CN102587876B - Method for improving recovery ratio of oil field by use of blasting type pre-crosslinking gel particles - Google Patents
Method for improving recovery ratio of oil field by use of blasting type pre-crosslinking gel particles Download PDFInfo
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Abstract
The invention provides a method for improving the recovery ratio of an oil field by use of blasting type pre-crosslinking gel particles, and particularly relates to a method for improving the recovery ratio of an old oil field with high water cut. The method adopts a kind of pre-crosslinking gel particles; the pre-crosslinking gel particles absorb water to expand and form a solution after staying for a certain time at the formation temperature and pH condition; and the method for improving the recovery ratio of an old oil field with high water cut comprises the following steps of: mixing the pre-crosslinking gel particles with water so that the pre-crosslinking gel particles absorb water to expand; injecting the pre-crosslinking gel particles underground so that the pre-crosslinking gel particles firstly block big pore channels and ultrahigh-permeability layers near the well in an oil pool, wherein after the pre-crosslinking gel particles experience the action of the oil pool temperature for a certain time, the gel particles automatically blast to form a polymer viscose solution which enters the deep of the oil pool to realize control on oil-water fluidity; and performing oil extraction. The method provided by the invention is suitable for improving the petroleum recovery ratio of the oil pool at the stage of high water cut.
Description
Technical field
The present invention relates to improve the particularly method of high moisture old filed recovery ratio of oil field in oil exploitation, particularly about utilizing a kind of method with profile control and the bifunctional explosion type of polymer flooding pre-crosslinked gel particle raising oil recovery rate.
Background technology
Along with continually developing of oil field, Reservoir Heterogeneity is more and more serious, and injected water washes away in a large number, and oil reservoir clay and cement expand, corrosion, and fine migration shakes out and increases the weight of etc., causes geology heterogeneous body situation further to worsen.Often show on stream following problem, as outstanding in: horizontal contradiction, plane injected water is along the high permeability zone formation water channel of advancing by leaps and bounds; Interlayer contradiction is outstanding, produces that to inhale section inhomogeneous, has the individual layer phenomenon of advancing by leaps and bounds on longitudinally; Underground viscosity of crude is high, and viscosity ratio of oil and water is large, and Character of Viscous Finger is serious etc.
At present, east China oil field has all entered high water-cut stage mostly, and the recovery ratio that how to improve high water-cut stage is oil circle question of common concern.In recent years, though the tertiary oil recovery measures such as polymer flooding obtain, more there is good effect, also had the problems such as displacement of reservoir oil cost is high, field conduct difficulty is large; For serious heterogeneity, there is the oil reservoir of high permeable strip or " macropore ", still exist part well to alter poly-serious problem, affected the poly-effect of note, and due to the limitation of polymer itself, make its effective viscosity loss in the stratum of high temperature, high salinity very large, often do not reach expection object.Ternary composite driving technology is also widely used gradually at old fileds such as grand celebrations, ternary composite driving utilizes the effect of decreasing by surfactant interfacial tension that capillary force is significantly reduced, profit reaches mixed phase and flows, thereby the residual oil in startup low-permeability oil deposit, but there is Similar Problems in ternary composite driving technology and polymer flooding: shear shinning, affected by reservoir condition, and polymer flooding and ternary composite driving all can pollute oil-containing low infiltration layer, make follow-up water drive can not reach best effect.
Conventional profile control agent has two classes, the one, gel-like, the 2nd, particulate species at present.
Gel-like comprises body gel, weak gel and colloidal dispersed gel.The function of body gel is mainly the high strength water breakthrough passage of shutoff near wellbore zone, because form is semi-solid state, therefore cannot go deep into stratum, is applicable to crack, near wellbore zone and high permeability zone shutoff; Weak gel be take intramolecular crosslinking as main, and intermolecular cross-linking is auxiliary, forms the weak three-dimensional net structure of crosslinking degree, the feature with the dehydration of body gel, has certain integrality, can flow, but the distance of going deep into stratum is limited, can not reach the effect of adjusting mobility ratio; Colloidal dispersed gel is by the gel rubber system of the non-three-dimensional net structure of the polymer of low concentration and crosslinking agent formation, because the concentration of polymer and crosslinking agent is low, the intermolecular chance bumping is few, the tridimensional network of unlikely formation intermolecular cross-linking, the main colloidal particle consisting of the polymer coils of intramolecular crosslinking is dispersed in aqueous medium, forms the thermodynamic stable system with gel attribute and colloidal nature, and this system does not have globality, there is no shape, can flow.The feature of colloidal dispersed gel is: cost is low, and gelation time is long, is applicable to deep profile controlling and the displacement of reservoir oil, but is not suitable for crack and macropore, and the applicable reservoir temperature limit is 94 ℃, clear water preparation, bad adaptability.
Particulate species gel adopts the method for precrosslink to have good heatproof, salt tolerant, shear-stable ability, comprises polymer microballoon, volume expansion grain, flexible particle and microcapsules etc.The expansion rate of polymer microballoon is subject to the impact of formation water salinity, and the average grain diameter of the microballoon after expansion is tens nanometers, shut-off capacity a little less than; Volume expansion grain can carry out particle diameter adjustment according to different reservoir conditions, and expansion multiple is affected by formation water salinity, makes intensity influenced less, because volume expansion grain particle diameter is larger, so deep flooding fluid turn to limited in one's ability.Flexible particle can be migrated in duct, distortion is passed through, produce temporarily stifled dynamic resistance, there is pulsation phenomenon, can realize deep flooding fluid turns to, the proportion of flexible particle can be adjusted according to the proportion of oilfield injection water, and particle diameter can regulate according to the size in oil field stratum " macropore " and crack.Flexible particle can form dynamic plugging at oil deposit deep part, but for nearly well because current high strength is washed away crack and the superelevation permeable formation causing, must use high strength blocking agent to carry out anti-channeling operation, otherwise the effect of the raising recovery ratio of compliance steer agent can not be brought into play to greatest extent.
In sum, up to the present, in the water plugging and profiling technology of oil exploitation, profile control, the adjustment of profit mobility ratio can not synchronously be carried out, and there is not yet prior art report and address this problem.
Summary of the invention
One object of the present invention is the blank and the defect that according to above-mentioned prior art field, exist, a kind of particularly method of high moisture old filed recovery ratio of oil field that improves is provided, wherein utilize a kind of have profile control and the bifunctional explosion type of polymer flooding pre-crosslinked gel particle, improve the recovery ratio in the oil field of high water-cut stage.
For reaching above-mentioned purpose; the invention provides a kind of method that improves high moisture old filed recovery ratio; in the method, use a kind of pre-crosslinked gel particle; described pre-crosslinked gel particle can imbibition also can form solution after a period of time under formation temperature and pH condition, and the method for the high moisture old filed recovery ratio of described raising comprises:
Described pre-crosslinked gel particle is mixed with water, make pre-crosslinked gel particle imbibition, and under Injection Well, make the pre-crosslinked gel particle first macropore of shutoff near wellbore zone and superelevation permeable formation in oil reservoir;
Until pre-crosslinked gel particle, under reservoir temperature effect after a period of time, gel particle automatic-explosion forms polymeric adhesive solution, enters oil deposit deep part and realizes profit mobility control; Recover the oil.
According to specific embodiment of the invention scheme, in the present invention, pre-crosslinked gel particle used is to be ground after drying and formed by compound monomer and astable crosslinking agent body gel crosslinked through initator initiated polymerization and that obtain, wherein:
Described compound monomer comprises acrylamide (AM) and acrylic acid (AA);
Described astable crosslinking agent is selected from: polyethyleneglycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, glycol diacrylate, three methanol-based propane triacrylate, ethyoxyl tri methylol triacrylate, ethyoxyl tetramethylol methane tetraacrylate with and derivative in one or more.
Pre-crosslinked gel particle used in the present invention, compound monomer and astable crosslinking agent through initator initiated polymerization crosslinked and body gel grind after drying and form, after this pre-crosslinked gel particle is mixed with water, water suction volume expansion, the pre-crosslinked gel particle expanding injects after oil reservoir in oil reservoir near wellbore zone first macropore plugging and superelevation permeable formation, makes injected water enter low-permeability layer district and starts residual oil.The pre-crosslinked gel particle expanding under reservoir temperature, salinity and the effect of pH value after a period of time, automatic hydrolysis explosion is polymeric adhesive solution, this generated in-situ polymer solution can continue to move into oil deposit deep part, realize profit mobility control, combine the dual-use function of profile control and polymer flooding, be suitable for High Water Cut Reservoir and improve oil recovery.Technology of the present invention, owing to being that under oil reservoir environment and after the fixed time, gel particle is just understood explosion and become polymer solution, has therefore been avoided the problem of the shear shinning in injection process of polymer flooding problem in prior art.
According to specific embodiment of the invention scheme, in pre-crosslinked gel particle of the present invention, in described compound monomer, acrylamide and acrylic acid mass ratio are 12～24:1.5～6; Mass ratio between described compound monomer and astable crosslinking agent is 1:1/20～1/8000.In the present invention, except indicating especially, described ratio and content are mass ratio and content.
According to specific embodiment of the invention scheme, in pre-crosslinked gel particle of the present invention, in described compound monomer, also can further optionally comprise other monomer; Described other monomer is selected from: one or more in 2-acrylamide-2-methylpro panesulfonic acid sodium salt, methacrylic acid, maleic acid, 2-acrylic acid, sulfopropyl acrylic acid, dimethylaminoethylacmethyl methyl chloride and dimethyl diallyl ammonium chloride, are preferably 2-acrylamide-2-methylpro panesulfonic acid sodium salt.More specifically, the quality of acrylamide in described compound monomer of take is 12～24 parts, and the quality of described other monomer is less than or equal to 6 parts for being greater than 0, is preferably more than to equal 0.1 and be less than or equal to 6 parts, more preferably greater than equaling 1, is less than or equal to 6 parts.
According to specific embodiment of the invention scheme, described compound monomer by the acrylamide of 12～24 weight portions, the 2-acrylamide-2-methylpro panesulfonic acid sodium salt of the acrylic acid of 1.5～6 weight portions and 0.1～6 weight portion (preferably 1～6 weight portion) form.
According to specific embodiment of the invention scheme, in pre-crosslinked gel particle of the present invention, described initator is selected from: one or more in potassium peroxydisulfate, ammonium persulfate, are preferably potassium peroxydisulfate.
According to specific embodiment of the invention scheme, the particle diameter of pre-crosslinked gel particle of the present invention is 100～120 orders.
According to specific embodiment of the invention scheme, described pre-crosslinked gel particle is prepared in accordance with the following methods, and the method comprising the steps of:
Compound monomer and astable crosslinking agent are added to the water to abundant dissolving; In this process, preferably controlling monomer concentration scope is 10% to 50%;
In above-mentioned solution, add initator;
Make above-mentioned solution polymerization reaction take place, obtain body gel, through purifying, grinding, obtain described pre-crosslinked gel particle afterwards.
Because pre-crosslinked gel particle feature of the present invention is to adopt astable crosslinking agent to make polymer monomer carry out precrosslink, the concentration of adjusting astable crosslinking agent can make the explosion under specific reservoir temperature of precrosslink microparticle become the time of polymer solution to be controlled.Therefore for different reservoir medias, can adopt the astable crosslinking agent of variable concentrations, the hydrolysis time of precrosslink microparticle and temperature can be hydrolyzed in such oil reservoir in good time.
As previously mentioned, in pre-crosslinked gel particle of the present invention, described compound monomer is mainly to comprise acrylamide, acrylic acid, also optionally contains other monomers.Described compound monomer is to take acrylamide as main, but, owing to adopting astable crosslinking agent to be cross-linked, astable crosslinking agent (being under reservoir media) in the situation that calcium carbonate exists can degrade or decompose, therefore in order to keep, gel is stable within a certain period of time does not degrade, keeps integrality, adds a certain proportion of acrylic acid (or further adding other monomer) and acrylamide generation copolyreaction.In the present invention, the amount of acrylamide in compound monomer of take is 12～24 weight portions, and described acrylic acid consumption can be 1.5～6 weight portions.Described other monomer can be selected from: 2-acrylamide-2-methylpro panesulfonic acid sodium salt (AMPS), methacrylic acid (methacrylic acid), maleic acid (maleic acid), 2-acrylic acid (2-Propenoic acid), sulfopropyl acrylic acid (sulfopropyl acrylic acid), dimethylaminoethylacmethyl methyl chloride salt (dimethylaminoethylacrylate methyl chloride quaternary salt), one or more in dimethyl diallyl ammonium chloride (diallyldimethyl ammonium chloride), be preferably 2-acrylamide-2-methylpro panesulfonic acid sodium salt, these other monomers can be to be greater than 0 weight portion, for example, can be 1～6 weight portion (amount of acrylamide in compound monomer of take is 12～24 weight portions).In a preferred embodiment of the present invention, compound monomer is by 12～24 parts of acrylamides, 1.5～6 parts, acrylic acid, 0～6 part preferably 1～6 part of 2-acrylamide-2-methylpro panesulfonic acid sodium salt (AMPS).
In the present invention, spendable astable crosslinking agent can be selected from: polyethyleneglycol diacrylate (polyethylene glycol diacrylate), polyethylene glycol dimethacrylate (polyethylene glycol dimethacrylat), polypropylene glycol diacrylate (polypropylene glycol diacrylate), glycol diacrylate (ethylene glycol diacrylate), three methanol-based propane triacrylate (trimethylopropane trimethacrylate), ethyoxyl tri methylol triacrylate (ethoxylated trimethylol triacrylate), one or more in ethyoxyl tetramethylol methane tetraacrylate (ethoxylated pentaerythritol tetracrylate) and their derivative, the mass ratio of described astable crosslinking agent and compound monomer is 1/20～1/8000:1, the profile control that in this proportion, polymerization obtains is larger by the temperature range for hydrolysis of gel particle, conventionally at 40 ℃ to 100 ℃, required hydrolysis time for different oil reservoirs and setting, the screening test that those skilled in the art carry out limited number of time within the scope of the invention can realize object of the present invention.In a preferred embodiment of the present invention, described astable crosslinking agent is polyethylene glycol dimethacrylate (polyethylene glycol dimethacrylat), and the ratio of itself and compound monomer is 1/200～1/8000:1.
According to specific embodiment of the invention scheme, the present invention's initator used can be selected from: potassium peroxydisulfate (K
2s
2o
8), one or more in ammonium persulfate, be used for to monomer A M, AA, AMPS initiated polymerization, the consumption of these initators is that the routine in affiliated field is selected consumption.In a preferred embodiment of the invention, described initator is potassium peroxydisulfate, the amount ratio 1/800～1/2500:1 of this initator and compound monomer.
According to specific embodiment of the invention scheme, in the process of the described pre-crosslinked gel particle of preparation, can also be to optionally having added one or more in some auxiliary agents such as sodium carbonate, urea, ammoniacal liquor, NaOH, tetramethylethylenediamine in the aqueous solution of compound monomer and astable crosslinking agent.Wherein, take redox reaction that potassium peroxydisulfate and/or ammonium persulfate be initator while producing free radical solution need to keep neutrality or alkalescent, therefore can add sodium carbonate and/or NaOH to be used for neutralization solution to neutrality or alkalescent; Thereby urea add can with monomer form polymer gel that strong hydrogen bond makes to form have less degree of porosity and and narrow distribution; Tetramethylethylenediamine is added into inspire polymerisation, and adding of ammoniacal liquor can be accelerated polymerization rate, by the efficiency of initiation that adds to improve redox reaction of these auxiliary agents; To improve the performances such as intensity, stability of the gel prepare gained, realize better the function that is regularly hydrolyzed, has concurrently profile control and polymer flooding.The addition of described sodium carbonate, urea, ammoniacal liquor, NaOH and tetramethylethylenediamine and the mass ratio of described compound monomer are respectively: sodium carbonate 1/10～1/20:1, urea 1/20～1/400:1, ammoniacal liquor 1/100～1/200:1, NaOH 1/1000～1/2000:1, tetramethylethylenediamine 1/100～1/800:1.
According to specific embodiment of the invention scheme, described pre-crosslinked gel particle in the preparation, the solution that has added compound monomer, astable crosslinking agent (or further having added initator, described auxiliary agent) is nitrogen injection deoxygenation (deoxygenation is 5～50 minutes conventionally) as required, in order to the carrying out of polymerisation.
According to specific embodiment of the invention scheme, described in added the solution polymerization reaction take place of compound monomer, astable crosslinking agent, initator, described auxiliary agent to refer to the temperature of solution to be controlled within the scope of 4 ℃ to 40 ℃, to be preferably controlled at 9 ℃ to 12 ℃.Best polymerization time 12 hours to 24 hours, at nitrogen with polymerization in vacuumizing environment, is beneficial to polymerisation and moves to forward balance.Described purification process refers to and body gel is soaked in water with imbibition dry to remove the process of the impurity in gel, preferred synthetic 2～3 expansions of body gel repetition, dry process are to purge the impurity in gel, expansion carries out in distilled water that (temperature can be controlled at 40～80 ℃, for example 45 ℃, 60 ℃, 80 ℃), then body gel is preferably dry in the temperature below 60 ℃, and the dry body gel after purification grinds to form granule.The desiccant gel particle that obtains 100～120 orders (125～150 μ m) after sieve series, is pre-crosslinked gel particle of the present invention.
According to specific embodiment of the invention scheme, utilizing described pre-crosslinked gel particle to carry out oil reservoir exploitation when improving high moisture old filed recovery ratio, on ground, pre-crosslinked gel particle to be mixed with to the mixed liquor that contains pre-crosslinked gel particle with injected water (preparation of described pre-crosslinked gel particle can be used well injected water, according to site operation equipment situation, can adopt return water or clear water, injecting on-the-spot preparation, compound concentration can be according to the make out the scale of down-hole macropore and high permeability zone, preferably, the mass percentage content of gel particle is generally 0.1%～0.6%), after gel gel particle is expanded, (generally can place about 4～6 hours, gel imbibition is reached after balance), use injection pump under the mixed liquor Injection Well that contains gel particle, to need the oil reservoir of profile control, observe injection pressure, adjust injection rate, measure intake profile.More specifically, in the profile control transfer drive of utilizing described gel particle to carry out high water cut oil field, when improving tar productivity, the mode under Injection Well and according to carrying out with reference to conventional method, is specifically related to following formula and step.
1. theoretical calculating
1) place the degree of depth
Wherein:
In formula:
R
a-treatment radius, m
R
e-water filling the radius of influence, m
R
w-wellbore radius, m
F
g-the ratio of water injection capacity before and after processing
Q
1, q
2-daily water-injection rate before and after processing, m
3/ d
△ p
po, △ p
posdifference between reservoir pre ssure and injection pressure before and after-processing, MPa
F
rr-residual resistance factor
2) consumption:
In formula:
V-injection rate, m
3/ d
H
i-i layer thickness, m
φ
ithe degree of porosity of-i layer
R
ithe treatment radius of-i layer, m
N-number of plies
2. construction sequence
(1) survey construction well intake profile, falloff curve;
(2) check well head, dispensing well is tested envelope;
(3) bring up to construction equipment, and commissioning test;
(4) ground pressure testing, stratum injection test;
(5) gel-filled particle;
(6) the normal water filling of becoming a full member;
(7) remove construction equipment, recover well site environment;
(8) within after water filling 10-15 days, survey intake profile, falloff curve.
(9) survey intake profile, falloff curve after reaching blasting time.
According to specific embodiment of the invention scheme, in the present invention, pre-crosslinked gel particle enters after high watercut layer, first the macropore of shutoff near wellbore zone and superelevation permeable formation, force injected water preferentially to enter less permeable layer residual oil district and start residual oil, the grade pre-crosslinked gel particle of shutoff near wellbore zone under the effect of formation temperature pressure after the control time of setting explosion form polymeric adhesive solution (or micron order and submicron order granule), enter oil deposit deep part, play the effect that deep flooding fluid turns to.In the present invention, be by controlling the mass ratio of described pre-crosslinked gel particle astable crosslinking agent and compound monomer in preparation process, controlling pre-crosslinked gel particle and form the blasting time of solution under formation temperature and pH condition.
In sum, in method of the present invention, adopt the pre-crosslinked gel particle of the described double effects that can realize profile control and polymer flooding to carry out oil reservoir exploitation, can control by adjusting astable crosslinker concentration the hydrolysis blasting time of pre-crosslinked gel particle.Raising along with astable glue crosslinking agent concentration, gel particle explosion temperature and explosion cycle all improve thereupon, because the geological condition of different oil reservoirs is widely different, therefore for temperature and required shutoff time of engineering design of different oil reservoirs, adjust the concentration of astable glue crosslinking agent, reach the requirement of working design.In the practice of construction of prior art, conventionally need to, before injection profile agent, to strong washing layer, carry out anti-channeling operation, to improve the efficiency of follow-up transfer drive operation.And the application of the inventive method, pre-crosslinked gel particle wherein combines the function of anti-channeling and polymer flooding, can simplify complicated profile control and polymer flooding operation, cost-saving.
Accompanying drawing explanation
Fig. 1 is the action principle schematic diagram of pre-crosslinked gel particle of the present invention in oil reservoir.
Fig. 2 is the swelling of pre-crosslinked gel microparticle of the present invention and the mechanism schematic diagram of decomposition.
Fig. 3 is the three-dimensional oil reservoir physical model schematic diagram of oil production method of the present invention.
Fig. 4 shows that the injection pressure in the oil production method of the present invention's one specific embodiment changes.
Fig. 5 shows that in the oil recovery process of the present invention's one specific embodiment, recovery ratio changes.
The specific embodiment
In order more clearly to understand the present invention, below enumerate specific embodiment and further describe the present invention.Embodiment does not only limit the present invention in any way for explanation.
Embodiment 1
Formula
24 grams of acrylamides
6 grams, acrylic acid
0.15 gram of polyethylene glycol dimethacrylate (polyethylene glycol 200 dimethacrylate)
NaCO
31.5 gram
Tetramethylethylenediamine (TMEDA) 80mg
Urea 750mg
Ammoniacal liquor 150mg
NaOH 15mg
Potassium peroxydisulfate (K
2s
2o
8) 15mg
Aqueous solvent 110g
Add up to: 142.66g
The mass percent concentration of monomer (AA+AM) is 30g/142.66=21%.The ratio of astable crosslinking agent and compound monomer is 1:200.
Polymerization technology
Acrylamide, acrylic acid and polyethylene glycol dimethacrylate are added in 110 grams of water and fully dissolved.After dissolving, add NaCO
3neutralization solution.Then add TMEDA, urea, ammoniacal liquor and NaOH.To nitrogen injection in solution, purify 30 minutes, then in solution, add K
2s
2o
8, the solution obtaining re-injects nitrogen purge and after 10 minutes, puts into 10 ℃ of insulating boxs.First be evacuated to-10KPa30 minute, remove airborne oxygen, then keep vacuum state to inject pure nitrogen gas simultaneously, remove the oxygen in solution, start polymerization process, after 12 hours, complete plastic, obtains body gel.
After plastic, body gel is put into distilled water, in the stirring at low speed process of 200 revs/min, soak 5 hours, remove unreacted monomer and additive, then in 60 ℃ of baking ovens, be dried and grind to form the particle of specifying particle diameter, grain diameter is 100～120 orders.
The action principle schematic diagram of pre-crosslinked gel particle of the present invention in oil reservoir is shown in Figure 1.As can be seen from the figure, in profile control operation, first pre-crosslinked gel particle injects crack, down-hole plugging near wellbore zone and superelevation infiltration area, K2 represents the crack of long-term injecting water formation and the permeability of superelevation infiltration area, K3 representative be not injected into ripples and the permeability of petroleum province, K2>>K3.Through bulky grain automatic-explosion after a period of time, be deformed into polymer solution, continue to move at inhomogeneous formation, reach the object of improving oil deposit deep part profit mobility ratio.
Fig. 2 is the swelling of pre-crosslinked gel microparticle of the present invention and the mechanism schematic diagram of decomposition.Because pre-crosslinked gel microparticle of the present invention is in building-up process, the crosslinking method of gel adopts non-thermally-stabilised crosslinked, and gel particle expands in formation water solution, under certain formation temperature and pH condition, astable crosslinked fracture, particle deformation becomes polymer solution, improves sweep efficiency.
Hydrolysis experiment
Testing procedure: the pre-crosslinked gel particle that profile control prepared by embodiment 1 and polymer flooding are used is dissolved in NaCl solution, and solvent is 1% NaCl solution, and gel solution initial concentration is 0.5wt%, and it is 80 ℃, 60 ℃, 45 ℃ that temperature is made as respectively;
Test result: when the temperature of mixed solution is 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needs 12 days, and the polymer solution viscosity obtaining after hydrolysis is 170cp; When the temperature of mixed solution is 60 ℃, pre-crosslinked gel particle complete hydrolysis needs 80 days, and the polymer solution viscosity obtaining after hydrolysis is 290cp; When the temperature of mixed solution is 45 ℃, after half a year, pre-crosslinked gel particle does not yet have complete hydrolysis; Wherein, when the temperature of mixed solution is 80 ℃, 60 ℃, the difference of resulting polymer solution viscosity is because the main chain of polymer molecule unstable fracture at high temperature caused.
Embodiment 2
Formula
13.5 grams of acrylamides
1.5 grams, acrylic acid
Polyethylene glycol dimethacrylate (polyethylene glycol200dimethacrylate): 0.0375 gram
Tetramethylethylenediamine (TMEDA) 80mg
NaCO
31.5 gram
Urea 750mg
Ammoniacal liquor 150mg
NaOH 15mg
K
2S
2O
8 15mg
Aqueous solvent 110g
Add up to: 127.4675g
The mass percent concentration of monomer (AA+AM) is 15g/127.4675=11.76%
The ratio of astable crosslinking agent and compound monomer is 1:400
Polymerization technology
Acrylamide, acrylic acid and polyethylene glycol dimethacrylate are added to the water to abundant dissolving.After dissolving, add NaCO
3neutralization solution.Then add TMEDA, urea, ammoniacal liquor and NaOH.To nitrogen injection in solution, purify 30 minutes, then in solution, add K2S2O8, the solution obtaining re-injects nitrogen purge and after 10 minutes, puts into 10 ℃ of insulating boxs.First be evacuated to-10KPa30 minute, remove airborne oxygen, then keep vacuum state to inject pure nitrogen gas simultaneously, remove the oxygen in solution, start polymerization process, after 13 hours, complete plastic, obtains body gel.
After plastic, body gel is put into distilled water, in the stirring at low speed process of 200 revs/min, soak 5 hours, remove unreacted monomer and additive, then dry in 60 ℃ of baking ovens, dried gel is soaked 5 hours again in water, then dry to purify in 60 ℃ of baking ovens, and grinding to form the particle of specifying particle diameter, grain diameter is 100～120 orders.
Hydrolysis experiment
Hydrolysising experiment step is with embodiment 1.
In the time of 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needs 8 days, and the polymer solution viscosity obtaining after hydrolysis is 135cp; In the time of 60 ℃, approximately need 60 days complete hydrolysis, the polymer solution viscosity of gained is 210cp.For 45 ℃, after half a year, also there is no complete hydrolysis.
Embodiment 3
Formula
18 grams of acrylamides
6 grams, acrylic acid
6 grams of AMPS
Polyethylene glycol dimethacrylate (polyethylene glycol200dimethacrylate): 0.03 gram
NaCO
31.5 gram
Tetramethylethylenediamine (TMEDA) 80mg
Urea 750mg
Ammoniacal liquor 150mg
NaOH 15mg
K
2S
2O
8 15mg
Aqueous solvent 110g
Add up to: 142.54g
The mass percent concentration of monomer (AA+AM+AMPS) is 30/136.54=22.0%
The ratio of astable crosslinking agent and compound monomer is 1:1000
Polymerization technology
With embodiment 1.
Hydrolysis experiment
Hydrolysising experiment step is with embodiment 1.
In the time of 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needs 6 days, and the polymer solution viscosity obtaining after hydrolysis is 100cp; In the time of 60 ℃, approximately need 35 days complete hydrolysis, the polymer solution viscosity of gained is 160cp.For 45 ℃, hydrolysis afterwards in 150 days, the viscosity of the polymer solution of gained is 190cp.
Embodiment 4
Formula
10.5 grams of acrylamides
3 grams, acrylic acid
1.5 grams of AMPS
Polyethylene glycol dimethacrylate (polyethylene glycol200dimethacrylate): 0.003 gram
NaCO
30.75 gram
Tetramethylethylenediamine (TMEDA) 40mg
Urea 37.5mg
Ammoniacal liquor 75mg
NaOH 7.5mg
K
2S
2O
8 7.5mg
Aqueous solvent 55g
Add up to: 70.9205g
The mass percent concentration of monomer (AA+AM+AMPs) is 15/70.9205=21.15%
The ratio of astable crosslinking agent and compound monomer is 1:5000
Polymerization technology
With embodiment 1.
Hydrolysis experiment
In the time of 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needs 4 days, and the viscosity of the polymer solution obtaining after hydrolysis is 70cp; In the time of 60 ℃, approximately need 20 days complete hydrolysis, the polymer solution viscosity of gained is 110cp.For 45 ℃, hydrolysis afterwards in 90 days, the viscosity of the polymer solution of gained is 130cp.
Embodiment 5
Formula
10.5 grams of acrylamides
3 grams, acrylic acid
1.5 grams of AMPS
Polyethylene glycol dimethacrylate (polyethylene glycol200dimethacrylate): 0.00195 gram
NaCO
30.75 gram
Tetramethylethylenediamine (TMEDA) 40mg
Urea 37.5mg
Ammoniacal liquor 75mg
NaOH 7.5mg
K
2S
2O
8 7.5mg
Aqueous solvent 23g
Add up to: about 38.92g
The mass percent concentration of monomer (AA+AM+AMPS) is about 15/38.92=38.5%
The ratio of astable crosslinking agent and compound monomer is 1:7692
Polymerization technology
With embodiment 1.
Hydrolysis experiment
In the time of 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needs 1 day, and the viscosity of the polymer solution obtaining after hydrolysis is 35cp; In the time of 60 ℃, approximately need 10 days complete hydrolysis, the polymer solution viscosity of gained is 60cp.For 45 ℃, hydrolysis afterwards in 45 days, the viscosity of the polymer solution of gained is 80cp.
As can be seen from the above embodiments, in the number range giving in the present invention, can prepare the pre-crosslinked gel particle of plurality of specifications, thereby those skilled in the art can adjust parameter according to the concrete condition of oil reservoir, prepare applicable pre-crosslinked gel particle for improving oil recovery.
Embodiment 6 injects the physical simulation experiment that gel particle improves oil recovery factor
1, model
The geologic information providing according to certain oil field is set up the three-dimensional non-homogeneous model meeting with actual conditions, model volume 500mm * 500mm * 150mm, in model, arrange 30 differential pressure pickups and 31 saturation ratio measuring probes, 30 differential pressure pick-ups, divide three layers of distribution of upper, middle and lower, every layer of 10 differential pressure pick-up that distributes, three layers of differential pressure pick-up is respectively 2.5,7.5,12.5 apart from the distance of model bottom; The copper pipe that a longitudinal failure model is arranged respectively at two diagonal angles of model is as Injection Well and producing well, the long 10cm of well, and on the cross section that perforation density is every 1cm, perforation is 4, angle 90 degree between two holes, bag gauze.See Fig. 3.
2, displacement of reservoir oil step:
In model, inject formation water and make it saturated, the water phase permeability of measurement model and voids volume in this process;
To model, inject crude oil and make it saturated, recording saturated former oil mass, saturated former oil mass is 7520mL altogether;
Carry out water drive until moisture content reaches 95%, the salinity of the injected water that water drive is used is 5000ppm, and injection rate is 0.5mL/min;
After water drive completes, with the speed of 0.5mL/min, inject the gel particle (gel particle joins injected water with 0.5% mass concentration in advance and soaks imbibition in approximately 5 hours) of the embodiment 1 of 0.1PV;
After injecting gel particle, then continue water drive 1PV, then closing well, heats to 80 ℃, keeps 3 months, then drives a well, and water drive to moisture content is 95%.
The basic physical-property parameter of model is in Table 1, and dispersion gel particle injection parameter is in Table 2.
Table 1 three-dimensional physical model physical-property parameter
The injection parameter of table 2II type dispersion gel particle
| Type | Form | Inject volume | Injection rate |
| II type dispersion gel granular system | Body gel before explosion | 0.1PV | 0.5mL/min |
3, interpretation of result
Pressure stability when water drive is for the first time in 10KPa left and right, and while injecting gel particle, pressure rises to rapidly 1.4MPa, and while again carrying out water drive, pressure drop is to about 1MPa; In continuation water drive process after closing well keeps 80 ℃ to drive a well again, injection pressure drops to 70KPa left and right and keeps stable, and pressure change procedure is shown in Fig. 4.After injecting gel particle, oil recovery factor has improved 3%, under reservoir temperature, keeps after 3 months, recovers water drive, improves recovery ratio 5%, always improves recovery ratio 8%.Recovery ratio change procedure is shown in Fig. 5.
Claims (7)
1. a method that improves high moisture old filed recovery ratio; in the method, use a kind of pre-crosslinked gel particle; described pre-crosslinked gel particle can imbibition also can form solution after a period of time under formation temperature and pH condition, and the method for the high moisture old filed recovery ratio of described raising comprises:
By particle diameter, be that 100～120 object pre-crosslinked gel particles mix with water, make pre-crosslinked gel particle imbibition, and under Injection Well, make the pre-crosslinked gel particle first macropore of shutoff near wellbore zone and superelevation permeable formation in oil reservoir;
Until pre-crosslinked gel particle, under reservoir temperature effect after a period of time, gel particle automatic-explosion forms polymeric adhesive solution, enters oil deposit deep part and realizes profit mobility control; Recover the oil;
Wherein, described pre-crosslinked gel particle is to be ground after drying and formed by compound monomer and astable crosslinking agent body gel crosslinked through initator initiated polymerization and that obtain, wherein: described compound monomer comprises acrylamide and acrylic acid; Described astable crosslinking agent is selected from: polyethyleneglycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, glycol diacrylate, three methanol-based propane triacrylate, ethyoxyl tri methylol triacrylate, ethyoxyl tetramethylol methane tetraacrylate with and derivative in one or more; Wherein, in described compound monomer, acrylamide and acrylic acid mass ratio are 12～24:1.5～6; Mass ratio between described compound monomer and astable crosslinking agent is 1:1/20～1/8000;
And described pre-crosslinked gel particle prepares in accordance with the following methods:
Compound monomer and astable crosslinking agent are added to the water to dissolving;
Then in solution, add initator;
Make above-mentioned solution polymerization reaction take place, obtain body gel, through purifying, grinding, obtain described pre-crosslinked gel particle afterwards.
2. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, also comprises other monomer in described compound monomer; Described other monomer is selected from: one or more in 2-acrylamide-2-methylpro panesulfonic acid sodium salt, methacrylic acid, maleic acid, 2-acrylic acid, sulfopropyl acrylic acid, dimethylaminoethylacmethyl methyl chloride and dimethyl diallyl ammonium chloride; The quality of acrylamide in described compound monomer of take is 12～24 parts, and the quality of described other monomer is less than or equal to 6 weight portions for being greater than 0 weight portion.
3. the method for the high moisture old filed recovery ratio of raising according to claim 2, wherein, the quality of acrylamide in described compound monomer of take is 12～24 parts, the quality of described other monomer is less than or equal to 6 parts for being greater than 1.
4. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, described initator is selected from: one or more in potassium peroxydisulfate, ammonium persulfate.
5. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, described pre-crosslinked gel particle is in preparation process, also to having added one or more in sodium carbonate, urea, ammoniacal liquor, NaOH, tetramethylethylenediamine in the aqueous solution of compound monomer and astable crosslinking agent;
The addition of described sodium carbonate, urea, ammoniacal liquor, NaOH, tetramethylethylenediamine and the mass ratio of described compound monomer are respectively: sodium carbonate 1/10～1/20:1, urea 1/20～1/400:1, ammoniacal liquor 1/100～1/200:1, NaOH 1/1000～1/2000:1, tetramethylethylenediamine 1/100～1/800:1;
Described polymerisation is to add under the environment that fills nitrogen and react 12～24 hours at 4～40 ℃, vacuum;
Described purification is that described body gel is processed 1～3 time through expanding, being dried.
6. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, on ground, pre-crosslinked gel particle to be mixed with to the mixed liquor that contains pre-crosslinked gel particle with injected water, after gel particle is expanded, use injection pump under the mixed liquor Injection Well that contains gel particle, to need the oil reservoir of profile control, observe injection pressure, adjust injection rate, measure intake profile.
7. method according to claim 6, wherein, controls the mass ratio of described pre-crosslinked gel particle astable crosslinking agent and compound monomer in preparation process, controls pre-crosslinked gel particle and under formation temperature and pH condition, forms the blasting time of solution.
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| CN109751023A (en) * | 2018-08-16 | 2019-05-14 | 郭志东 | Drive, tune, the stifled integration that wide scope permanently reduces blowhole improve recovery ratio method |
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| CN103113702B (en) * | 2013-01-23 | 2016-01-20 | 中国石油化工股份有限公司 | A kind of blocking up calls cross-linking polymer system thermo-stabilizer and its preparation method and application |
| FR3061909B1 (en) * | 2017-01-19 | 2019-05-24 | S.P.C.M. Sa | PROCESS FOR ASSISTED OIL RECOVERY BY INJECTION OF A POLYMERIC AQUEOUS COMPOSITION CONTAINING MICROGELS |
| CN109233769A (en) * | 2018-09-07 | 2019-01-18 | 中国石油化工股份有限公司 | A kind of pre-crosslinked gel particle and preparation method thereof for low-temperature reservoir profile control |
| CN112112599B (en) * | 2020-10-09 | 2022-05-06 | 西南石油大学 | Low-viscosity plugging system for fractured reservoir and preparation method thereof |
| CN115059440B (en) * | 2022-07-08 | 2024-03-26 | 中海石油(中国)有限公司 | Large-scale multidimensional profile adjusting method for oilfield water injection well |
| CN115853482B (en) * | 2023-02-27 | 2023-05-02 | 中国石油大学(华东) | Method and system for improving recovery ratio of capsule polymer flooding |
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