CN113072921B - A Viscosity Reducer for Well Bore Super Heavy Oil - Google Patents

Abstract

The invention belongs to the technical field of oilfield application chemistry, and particularly relates to a viscosity reducer for shaft super heavy oil. The viscosity reducer comprises the following components in parts by weight: 1-10 parts of nano auxiliary agent, 10-100 parts of anionic non-ionic polymer surfactant, 10-100 parts of anionic surfactant, 1-10 parts of penetrating agent, 1-10 parts of dispersing agent and 0.1-2000 times of water in total amount of the components. The viscosity reducer for thick oil in the shaft has the characteristic of strong salt and temperature resistance, can efficiently emulsify and disperse thick oil with high colloid and asphaltene content in the viscosity reducing shaft under the condition of micro disturbance, and has the viscosity reduction rate of more than 98 percent.

Description

A Viscosity Reducer for Well Bore Super Heavy Oil

technical field

The invention belongs to the technical field of oilfield applied chemistry, and in particular relates to a viscosity reducer for wellbore super heavy oil.

Background technique

The content of light components in super-heavy oil is low, the content of asphaltene and colloid is high, and the content of straight-chain hydrocarbons is low. As a result, most super-heavy oil has the characteristics of high viscosity and high density, and it is quite difficult to mine and transport. Especially in the process of gathering and transportation, when the ultra-heavy oil is lifted from the wellbore to the surface, the viscosity of the ultra-heavy oil increases rapidly due to the influence of factors such as temperature drop, resulting in channel blockage. Viscosity methods include heating method, thin oil method and chemical agent viscosity reduction method. Among them, adding emulsification viscosity reducer is a relatively new wellbore super heavy oil viscosity reduction technology. The main component of emulsification viscosity reducer is surfactant. By reducing the oil-water interfacial tension, the super heavy oil in the wellbore can be transformed from water in oil The emulsified state is transformed into the emulsified state with water as the external phase, so that the viscosity of super heavy oil is greatly reduced, which can greatly save energy consumption and operating costs.

Since the 1990s, many heavy oil reservoirs have implemented field tests of heavy oil pipeline transportation by adding surfactants, and gained a lot of valuable experience. Great progress has been made in the production and transportation of heavy oil. The emulsification viscosity reduction rate exceeds 90%. At the same time, the demulsification and dehydration technology of crude oil emulsion is also studied, which provides valuable technical support for the realization of heavy oil emulsification and normal temperature transportation. Many articles and patents have been published on the research on viscosity reduction of heavy oil, but there are still many problems, such as the universality of viscosity reducer, temperature resistance and salt resistance, demulsification after viscosity reduction, etc. Especially the viscosity reduction of super heavy oil is very difficult. The following are typical examples of viscosity reduction studies:

Recently, a new composite viscosity reducer was reported in China, which combines the advantages of oil-soluble and water-soluble viscosity reducers. The molecular chain of the viscosity reducer is grafted with a relatively high carbon number amphiphilic group and a salt-tolerant hydrophilic group, and reduces viscosity through dispersing and emulsifying capabilities. Experimental tests have shown that without water, the viscosity reducer can achieve a 50% reduction in the viscosity of super heavy oil. The agent can achieve ultra-low interfacial tension and form a relatively stable O/W emulsion.

Chinese patent application CN 102140909 A discloses a method for emulsifying and reducing the viscosity of heavy oil, comprising mixing one or more of agent A selected from refinery distillate oil, light oil or medium oil with heavy oil; Add it into the mixture of thick oil and agent A, and form an oil-in-water emulsion after mixing. The agent B is composed of anionic surfactant, nonionic-anionic surfactant and water. The emulsification and viscosity reduction method of the present invention does not use alkali, has strong resistance to mineral salts, especially can emulsify ultra-high-viscosity heavy oil with a viscosity greater than 500,000 mPa.s at 50°C, and the emulsified heavy oil has low viscosity and moderate emulsification cost. This method is more complicated and costly. In fact, light oil has been used to reduce viscosity in the first step.

Chinese patent CN 105001847 B discloses a salt-resistant heavy oil dispersion drag reducer and its preparation method. The weight percentage of each component of the salt-resistant heavy oil dispersion drag reducer is: intermediate 5-10%, fatty alcohol poly Oxyethylene polyoxypropylene ether 5-10%, EDY 20-30%, the rest is water; the weight percentage of each component of the intermediate is: modified acrylic acid 5-10%, acrylamide 80-90%, fatty alcohol polyoxyethylene ether 5-10% of acrylate, the ratio of modified acrylic acid is 75-85% of dodecyl aniline, and 15-25% of acrylic acid. The invention is suitable for the exploitation of heavy oil in oilfields. The salt-resistant heavy oil dispersing drag reducer can penetrate into the colloidal asphaltene molecules in the crude oil without stirring or micro-stirring, and disperse the stacked colloidal asphaltene molecular structure. The anti-phase component can change the hydrophilic-lipophilic balance of colloidal asphaltene molecules, thereby reducing the production viscosity of heavy oil and increasing crude oil production. This method does not mention the viscosity reduction situation of super heavy crude oil with a viscosity exceeding 50000mP.s.

CN100516164C discloses a high-temperature and high-salt-resistant nano-emulsion viscosity reducer. The viscosity reducer is composed of non-ionic surfactant, anionic surfactant, modified nano auxiliary agent, NaOH, accelerator and water. The preparation method is: add 5-7% of OP-10, 2-5% of accelerator, 0.5-2% of modified nano additives at normal temperature and pressure, and stir evenly; then add anionic surfactant 30-45 %, flat plus 1-3%; finally add 20-30% NaOH and 20-40% water, and then stir continuously at a speed of 60-120r/min for 60-90min to obtain the nano-emulsified viscosity reducer product. The viscosity reducer system has good stability and will not coalesce during storage; the formed oil-in-water particles are smaller and more uniform, which improves the seepage capacity; it can greatly reduce interfacial tension and improve oil displacement efficiency, and can be used for heavy oil recovery and delivery fields. This method has the problem of increased difficulty in demulsification after emulsification and viscosity reduction, which is not conducive to the later oil-water separation.

However, there are several problems in the existing emulsification viscosity reduction technology for wellbore ultra-heavy oil viscosity reduction. One is that the temperature and salt resistance of surfactants is poor, which cannot meet the high temperature conditions of the wellbore after steam flooding; the other is emulsification viscosity reduction. The resulting emulsion system is difficult to demulsify; the third is that there is no violent disturbance in the wellbore, and the viscosity reducing agent is mixed with the production fluid, and the viscosity reducing effect is not good.

Contents of the invention

In order to overcome the above-mentioned technical defects, the present invention provides a viscosity reducer for wellbore super heavy oil. The heavy oil viscosity reducer prepared by the invention has high viscosity reduction rate, low use concentration and good temperature and salt resistance. Under the condition of slight disturbance, the chemical agent of the invention can effectively fully interact with the ultra-heavy oil in the wellbore, reduce the viscosity and improve the fluidity.

The main purpose of the present invention is to provide a viscosity reducer for wellbore ultra-heavy oil. The chemical agent includes the following components and parts by weight: 1-10 parts of nano additives, 10-10 parts of anionic nonionic polymer surfactant 100 parts, 10-100 parts of anionic surfactant, 1-10 parts of penetrating agent, 1-10 parts of dispersant, and 0.1-2000 times of the total amount of water above.

Preferably, the following components and their parts by weight are included: 1 part of nano additives, 20-90 parts of anionic nonionic polymer surfactant, 20-90 parts of anionic surfactant, 2-9 parts of penetrating agent, 2 parts of dispersing agent -9 parts, water is 0.2-1500 times of the total amount of the above components.

Preferably, the nano-auxiliary is modified nano-silica.

Preferably, the particle size of the modified nano-silica is 10-100 nm, and the surface is modified by silane coupling agent K570.

Preferably, the anion-nonionic polymeric surfactant is a phosphate or sulfate ester salt of a phenolic resin polyoxyethylene polyoxypropylene block polymer.

Preferably, the anionic surfactant is sodium dodecylbenzenesulfonate. The anionic surfactant is cheap and easy to obtain, and is easy to interact with the gum and asphaltenes in the heavy oil.

Preferably, the penetrating agent is a high-carbon alcohol polyoxyethylene ether phosphate salt with high temperature resistance.

Preferably, the dispersant is a water-soluble polymer polyvinyl alcohol, polyacrylate or polyacrylamide.

Preferably, the degree of polymerization of the phenolic resin in the anion-nonionic polymer surfactant is 2 to 10, and the block polyether is a three-block polymer, and the order is respectively polyethylene oxide-polypropylene oxide-polyethylene oxide. Ethylene oxide has a degree of polymerization of 3-90, 3-90, and 3-90, respectively.

Preferably, the penetrating agent is a high-carbon alcohol with 8-18 carbon atoms and a polyoxyethylene polymerization degree of 3-20.

The higher the degree of polymerization of phenolic resin and block polyether, the higher the number of carbon atoms and the degree of polymerization of the penetrant, and the higher the corresponding viscosity reduction efficiency. To produce coagulation, the application effect of the degree of polymerization within the scope of the present invention is the best.

The wellbore heavy oil viscosity reducer provided by the present invention has the characteristics of strong salt and temperature resistance, and can efficiently emulsify and disperse heavy oil containing high colloid and asphaltene in the wellbore for viscosity reduction under the condition of slight disturbance, and the viscosity reduction rate is 98%. above.

The heavy oil viscosity reducer of the invention is suitable for reducing the viscosity of ordinary heavy oil, extra heavy oil and super heavy oil in wellbore, and the water content is required to be more than 30%, and is suitable for reducing the viscosity of super heavy oil under various salinity formation conditions. The dispersion system after emulsification and viscosity reduction is beneficial to pipeline transportation and does not affect the subsequent demulsification work.

detailed description

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations and/or combinations thereof.

In order to enable those skilled in the art to understand the technical solution of the present invention more clearly, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

Example 1

Get modified nano silicon dioxide 1g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 10, and block polyether is polyethylene oxide-polyoxypropylene-polyethylene oxide) Ethylene oxide, the degree of polymerization is 90) 30g, sodium dodecylbenzene sulfonate 20g, lauryl alcohol polyoxyethylene ether (polymerization degree 10) phosphate ester 1g, polyacrylate 1g, water 47g, at 30 ℃ Stir in a 250mL three-neck flask for 30min to obtain a viscosity reducer.

Example 2

Get modified nano silicon dioxide 0.5g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 10, block polyether is polyethylene oxide-polypropylene oxide- Polyethylene oxide, the degree of polymerization is 90) 20g, sodium dodecylbenzenesulfonate 10g, polyoxyethylene lauryl ether (degree of polymerization 10) phosphate ester 0.5g, polyacrylate 1g, water 68g, in Stir in a 250mL three-neck flask at 30°C for 30min to obtain the viscosity reducer.

Example 3

Get modified nano silicon dioxide 0.1g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 10, block polyether is polyethylene oxide-polypropylene oxide- Polyethylene oxide, degree of polymerization is 90) 10g, sodium dodecylbenzenesulfonate 5g, polyoxyethylene lauryl ether (degree of polymerization 10) phosphate ester 0.4g, polyacrylate 0.5g, water 84g, Stir in a 250mL three-necked flask at 30°C for 30min to obtain a viscosity reducer.

Example 4

Get modified nano silicon dioxide 0.05g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 10, block polyether is polyethylene oxide-polypropylene oxide- Polyethylene oxide, the degree of polymerization is 90) 5g, sodium dodecylbenzenesulfonate 3g, polyoxyethylene lauryl ether (degree of polymerization 10) phosphate ester 0.25g, polyacrylate 0.2g, water 91.5g , Stir in a 250mL three-neck flask at 30°C for 30min to obtain a viscosity reducer.

Example 5

Get modified nano silicon dioxide 0.5g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 2, block polyether is polyethylene oxide-polypropylene oxide- Polyethylene oxide, the degree of polymerization is 3) 20g, sodium dodecylbenzenesulfonate 10g, octanol polyoxyethylene ether phosphate (polyoxyethylene polymerization degree is 3) 0.5g, polyacrylate 1g, water 68g, stirred in a 250mL three-necked flask at 30°C for 30min to obtain a viscosity reducer.

Example 6

Get modified nano silicon dioxide 0.5g, alkyl phenolic resin polyoxyethylene polyoxypropylene block polyether sulfate (phenolic resin polymerization degree is 10, block polyether is polyethylene oxide-polypropylene oxide- Polyethylene oxide, the degree of polymerization is 90) 20g, sodium dodecylbenzenesulfonate 10g, stearyl polyoxyethylene ether phosphate (polyoxyethylene polymerization degree is 20) 0.5g, polyacrylate 1g, 68g of water was stirred in a 250mL three-necked flask at 30°C for 30min to obtain a viscosity reducer.

Comparative example 1

The difference with embodiment 2 is that anionic surfactant used is sodium petroleum sulfonate formaldehyde condensate, and others are all identical with embodiment 2.

Comparative example 2

The difference from Example 2 is that the anionic surfactant used is sodium nonylphenol polyoxyethylene ether carboxylate, and the others are the same as in Example 2.

Applications:

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and prepare it using Examples 1-6 and Comparative Examples 1-2 Viscosity reducer, according to the oil-water ratio of 3:7, wherein the viscosity reducer content is 0.3%, the viscosity reduction temperature is 130 ℃, and the viscosity reduction rate is measured. The specific viscosity reduction ratios are shown in Table 1 below:

Table 1

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, in which the viscosity reducing agent content is 0.3%, the viscosity reducing temperature is 90°C, and the viscosity reducing rate is 99.5%.

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, in which the viscosity reducing agent content is 0.3%, the viscosity reducing temperature is 70°C, and the viscosity reducing rate is 99.3%.

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, wherein the content of viscosity reducing agent is 0.3%, the viscosity reducing temperature is 60℃, and the viscosity reducing rate is 93.5%.

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, in which the viscosity reducing agent content is 0.2%, the viscosity reducing temperature is 130°C, and the viscosity reducing rate is 99.6%.

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, in which the viscosity reducing agent content is 0.2%, the viscosity reducing temperature is 80°C, and the viscosity reducing rate is 99.1%.

Select the ultra-heavy oil sample (viscosity of 300,000 mPa.s at 50°C and salinity of produced water of 20,000 ppm) in the Zheng 411 block of the Shengkai Management Area of the Oilfield Petroleum Development Center, and use the viscosity reducer prepared in Example 2. According to the oil-water ratio The ratio of 3:7, wherein the content of viscosity reducing agent is 0.15%, the viscosity reducing temperature is 80℃, and the viscosity reducing rate is 89.5%.

The viscosity reducer prepared in Example 2 was used to reduce viscosity in the borehole of Ping-19# ultra-heavy oil well in Zheng 411 block, Shengkai management area of Shengli Oilfield Petroleum Development Center. The wellbore temperature is 130-150°C, the daily fluid production is about 10m ³ , and the water cut is 50-60%. The well directly adopts the continuous dosing method, and the daily dosing amount is reduced from 50kg to 6kg. After 30 days, the electric heating is gradually reduced from 75A to 20A.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (2)

1. The viscosity reducer for the ultra-thick oil of the shaft is characterized by comprising the following components in parts by weight: 1-10 parts of nano assistant, 10-100 parts of anionic non-ionic polymer surfactant, 10-100 parts of anionic surfactant, 1-10 parts of penetrating agent, 1-10 parts of dispersing agent and 0.1-2000 times of water;

the nano-additive is modified nano-silica, the particle size of the modified nano-silica is 10-100 nm, and the surface of the modified nano-silica is modified by a silane coupling agent K570;

the anionic nonionic polymer surfactant is phosphate or sulfate of phenolic resin polyoxyethylene polyoxypropylene block polymer;

the anionic surfactant is sodium dodecyl benzene sulfonate;

the penetrant is high-temperature-resistant high-alcohol polyoxyethylene ether phosphate;

the dispersant is water-soluble polymer polyvinyl alcohol, polyacrylate or polyacrylamide;

the polymerization degree of the phenolic resin is 2-10, the block polyether is a triblock polymer, the triblock polymer is respectively polyethylene oxide-polypropylene oxide-polyethylene oxide in sequence, and the polymerization degrees are respectively 3-90, 3-90 and 3-90;

the higher alcohol has 8 to 18 carbon atoms and the degree of polymerization of polyoxyethylene is 3 to 20.

2. The viscosity reducer according to claim 1, which comprises the following components in parts by weight: 1 part of nano-additive, 20-90 parts of anionic non-ionic polymer surfactant, 20-90 parts of anionic surfactant, 2-9 parts of penetrating agent, 2-9 parts of dispersing agent and 0.2-1500 times of water of the total amount of the components.