阅读说明：本技术 水基钻井液用增效剂及其制备方法、水基钻井液和应用 (Synergist for water-based drilling fluid, preparation method of synergist, water-based drilling fluid and application of synergist ) 是由 全晓虎 曹宇 尤维志 杨静 王义虎 马洪礼 黄耀存 尤志良 *** 倪长宇 余加 于 2020-07-15 设计创作，主要内容包括：本发明提出水基钻井液用增效剂及其制备方法、水基钻井液和应用,属于钻井液技术领域,该增效剂由包括如下重量份数的原料制备而得：苯乙烯磺酸钠15～25份,烯丙基三甲基氯化铵8～15份,双十二烷基二甲基溴化铵2～8份,正辛基三乙氧基硅烷1～5份,丙基三乙氧基硅烷1～5份,月桂醇磺基琥珀酸酯二钠1～5份,纳米二氧化硅10～20份,石蜡8～15份等。该增效剂可用于水基钻井液的制备及页岩气开发领域,可降低岩石表面自由能,改变水相或油相与岩石储层表面的接触角,阻止水相或油相进入储层,并且,可同时作为抑制剂、润滑剂和油气层保护剂使用。此外,该增效剂具有微-纳结构,可实现对不同尺寸微裂缝的全尺寸封堵。(The invention provides a synergist for a water-based drilling fluid, a preparation method thereof, the water-based drilling fluid and application, and belongs to the technical field of drilling fluids, wherein the synergist is prepared from the following raw materials in parts by weight: 15-25 parts of sodium styrene sulfonate, 8-15 parts of allyl trimethyl ammonium chloride, 2-8 parts of didodecyl dimethyl ammonium bromide, 1-5 parts of n-octyl triethoxysilane, 1-5 parts of propyl triethoxysilane, 1-5 parts of disodium lauryl sulfosuccinate, 10-20 parts of nano silicon dioxide, 8-15 parts of paraffin and the like. The synergist can be used in the fields of preparation of water-based drilling fluid and development of shale gas, can reduce free energy on the surface of rock, change a contact angle between a water phase or an oil phase and the surface of a rock reservoir, prevent the water phase or the oil phase from entering the reservoir, and can be used as an inhibitor, a lubricant and a hydrocarbon reservoir protective agent at the same time. In addition, the synergist has a micro-nano structure, and can realize full-size plugging of microcracks with different sizes.)

1. A synergist for water-based drilling fluid is characterized in that,

the compound is prepared from the following raw materials in parts by weight:

15-25 parts of sodium styrene sulfonate, 8-15 parts of allyl trimethyl ammonium chloride, 2-8 parts of didodecyl dimethyl ammonium bromide, 1-5 parts of n-octyl triethoxysilane, 1-5 parts of propyl triethoxysilane, 1-5 parts of disodium lauryl sulfosuccinate, 10-20 parts of nano silicon dioxide, 8-15 parts of paraffin, 2-8 parts of ethanol and 25-35 parts of water.

2. The enhancer as claimed in claim 1,

the particle size of the nano silicon dioxide is 100-500 nm.

3. A process for the preparation of the potentiator of claim 1 or 2, comprising the steps of,

1) mixing didodecyldimethylammonium bromide, distilled water and ethanol, heating to 65-75 ℃, adding nano silicon dioxide, n-octyltriethoxysilane and paraffin, and reacting to obtain a surface modified product;

2) and cooling the surface modified product, adding sodium styrene sulfonate, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate and propyltriethoxysilane, heating to 50-75 ℃, and reacting to obtain the synergist.

4. The method of claim 3,

in the step 1), the reaction temperature is 65-75 ℃; the reaction time is 2-3 h.

5. The method of claim 3,

in the step 2), cooling the surface modified product obtained in the step 1) to 20-40 ℃; the reaction temperature is 50-75 ℃; the reaction time is 8-16 h.

6. A water-based drilling fluid is characterized in that,

comprising the synergist of claim 1 or 2.

7. The drilling fluid of claim 6,

the compound is prepared from the following raw materials in parts by weight:

90-110 parts of soil slurry, 2-4 parts of synergist, 1-2 parts of bionic inhibitor, 2-3 parts of bionic blocking agent, 2-3 parts of bionic wall-fixing agent, 1-3 parts of high-temperature-resistant filtrate reducer, 1-3 parts of bonding lubricant, 0.2-0.5 part of coating agent, 4-30 parts of salt and weighting agent.

8. The drilling fluid of claim 7,

the biomimetic inhibitor is aromatic amine hydrochloride;

the bionic plugging agent is polyimide modified nano graphene oxide;

the bionic wall-fixing agent is characterized in that the main chain is methacrylate copolymer, and dopamine hydrochloride is grafted on the side chain.

9. The drilling fluid of claim 7,

the bonding lubricant is a fatty acid glyceride lubricant;

the coating agent is obtained by copolymerizing acrylamide;

the weighting agent comprises barite or limestone.

10. The use of the drilling fluid according to any one of claims 6 to 9 in shale gas development.

Technical Field

The invention belongs to the technical field of drilling fluid, and particularly relates to a synergist for a water-based drilling fluid, a preparation method of the synergist, the water-based drilling fluid and application of the synergist.

Background

With the increasing development of drilling technology, high-difficulty wells such as ultra-deep wells and extended reach wells become the main research direction for oil and gas drilling. However, when drilling in a shale stratum in the drilling process, the shale is easy to hydrate, expand and disperse when meeting the traditional drilling fluid, and is difficult to drill in an effective oil-gas layer, so that the problems of instability of a well wall, damage to a reservoir layer and the like are caused.

In 2000, the professor of Jiang Cheng and others put forward a basic theory system of gas-moisture property of a porous medium oil and gas reservoir for the first time, and establish a theory of amphiphobicity of the rock surface of the oil and gas reservoir, so that the problem of borehole wall instability can be effectively solved. CN108165241B discloses a super-hydrophobic composite material prepared by mixing nano TiO₂And nano SiO₂After the first mixing, nano TiO is obtained₂And nano SiO₂The dispersion liquid is mixed with a fluorine-containing silicon coupling agent, and the double-sparse type composite material can be used in water-based drilling fluid, can strongly inhibit hydration expansion and dispersion, and effectively solves the problems of borehole wall instability, reservoir damage and the like.

Disclosure of Invention

The invention provides a synergist for a water-based drilling fluid and a preparation method thereof, the water-based drilling fluid and a preparation method and application thereof.

On one hand, the invention provides a synergist for a water-based drilling fluid, which is prepared from the following raw materials in parts by weight:

15-25 parts of sodium styrene sulfonate, 8-15 parts of allyl trimethyl ammonium chloride, 2-8 parts of didodecyl dimethyl ammonium bromide, 1-5 parts of n-octyl triethoxysilane, 1-5 parts of propyl triethoxysilane, 1-5 parts of disodium lauryl sulfosuccinate, 10-20 parts of nano silicon dioxide, 8-15 parts of paraffin, 2-8 parts of ethanol and 25-35 parts of water.

Furthermore, the particle size of the nano silicon dioxide is 100-500 nm.

In another aspect, the present invention provides a method for preparing any of the above synergists, comprising the steps of,

1) mixing didodecyldimethylammonium bromide, distilled water and ethanol, heating to 65-75 ℃, adding nano silicon dioxide, n-octyltriethoxysilane and paraffin, and reacting to obtain a surface modified product;

2) and cooling the surface modified product, adding sodium styrene sulfonate, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate and propyltriethoxysilane, heating to 50-75 ℃, and reacting to obtain the synergist.

Further, in the step 1), the reaction temperature is 65-75 ℃; the reaction time is 2-3 h.

Further, in the step 2), cooling the reaction product to 20-40 ℃; the reaction temperature is 50-75 ℃; the reaction time is 8-16 h.

In yet another aspect, the present invention provides a water-based drilling fluid comprising any of the above synergists.

Further, the compound is prepared from the following raw materials in parts by weight:

90-110 parts of soil slurry, 2-4 parts of synergist, 1-2 parts of bionic inhibitor, 2-3 parts of bionic blocking agent, 2-3 parts of bionic wall-fixing agent, 1-3 parts of high-temperature-resistant filtrate reducer, 1-3 parts of bonding lubricant, 0.2-0.5 part of coating agent, 4-30 parts of salt and weighting agent.

Further, the biomimetic inhibitor is aromatic amine hydrochloride;

the bionic plugging agent is polyimide modified nano graphene oxide;

the bionic wall-fixing agent is a methacrylate copolymer with a main chain and dopamine hydrochloride grafted on a side chain.

Further, the bonding lubricant is a fatty acid glyceride type lubricant;

the coating agent is obtained by copolymerizing acrylamide;

the weighting agent comprises barite or limestone.

In another aspect, the invention provides an application of any one of the drilling fluids in shale gas development.

The invention has the following advantages:

the invention provides a synergist for a water-based drilling fluid and a double-thinning type high-efficiency water-based drilling fluid, wherein the synergist is ester emulsion formed by scientifically compounding didodecyl dimethyl ammonium bromide, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate, hydrophobic monomers of n-octyl triethoxysilane, propyl triethoxysilane and the like, can reduce the free energy of the surface of a rock, change the contact angle between a water phase or an oil phase and the surface of a rock reservoir, prevent the water phase or the oil phase from entering the reservoir, and reduce the pressure of a capillary tube, so that the synergist can be simultaneously used as an inhibitor, a lubricant and an oil-gas layer protective agent in the water-based drilling fluid. In addition, the synergist has a micro-nano structure, and can realize full-size plugging of micro cracks with different sizes.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a transmission electron micrograph of the synergist obtained in example 1;

FIG. 2 is a scanning electron micrograph of the synergist obtained in example 1;

FIG. 3 is a graph showing the change of water contact angle of the core before and after the synergist obtained in example 1 is treated;

FIG. 4 is a graph showing the effect of the synergist obtained in example 1 on the surface free energy of a core;

FIG. 5 shows the results of the natural imbibition test of the synergist obtained in example 1;

FIG. 6 is a graph of the hydrophobic effect of the drilling fluid obtained in example 4 and comparative example 1; wherein, FIG. 6(a) is a graph of the hydrophobic effect of the drilling fluid obtained in example 4, and FIG. 6(b) is a graph of the hydrophobic effect of the drilling fluid of the environmental protection system in comparative example 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict. The source of the reaction raw material is not particularly limited.

The embodiment of the invention provides a synergist for a water-based drilling fluid, which is prepared from the following raw materials in parts by weight:

15-25 parts of sodium styrene sulfonate, 8-15 parts of allyl trimethyl ammonium chloride, 2-8 parts of didodecyl dimethyl ammonium bromide, 1-5 parts of n-octyl triethoxysilane, 1-5 parts of propyl triethoxysilane, 1-5 parts of disodium lauryl sulfosuccinate, 10-20 parts of nano silicon dioxide, 8-15 parts of paraffin, 2-8 parts of ethanol and 25-35 parts of water.

The synergist drill provided by the embodiment of the invention is an additive composition for water-based drilling fluid, can improve the performance of the water-based drilling fluid, and simultaneously plays a role of a hydrophobic agent, an inhibitor, a lubricant, a hydrocarbon reservoir protective agent and a blocking agent.

According to the synergist provided by the embodiment of the invention, didodecyl dimethyl ammonium bromide, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate and the like react with hydrophobic monomers, namely n-octyl triethoxysilane and propyl triethoxysilane, so as to obtain the ester emulsion synergist with the hydrophobic and oleophobic effects. The size of the particles in the obtained ester emulsion is between 50 and 100nm, a nanoscale rough structure with unevenness is formed on the surface after the ester emulsion is used, and meanwhile, branches connected among synergist products integrally form a micron-scale physical structure.

The synergist provided by the embodiment of the invention can reduce the free energy of the rock surface, change the contact angle between the water phase or the oil phase and the rock reservoir surface, prevent the water phase or the oil phase from entering the reservoir, and simultaneously reduce the capillary pressure, so that the synergist can be simultaneously used as an inhibitor, a lubricant and an oil-gas layer protective agent in a water-based drilling fluid, thereby inhibiting the hydration expansion and dispersion, realizing the lubrication effect of reducing resistance and viscosity, the self-cleaning effect and the excellent oil-gas layer protective effect, and further effectively protecting the reservoir. In addition, the micro-nano structure can realize full-size plugging of micro cracks with different sizes, and the surface tension of each contact surface is changed to achieve the purpose of synergy. The synergist has low toxicity, good compatibility, high temperature resistance up to 150 deg.C, and wide application range.

Furthermore, the particle size of the nano silicon dioxide is 100-500 nm. After the nano-scale silicon dioxide is modified, the modified nano-scale silicon dioxide is polymerized with monomers such as sodium styrene sulfonate and the like, so that nano-scale particles are contained in the ester emulsion synergist, and meanwhile, branches connected among synergist products form a micron-scale physical structure integrally, and the micro-nano multi-scale physical structure is favorable for hydrophobic and oleophobic characteristics.

The embodiment of the invention also provides a preparation method of the synergist, which comprises the following steps,

1) mixing didodecyldimethylammonium bromide, distilled water and ethanol, heating to 65-75 ℃, adding nano silicon dioxide, n-octyltriethoxysilane and paraffin, and reacting to obtain a surface modified product;

2) and cooling the surface modified product, adding sodium styrene sulfonate, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate and propyltriethoxysilane, heating to 50-75 ℃, and reacting to obtain the synergist.

The synergist provided by the embodiment of the invention is prepared by firstly utilizing didodecyl dimethyl ammonium bromide, paraffin and n-octyl triethoxysilane to modify the surface of nano-scale silicon dioxide, and then polymerizing the nano-scale silicon dioxide with sodium styrene sulfonate, allyl trimethyl ammonium chloride, disodium lauryl sulfosuccinate and propyl triethoxysilane to obtain the ester emulsion synergist with the hydrophobic and oleophobic effects. Hydrophobic monomers are added in the surface modification and polymerization reaction stages, which is beneficial to the hydrophobic and oleophobic properties of the product.

Further, in the step 1), the reaction temperature is 65-75 ℃; the reaction time is 2-3 h.

Further, in the step 2), cooling the reaction product to 20-40 ℃; the reaction temperature is 50-75 ℃; the reaction time is 8-16 h.

The embodiment of the invention also provides a water-based drilling fluid which comprises the synergist.

Specifically, the water-based drilling fluid provided by the embodiment of the invention is prepared from the following raw materials in parts by weight:

90-110 parts of soil slurry, 2-4 parts of synergist, 1-2 parts of bionic inhibitor, 2-3 parts of bionic blocking agent, 2-3 parts of bionic wall-fixing agent, 1-3 parts of high-temperature-resistant filtrate reducer, 1-3 parts of bonding lubricant, 0.2-0.5 part of coating agent, 4-30 parts of salt and weighting agent.

The water-based drilling fluid provided by the embodiment of the invention is a double-thinning high-efficiency water-based drilling fluid, and is characterized in that a synergist, a bionic inhibitor, a bionic blocking agent, a bionic wall-fixing agent, a high-temperature-resistant filtrate reducer, a coating agent and the like are scientifically compounded, liquid phase is prevented or reduced from entering a rock by changing the free energy of the surface of the rock, meanwhile, the change of the free energy prevents the capillary effect of the rock, reduces the damage to the rock, enhances the cohesive force of rock particles, and avoids borehole wall instability caused by the capillary force; in addition, the nanoparticles in the synergist can realize the plugging of rock gaps. Therefore, the double-thinning type high-efficiency water-based drilling fluid can achieve the four-in-one effects of reducing drag, protecting an oil-gas layer, stabilizing a well wall and increasing speed, and further achieves the drilling target of safety, high efficiency, economy and environmental protection.

Further, the soil slurry is bentonite soil slurry with the mass fraction of 1% -4%. Specifically, bentonite for drilling fluid can be added into water, stirred at a high speed for 20min, and maintained at normal temperature for 24h to obtain the bentonite for drilling fluid.

Further, the biomimetic inhibitor is aromatic amine hydrochloride. Specifically, the biomimetic inhibitor takes aromatic amine as a raw material, and synthesizes aromatic amine hydrochloride with biomimetic groups (dopamine hydrochloride) through multi-step organic reaction.

Further, the bionic plugging agent is polyimide modified nano graphene oxide. Specifically, the bionic plugging agent is obtained by taking graphene oxide as a raw material and performing polyimide surface modification on a graphene oxide nano material.

Furthermore, the main chain of the bionic wall-fixing agent is methacrylate copolymer, and dopamine hydrochloride is grafted on the side chain. Wherein the methacrylate copolymer comprises at least one of octadecyl methacrylate and polyethylene glycol methacrylate. Specifically, the bionic wall-fixing agent is a water-soluble polymer with a bionic group, which is synthesized by taking a water-soluble polymer methacrylate copolymer with a large number of hydroxyl groups as a main chain and grafting the bionic group (dopamine hydrochloride) to a polymer side chain through a free radical graft polymerization reaction.

Further, the bonding lubricant is a fatty acid glyceride type lubricant. Specifically, the bonding lubricant is a fatty acid glyceride type lubricant synthesized by simulating bonding between mucus secreted by earthworms and clay.

Further, the coating agent is obtained by copolymerizing acrylamide. Specifically, the coating agent is a multi-component copolymer emulsion which is prepared by taking acrylamide as a main raw material and performing multi-component copolymerization.

Further, the high-temperature resistant fluid loss additive is prepared by reacting fibers and high-temperature resistant materials serving as raw materials.

Further, the salt includes at least one of sodium chloride, potassium chloride, sodium formate, and potassium formate.

Further, the weighting agent comprises at least one of barite and limestone. Wherein the density of the weighting agent can be 1-3 g/cm³. For example, the barite may have a density of 1.4g/cm³。

Further, the drilling fluid also includes an alkali, such as NaOH, and the like. Mainly for adjusting the pH of the drilling fluid.

An embodiment of the present invention further provides a preparation method of the drilling fluid, including the following steps:

mixing the soil slurry, the bionic inhibitor, the bionic plugging agent and the bionic wall-fixing agent;

adding a high-temperature resistant filtrate reducer and mixing;

adding synergist, bonding lubricant and coating agent, and mixing;

adding salt and weighting agent, and mixing to obtain the product.

Specifically, the method comprises the following steps:

placing the soil slurry into a slurry cup of a stirrer, adjusting the stirring speed of the stirrer to 70-80 r/min, adding the bionic inhibitor, the bionic plugging agent and the bionic wall-fixing agent while stirring, and stirring for 10 min; adding high temperature resistant filtrate reducer, and stirring for 10 min; adding synergist, bonding lubricant and coating agent, and stirring for 10 min; adding salt and weighting agent, and stirring for 1h to obtain the product.

The embodiment of the invention also provides application of the drilling fluid in shale gas exploitation.

The present invention will be described in detail with reference to examples.