Method for non-uniform oil reservoir development

FIELD: oil production, particularly by reservoir waterflooding.

SUBSTANCE: method involves cyclically injecting polymeric dispersed system components in reservoir, wherein the polymeric dispersed system includes polyacrylamide, mud powder, chromium composition and water. The mud powder is modified bentonite mud powder. The polymeric dispersed system is injected in the following way. First of all 4-6% modified bentonite mud powder suspension in 0.04-0.12% aqueous polyacrylamide solution is injected in well. Then the suspension is forced in reservoir with buffer water volume and holding in reservoir within 1-3 hours. After that 1-6% modified bentonite mud powder suspension in water including 0.005-0.015% of chromium composition is injected in well under pressure 10-40% higher than water injection pressure in series with mixture including 0.07-0.25% aqueous polyacrylamide solution and 0.033-0.1% chromium composition solution under water injection pressure.

EFFECT: increased oil recovery from reservoirs, decreased water content in produced product and prevention of reservoir bottom area mudding.

2 ex

 

The invention relates to the oil industry and can be used in the development of oil reservoir water flooding.

There is a method of developing a heterogeneous oil reservoir, including flooding, sequential injection of an aqueous solution of partially hydrolyzed polyacrylamide and clay suspension (see avts of the Russian Federation No. 1778280, EV 43/12, 1992).

The method provides increased oil recovery by isolating the most high-permeability layers.

The disadvantage of this method is low efficiency of regulating the development of heterogeneous reservoirs and reservoirs with zonal heterogeneity, due to the low penetrating power of clay suspension and short-term impact on the formation.

There is a method of developing oil deposits, including injection water suspension on the basis of polyacrylamide, bentonite clay and chrome compounds and aqueous suspension based on wood flour, condensed sulfite-alcohol stillage and bichromate of potash (see RF patent №2205946, EV 43/22, 2003).

The method aligns the injectivity profile and increased coverage of reservoir flooding due to clogging of highly water-producing zones of the formation.

The disadvantages of this method are the low efficiency when used on fields with zonal what odnorodnosti, due to the shallow depth filtration of dispersed particles in the volume of the reservoir, and the limited duration of the technological effect.

The disadvantages of the method are also mudding separate reservoir intervals in the injection of wood flour and blocking oil reserves in low-permeability intervals.

The closest analogue is the way to develop heterogeneous formations, including flooding, cyclic injection components polymer dispersed system containing polyacrylamide, bentonite, the chromium compound and water (see RF patent №2135756, EV 43/22, 1999).

The method aligns the injectivity profile and redistribution of filtration flows due to clogging of highly water-producing zones of the formation.

The main disadvantage of this method is low efficiency when exposed to highly permeable and fractured reservoirs of oil, water deposits, and the processing sections dagger breakthroughs water, due to low viscosity structural properties injected into the reservoir suspension of bentonite. The known method does not provide effective impact on remote areas of the reservoir (the reservoir with the zonal heterogeneity), which is associated with low sedimentation stability of clay suspensions on the basis of normal glinoer the Cabinet, which blocks the pores and cracks near bottomhole zone of the formation.

The task of the invention is to increase oil recovery from zonal heterogeneity and layers at the late stage of development, and reducing the water content in crude production by increasing the efficiency and depth of impact polymer dispersed system on the formation and the removal of the clogging layer zones in the deposition of clay particles.

The problem is solved in that way the development of heterogeneous oil reservoirs, including flooding, cyclic injection components polymer dispersed system containing polyacrylamide, bentonite, the chromium compound and water, according to the invention as bentonite use modified bentonite bentonite in this case, initially pumped 4-6%suspension of modified bentonite bentonite in 0,04 -0,12%aqueous solution of polyacrylamide, push it into the reservoir buffer volume of water and incubated for 1-3 hours, then inject the suspension of modified bentonite bentonite in water containing 0,005-0,015% chrome compounds, at a pressure discharge by 10-40% higher than the discharge pressure of the water, and the mixture of polyacrylamide with a concentration of 0.07-0.25% and 0,033-0.1%solution of the compounds of chromium when the discharge pressure is used for water flooding.

The method is used when carrying out works on injection wells water-saturated oil fields for the purpose of integrated stimulation, including the alignment of the injectivity profile of the well, the redistribution of filtration flows and increased coverage of reservoir flooding.

The essence of the proposed method of development of heterogeneous oil reservoirs is that as a component of polymer-dispersed systems use modified bentonite bentonite. Modified bentonite bentonite (MBG) differs from the usual dry high swelling ability and sediment stability in water. It forms a homogeneous suspension, easily miscible with water.

MBG is injected into the formation in the form of 4-6%suspension. The choice of such a range of concentrations of the modified bentonite bentonite is due to the possibility of obtaining thus a homogeneous and stable suspension. At a concentration of more than 6% suspension becomes quite viscous and poorly filtered, at a concentration of less than 4%, it becomes nonuniform and allocates water.

Modified bentonite bentonite is injected into 0,04-0,12%aqueous solution of polyacrylamide. This ensures that over time additional increase in viscosity of 4-6 times, with the protected uniformity of the whole system. At higher concentrations of polymer, it coagulates particles modified bentonite bentonite, which leads to stratification of the suspension, the formation of clay lumps and sharp decrease in viscosity. When the concentration of the polymer to less than 0.04% suspension has a viscosity properties, slightly exceeding the properties of the original clay suspension.

The resulting suspension MBG forced into the reservoir buffer volume of water and incubated for 1-3 hours. During this time, the modified bentonite bentonite swells and finally when the selected proportions of the ingredients formed a homogeneous viscous polimergranita suspension, which preserves mobility, well filtered and delaminate over time. Promotion and suspension of high-permeability channels of the reservoir provides the distribution of seepage in remote areas.

After the injection of a suspension of MBG in the polymer solution in the reservoir to inject the suspension of modified bentonite bentonite in water containing 0,005-0,015% chrome compounds. In solution compounds of chromium (in the framework of the method uses a chromium acetate, chromalive alum or alkali metal bichromate) with the selected concentration of the swelling properties of MBG particles in the water is reduced to 1.5-2.5 times. Therefore, they are better filtered in a porous medium and further penetrated the Ute into the reservoir along the line of water injection, what contributes to the redistribution of filtration flows in the volume of the reservoir. Further, after pumping water, particles MBG fully swell, which leads to additional reduce the permeability of the treated areas, reinforces the redistribution of flows and contributes to the reduction of the water content of produced fluids. Deeper penetration of MBG particles in the volume of the reservoir is ensured by the fact that the injection pressure of the mixture of the modified bentonite bentonite and mortar compounds of chromium increase by 10-40% higher discharge pressure injected into the formation water.

Later in the reservoir pumped a mixture of polyacrylamide and 0,033-0.1%solution of chromium compounds. As a result of interaction of components in the reservoir is formed of cross-linked polymer gel. For injection into oil reservoirs using solutions with a polymer concentration of 0.07 to 0.25%. Such solutions are well-bound chromium compounds and form a homogeneous movable structure. The crosslinking of the polymer in the method using a solution of compounds of chromium with a concentration of 0,033-0,1%. With this concentration, the compounds of chromium cross-linking of the polymer occurs within 5-12 hours, the polymer gel is not diluted with injected water. The injection of a mixture of polyacrylamide and mortar chrome compounds are produced when the discharge pressure of water, which ensures a uniform movement of liquids and the formation and expulsion of oil from the bypassed intervals. The developed method allows the injection of polyacrylamide in aqueous suspension.

The proposed set of features of the developed method provides in General the course of the following processes. After soaking in the reservoir suspension of modified bentonite bentonite in aqueous solution of polyacrylamide increases the viscosity and forms a homogeneous composition, which is not eroded the injected water and moves through the formation of a single mass. This contributes to the redistribution of filtration flows near PZP well and the volume of the reservoir and provides a prolonged blocking of water breakthrough on the most high-permeability intervals of the formation. Subsequent injection of the suspension MBG in solution compounds of chromium, containing not swollen particles of modified bentonite bentonite is directed to additional clogging high-permeability intervals and reduce the permeability of the zones adjacent to the high-permeability intervals. Eliminating leading breakthroughs water on these intervals. Further injected with the mixture of polyacrylamide and mortar compounds of chromium, which provides a uniform displacement of oil from bypassed intervals of the formation.

Overall, as a result of stimulation when using the proposed method is extended blocking breakthroughs in the water, intensive redistribution of filtration flows and decreased water content of produced fluids.

To implement the method using the following ingredients, produced by industry:

- modified bentonite bentonite on THE 2164-006-41219638-2005, mark PBMA, PBMB;

- chromium acetate on THE 2499-001-50635131-00 (am.1), bichromate of potash, GOST 2652-78, sodium bichromate, GOST 2651-88, chromecacheview alum GOST 4169-79;

- polyacrylamide brand PDA, PDS 40 NT, CYPAN, Accotrol and others.

The method is as follows.

In the reservoir, developed by the flooding, with the help of a pump unit pump 4-6%suspension of modified bentonite bentonite in 0,04-0,12%aqueous solution of polyacrylamide. The injection is made by dispensing the calculated amount of the modified bentonite bentonite through the ejector into the solution of polyacrylamide or by dispensing a dry mixture of modified bentonite bentonite and polyacrylamide prepared in a predetermined ratio. The suspension is forced into the reservoir buffer volume of water in the amount of 10-14 m3and incubated for 1-3 hours. Then through the ejector pump, the suspension is modified bentonite bentonite with a concentration of 1-6%, dosing it 0,005-0,015%aqueous solution of chromium compounds, when the discharge pressure by 10-40% vicedomini discharge injected into the formation water. Later in the reservoir pumped a mixture of polyacrylamide with a concentration of 0.07-0.25% and 0,033-0,1%solution of chromium compounds when the discharge pressure is injected into the formation water.

The proposed method for the design of heterogeneous oil reservoirs is illustrated by the following examples.

Example 1. Reservoir group And the oil fields in Western Siberia with a pronounced zonal heterogeneity is complicated by the heavy thickness of sand reservoir, heterogeneous lithology. Average reservoir permeability - 0,270 μm2. The reservoir is characterized by the secretion of stocks. The current flow rate of the liquid exceeds 100 tons/day, the average water content for layer - 90,5%. Oil reservoir is developed using flooding. Middle pickup injection wells is 300 m3/day. On a separate injection well, the injection of more than 900 m3/day.

In the injection well with the pickup 930 m3/day at discharge pressure 81,0 ATM using a pump unit pumped 4%suspension of modified bentonite bentonite grade PMMA 0.06%aqueous solution of polyacrylamide brand PDA. The injection was made by dispensing the calculated amount of the modified bentonite bentonite through the ejector into the solution of polyacrylamide. The suspension is pushed into the reservoir in the morning the major volume of water at 10 m 3and stood for 2 hours. Then through the ejector've added 3%suspension of modified bentonite bentonite batching it in a 0.005%aqueous solution of chromium acetate, when the discharge pressure of 89.1 ATM (10% higher discharge pressure injected into the formation water). Later in the reservoir was pumped mixture of polyacrylamide with a concentration of 0.1% and 0.05%solution of chromium acetate at discharge pressure injected into the formation water, pushed the reagents in the reservoir and ran well.

After the injection of a polymer dispersed system pickup wells decreased to 480 m3/day. After 6 months after treatment wells cumulative incremental oil production from the producing wells was 5,016 thousand tons In producing wells installed to reduce the water content of products produced by 2.0-3.2% and increase production of oil.

Example 2. Reservoir group B oil field in Western Siberia complicated powerful thickness of the sand reservoir, heterogeneous lithology. Average reservoir permeability - 0,203 μm2certain intervals - more than 1.5 μm2. The reservoir is characterized by the secretion of stocks. The current flow rate of the liquid is 167,9 t/d, the average water content in the layer is 91.5%. Oil reservoir is developed using flooding. The average priemysel the injection wells is 391 m 3/day, in individual wells of up to 1000 m3/day.

In the injection well with the pickup 974 m3/day at discharge pressure of 93 bar with pump unit've added 6%suspension of modified bentonite bentonite brand PBMB in 0.1%aqueous solution of polyacrylamide brand PDS 40 NT. The injection is produced by dispensing through the ejector dry mixture of modified bentonite bentonite and polyacrylamide prepared in a predetermined ratio. The suspension is pushed into the reservoir buffer volume of water in the amount of 12 m3and stood for 3 hours. Then through the ejector pumped 4%suspension of modified bentonite bentonite batching it in 0,015%aqueous solution of sodium bichromate, when the discharge pressure 107,0 ATM (15% higher discharge pressure injected into the formation water). Later in the reservoir was pumped a mixture of powdered polyacrylamide based on the 0.15%concentration and 0.1%aqueous solution of chromium acetate at discharge pressure injected into the formation water, pushed the reagents in the reservoir and ran well.

After the injection of a polymer dispersed system pickup wells declined to 406 m3/day. After 6 months after treatment wells cumulative incremental oil production from the producing wells was 5,583 thousand tons In producing IC is aging the decrease of water content in crude production by 1.7-2.4% and increase production of oil.

Thus, the developed method allows to effectively regulate the development of oil fields by flooding to increase oil recovery. The method can be used for reservoir stimulation with different reservoir properties, including the formation of zonal heterogeneity and fractured reservoirs.

The way to develop heterogeneous oil reservoirs, including flooding, cyclic injection components polymer dispersed system containing polyacrylamide, bentonite, the chromium compound and water, characterized in that as bentonite use modified bentonite bentonite in this case, initially pumped 4-6%suspension of modified bentonite bentonite in 0,04-0,12%aqueous solution of polyacrylamide, push it into the reservoir buffer volume of water and incubated for 1-3 hours, then pumped 1-6%suspension of modified bentonite bentonite in water containing 0,005-0,015% chrome compounds, at a pressure by 10-40% higher than the discharge pressure of the water, and the mixture of 0.07-0.25%aqueous solution of polyacrylamide and 0,033-0.1%solution of chromium compounds when the discharge pressure of the water.



 

Same patents:

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SUBSTANCE: method involves injecting hydrophobic composition in water influx channels; lowering and installing shutter provided with shoe at shutter end within water influx interval. The shoe may slide upwards in axial direction and is retained with shear members. The shoe has longitudinal and side communicating channels. Before hydrophobic composition injection the shutter is lowered to well bottom without supporting thereof. After that low-diameter pipe string is additionally inserted in shutter to provide airtight cooperation thereof with longitudinal channel. After hydrophobic composition injection through side channels the shutter is lowered to well bottom up to upward shoe movement with side channel closing. Low-diameter pipe string is removed from well before shutter installation.

EFFECT: improved water influx isolation.

1 dwg

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20 cl, 5 ex, 3 tbl

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1 tbl

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2 cl, 2 dwg, 1 tbl

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1 tbl

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3 cl, 3 tbl, 3 dwg

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31 cl, 3 dwg, 2 ex

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5 cl, 2 tbl

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3 ex, 1 tbl

FIELD: oil production, particularly to develop non-uniform oil reservoir to limit water inflow in production wells and to increase oil recovery.

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3 ex, 1 tbl

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11 cl, 1 tbl

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7 cl, 6 tbl

FIELD: oil and gas production.

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13 cl, 20 dwg, 1 tbl, 3 ex

FIELD: oil and gas production.

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1 tbl

FIELD: oil production, oil refinery and petrochemical industries, particularly for hydrogen sulfide and mercaptan neutralization in hydrocarbon medium with the use of chemical neutralization agents.

SUBSTANCE: hydrogen sulfide and mercaptan neutralizing agent comprises 30-58% by weight of formalin, alkali metal, preferably sodium, hydroxide or carbonate in amount of 0.1-3% by weight, hexamethylenetetramine in amount of 15-25% by weight, remainder is tertiary alkamine, preferably triethanolamine and/or methyldethanolamine. Neutralizing agent in accordance with the second embodiment additionally includes bactericide composition.

EFFECT: increased neutralizing agent efficiency, enhanced manufacturability (low solidification temperature) and reactivity, provision of high hydrocarbon medium (oil, oil product and gaseous hydrocarbon) cleaning of hydrogen sulfide and light-weight mercaptans at room and increased temperatures (of 10-90°C and higher), improved bactericidal activity and corrosion inhibiting effect in hydrogen sulfide mediums, possibility of neutralizing agent usage as bactericide and corrosion inhibitor in oil-field media.

7 cl, 15 ex, 1 tbl

FIELD: oil production, particularly to increase oil reservoir productivity and intake capacity of injection well by mud removal from well bottom zone of terrigenous clay reservoir having low permeability and/or from bottom of well characterized by decreased output resulted from pore mudding with clay material.

SUBSTANCE: method involves injecting aqueous hydrochloric acid solution; supplying aqueous surfactant solution; injecting aqueous oxygen-containing agent solution and performing time delay; supplying aqueous surfactant solution; injecting aqueous hydrochloric acid solution; executing time delay and developing well. Aqueous hydrochloric acid solution includes inhibited hydrochloric acid taken in amount of 4-12 % by weight, hydrofluoric acid in amount of 0.01-4% by weight, acetic acid in amount of 0.1-4% by weight, surfactant, namely oxyethylated monoalkylphenols based on propylene terpolymer in amount of 0.05-4% by weight, remainder is water. Volume of aqueous hydrochloric acid solution is equal to 0.1-3 m3 per 1 m of perforated productive reservoir thickness. The aqueous surfactant solution includes 0.1-3% by weight of surfactant and water and is taken in amount of 0.2-1 m3 per 1 m of perforated productive reservoir thickness. Aqueous oxygen-containing agent solution is 5-12% aqueous sodium carbonate perhydrate solution or 5-12% aqueous sodium borate perhydrate solution or 5-15% aqueous carbamide perhydrate solution or 3-10% aqueous hydrogen peroxide solution or 5-20% aqueous sodium hypocloride or 5-20% aqueous potassium hypocloride solution and is taken in amount of 0.1-3 m3 per 1 m of perforated productive reservoir thickness. Aqueous oxygen-containing agent solution may additionally include surfactant, namely oxyethylated monoalkylphenols based on propylene terpolymer in amount of 0.05-4% by weight. Time delay is carried out for not more than 8 hours.

EFFECT: increased treatment efficiency, increased well bottom zone permeability and well productivity.

3 cl, 1 tbl

FIELD: oil and gas production.

SUBSTANCE: invention provides a method of developing oil pool allowing production of oil from water-rich oil reservoir under difficult geological-tectonic conditions in the last development stage. In the method, neutral salt of carbonic acid and acid solution are forced into formation through injecting well with water generated in gas-liquid fringe created in formation. After pumping of neutral salt of carbonic acid, acid solution is pumped by portions alternating with water pumping. Before pumping of acid solution portions beginning by at least second portion, selective insulation of high-permeable formation intervals is performed. Aforesaid neutral salt of carbonic acid utilized is sodium carbonate aqueous solution or aqueous suspension of calcium carbonate and aforesaid acid solution is aqueous hydrochloric acid solution. Selective insulation of high-permeable formation intervals involves use of freshly prepared controllable viscoelastic composition containing water-soluble acrylic polymer, cross-linking agent, thermal stabilizer, surfactant, and water. Summary concentration of acid solution is determined from concentration of neutral salt of carbonic acid on the base of stoichiometric proportions.

EFFECT: increased efficiency of maintaining formation pressure and thereby oil recovery of formation due to leveled displacement front and reduced probability of the rupture of formation rock backbone, and simplified control of phase state of gas-liquid fringe by changing pressure of pumped acid solution portions.

8 cl

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