CN102587876A - 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 in the oil exploitation method of the particularly high moisture old filed recovery ratio in oil field, 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, the oil reservoir non-homogeneity is more and more serious, and inject water and wash away in a large number, oil reservoir clay and cement expansion, corrosion, fine migration shakes out and increases the weight of etc., causes geology heterogeneous body situation further to worsen.Often show following problem on stream, outstanding like: horizontal contradiction, water is injected along the high permeability zone formation water channel of advancing by leaps and bounds in the plane; Interlayer contradiction is outstanding, produces that to inhale section inhomogeneous, has the individual layer phenomenon of advancing by leaps and bounds on vertically; Underground viscosity of crude is high, and viscosity ratio of oil and water is big, and the viscous fingering phenomenon is serious etc.
At present, the east China oil field has all got into high water-cut stage mostly, and the recovery ratio that how to improve high water-cut stage is an oil circle question of common concern.In recent years, good effect has more been arranged, also had problems such as displacement of reservoir oil cost is high, the field conduct difficulty is big though tertiary oil recovery measures such as polymer flooding obtain; Oil reservoir for serious heterogeneity, existence high infiltration band or " macropore "; Still exist partial wells to scurry and gather serious problem; Influenced to annotate and gathered effect; And, often do not reach intended purposes because the limitation of polymer itself makes its effective viscosity loss in the stratum of high temperature, high salinity very big.The ternary composite driving technology also is widely used at old fileds such as grand celebrations gradually; The effect that ternary composite driving utilizes surfactant to reduce interfacial tension reduces capillary force significantly; Profit reaches mixed phase and flows, thereby starts the residual oil in the low-permeability oil deposit, but there is similar problem in the ternary composite driving technology with polymer flooding: shear shinning, influenced by reservoir condition; And polymer flooding and ternary composite driving all can pollute the oil-containing low infiltration layer, make follow-up water drive can not reach best effect.
Profile control agent commonly used at present has two types, and the one, gel-like, the 2nd, particulate species.
Gel-like comprises body gel, weak gel and colloidal dispersed gel.The function of body gel mainly is the high strength water breakthrough passage of shutoff near wellbore zone, because form is a semi-solid state, therefore can't go deep into the stratum, is applicable to crack, near wellbore zone and high permeability zone shutoff; Weak gel is main with intramolecular crosslinking, and intermolecular cross-linking is auxilliary, forms the more weak three-dimensional net structure of crosslinking degree; Characteristics with dehydration of body gel have certain integrality, can flow; But the distance of going deep into the stratum is limited, can not reach the effect of adjustment mobility ratio; Colloidal dispersed gel is that because the concentration of polymer and crosslinking agent is low, the intermolecular chance that bumps is few through the gel rubber system of the non-three-dimensional net structure of the polymer of low concentration and crosslinking agent formation; The tridimensional network of unlikely formation intermolecular cross-linking; The main colloidal particle that is made up of the polymer molecule ball of string of intramolecular crosslinking is dispersed in the aqueous medium, forms the thermodynamic stable system with gel attribute and colloidal nature, and this system does not have globality; Do not have shape, can flow.The characteristics of colloidal dispersed gel are: cost is low, and gelation time is long, is fit to the deep profile controlling and the displacement of reservoir oil, but is not suitable for crack and macropore, and the suitable reservoir temperature limit is 94 ℃, clear water preparation, bad adaptability.
The 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 receives the influence of formation water salinity, and the average grain diameter of the microballoon after the expansion is tens nanometers, shut-off capacity a little less than; Volume expansion grain can carry out the particle diameter adjustment according to different reservoir conditions, and expansion multiple is influenced by formation water salinity, makes intensity influenced less, because the volume expansion grain particle diameter is bigger, so the deep fluid diversion is limited in one's ability.Flexible particle can be migrated in the duct; Distortion is passed through; Produce temporarily stifled dynamic resistance, pulsation phenomenon is arranged, can realize the deep fluid diversion; The proportion of flexible particle can be adjusted according to the proportion of oilfield injection water, and particle diameter can be regulated 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 since current high strength wash away crack and the superelevation permeable formation that causes; Must use the stifled agent of high strength to carry out the 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 be carried out synchronously, do not see the prior art report as yet and address this problem.
Summary of the invention
One object of the present invention is blank and the defective according to the existence of above-mentioned prior art field; A kind of method that improves the particularly high moisture old filed recovery ratio in oil field 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; Use a kind of pre-crosslinked gel particle in this method; Described pre-crosslinked gel particle can imbibition also can form solution after following a period of time of condition at formation temperature and pH, and the method for the high moisture old filed recovery ratio of said raising comprises:
Said pre-crosslinked gel particle is mixed with water, make the pre-crosslinked gel particle imbibition, and inject the down-hole, make the pre-crosslinked gel particle at first macropore of shutoff near wellbore zone and superelevation permeable formation in oil reservoir;
Treat pre-crosslinked gel particle at reservoir temperature after following a period of time of effect, the automatic explosion of gel particle forms polymeric adhesive solution, gets into oil deposit deep part and realizes the profit mobility control; Recover the oil.
According to specific embodiments of the present invention, among the present invention used pre-crosslinked gel particle be by compound monomer and astable crosslinking agent through the initator initiated polymerization crosslinked and the body gel after drying, grind and form, wherein:
Said compound monomer comprises acrylamide (AM) and acrylic acid (AA);
Said astable crosslinking agent is selected from: polyethyleneglycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, glycol diacrylate, three methanol-based propane, three acrylic acid fat, ethyoxyl tri methylol triacrylate, ethyoxyl tetramethylol methane tetraacrylate with and derivative in one or more.
Used pre-crosslinked gel particle among the present invention; Be compound monomer and astable crosslinking agent through the initator initiated polymerization crosslinked and the body gel after drying, grind and form; With this pre-crosslinked gel particle with after water mixes; At first macropore plugging and superelevation permeable formation are injected behind the oil reservoir in the oil reservoir near wellbore zone in suction volume expansion, the pre-crosslinked gel particle of expansion, make to inject water and get into low-permeability layer district startup residual oil.The pre-crosslinked gel particle that expands under reservoir temperature, salinity and the effect of pH value after a period of time; The automatic hydrolysis explosion is a polymeric adhesive solution; This generated in-situ polymer solution can continue to move into oil deposit deep part; Realize the profit mobility control,, be suitable for High Water Cut Reservoir raising oil recovery in conjunction with the dual-use function of profile control with polymer flooding.Technology of the present invention is owing to be just to understand explosion at the gel particle oil reservoir environment under and after the fixed time to become polymer solution, so avoided the problem of the shear shinning in injection process of polymer flooding problem in the prior art.
According to specific embodiments of the present invention, in the pre-crosslinked gel particle of the present invention, acrylamide and acrylic acid mass ratio are 12～24: 1.5～6 in the said compound monomer; Mass ratio between said compound monomer and the astable crosslinking agent is 1: 1/20～1/8000.Among the present invention, except that indicating especially, said ratio and content are mass ratio and content.
According to specific embodiments of the present invention, in the pre-crosslinked gel particle of the present invention, also can further optionally comprise other monomer in the said compound monomer; Said other monomer is selected from: one or more in 2-acrylamido-2-methyl propane sulfonic acid sodium salt, methacrylic acid, maleic acid, 2-acrylic acid, sulfopropyl acrylic acid, dimethylaminoethylacmethyl methyl chloride and the dimethyl diallyl ammonium chloride are preferably 2-acrylamido-2-methyl propane sulfonic acid sodium salt.More specifically, be 12～24 parts in the quality of acrylamide in the said compound monomer, the quality of said other monomer is greater than 0 smaller or equal to 6 parts, is preferably more than to equal 0.1 smaller or equal to 6 parts, more preferably greater than equaling 1 smaller or equal to 6 parts.
According to specific embodiments of the present invention, said compound monomer is made up of the 2-acrylamido-2-methyl propane sulfonic acid sodium salt of acrylamide, 1.5～6 parts by weight of acrylic and 0.1～6 weight portion (preferred 1～6 weight portion) of 12～24 weight portions.
According to specific embodiments of the present invention, in the pre-crosslinked gel particle of the present invention, described initator is selected from: one or more in potassium peroxydisulfate, the ammonium persulfate are preferably potassium peroxydisulfate.
According to specific embodiments of the present invention, the particle diameter of pre-crosslinked gel particle of the present invention is 100～120 orders.
According to specific embodiments of the present invention, said pre-crosslinked gel particle prepares according to following method, and the method comprising the steps of:
Compound monomer and astable crosslinking agent are added fully dissolving in the entry; In this process, preferably controlling the monomer concentration scope is 10% to 50%;
In above-mentioned solution, add initator;
Make above-mentioned solution polymerization reaction take place, obtain the body gel, through purifying, grinding, obtain said pre-crosslinked gel particle afterwards.
Because pre-crosslinked gel particle characteristics of the present invention are 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 able to control.Therefore to different reservoir medias, can adopt the astable crosslinking agent of variable concentrations, make the hydrolysis time of precrosslink microparticle and the temperature can in good time hydrolysis in such oil reservoir.
As previously mentioned, in the pre-crosslinked gel particle of the present invention, said compound monomer mainly is to comprise acrylamide, acrylic acid, also optionally contains other monomers.Said compound monomer is to be main with acrylamide; But; Owing to adopt astable crosslinking agent to carry out crosslinked; Astable crosslinking agent (being under the reservoir media) under the situation that calcium carbonate exists can degraded or is decomposed, and therefore gel is not stablely within a certain period of time degraded, being kept perfectly property in order to keep, and adds a certain proportion of acrylic acid (or further adding other monomer) and acrylamide generation copolyreaction.Among the present invention, be 12～24 weight portions in the amount of acrylamide in the compound monomer, said acrylic acid consumption can be 1.5～6 weight portions.Said other monomer can be selected from: one or more in 2-acrylamido-2-methyl propane sulfonic 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), the dimethyl diallyl ammonium chloride (diallyldimethyl ammonium chloride) are preferably 2-acrylamido-2-methyl propane sulfonic acid sodium salt; These other monomers can be greater than 0 weight portion, for example can be 1～6 weight portion (amount in acrylamide in the compound monomer are 12～24 weight portions).In a preferred embodiment of the present invention, compound monomer is by 0～6 part preferred 1～6 part of 12～24 parts of acrylamide, 1.5～6 parts in acrylic acid, 2-acrylamido-2-methyl propane sulfonic acid sodium salt (AMPS).
Among the present invention; Spendable astable crosslinking agent can be selected from: one or more in 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, three acrylic acid fat (trimethylopropane trimethacrylate), ethyoxyl tri methylol triacrylate (ethoxylated trimethylol triacrylate), ethyoxyl tetramethylol methane tetraacrylate (ethoxylated pentaerythritol tetracrylate) and their derivative; The mass ratio of said astable crosslinking agent and compound monomer is 1/20～1/8000: 1; The profile control that polymerization obtains in this proportion is bigger with the temperature range for hydrolysis of gel particle; Usually at 40 ℃ to 100 ℃; To the required hydrolysis time of 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 the object of the invention.In a preferred embodiment of the present invention, said 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 embodiments of the present invention, the used initator of the present invention can be selected from: potassium peroxydisulfate (K
2S
2O
8), in the ammonium persulfate one or more, 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, said initator is a potassium peroxydisulfate, the amount ratio 1/800～1/2500: 1 of this initator and compound monomer.
According to specific embodiments of the present invention; In the process of the described pre-crosslinked gel particle of preparation, in some auxiliary agents such as sodium carbonate, urea, ammoniacal liquor, NaOH, tetramethylethylenediamine one or more can also in the aqueous solution of compound monomer and astable crosslinking agent, have optionally been added.Wherein, solution need keep neutrality or alkalescent when the redox reaction that with potassium peroxydisulfate and/or ammonium persulfate is initator produces free radical, therefore can add sodium carbonate and/or NaOH and be used for neutralization solution to neutrality or alkalescent; Thereby the adding of urea can with monomer form polymer gel that strong hydrogen bond makes formation have less degree of porosity with and narrow distribution; Tetramethylethylenediamine is added in order to inspire polymerisation, and the adding of ammoniacal liquor can be accelerated polymerization rate, improves the efficiency of initiation of redox reaction through the adding of these auxiliary agents; With performances such as the intensity of the gel that improves the preparation gained, stability, realize regularly hydrolysis better, have the function of profile control and polymer flooding concurrently.The addition of said sodium carbonate, urea, ammoniacal liquor, NaOH and tetramethylethylenediamine and the mass ratio of said 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 embodiments of the present invention; Described pre-crosslinked gel particle in the preparation; The solution that has added compound monomer, astable crosslinking agent (or further having added initator, said auxiliary agent) is nitrogen injection deoxygenation (deoxygenation got final product in 5～50 minutes usually) as required, in order to the carrying out of polymerisation.
According to specific embodiments of the present invention, the said solution polymerization reaction take place that has added compound monomer, astable crosslinking agent, initator, said auxiliary agent is meant that the temperature with solution is controlled in 4 ℃ to the 40 ℃ scopes, preferably is controlled at 9 ℃ to 12 ℃.Best polymerization time 12 hours to 24 hours, nitrogen with vacuumize polymerization in the environment, be beneficial to polymerisation and move to the forward balance.Said purification process is meant the body gel is soaked in water with imbibition and dry to remove the process of the impurity in the gel; Preferred synthetic body gel repeats to expand for 2～3 times, dry process to be to purge the impurity in the gel, expands to carry out in distilled water that (temperature can be controlled at 40～80 ℃, for example 45 ℃; 60 ℃; 80 ℃), the body gel is preferably dry in the temperature below 60 ℃ then, and the dry body gel after the purification grinds to form granule.Through obtaining the desiccant gel particle of 100～120 orders (125～150 μ m) behind the sieve series, be pre-crosslinked gel particle of the present invention.
According to specific embodiments of the present invention; Utilizing described pre-crosslinked gel particle to carry out oil reservoir exploitation when improving high moisture old filed recovery ratio, is on ground pre-crosslinked gel particle to be mixed with the mixed liquor that contains pre-crosslinked gel particle with injection water (preparation of said pre-crosslinked gel particle can be used well injection water, can adopt return water or clear water according to site operation equipment situation; Injecting on-the-spot preparation; Compound concentration can confirm that preferably, the mass percentage content of gel particle is generally 0.1%～0.6% according to the scale of down-hole macropore and high permeability zone); (generally can place about 4～6 hours after the gel gel particle is expanded; After making the gel imbibition reach balance), use the mixed liquor that injection pump will contain gel particle to inject the oil reservoir that the down-hole needs profile control, observe injection pressure; The adjustment injection rate is measured intake profile.More specifically,, inject the mode of down-hole and, be specifically related to following formula and step when improving tar productivity in the profile control transfer drive of utilizing described gel particle to carry out highly aqueous field according to carrying out with reference to conventional method.
1. Theoretical Calculation
1) places the degree of depth
Wherein:
In the 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 handling
q
1, q
2-daily water-injection rate before and after handling, m
3/ d
Δ p
Po, Δ p
PosDifference between reservoir pre ssure and injection pressure before and after the-processing, MPa
f
Rr-residual resistance factor
2) consumption:
In the formula:
The 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
The n-number of plies
2. construction sequence
(1) surveys construction well intake profile, falloff curve;
(2) inspection well head divides the notes well to test envelope;
(3) bring up to construction equipment, and commissioning test;
(4) ground pressure testing, the stratum injection test;
(5) gel-filled particle;
(6) the normal water filling of becoming a full member;
(7) remove construction equipment, recover the well site environment;
(8) 10-15 days survey intake profiles after the water filling, falloff curve.
(9) survey intake profile, falloff curve after reaching blasting time.
According to specific embodiments of the present invention; Among the present invention; After pre-crosslinked gel particle gets into high watercut layer; At first the macropore of shutoff near wellbore zone and superelevation permeable formation force injection water preferentially to get into less permeable layer residual oil district and start residual oil, and millimeter level pre-crosslinked gel particle explosion after the control time of process setting under the effect of formation temperature pressure of shutoff near wellbore zone forms the polymer property read solution (or micron order and submicron order granule); Get into oil deposit deep part, play the effect of deep fluid diversion.Among the present invention, be through controlling the mass ratio of said pre-crosslinked gel particle astable crosslinking agent and compound monomer in the preparation process, controlling pre-crosslinked gel particle forms solution under formation temperature and pH condition blasting time.
In sum, in the method for the present invention, adopt the described pre-crosslinked gel particle of the double effects of profile control and polymer flooding of can realizing to carry out the oil reservoir exploitation, can control the hydrolysis blasting time of pre-crosslinked gel particle through adjusting astable crosslinker concentration.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 to the temperature and the 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, need before injecting profile control agent, carry out the anti-channeling operation to strong washing layer, usually to improve follow-up transfer drive efficiency of 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, practices thrift cost.
Description of drawings
Fig. 1 is the action principle sketch map 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 sketch map of decomposition.
Fig. 3 is the three-dimensional oil reservoir physical model sketch map 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 recovery ratio changes in the oil recovery process of the present invention's one specific embodiment.
The specific embodiment
In order more to be expressly understood the present invention, below to enumerate specific embodiment and further describe the present invention.Embodiment only is used for explaining and does not limit the present invention in any way.
Prescription
Acrylamide 24 grams
Acrylic acid 6 grams
Polyethylene glycol dimethacrylate (polyethylene glycol 200dimethacrylate) 0.15 gram
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 fully dissolving in the 110 gram water.The dissolving back adds NaCO
3Neutralization solution.Add TMEDA, urea, ammoniacal liquor and NaOH then.Nitrogen injection purifies 30 minutes in solution, in solution, adds K then
2S
2O
8, the solution that obtains re-injects nitrogen purge and puts into 10 ℃ of insulating boxs after 10 minutes.Be evacuated to earlier-10KPa 30 minutes, remove airborne oxygen, keep vacuum state to inject pure nitrogen gas simultaneously then, remove the oxygen in the solution, the beginning polymerization process becomes glue fully after 12 hours, obtain the body gel.
After becoming glue, the body gel is put into distilled water, in 200 rev/mins stirring at low speed process, soaked 5 hours, remove unreacted monomer and additive, dry and grind to form the appointment size particles in 60 ℃ of baking ovens then, grain diameter is 100～120 orders.
The action principle sketch map of pre-crosslinked gel particle of the present invention in oil reservoir sees also shown in Figure 1.As can be seen from the figure; Pre-crosslinked gel particle at first injects crack, shutoff near wellbore zone, down-hole and superelevation infiltration area in the profile control operation; The crack and the permeability of superelevation infiltration area that on behalf of long-term injecting water, K2 form, K3 representative are not injected into the permeability of the petroleum province that ripples reach, K2＞＞K3.The automatic explosion of bulky grain is deformed into polymer solution after after a while, continues to move at inhomogeneous formation, reaches the purpose 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 sketch map 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 the profile control and the polymer flooding of embodiment 1 preparation are used is dissolved in the NaCl solution, and solvent is 1% NaCl solution, and the 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 was 80 ℃, pre-crosslinked gel particle is hydrolyzed into polymer solution needed 12 days, and the polymer solution viscosity that obtains after the hydrolysis is 170cp; When the temperature of mixed solution was 60 ℃, the pre-crosslinked gel particle complete hydrolysis needed 80 days, and the polymer solution viscosity that obtains after the hydrolysis is 290cp; When the temperature of mixed solution was 45 ℃, pre-crosslinked gel particle did not yet have complete hydrolysis after half a year; Wherein, when the temperature of mixed solution was 80 ℃, 60 ℃, the difference of resulting polymer solution viscosity was that the main chain instability at high temperature owing to polymer molecule ruptures and causes.
Prescription
Acrylamide 13.5 grams
Acrylic acid 1.5 grams
Polyethylene glycol dimethacrylate (polyethylene glycol 200dimethacrylate): 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 fully dissolving in the entry.The dissolving back adds NaCO
3Neutralization solution.Add TMEDA, urea, ammoniacal liquor and NaOH then.Nitrogen injection purifies 30 minutes in solution, in solution, adds K then
2S
2O
8, the solution that obtains re-injects nitrogen purge and puts into 10 ℃ of insulating boxs after 10 minutes.Be evacuated to earlier-10KPa 30 minutes, remove airborne oxygen, keep vacuum state to inject pure nitrogen gas simultaneously then, remove the oxygen in the solution, the beginning polymerization process becomes glue fully after 13 hours, obtain the body gel.
After becoming glue, the body gel is put into distilled water, in 200 rev/mins stirring at low speed process, soaked 5 hours; Remove unreacted monomer and additive; Dry in 60 ℃ of baking ovens then, dried gel was soaked 5 hours in water again, dry to purify in 60 ℃ of baking ovens then; And grinding to form the appointment size particles, grain diameter is 100～120 orders.
Hydrolysis experiment
The 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 that obtains after the hydrolysis is 135cp; In the time of 60 ℃, approximately need 60 days complete hydrolysis, the polymer solution viscosity of gained is 210cp.For 45 ℃, also there is not complete hydrolysis after half a year.
Prescription
Acrylamide 18 grams
Acrylic acid 6 grams
AMPS 6 grams
Polyethylene glycol dimethacrylate (polyethylene glycol 200 dimethacrylate): 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
The 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 that obtains after the hydrolysis is 100cp; In the time of 60 ℃, approximately need 35 days complete hydrolysis, the polymer solution viscosity of gained is 160cp.For 45 ℃, posthydrolysis in 150 days, the viscosity of the polymer solution of gained is 190cp.
Prescription
Acrylamide 10.5 grams
AMPS 1.5 grams
Polyethylene glycol dimethacrylate (polyethylene glycol 200dimethacrylate): 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 that obtains after the hydrolysis is 70cp; In the time of 60 ℃, approximately need 20 days complete hydrolysis, the polymer solution viscosity of gained is 110cp.For 45 ℃, posthydrolysis in 90 days, the viscosity of the polymer solution of gained is 130cp.
Prescription
Acrylamide 10.5 grams
AMPS 1.5 grams
Polyethylene glycol dimethacrylate (polyethylene glycol 200dimethacrylate): 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 that obtains after the hydrolysis is 35cp; In the time of 60 ℃, approximately need 10 days complete hydrolysis, the polymer solution viscosity of gained is 60cp.For 45 ℃, posthydrolysis in 45 days, the viscosity of the polymer solution of gained is 80cp.
Can find out from above embodiment; In the number range that the present invention gives, can prepare the pre-crosslinked gel particle of plurality of specifications, be used to improve oil recovery thereby those skilled in the art can prepare suitable pre-crosslinked gel particle according to the concrete condition adjustment parameter of oil reservoir.
Embodiment 6 injects the physical simulation experiment that gel particle improves oil recovery factor
1, model
Geologic information according to certain oil field provides is set up the three-dimensional non-homogeneous model that meets 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, on the branch in following three layers of distribution; Every layer of 10 differential pressure pick-up that distributes, three layers of differential pressure pick-up are respectively 2.5,7.5,12.5 apart from the distance bottom the model; Two diagonal angles of model are arranged a copper pipe that vertically connects model respectively as injecting well and producing well, and the long 10cm of well, perforation density are 4 of perforations on the cross section of every 1cm, and angle 90 degree between two holes wrap 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;
Inject crude oil and make it saturated to model, write down saturated former oil mass, saturated altogether former oil mass is 7520mL;
Carry out water drive and reach 95% up to moisture content, the salinity of the employed injection water of water drive is 5000ppm, and injection rate is 0.5mL/min;
After water drive is accomplished, inject the gel particle (gel particle joins with 0.5% mass concentration in advance and injects water and soak imbibition in about 5 hours) of the embodiment 1 of 0.1PV with the speed of 0.5mL/min;
Inject after the gel particle, continue water drive 1PV again, closing well is heated to 80 ℃ then, keeps 3 months, drives a well then, and water drive to moisture content is 95%.
The basic physical-property parameter of model is seen table 1, and dispersion gel particle injection parameter is seen 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 the explosion | 0.1PV | 0.5mL/min |
3, interpretation of result
The first time pressure stability during water drive about 10KPa, pressure rises to 1.4MPa rapidly when injecting gel particle, when carrying out water drive once more, pressure drops to about 1MPa; In the continuation water drive process after closing well keeps 80 ℃ to drive a well again, injection pressure drops to about 70KPa and keeps stable, and the pressure change procedure is seen Fig. 4.Oil recovery factor has improved 3% after injecting gel particle, under reservoir temperature, keeps recovering water drive after 3 months, improves recovery ratio 5%, always improves recovery ratio 8%.The recovery ratio change procedure is seen Fig. 5.
Claims (10)
1. method that improves high moisture old filed recovery ratio; Use a kind of pre-crosslinked gel particle in this method; Described pre-crosslinked gel particle can imbibition also can form solution after following a period of time of condition at formation temperature and pH, and the method for the high moisture old filed recovery ratio of said raising comprises:
Said pre-crosslinked gel particle is mixed with water, make the pre-crosslinked gel particle imbibition, and inject the down-hole, make the pre-crosslinked gel particle at first macropore of shutoff near wellbore zone and superelevation permeable formation in oil reservoir;
Treat pre-crosslinked gel particle at reservoir temperature after following a period of time of effect, the automatic explosion of gel particle forms polymeric adhesive solution, gets into oil deposit deep part and realizes the profit mobility control; Recover the oil.
2. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, described pre-crosslinked gel particle be by compound monomer and astable crosslinking agent through the initator initiated polymerization crosslinked and the body gel after drying, grind and form, wherein:
Said compound monomer comprises acrylamide and acrylic acid;
Said astable crosslinking agent is selected from: polyethyleneglycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, glycol diacrylate, three methanol-based propane, three acrylic acid fat, ethyoxyl tri methylol triacrylate, ethyoxyl tetramethylol methane tetraacrylate with and derivative in one or more.
3. the method for the high moisture old filed recovery ratio of raising according to claim 2, wherein, acrylamide and acrylic acid mass ratio are 12～24: 1.5～6 in the said compound monomer; Mass ratio between said compound monomer and the astable crosslinking agent is 1: 1/20～1/8000.
4. the method for the high moisture old filed recovery ratio of raising according to claim 2 wherein, also comprises other monomer in the said compound monomer; Said other monomer is selected from: one or more in 2-acrylamido-2-methyl propane sulfonic acid sodium salt, methacrylic acid, maleic acid, 2-acrylic acid, sulfopropyl acrylic acid, dimethylaminoethylacmethyl methyl chloride and the dimethyl diallyl ammonium chloride are preferably 2-acrylamido-2-methyl propane sulfonic acid sodium salt; Quality in acrylamide in the said compound monomer is 12～24 parts, the quality of said other monomer be greater than 0 weight portion smaller or equal to 6 weight portions, be preferably more than 1 smaller or equal to 6 parts.
5. the method for the high moisture old filed recovery ratio of raising according to claim 2, wherein, described initator is selected from: one or more in potassium peroxydisulfate, the ammonium persulfate.
6. the method for the high moisture old filed recovery ratio of raising according to claim 1, wherein, the particle diameter of said pre-crosslinked gel particle is 100～120 orders.
7. the method for the high moisture old filed recovery ratio of raising according to claim 2, wherein, said pre-crosslinked gel particle prepares according to following method:
Compound monomer and astable crosslinking agent added in the entry dissolve;
In solution, add initator then;
Make above-mentioned solution polymerization reaction take place, obtain the body gel, through purifying, grinding, obtain said pre-crosslinked gel particle afterwards.
8. the method for the high moisture old filed recovery ratio of raising according to claim 7; Wherein, Said pre-crosslinked gel particle has also added in sodium carbonate, urea, ammoniacal liquor, NaOH, the tetramethylethylenediamine one or more in the aqueous solution of compound monomer and astable crosslinking agent in the preparation process;
Preferably; The addition of said sodium carbonate, urea, ammoniacal liquor, NaOH, tetramethylethylenediamine and the mass ratio of said 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;
More preferably, said polymerisation is to add under the environment that fills nitrogen reaction 12～24 hours at 4～40 ℃, vacuum;
Said purification be with said body gel through expand, dried 1～3 time.
9. the method for the high moisture old filed recovery ratio of raising according to claim 1; Wherein, be pre-crosslinked gel particle to be mixed with the mixed liquor that contains pre-crosslinked gel particle with injection water on ground, the gel gel particle is expanded after; Use the mixed liquor that injection pump will contain gel particle to inject the oil reservoir that the down-hole needs profile control; Observe injection pressure, the adjustment injection rate is measured intake profile.
10. method according to claim 9 wherein, is controlled the mass ratio of said pre-crosslinked gel particle astable crosslinking agent and compound monomer in the preparation process, controls pre-crosslinked gel particle forms solution under formation temperature and pH condition blasting time.
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| 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 |
| CN115853482A (en) * | 2023-02-27 | 2023-03-28 | 中国石油大学(华东) | Method and system for increasing recovery ratio by capsule polymer flooding |
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