limit the invention, for this areaFor technical staff, the present invention can have various modifications and variations.That is made within the spirit and principles of the invention is anyModification, equivalent substitution, improvement etc., should be included in the scope of the protection.