A kind of viscosity-depression agent of polyacrylamide polymer
Technical field
The invention belongs to oilfield prospecting developing field, be specifically related to a kind of viscosity-depression agent of polyacrylamide polymer.
Background technology
World's conventional gas stock number is 436 tcms, and shale gas, then up to 456,000,000,000,000 sides (according to EIA), is one of important development direction of following clean energy.China's shale gas reserves are very abundant, and be mainly distributed in the areas such as the Sichuan Basin, Ordos Basin, Bohai gulf basin, Song-liao basin, Tarim Basin and the Junggar Basin, domestic relevant unit assessment technology mining resources amount is more than 10 tcms.And according to EIA assessment, in each main shale gas resource distribution state of the world, China occupies the first in the world with the mining resources amount of 36.1 tcms.Current domestic shale gas exploitation, extensive " drag reduction water+glue " the segmentation Sand Fracturing Technology of normal employing horizontal well, and polyacrylamide polymer and derivative can be attached in shaft column and stratum in fracturing process, blocking pit shaft or stratum, affect construction progress and per-well production.
And, for polyacrylamide polymer and derivative fracturing liquid, in subsequent treatment process, usually adopt ammonium persulphate to carry out viscosity reduction polymkeric substance as broken colloid system, ammonium persulphate breaks the weak point that colloid system exists following several respects: it is long that (1) ammonium persulphate breaks the glue time.When 70 DEG C, the transformation period of ammonium persulphate is 8h; When 50 DEG C, the transformation period of ammonium persulphate is 152h, decomposes too slow; Lower than at 50 DEG C of temperature, ammonium persulphate breaks glue ability and declines rapidly, can not as the gel breaker of aqueous fracturing fluid.(2) broken glue is not thorough.In pressing crack construction process, under the prerequisite of sand is taken in guarantee smoothly, optimize breaker concentration, thoroughly break glue fast, but fracturing liquid is when pumping and crack closure, due to fluid loss, polymer concentration can increase 5-7 doubly, concentrating to the larger difficulty of broken adhesive tape of polymkeric substance.
Chinese patent CN101104844B discloses a kind of sulfate-reducing bacteria and the application thereof with polyacrylamide viscosity reduction function, sulphate reducing bacteria is adopted to carry out viscosity reduction to polyacrylamide, but sulphate reducing bacteria is a kind of anerobe, and needing suitable growth and breeding environment, key is that the sulphate reducing bacteria of high density is limited to high concentration polymer viscosity reduction.Chinese patent CN103043830A discloses a kind of method of polyacrylamide with chlorine dioxide by acid activator viscosity reduction, environment pH is 4-12, then utilize hydrochloric acid or phosphoric acid to cause chlorine dioxide decomposition and produce free radical, produce and produce superoxide viscosity reduction polyacrylamide, but to the strong acid such as hydrochloric acid be added in reactivation process, corrosion in various degree can be caused to flow string; And, carry out viscosity reduction by dioxide peroxide release free radical, long with the temperature oil relevant viscosity reduction time.
In addition, " in oilfield sewage the research of polyacrylamide viscosity-reducing mechanism ", petrochemical complex is applied; " the chemical viscosity reduction research of polyacrylamide ", Daqing Petroleum Institute's journal; " the chemical viscosity reduction research of polyacrylamide "; oil-gas field environment protection; introduce the different methods of polyacrylamide viscosity reduction respectively; what current oil field was commonly used is oxidizing reduction; utilize in document and add reducing substances and strong oxidizer generation redox reaction; release produces free radical viscosity reduction polyacrylamide, but these methods are all relevant with temperature, and viscosity reduction speed is slower.
Summary of the invention
Technical problem to be solved by this invention is the deficiency that exists for above-mentioned prior art and provides a kind of viscosity-depression agent of polyacrylamide polymer, has that working concentration is low, after fast, the viscosity reduction of viscosity reduction speed, liquid viscosity is tending towards the feature of water, the easily row of returning under normal temperature.
The technical scheme that the problem that the present invention is the above-mentioned proposition of solution adopts is:
A viscosity-depression agent for polyacrylamide polymer, is become to be grouped into by following by massfraction: salinity conditioning agent 2.2-30%, viscosity modifier 0.1-0.5%, tensio-active agent 0.1-0.5%, inhibiter 0.5-2%, clean-out system 0.1-1%, surplus is water, and each component sum is 100%.
By such scheme, described polyacrylamide polymer is polyacrylamide polymers and derivative thereof.
By such scheme, described salinity conditioning agent is selected from one or more mixtures in any proportion in sodium-chlor, Repone K, magnesium chloride, calcium chloride etc.Preferably, described salinity conditioning agent is become to be grouped into by following by massfraction: 5-50%KCl, 5-50%NaCl, 0.5-25%MgCl
2and 0.5-25%CaCl
2.More preferably, described salinity conditioning agent is become to be grouped into by following by massfraction: 30-50%KCl, 30-50%NaCl, 3-20%MgCl
2and 3-20%CaCl
2.
By such scheme, described viscosity modifier is selected from citric acid.
By such scheme, described tensio-active agent is fluorine carbon tensio-active agent.
By such scheme, described inhibiter is organic phosphate inhibiter.
By such scheme, described clean-out system is iron(ic) chloride, iron protochloride.
The preparation method of the viscosity-depression agent of above-mentioned polyacrylamide polymer, comprises the steps:
(1) take following composition by massfraction: salinity conditioning agent 1.2-30%, viscosity modifier 0.1-0.5%, tensio-active agent 0.1-0.5%, inhibiter 0.5-2%, clean-out system 0.1-1%, surplus is water, and each component sum is 100%;
(2) by step (1) described proportioning, Xiang Shuizhong adds salinity conditioning agent, stir and fully dissolve, then add after tensio-active agent and viscosity modifier stir, add clean-out system and inhibiter again, be stirred to and dissolve completely, namely obtain the viscosity-depression agent of polyacrylamide polymer.
The application method of the viscosity-depression agent of above-mentioned polyacrylamide polymer is: add this viscosity-depression agent to containing in the solution of polyacrylamide polymer, viscosity-depression agent add-on is that this contains the 0.1wt%-0.5wt% of the solution quality of polyacrylamide polymer, react 30-120s under normal temperature, this polymer solution viscosity reduces to 1.1-1.5mPas.
In application method, the described solution containing polyacrylamide polymers is generally fracturing liquid, and polyacrylamide polymers mass concentration is usually less than 1%; And the amount of viscosity-depression agent can take the circumstances into consideration adjustment according to concentration, cost and time.
Principle of the present invention is: the major ingredient of drag reduction water and glue is polyacrylamide and derivative thereof, and such hydrophilic is extremely strong, soluble in water, hydrogen bond can be formed with water, after aquation, molecular chain generation electrical function, molecular chain is stretched greatly, thus obtain larger ydrodynamics volume, play the effect of thickening, but, this molecular chain is flexible chain, in the salts solution that salinity conditioning agent is formed, molecular chain can occur curling, thus reduces viscosity; And the electric repulsion between carboxylic acid ion in viscosity modifier, polymer coils is rolled up, and apparent size reduces, and unfolds degree and reduce the viscosity that effectively can reduce polymers soln in water, increases mobility; And clean-out system makes polyacrylamide polymer show obvious viscosity loss in aqueous, viscosity reduction is very serious, can lose most viscosity, lose use properties completely within very short time.In addition, the present invention also added etching reagent and tensio-active agent, can play the effect of the row of returning and protection shaft column fast.
Compared with prior art, the invention has the beneficial effects as follows:
The first, viscosity-depression agent provided by the present invention can realize quick viscosity reduction polyacrylamide polymer, and carry out viscosity reduction to high density polypropylene amine amide polymer fracturing liquid, the liquid viscosity after viscosity reduction is tending towards water, is easy to the row of returning.
The second, working conditions of the present invention is extensive, and dosage is few, and working concentration is low, and dosing is simple, and the normal temperature lower short period of time can realize quick viscosity reduction, without particular requirement, can not damage in construction process to devices such as tubing strings.
3rd, viscosity-depression agent of the present invention with electric charge and molecular structure by self, just can be made polymer molecule flocculation sediment, make polyacrylamide polymer show obvious viscosity loss in aqueous, not need to add any initiator; And, direct application ferric ion and other metal ion synergistic effects are on the impact of polyacrylamide polymer molecular structure, polyacrylamide polymer is made to roll up viscosity reduction in aqueous, feature is that speed of response is fast, the viscosity reduction time is short, in addition ferric ion stable performance, easy to operate in construction at the scene.
4th, component contained by viscosity-depression agent of the present invention is conventional medicament, and cheap easy purchase, compound method is simple, is convenient to execute-in-place.
For there is the blocking pipe that a large amount of concentrated polyacrylamide polymer causes, the technical problem affecting construction progress in pit shaft, quick viscosity-depression agent provided by the present invention can realize quick viscosity reduction and the row of returning, and is with a wide range of applications in shale gas high-efficiency mining process.
Accompanying drawing explanation
The apparent viscosity of the 0.4wt% fracturing liquid 25 DEG C that Fig. 1 adopts for application testing.
Fig. 2 after viscosity-depression agent process described in embodiment 1, the apparent viscosity of the 0.4wt% fracturing liquid that application testing adopts 25 DEG C.
Fig. 3 after viscosity-depression agent process described in embodiment 2, the apparent viscosity of the 0.4wt% fracturing liquid that application testing adopts 25 DEG C.
Fig. 4 after viscosity-depression agent process described in embodiment 3, the apparent viscosity of the 0.4wt% fracturing liquid that application testing adopts 25 DEG C.
Embodiment
In order to understand the present invention better, illustrate content of the present invention further below in conjunction with embodiment, but the present invention is not only confined to the following examples.
The performance test of viscosity-depression agent of the present invention, all be applied to fracturing liquid (this of the fracturing fluid concrete formula be 0.4% viscosifying agent (polyacrylamide polymer)+0.15% synergistic agent+0.3% auxiliary rheological agents+0.02% defoamer+0.05% viscosity modifier, surplus be water) to test, this fracturing liquid pH value partial neutral.Certainly, the present invention is applicable to the fracturing liquid that viscosifying agent is polyacrylamide and derivative thereof, and each concentration of component of fracturing liquid can be different from formula provided by the invention.
Embodiment 1
A viscosity-depression agent for polyacrylamide polymer, is become to be grouped into by following by massfraction: salinity conditioning agent 2.2%, viscosity modifier citric acid 0.5%, fluorocarbon surfactant 0.1%, organic phosphate inhibiter KD-GH022%, clean-out system FeCl
31%, surplus is water, and each component sum is 100%.Wherein, described salinity conditioning agent is become to be grouped into by following by massfraction: 45.5%KCl, 45.5%NaCl, 4.5%MgCl
2and 4.5%CaCl
2.
The preparation method of the viscosity-depression agent of above-mentioned polyacrylamide polymer, comprise the steps: by said ratio, measuring water pours in stirred vessel, the whirlpool regulating agitator speed to liquid to be formed can see propeller-blade axis top, Xiang Shuizhong adds salinity conditioning agent, fully stirs until dissolve completely, then adds fluorocarbon surfactant and citric acid, stir 4-5min, finally add FeCl
3and inhibiter, fully stir until dissolve completely, namely obtain the viscosity-depression agent of polyacrylamide polymer.
The application method of the viscosity-depression agent of above-mentioned polyacrylamide polymer is: the viscosity-depression agent adding embodiment 1 in the fracturing liquid of the polyacrylamide polymer of concentration 0.4wt%, viscosity-depression agent add-on is the 0.4wt% of this fracturing liquid quality, abundant stirring, reacting 53s under normal temperature, to record fracturing liquid viscosity be 1.09mPas.As depicted in figs. 1 and 2, when adding viscosity-depression agent, this of the fracturing fluid apparent viscosity is 86mPas to test-results, and after adding example 1 viscosity-depression agent 53s, apparent viscosity will be 1.09mPas.
Embodiment 2
A viscosity-depression agent for polyacrylamide polymer, is become to be grouped into by following by massfraction: salinity conditioning agent 30%, viscosity modifier citric acid 0.1%, fluorocarbon surfactant 0.5%, organic phosphate inhibiter KD-GH020.5%, clean-out system FeCl
30.1%, surplus is water, and each component sum is 100%.Wherein, described salinity conditioning agent is become to be grouped into by following by massfraction: 33.3%KCl, 33.3%NaCl, 16.7%MgCl
2and 16.7%CaCl
2.
The preparation method of the viscosity-depression agent of above-mentioned polyacrylamide polymer, comprise the steps: by said ratio, measuring water pours in stirred vessel, the whirlpool regulating agitator speed to liquid to be formed can see propeller-blade axis top, Xiang Shuizhong adds salinity conditioning agent, fully stirs until dissolve completely, then adds fluorocarbon surfactant and citric acid, stir 4-5min, finally add FeCl
3and inhibiter, fully stir until dissolve completely, namely obtain the viscosity-depression agent of polyacrylamide polymer.
The application method of the viscosity-depression agent of above-mentioned polyacrylamide polymer is: the viscosity-depression agent adding embodiment 2 in the fracturing liquid of the polyacrylamide polymer of concentration 0.4wt%, viscosity-depression agent add-on is 0.4% of this fracturing liquid quality, abundant stirring, reacting 117s under normal temperature, to record fracturing liquid viscosity be 1.21mPas.As shown in figures 1 and 3, when adding viscosity-depression agent, this of the fracturing fluid apparent viscosity is 86mPas to test-results, and after adding example 2 viscosity-depression agent 117s, apparent viscosity will be 1.21mPas.
Embodiment 3
A viscosity-depression agent for polyacrylamide polymer, is become to be grouped into by following by massfraction: salinity conditioning agent 16%, viscosity modifier citric acid 0.5%, fluorocarbon surfactant 0.2%, organic phosphate inhibiter KD-GH021.5%, clean-out system FeCl
30.4%, surplus is water, and each component sum is 100%.Wherein, described salinity conditioning agent is become to be grouped into by following by massfraction: 31.3%KCl, 31.3%NaCl, 18.8%MgCl
2and 18.8%CaCl
2.
The preparation method of the viscosity-depression agent of above-mentioned polyacrylamide polymer, comprise the steps: by said ratio, measuring water pours in stirred vessel, the whirlpool regulating agitator speed to liquid to be formed can see propeller-blade axis top, Xiang Shuizhong adds salinity conditioning agent, fully stirs until dissolve completely, then adds fluorocarbon surfactant and citric acid, stir 4-5min, finally add FeCl
3and inhibiter, fully stir until dissolve completely, namely obtain the viscosity-depression agent of polyacrylamide polymer.
The application method of the viscosity-depression agent of above-mentioned polyacrylamide polymer is: the viscosity-depression agent adding embodiment 3 in the fracturing liquid of the polyacrylamide polymer of concentration 0.4wt%, viscosity-depression agent add-on is the 0.4wt% of this fracturing liquid quality, abundant stirring, reacting 83s under normal temperature, to record fracturing liquid viscosity be 1.13mPas.As shown in Figure 1 and Figure 4, when adding viscosity-depression agent, this of the fracturing fluid apparent viscosity is 86mPas to test-results, and after adding example 3 viscosity-depression agent 86s, apparent viscosity will be 1.13mPas.
The above is only the preferred embodiment of the present invention, it should be pointed out that for the person of ordinary skill of the art, and without departing from the concept of the premise of the invention, can also make some improvement and conversion, these all belong to protection scope of the present invention.