CN101775971B - Oil field maximum swept volume chemical flooding oil extraction method - Google Patents

Abstract

A maximum swept volume chemical flooding oil extraction method is applied to the technical field of oil field oil extraction. The suitable oil reservoirs are all oil reservoirs which can be developed by water drive but not developed by water drive. During oil exploitation, the self energy of the oil reservoir stratum is utilized to perform self-injection oil production or swabbing oil extraction, when the oil field of the self-injection oil production or swabbing oil extraction reaches the exploitation economic benefit limit, the self-injection oil production or swabbing oil extraction is finished, the water-flooding oil extraction is not performed, and the chemical flooding injected with the surfactant as the main agent is directly adopted to perform the enhanced oil extraction. The effect is as follows: at the moment, the swept volume of the displacement of the chemical displacement fluid is the largest, which is most beneficial to exerting the oil washing effect of the surfactant, thereby maximizing the petroleum recovery ratio.

Description

A kind of oil field maximum swept volume chemical flooding oil production method

Technical field

The present invention relates to the oil extraction in oil field technical field, be particularly related to a kind of oil field development method, but be a kind ofly to be applicable to waterflooding development and not carry out the oil reservoir of waterflooding development, when maximum swept volume, inject the surfactant that improves displacement efficiency and make the maximized oil field development method of oil recovery.

Background technology

At present, the oil production method order that conventional oil field development is continued to use utilized the reservoir formation self-energy to carry out oil flow production or swabbing production before this, and system often is called primary oil recovery; From Injection Well injected water makeup energy and displacement crude oil, carry out simultaneously the producing well pumping and produce after the oil reservoir energy attenuation, system often is called secondary oil recovery; Secondary oil recovery still has later 55～70% crude oil to be detained underground, palpus adopts polymer-thickened or gel profile-controlling improves the chemical agent intensified oil reduction measures such as intake profile and decreasing by surfactant oil water interfacial tension raising displacement efficiency to improve oil recovery, and system often is called tertiary oil recovery.

Primary oil recovery described here is to utilize natural energy to recover the oil, and is depleted with natural energy, and oil well does not go out or production capacity changes the secondary waterflooding development over to when very low and recovers the oil.

Secondary oil recovery described here is that waterflooding development recovers the oil, and namely replenishes or increase oil reservoir energy from the Injection Well injected water, and crude oil drives along Injection Well and sweeps to producing well, produces from the producing well oil pumping.Reach 95% or during higher economic limit when the producing well Produced Liquid is moisture, change tertiary oil recovery over to;

Tertiary oil recovery described here refers to inject the intensified oil reduction method of any one or two kinds of combinations or three kinds of combinations of surfactant, alkali, polymer three class chemical agents.Reduce in order to reduce oil/water mobility ratio driven water-replacing the fingering phenomenon, enlarge swept volume and improve intake profile, usually add high molecular polymer, such as polyacrylamide etc. to improve the viscosity of displacing fluid; In order to improve displacement efficiency, usually add surfactant to reduce interfacial tension, improve wetability and to strengthen emulsifiability; For the oil recovery effect of synergistic surfactant, usually add the alkali synergistic surfactant and reduce to greatest extent interfacial tension to improve displacement efficiency.The common comparable water drive of surfactant-alkali-polymer ternary combination flooding improves the approximately oil recovery of 20%OOIP (accounting for the oil recovery percentage of original oil in place), its conventional working concentration is respectively surfactant 0.2%～0.4% (w/w), alkali 1.0%～1.6% (w/w), polymer 0.1%～0.25 (w/w), injection rate 0.5～0.8PV (reservoir pore volume), concentration is high, consumption is large, cost is very high.

Existing suitable water drive is carried out the oil field of secondary oil recovery exploitation, and its development sequence all is through primary oil recovery, secondary oil recovery, enters at last tertiary oil recovery.The shortcoming of this development sequence is:

1, water drive washes away the strong suction layer that leaks

After sandstone recovered the oil through long-period water drive, washing thickness was more and more thinner until relative strong water accepting layer occurs, causes at last " poor efficiency is invalid " circulation of water-drive oil recovery.Though the permeability of oil reservoir height, the difference that layer is interior or interlayer deposits of certain core intersection, a large amount of water bodys wash away rear relative strong water accepting layer and " poor efficiency is invalid " circulating phenomenon of all can occurring, and namely water drive finishes the large problem of rear oil reservoir appearance " leaking ".Usually the recovery ratio of water-drive oil recovery is 30～45%OOIP (accounting for the percentage of original crude content), and most of crude oil also remains in underground behind the water-drive oil recovery.

After 90 years last century, Daqing oil field has newly been beaten a collection of sealed coring well, and data shows: along with the passing of waterflooding extraction process, and relative homogeneous on average approximately 1000 * 10^-3μ m²Reservoir physical property great changes have occured, cause permeability grade to become large, high infiltration section thickness occupies certain ratio (seeing Table 1).

The thickness that high infiltration section occurs after table 1 water drive

	New well-digging number	Greater than 3000 * 10-3μm2	Greater than 5000 * 10-3μm2
				Oil extraction No.1 Factory	12	19.3％
Three factories of recovering theoil	3	10.2％	3.9％
				Six factories of recovering theoil	3	20.7％	6.5％

Survey intake profile result (consulting table 2) from the Daqing oil field six factories isotopes that recover the oil, passing along with water injection time, water sucting thickness and swept volume alter a great deal in the layer, and injected water is advanced by leaps and bounds along the high infiltration of macropore position at last, forms " invalid and poor efficiency " circulation.The grand celebration three monolayer assay district P of factory that recover the oil_I1-3When layer is surveyed production profile after well water 95%, find that the thickness ofoil reservoir bottom 1/3rd accounts for 80% of holostrome production fluid amount.

Water sucting thickness changes after table 2 water drive

	Initial stage of development	At present
			Water sucting thickness in the layer	99.9％	87.79％
Main water absorbing section thickness proportion	75.63％	33.08％

2, chemical agent intensified oil reduction

The chemical flooding intensified oil reduction of implementing after water-drive oil recovery finishes is in fact for administering that water-drive oil recovery causes " leaking " problem and in conjunction with the raising recovery ratio method of washing oil.Enlarge swept volume in order to control water breakthrough, tertiary oil recovery often adopts gel and polymer solution to adjust intake profile (polymer displacement of reservoir oil is applied in China) on a large scale, but the effect of this profile control is not very desirable, usually only adjusts in the plane such as polymer flooding to enlarge swept volume.Ternary composite driving reduces tackifying and the viscoplasticity that interfacial tension, alkali have a strong impact on polymer and makes profile control effect it would be better polymer flooding owing to adding the alkali synergistic surfactant.As in the Daqing oil field Portugal_I1-4In the strata compound oil displacement process, find that polymer produced quantity in oil well is very large, implantation concentration 1000mg/L, and extraction concentration is up to 600-800mg/L, the appearance of this phenomenon is exactly that the oil reservoir vertical heterogeneity causes greatly polymer solution to be advanced by leaps and bounds, and greatly reduces polymer in the poly-rate of depositing of oil reservoir.Also there is similar problem in the five factory polymer displacement of reservoir oil industrial test districts of recovering the oil, cause the poly-effect that improves recovery ratio of driving significantly to descend.The ternary composite driving industrialization field test in four factory's apricots two that recovers the oil, test result shows: P_I33Layer unit thickness accumulative total Injection volume is equivalent to P_I21P_I22P_I23The layer two times, cause ternary system can not give full play at each substratum the effect of ultralow interfacial tension washing oil, had a strong impact on the development effectiveness of ternary composite driving.And the ternary composite driving of polymer flooding or alkali+polymer+surfactant, the cost of chemical treatments is much larger than the injected water cost, and the leakage of this chemical agent solution alters that invalid circulation makes loss larger with poor efficiency!

Have method to control or delay the appearance of strong water accepting layer and prolong anhydrous period exploitation or improve by a larger margin oil recovery? does administering later appear in the layer that leaks that must wait until by force suction why again? does surfactant with strong washing oil function appear adding later in the layer that leaks that must wait until by force suction why again?

Summary of the invention

The purpose of this invention is to provide a kind of oil field maximum swept volume chemical flooding oil recovery new method, change oil field development and sequentially need to pass through primary oil recovery, secondary oil recovery, enter at last the conventional method of tertiary oil recovery, on the opportunity of the most suitable injection chemical agent---inject surfactant when being maximum swept volume or add again a small amount of auxiliary agent and carry out intensified oil reduction, improve oil recovery to improve displacement efficiency and then amplitude peak ground, reduce that chemical agent uses kind and consumption, decrease cost for oil production, greatly shortens the oil extraction time, many extraction oil to greatest extent; Most of crude oil also remains in underground deficiency after overcoming existing oil field development method water-drive oil recovery; Overcome that the waterflooding development time is long in the existing oil field development procedure, efficient is low, cause the water breakthrough major path to make the very deficiency such as difficulty of follow-up oil recovery.

The technical solution used in the present invention is: oil field maximum swept volume chemical flooding oil production method is characterized in that:

When the oil oil reservoir is exploited, at first utilize the reservoir formation self-energy to carry out oil flow production production or swabbing production (tradition is called primary oil recovery), when the oil field of oil flow production production or swabbing production reaches the economic benefit maximum conditions, finish oil flow production production or swabbing production, but the direct displacing fluid that injects surfactant or add a small amount of auxiliary agent that adopts carries out intensified oil reduction, (tradition is called tertiary oil recovery), do not carry out conventional waterflooding development and recover the oil, namely do not carry out the secondary oil recovery that traditional oil recovery program is implemented.When finishing oil flow production production or swabbing production, the swept volume of chemical agent displacing fluid displacement is maximum, is conducive to bring into play the washing oil effect of surfactant, improves the oil recovery maximization thereby make.

It is possess following two kinds of situations a kind of that oil reservoir reaches the oil recovery condition of injecting surfactant or adding the displacing fluid of a small amount of auxiliary agent again: 1. oil flow production be can not produce oil or oil pump capacity reaches the economic benefit limit, 2. the oil production of swabbing production reaches the economic benefit limit, just should in time adopt oil field of the present invention maximum swept volume chemical flooding oil production method.

The surfactant of described injection or add again a small amount of auxiliary agent and comprise: possess emulsifiability (Water-In-Oil or oil-in-water emulsified) surfactant, can form low by (10 with the oil reservoir profit^-1～10^-2MN/m) or ultralow (＜10^-2MN/m) surfactant of interfacial tension, reservoir wettability wet can be turned to the surfactant of neutrality or water-wet or possesses composite between the surfactant of above-mentioned oil recovery performance from glossy, and with collaborative high molecular polymer and the alkali that recovers the oil of surfactant

The described surfactant that possesses emulsifiability is:

NPE

OPEO

The described surfactant that can form low or ultralow interfacial tension with the oil reservoir profit is:

Petroleum sulfonate

Betaine

Describedly can wet turn to the surfactant of neutrality or water-wet to be from glossy reservoir wettability:

Betaine

The surfactant compound agent of described different oil recovery performances, each weight percentages of components be:

Betaine: 60～80% (w/w)

NPE: 15～30% (w/w)

Petroleum sulfonate: 5～10% (w/w)

Each component sum is absolutely.

Described synergistic surfactant recover the oil auxiliary agent---high molecular polymer and alkali comprise:

A, highly basic are NaOH, KOH etc.;

B, weak base are Na₂CO₃, NaHCO₃, Na₃PO₄Deng;

C, high molecular polymer are polyacrylamide, xanthans etc.

Described surfactant, high molecular polymer, the collaborative use of alkali, the concentration of use is:

The surfactant working concentration: 0.05%～1.0% (w/w), the solvent of employing is water.

The polymer working concentration: 0.01%～1.0% (w/w), the solvent of employing is water.

The alkali working concentration: 0.01%～2.0% (w/w), the solvent of employing is water.

Water-drive oil recovery in earlier stage washes core intersection and swept volume is maximum, and water-drive oil recovery adds surfactant in earlier stage can bring into play its reduction residual oil saturation, the effect that improves displacement efficiency to greatest extent.The surfactant of function admirable can reduce oil water interfacial tension to 10^-3MN/m or following ultra low levels, residual oil saturation can be reduced to approximately 10%OOIP.

The oil recovery of oil field maximum swept volume chemical flooding oil production method is greater than the recovery ratio of water drive+subsequent chemistry combination flooding sum! Oil production, cost for oil production and the equal optimization of exploitation timeliness.Hypotonic and special LOW PERMEABILITY RESERVOIR particularly, the polymer flooding after the water drive is difficult to carry out, and uses oil field maximum swept volume chemical flooding oil production method the most favourable.

The reason of oil field maximum swept volume chemical flooding oil production method is:

(1), get involved surfactant before the water-drive oil recovery, also do not exist this moment strong water accepting layer, surfactant and crude oil can interact fully to reduce interfacial tension raising displacement efficiency.And after water drive causes strong water accepting layer, get involved again, surfactant very easily " is missed " along strong water accepting layer.In the last few years, often there is the tertiary oil recovery combination flooding to increase the discussion of the single chemical agent contribution of oil, is the namely effect of polymer large or the effect of surfactant is large? experimental results show that, the polymer viscosified profile control is prerequisite and the necessary condition that improves recovery ratio, and surfactant is the adequate condition that increases substantially oil recovery.Only have polymer or gel to adjust intake profile relief surfactant and enter oil saturation zone, plateau its washing oil effect of competence exertion.According to the surfactant flooding that maximum swept volume chemical flooding oil production method is implemented, its recovery ratio is greater than the recovery ratio of water drive+subsequent chemistry combination flooding.

(2), the effect of surfactant is various, improves the displacement efficiency except ultralow interfacial tension reduces residual oil saturation, also has oil-in-water or invert emulsion, solubilising, foaming, transformation wetability etc. to increase the oil effect.Such as oil-water emulsifiers, can reduce viscosity of crude and improve its flowability.The invert emulsion of appropriateness (mainly being used in the surfactant flooding slug in earlier stage) obviously improves the viscosity of fluid, can play good profile control effect.

(3), adopt maximum swept volume chemical flooding oil production method, surfactant fully contacts with crude oil, the water-in-oil emulsion of formation and oily wall are controlled fluid front and are evenly advanced.Pile up at layer position water-in-oil emulsion and crude oil that relative permeability is large, flow resistance is larger, therefore has the fingering phenomenon that easily occurs when automatic profile control is avoided water drive.Swept volume is maximum, displacement efficiency oil recovery high, once maximum swept volume chemical flooding oil production method operation drives two subjob sums greater than water drive+subsequent chemistry.Experiment shows: by the surfactant flooding that maximum swept volume chemical flooding oil production method is implemented, its anhydrous period oil recovery shows that also much larger than (more than the high 20%OOIP) of water drive water body fingering phenomenon is less, and oily wall is evenly pushed ahead.

Beneficial effect of the present invention: the oil field of the present invention obvious advantage of maximum swept volume chemical flooding oil production method has: few water injection rate and sewage load, exempt from polymer and alkali, short operational period, high recovery ratio, above cost is at half.

(1), drive the surfactant that adds strong washing oil when sweeping swept volume in maximum, make the recovery ratio maximization, one-time surface surfactant flooding recovery ratio is greater than the recovery ratio of water drive+20%;

(2), be less than 0.7PV (surfactant solution drives+follow-up water drive) but totalinjection rate extraction 60%OOIP crude oil;

(3), with conventional first water drive subsequent chemistry flooding tertiary oil recovery again, the chemical agent component reduces to from three kinds in surfactant+alkali+polymer only has surfactant a kind of;

The consumption of surfactant when (4), the dosage of surfactant of the maximum swept volume chemical flooding in oil field oil production method approximates ternary composite driving;

(5), the oil recovery integrated cost reduces more than 50%;

(6), the oil producing operation time can reduce more than 2/3rds;

(7), environmental benefit is obvious, uses the little pollution of chemical dose little, do not damage oil reservoir, the Produced Liquid treating capacity reduces greatly and processing method is simplified;

(8) but, the method is applicable to waterflooding development and do not carry out that (or the water drive time is not long, moisture not high, the water breakthrough layer does not also appear) all oil reservoirs of waterflooding development, no matter be special hypotonic (surfactant has the augmented injection function) or high permeability reservoir, the serious heterogeneity oil reservoir can be transferred stifled the solution by invert emulsion ability or the ventilation formation foam of adjustment form surface-active agent.

Description of drawings

Fig. 1 is 0.2% concentration surfactant solution oil displacement efficiency schematic diagram.

Fig. 2 is 0.3% concentration surfactant solution oil displacement efficiency schematic diagram.

Fig. 3 is 0.4% concentration surfactant solution oil displacement efficiency schematic diagram.

Fig. 4 is 0.4% concentration surfactant solution 0.5PV slug oil displacement efficiency schematic diagram.

Fig. 5 is pure oilfield injection water oil displacement efficiency schematic diagram.

The specific embodiment

Embodiment 1: with the natural core in long celebrating oil field, adopt length to celebrate the reservoir conditions such as the crude oil in oil field, formation water, temperature, former oil saturation and use maximum swept volume chemical flooding oil production method, carrying out the indoor physical simulation oil displacement test is example, and invention is described in further detail.

A, long celebrating oil field development time are not long, and many newly-increased oils in place are arranged every year, and new producing well and the block newly developed of beating, the maximum swept volume chemical flooding of the very suitable utilization of new block oil production method.These new block are the lower sandstone of permeability, all can carry out waterflooding development and still also not implement waterflooding development.At first utilize the reservoir formation self-energy to carry out swabbing production, when the oil field of swabbing production reaches the exploitation economic limit, finish swabbing production, directly adopt the injection surfactant to carry out intensified oil reduction.

B, indoor physical simulation oil displacement test: the natural core of in core holding unit, packing into, under the reservoir temperature of long celebrating oil field, add and vacuumize rear saturated formation water after ring is pressed, long celebrating ground, the oil field dehydration Wellhead crue oil that reinjects is until crude oil is saturated.For subsequent use after the aging week.

C, carry out the comparative test of maximum swept volume chemical flooding oil production method and conventional water drive secondary development at the long celebrating of lab simulation oil field reservoir condition.The water drive imitation oil displacement experiment that carries out that the water drive blank compares is tested; Adopt the water drive of not carrying out of maximum swept volume chemical flooding oil production method directly to implement chemical flooding.

The surfactant that this test is injected is petroleum sulfonate, NPE and the betaine compound system that can form with the trial zone profit low interfacial tension or ultralow interfacial tension.

The weight ratio of the surfactant compound prescription of petroleum sulfonate, NPE and betaine is:

Betaine: 70% (w/w)

NPE: 23% (w/w)

Petroleum sulfonate: 7% (w/w)

Being mixed with surfactant concentration during actual the use is respectively 0.2%, 0.3% and 0.4% aqueous surfactant solution and carries out the indoor physical simulation oil displacement experiment.

D, employing natural core, ground dehydration Wellhead crue oil and oil field stratum water, under reservoir temperature, carry out the contrast test of the maximum swept volume chemical flooding oil production method that the blank contrast test of a water drive and 4 surfactant water flooding solution drives, detailedly the results are shown in Table 3.Blank water drive oil recovery 42.11%OOIP, anhydrous period oil recovery 32.16%OOIP (seeing Fig. 5).The aqueous surfactant solution of variable concentrations drives maximum swept volume chemical flooding oil production method, surfactant concentration is respectively 0.2%, 0.3% and 0.4% oil recovery is respectively 64.81%OOIP (seeing Fig. 1), 69.68%OOIP (seeing Fig. 2) and 74.34%OOIP (seeing Fig. 3), improve recovery ratio 22.7～32.33%OOIP than blank water drive, breakthrough recovery is respectively 52.46%OOIP (seeing Fig. 1), 54.83%OOIP (seeing Fig. 2) and 55.92%OOIP (seeing Fig. 3), improve recovery ratio 20.3～23.76%OOIP during than blank water drive, show that the water body fingering breaks through slow, the even forward impelling of oily wall.The displacement (seeing Fig. 4) of the aqueous solution 0.5PV slug of 0.4% surfactant concentration, recovery ratio is 73.08%OOIP, improve recovery ratio 30.97%OOIP than blank water drive, breakthrough recovery is 52.56%OOIP, improves recovery ratio 20.4%OOIP during than blank water drive.Shown all that below direct aqueous surfactant solution with low concentration drives maximum swept volume chemical flooding oil production method, its recovery ratio is higher than water drive 22.7～32.33%OOIP.

Calculate if improverecovery ratio 20%OOIP according to alkaline surfactant polymer flooding oil-field after the present water drive (method of raising oil recovery maximum---ternary composite driving improves approximately 20%OOIP of oil recovery in the tertiary oil recovery), adopt the recovery ratio of maximum swept volume chemical flooding oil production method one-stop operation greater than both sums of water drive+tertiary oil recovery (ternary composite driving)! And that the chemical agent component reduces to surfactant from three kinds of alkali, surfactant and polymers is a kind of, the dosage of surfactant that maximum swept volume chemical flooding method is used approximates the surface active agent composition consumption of ternary composite driving, and operating cost, oil production, chemical agent consumption, operation duration, Produced Liquid post processing are all optimized greatly.

Table 3 oil displacement test core parameters and recovery ratio

The rock core numbering	Apricot 56-18 (1-61/1 20)	Apricot 56-18 (1-55/12 0-3)	Apricot 56-18 (1-79/1 20)	Apricot 56-18 (2-13/70-1)	The 3-10 town
						The crude oil place of production	Long celebrating-the village	Long celebrating-the village	Long celebrating-the village	Long celebrating-the village	Long celebrating-the village
Drill core permeability rate	0.372	0.194	0.432	0.268	0.278
						Degree of porosity %	11.40	10.7	10.50	9.80	12.20
Rock density g/cm3	2.35	2.37	2.37	2.39	2.35
						Core quality g	61.64	62.48	61.47	62.61	58.973
Core length cm	5.3	5.3	5.3	5.3	5
						Core diameter cm	2.42	2.42	2.42	2.42	2.42
The displacement scheme	0.2% surfactant	0.3% surfactant	0.4% surfactant	0.4% surfactant 0.5PV	Water drive
						Displacement temperature ℃	65	65	65	65	65
The highest displacement pressure MPa	7.26	7.32	6.78	6.91	7.05
						Voids volume cm3	2.65	2.585	2.586	2.437	2.7
Saturated oils volume cm3	1.62	1.55	1.52	1.56	1.71
						Oil saturation	61.13％	59.96％	58.78％	64.01％	63.33％
Oil recovery volume cm3	1.05	1.08	1.13	1.14	0.72
						Recovery ratio % breakthrough recovery %	64.81 52.46	69.68 54.83	74.34 55.92	73.08 52.56	42.11 32.16

Displacement equipment: XS-50 type HTHP rock core displacement device.

The variable concentrations surfactant solution drives with blank water drive the results detailed in Fig. 1～Fig. 5, improves 22%～32%OOIP than water drive, and oil increasing effect is fine.

Embodiment 2: the initial stage of production of certain oil oil reservoir, utilize the reservoir formation self-energy to carry out oil flow production production, when oil is can not produce in oil flow production, finish oil flow production production, do not carry out conventional water-drive oil recovery, but directly adopt the displacement of injection surfactant solution to carry out intensified oil reduction.

The surfactant of the injection of adopting is: possess the surfactant of emulsifiability (Water-In-Oil or oil-in-water emulsified), specifically NPE.The working concentration of NPE is 0.2% (w/w), and the solvent of employing is water.

Embodiment 3: when certain oil oil reservoir exploitation, at first utilize the reservoir formation self-energy to carry out swabbing production, when the oil field of swabbing production reaches the exploitation economic benefit limit, the cost that namely puts into production approaches or when equaling the output cost, finish swabbing production, do not carry out conventional water-drive oil recovery, but the displacing fluid that directly adopts the injection surfactant to add again a small amount of auxiliary agent carries out intensified oil reduction.

The displacing fluid that the injection surfactant that adopts adds a small amount of auxiliary agent again is: the surfactant compound of two kinds of different oil recovery performances adds a small amount of alkali again, and each weight percentages of components is:

Betaine: 86% (w/w)

Petroleum sulfonate: 12% (w/w)

Alkali---sodium carbonate: 2% (w/w)

During use, the surfactant compound of two kinds of different oil recovery performances adds the working concentration of a small amount of alkali again: 0.35% (w/w), the solvent of employing is water.

Embodiment 4: the initial stage of production of certain oil oil reservoir, utilize the reservoir formation self-energy to carry out oil flow production production, when oil is can not produce in oil flow production, finish oil flow production production, do not carry out conventional water-drive oil recovery, but directly adopt the displacement of injection surfactant solution to carry out intensified oil reduction.

The surfactant of the injection of adopting is: can be with reservoir wettability from the glossy wet surfactant betaine that turns to neutrality or water-wet.The working concentration of betaine is 0.3% (w/w), and the solvent of employing is water.

Claims (1)

1. the maximum swept volume chemical flooding in oil field oil production method, it is characterized in that: when the oil oil reservoir is exploited, at first utilize the reservoir formation self-energy to carry out oil flow production production or swabbing production, when the oil field of oil flow production production or swabbing production reaches the exploitation economic benefit limit, finish oil flow production production or swabbing production, no longer then, carry out conventional water-drive oil recovery, but the direct displacing fluid that injects surfactant or add a small amount of auxiliary agent that adopts carries out intensified oil reduction;

It is possess following two kinds of situations a kind of that described oil reservoir reaches the oil recovery condition of injecting surfactant or adding the displacing fluid of a small amount of auxiliary agent again: 1. oil flow production be can not produce oil or oil pump capacity reaches the economic benefit limit, and 2. the oil production of swabbing production reaches the economic benefit limit;

The surfactant of described injection or add again a small amount of auxiliary agent and comprise: possess emulsifiability Water-In-Oil or oil-in-water emulsified surfactant, can form 10 with the oil reservoir profit^-1～10^-2MN/m or＜10^-2The surfactant of mN/m interfacial tension, reservoir wettability wet can be turned to the surfactant of neutrality or water-wet or possesses composite between the surfactant of above-mentioned oil recovery performance from glossy, the auxiliary agent that synergistic surfactant recovers the oil comprises high molecular polymer and alkali;

The surfactant that possesses emulsifiability is NPE, or OPEO;

The surfactant that can form low or ultralow interfacial tension with the oil reservoir profit is petroleum sulfonate, or betaine;

Can wet to turn to the surfactant of neutrality or water-wet be betaine from glossy with reservoir wettability;

Each weight percentages of components of the surfactant compound of oil recovery performance is:

Betaine: 60～80%;

NPE: 15～30%;

Petroleum sulfonate: 5～10%;

Each component sum is absolutely;

Described synergistic surfactant recover the oil auxiliary agent---high molecular polymer and alkali comprise:

A, NaOH or KOH;

B, Na₂CO₃, NaHCO₃Or Na₃PO₄

C, polyacrylamide or xanthans;

The surfactant of described oil recovery performance, high molecular polymer, the collaborative use of alkali, the weight percent concentration of use is:

The surfactant working concentration of oil recovery performance: 0.05%～1.0%, adopting solvent is water;

The polymer working concentration: 0.01%～1.0%, adopting solvent is water;

Alkali is worked in coordination with working concentration: 0.01%～2.0%, and adopting solvent is water.

Images