CN104453770B - Method of selective water shutoff in oil well depth by using waste diapers - Google Patents

Abstract

The invention relates to a method for implementing selective water plugging in deep parts of oil wells by using waste diapers, which comprises the following steps: preparing a plugging agent solution: adding 10 parts by weight of resin particles in the waste diaper into 5-15 parts by weight of organic solvent, stirring and dissolving at 40-60 ℃, adding 10-200 parts by weight of diesel oil, and stirring and mixing to obtain a plugging agent solution; wherein the organic solvent is selected from one or more of toluene, xylene, methyl acetate, ethyl acetate and acetone; adding the plugging agent solution into the carrier fluid by taking diluted crude oil as the carrier fluid to obtain plugging agent oil, and extruding the plugging agent oil into the stratum from the oil sleeve annulus; ejecting the plugging agent oil liquid into the deep part of the stratum by using a displacement liquid; and closing the well for 1-2 days, and normally opening the well for production. The invention utilizes the super absorbent resin in the waste diaper to selectively block water in the deep part of the oil well, can effectively control water outlet in a water layer, and does not pollute and damage an oil layer.

Description

Method of selective water shutoff in oil well depth by using waste diapers

technical field

The invention relates to a method for selective water shutoff in the deep part of an oil well, in particular to a method for implementing selective water shutoff in the deep part of an oil layer by using waste diapers, and belongs to the field of oilfield water shutoff.

Background technique

Oil well plugging refers to controlling the production of water from oil wells, with the purpose of improving the production efficiency of oil wells. Chemical water plugging is a method of injecting chemical plugging agent into the water outlet layer on the ground, and using the product of physical and chemical reactions between the plugging agent and the oil layer to plug the oil layer. Oil-soluble resin water plugging technology is based on the principle that oil-soluble resin can be dissolved in crude oil, but when it meets water, it will form agglomerated substances to block, so as to achieve the purpose of water blocking without oil blocking, and has certain selectivity. Related research on oil-soluble resin water blocking agent is as follows:

"Research on Oil-Soluble Resin Temporary Plugging Agent" (Li Kehua, Zhao Xiutai, West Prospector, 2001, S1) discloses that the use of oil-soluble resin temporary plugging agent is an important method to protect oil and gas layers. To achieve the purpose of temporarily blocking oil and gas layers. "Indoor Research on Water-based Oil-Soluble Plugging Agent" (Ding Rui, Meng Fantao, Oilfield Chemistry, 2001, 2) discloses the water-based oil-soluble plugging agent prepared by using bitumen, oil-soluble resin and appropriate modifiers and its performance The results of the core experiment show that the water plugging performance of the water-based oil-soluble plugging agent is better than that of active heavy oil, and even better than that of the water-based gel plugging agent, and the softening point is close to or lower than that of the core (formation) temperature. The average diameter of the particles can be greater than the average diameter of the core pores, and when the softening point is 20°C higher than the temperature of the core (formation), only particles with a diameter smaller than the diameter of the core pores can enter the core pores to play a plugging role. The softening of asphalt and petroleum resin The point can be increased by the addition of non-softening substances, and can also be decreased by the addition of oily substances. "Research and Application of Emulsified Oil-Soluble Resin Selective Plugging Regulator" (Ju Dengfeng, Xie Gang, etc., Petroleum Geology and Engineering, 2012, 5: 119-122) discloses an oil-soluble resin plugging regulator. The plugging agent can be miscible with any proportion of water, has good fluidity, and is easy to inject into the formation. After entering the formation, the oil-soluble resin particles will aggregate to form agglomerates to block the space occupied, or adhere to the rock surface, changing the density of the rock surface. Wettability, forming a mechanical blockage of water flow, and achieving the purpose of reducing water production and increasing crude oil production.

Although the use of oil-soluble resins as plugging agents in the prior art can partially solve the problem of selective water plugging, the disadvantages of these existing oil-soluble resin plugging agents are: the core of the plugging agent exists in solid form, and cannot reach the deep part of the oil layer, so it cannot Deep selective water blocking.

On the other hand, diapers (pads or sheets), commonly known as "diapers", have become the third largest source of waste after newspapers and food and beverage packaging. The diapers currently on the market are a type of superabsorbent resin, most of which cannot be biodegraded. According to the current landfill treatment method, it takes hundreds of years to rot. A baby needs an average of 3,600 pieces before learning to "squat on the toilet" Wet diapers, under the historical conditions of the high birth rate of babies in my country today, the huge pollution it brings to the environment can be imagined. The raw materials for making diapers are mainly petroleum products. Nowadays, chemical methods are used to extract methane or plastic from diapers in foreign countries. From the perspective of energy consumption, it will cause secondary pollution to the environment. Therefore how to utilize waste and old diapers, turn waste into wealth, and reduce environmental pollution is a topic worth studying.

The superabsorbent resin used in diapers can absorb pure water or salt water tens to hundreds of times its own mass. It is widely used in agricultural and forestry production, urban landscaping, drought resistance and water retention, and sand control. The role; this kind of super absorbent resin can also be used in many fields such as medical and health care, oil exploration, building materials, transportation and so on. In addition, because this kind of superabsorbent resin can form a viscoelastic gel after absorbing water, and has certain strength and toughness, it has been gradually applied to the field of oil and gas field development in recent years, mainly used as water plugging profile control agent, plugging agent (Wang Zhengliang, Wang Xiaojuan, Ding Tao, Journal of Petroleum and Natural Gas, March 2011, Volume 33, Issue 3, P138). However, the above-mentioned research focuses on the research on salt resistance, temperature influence, etc., and the product is expensive and cannot be popularized and applied on a large scale.

After investigation, we found a technical report on the application of superabsorbent resin for selective water shutoff in deep oil layers.

Contents of the invention

The main purpose of the present invention is to provide a method for selectively shutting off water in the deep part of the oil layer by using the superabsorbent resin in the waste diapers.

Another object of the present invention is to provide a plugging agent solution for selective water plugging in deep oil layers.

In order to achieve the above-mentioned purpose, the present invention provides a method for selective water shutoff in the deep part of an oil well. The method mainly uses the superabsorbent resin in the waste diapers to implement selective water shutoff in the deep part of the oil layer, and the high water-absorbent resin in the waste diapers The water-absorbing resin is formulated into a mixture of organic solvents or a mixture that further includes diesel oil, and then mixed with crude oil and/or diesel oil and sent to the deep part of the oil layer to achieve selective water shutoff.

Specifically, the present invention provides a method for selectively shutting off water in the deep part of an oil well, the method comprising the steps of:

(1) Prepare blocking agent solution: add 10 parts by weight of resin particles in waste diapers to 5-15 parts by weight of organic solvent, stir and dissolve at 40-60°C to obtain blocking agent solution; or further add 10-200 parts by weight part of diesel oil, stirred and mixed to obtain a blocking agent solution; wherein the organic solvent is selected from one or more of toluene, xylene, methyl acetate, ethyl acetate, acetone;

(2) Using dilute crude oil and/or diesel oil as the carrier fluid, add the plugging agent solution prepared in step (1) into the carrier fluid in such an amount that the resin particles in the waste diapers account for 0.8% to 2.5% of the weight of the carrier fluid, Obtain the plugging agent oil, and squeeze the plugging agent oil from the oil casing annulus into the formation;

(3) push the plugging agent oil liquid injected in step (2) into the deep formation with displacement fluid;

(4) Shut down the well for 1 to 2 days, and open the well for normal production.

The resin particles in waste diapers are mainly composed of superabsorbent polymers (Superabsorbentpolymers, SAP for short, also called superabsorbent resin, super absorbent machine, superabsorbent polymer), which is a kind of superabsorbent polymer that can absorb and retain relatively It is a new type of functional polymer material that is much larger than its own mass. The most common type is the polymerization of acrylic acid and sodium hydroxide in the presence of an initiator to produce sodium polyacrylate (sometimes referred to as sodium acrylonitrile. ), there are also other materials such as polyacrylamide copolymers, ethylene and maleic anhydride copolymers, cross-linked carboxymethyl cellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide and starch grafted polyacrylonitrile Copolymer etc. In the present invention, the high water absorption of these materials in the waste diapers is mainly utilized to turn waste into wealth. In specific applications, waste diapers of different brands can be recycled.

In the method of the present invention, the resin particles in the waste diapers are used to prepare liquid in advance, and then carry crude oil and/or diesel oil (in order to reduce costs, preferably dilute crude oil) to the deep part of the oil layer. In the case of a large amount of water, Precipitation from crude oil and/or diesel oil absorbs water and swells to form solid blockage, which can block the water outlet channel for a long time. The super absorbent resin in the oil outlet channel will not expand, and can meet a large amount of formation water during the production process as the crude oil is produced. , can still absorb water to form solid blockage, so as to achieve the purpose of selective water blockage. The water-absorbent resin is mainly clogged, and the initial plugging strength is high, and it will gradually dissolve in water and lose its effect.

According to a specific embodiment of the present invention, in the method for selectively shutting off water in deep oil wells of the present invention, the organic solvent described herein is preferably a mixed solvent, such as mixed benzene of toluene and xylene. In order to reduce costs, the mixed benzene can be directly commercially purchased Obtain; particularly preferred volume ratio is xylene: methyl acetate: acetone=1:2:1 mixed solvent, volume ratio is xylene: ethyl acetate: acetone=1:2:1 mixed solvent, volume ratio is toluene : Ethyl acetate: acetone = 2: 4: 1 mixed solvent and the volume ratio is xylene: ethyl acetate: acetone = 2: 4: 1 mixed solvent, so that the resin particles in the waste diapers are mixed in the mixed solvent After dissolving in medium, it can be mixed with crude oil and/or diesel oil to obtain a solid-free water shutoff agent. The selective addition of diesel oil in the plugging agent solution is mainly to make the plugging agent solution better mix with the carrier fluid during application, greatly reduce the viscosity of the plugging agent, and improve the pumpability. The carrier liquid can be thin crude oil and/or diesel oil, preferably thin crude oil, which can reduce the cost compared with diesel oil.

According to a specific embodiment of the present invention, in the method for selective water shutoff in the deep part of an oil well of the present invention, the thin crude oil is crude oil with a viscosity below 100 mPa.s.

According to a specific embodiment of the present invention, in the method for selective water shutoff in the deep part of the oil well of the present invention, in the carrier liquid in step (2), a water-in-oil emulsifier accounting for 0.5-1% of the weight of the carrier liquid is also added, such as oleic acid Wait.

According to a specific embodiment of the present invention, in the method for selective water shutoff in the deep part of the oil well of the present invention, the temperature of the plugging agent oil injected into the formation is 60-80°C.

According to a specific embodiment of the present invention, in the method for selective water shutoff in the deep part of the oil well of the present invention, the amount of plugging agent oil injected into the formation is 50-180m ³ .

According to a specific embodiment of the present invention, in the method for selectively shutting off water in deep oil wells of the present invention, the displacing fluid in step (3) is crude oil, clear water or reinjected sewage from oil fields, and the amount used is 100-500 m ³ . The amount of displacement fluid used in the present invention is larger than that of general water shutoff displacement fluid, the purpose of which is to enable the plugging agent oil to enter the deep part of the oil layer to achieve the purpose of deep water shutoff.

On the other hand, the present invention provides a plugging agent solution, which is a mixture of resin particles in waste diapers and an organic solvent or a mixture that further includes diesel oil, wherein the waste diapers The resin particle is 10 parts by weight, the organic solvent is 5 to 15 parts by weight, and the diesel oil further included is 10 to 200 parts by weight; wherein the organic solvent is selected from toluene, xylene, methyl acetate, ethyl acetate, One or more of acetone, the preferred volume ratio is a mixed solvent of xylene: methyl acetate: acetone = 1:2:1, and the volume ratio is a mixture of xylene: ethyl acetate: acetone = 1:2:1 The solvent, the mixed solvent whose volume ratio is toluene:ethyl acetate:acetone=2:4:1 and the mixed solvent whose volume ratio is xylene:ethyl acetate:acetone=2:4:1. Specifically, the plugging agent solution of the present invention is prepared according to the following method: 10 parts by weight of resin particles in waste diapers are added to 5-15 parts by weight of organic solvent, stirred and dissolved at 40-60°C, and the plugging agent solution is obtained. agent solution; or further add 10 to 200 parts by weight of diesel oil, stir and mix to obtain a blocking agent solution.

In the present invention, the "deep part" can refer to the technical field of deep profile control. Generally speaking, it can be distinguished from the near-wellbore zone. The deep part can be defined as a treatment radius greater than 10 meters or a treatment capacity exceeding 1000 cubic meters.

To sum up, the present invention provides a method for selectively shutting off water in deep oil reservoirs by using resin particles in waste diapers. The present invention has the following advantages:

(1) Low cost, wide source of raw materials, environmental protection and safety.

(2) There are no solid particles in the plugging agent, which can realize deep water plugging.

(3) Swelling by water absorption, strong selectivity, water-soluble degradation, and no pollution to the formation.

(4) The construction of the original pipe string has a simple process.

detailed description

The implementation and beneficial effects of the technical solution of the present invention are described in detail below through specific examples, aiming to help readers better understand the essence and characteristics of the present invention, and not as a limitation to the scope of implementation of this case.

Preparation and evaluation of embodiment 1 blocking agent solution

Add the recycled waste diaper wet particles (mainly superabsorbent sodium polyacrylate) into the mixed solvents according to schemes k to n in Table 1, heat to 40°C to 60°C, and stir to dissolve. Experiments show that the wet particles of waste diapers can be quickly dissolved in the mixed solvents in Table 1, and no precipitation occurs after cooling to room temperature. Can improve production time rate.

Table 1. The distribution ratio of each component of the mixed solvent

Example 2

A well in Huanxi Oilfield, 1088.50m~1115.00m, 19m/4 layers, steam injection for the 13th time. The average permeability is 2913.1mD (millidarcy), the daily liquid production is 53.7m ³ , the daily oil production is 1.1 tons, and the water content is 98%. The oil well has high water cut, so it is decided to adopt selective water shutoff in the deep part of the oil layer.

The implementation steps are as follows:

1. Recycle waste diapers, peel off the fabric outside the waste diapers, take out the filler (mainly super absorbent resins such as superabsorbent sodium polyacrylate, starch grafted polyacrylonitrile copolymer), and dry them for later use;

2. Preparation of plugging agent solution: The organic solvent is a mixed solution obtained by mixing xylene, ethyl acetate and acetone at a volume ratio of 2:4:1. Heat it in a water bath to 50°C, and dry 10 parts by weight of the above-mentioned waste urine for use Add the non-wet filler particles into 10 parts by weight of the organic solvent, and stir while adding, until the waste diaper filler particles are completely dissolved, then add 100 parts by weight of diesel oil, stir and mix evenly to obtain a blocking agent solution, and set aside ;

3. Prepare 100 cubic meters of crude oil at 70°C and a viscosity of 42mPa.s on site. Based on the weight of the crude oil as 100%, first add 1% oleic acid by weight, then add 20wt% of the prepared plugging agent solution, and stir evenly to obtain plugging agent oil;

4. Use a cement truck to squeeze the plugging agent oil from the oil casing annulus into the formation (the oil well keeps the original string);

5. Reinject 100 cubic meters of sewage from the oil field to replace the plugging agent oil to the deep part of the oil layer;

6. Close the well for 2 days, and start the well for normal production.

After implementation, the daily liquid production is 38.9 cubic meters, the daily oil production is 2.4 tons, the water content is 93.8%, the cumulative increase of oil is 126 tons, the precipitation is 1480 cubic meters, and the validity period is 102 days. The effect is obvious.

Claims (10)

1. utilizing the method that waste and old diaper implements well deep part selective water plugging, the method comprising the steps of:

(1) preparation blocking agent solution: the resin particle in the 10 waste and old diapers of weight portion is joined 5～15 weight parts organic solvent In, 40～60 DEG C of stirring and dissolving, add the diesel oil of 10～200 weight portions, stirring mixing, obtain blocking agent solution；Wherein said organic One or more in toluene, dimethylbenzene, methyl acetate, ethyl acetate, acetone of solvent；

(2) with dilute crude oil for carrying liquid, blocking agent solution step (1) prepared is according to the resin particle in the most waste and old diaper Account for carry liquid weight 0.8%～2.5% amount add carry in liquid, obtain blocking agent fluid, and blocking agent fluid squeezed from oil jacket annular space Enter stratum；

Step (2) is carried liquid is also added with account for and carry liquid weight 0.5～the water-in-oil emulsifier of 1%；

(3) with displacement fluid, the blocking agent fluid that step (2) is injected is headed into earth formation deep；

(4) closing well 1～2 days, normal opening well and making production.

Method the most according to claim 1, wherein said organic solvent be volume ratio be dimethylbenzene: methyl acetate: acetone The mixed solvent of=1:2:1, volume ratio are dimethylbenzene: ethyl acetate: the mixed solvent of acetone=1:2:1, volume ratio are toluene: Ethyl acetate: the mixed solvent of acetone=2:4:1 or volume ratio are dimethylbenzene: ethyl acetate: the mixing of acetone=2:4:1 is molten Agent.

Method the most according to claim 1, wherein, described dilute crude oil is the crude oil of below viscosity 100mPa.s.

Method the most according to claim 1, wherein, described water-in-oil emulsifier is oleic acid.

Method the most according to claim 1, wherein, the middle blocking agent oil liquid temperature 60 injecting stratum of step (2)～80 DEG C.

Method the most according to claim 1, wherein, in step (2), blocking agent fluid injects the consumption on stratum is 50～180m³。

Method the most according to claim 1, wherein, in step (3), displacement fluid is crude oil, clear water or oil field recharged waste water, Its consumption is 100～500m³。

8. a blocking agent solution, this blocking agent solution is the resin particle in waste and old diaper and organic solvent and the mixing of diesel oil Liquid, wherein, is in terms of 10 weight portions by the resin particle in waste and old diaper, and organic solvent is 5～15 weight portions, diesel oil be 10～ 200 weight portions；Wherein said organic solvent one in toluene, dimethylbenzene, methyl acetate, ethyl acetate, the acetone or Multiple.

Blocking agent solution the most according to claim 8, wherein, described organic solvent be volume ratio be dimethylbenzene: methyl acetate: The mixed solvent of acetone=1:2:1, volume ratio are dimethylbenzene: ethyl acetate: the mixed solvent of acetone=1:2:1, volume ratio are Toluene: ethyl acetate: the mixed solvent of acetone=2:4:1 or volume ratio are dimethylbenzene: ethyl acetate: acetone=2:4:1's is mixed Bonding solvent.

The most according to claim 8 or claim 9, blocking agent solution, this blocking agent solution prepares in accordance with the following methods and obtains: by 10 Resin particle in the waste and old diaper of weight portion joins in 5～15 weight parts organic solvent, 40～60 DEG C of stirring and dissolving, adds The diesel oil of 10～200 weight portions, stirring mixing, obtain blocking agent solution.