39results about How to "No solid phase" patented technology

The invention is a recycled solidfree micro-foam drilling fluid or a completion fluid, which comprises the following components in parts by weight: 1. 2-3 parts of recycled solidfree micro-foam composite treatment agent SD-LNA; 2. 0.5-1 part of low-density solidfree tackifier SD-LNV; 3 0.5-1 part of low-density modifier SD-LFD; 4. 0.5-1 part of low-density foam stabilizer SD-LFS; 5. 0.5-1 of low-density flow type modifier SD-LFR; and 6. 100 parts of water. According to a normal preparation method, the above substances are added into water successively, mixed and stirred evenly under normal temperature and normal pressure. The invention has the advantages of low density, high viscosity, small low fluid loss, good lubricating property, strong landwaste suspension property, easy maintenance,fine cleaning capability of wells, fine inhibitory capability on clay and shale, no micro-foam convergence, recycled use and the like, can be widely applied in engineering such as petroleum, geologicdrilling and the like, is particularly applicable to construction technology of well drilling and well completion of low-pressure reservoir and exhausted reservoir.

The invention relates to a medium-high temperature oil reservoir phenolic gel self-degradation temporary plugging agent and a preparation method thereof. The temporary plugging agent is prepared fromthe following components in percentage by mass: 2 to 2.5 percent of low molecular weight polymer, 0.2 to 0.25 percent of phenolic cross-linking agent, 0.2 to 0.6 percent of aldehyde cross-linking agent, 0.05 percent of stabilizer, 0.1 percent of catalyst, 0.5 to 2 percent of gel breaker and the balance of water, wherein the sum of the mass percent of all the components is 100 percent. The gel temporary plugging agent provided by the invention can meet the requirements that the oil reservoir temperature is 60-100 DEG C, the plugging time is adjustable within 120-168h, and the gel breaking timeis adjustable within 168-240h; the plugging rate of a rock core reaches 98% or above, the permeability damage rate after gel breaking is 10% or below, a high-permeability layer of a target stratum canbe effectively plugged, flowback is easy after automatic gel breaking, damage to the stratum is extremely small, and the plugging agent can be suitable for most conventional oil reservoirs and has good field application value.

The invention discloses an acid-salt solid-phase-free medium-density workover fluid and a preparation method thereof. The acid-salt solid-phase-free medium-density workover fluid comprises the following components in parts by weight: 39-42 parts of clear water, 56-60.2 parts of sodium dihydrogen phosphate, 0.05-0.3 part of sodium dodecyl benzene sulfonate and 0.3-0.5 part of corrosion inhibitor. The low-cost acid-salt solid-phase-free medium-density workover fluid has stable performance, the density can reach 1.40 g / cm<3>, and the temperature resistance can reach 160 DEG C. The low-cost acid-salt solid-phase-free medium-density workover fluid (with the density of 1.4 g / cm<3>) is free of any solid-phase component, and thus, has the advantage of no solid phase; and compared with the formate solid-phase-free workover fluid system with the same density, the cost is lowered by 20% or above.

The invention discloses an oil layer protective solution, which is composed of water, a tackifier, a filtrate reducer, an anti-swelling agent, a surfactant, and a bactericide. The protective solution utilizes a synergetic effect of the chemical agents mentioned above so as to realize multiple protective functions on oil layer. The preparation method of the oil layer protective solution comprises the following steps: adding a surfactant and a bactericide into clean water, stirring so as to prepare a basic solution; mixing a tackifier, a filtrate reducer, and an anti-swelling agent according to a ratio so as to make into a uniform solid mixture, then adding the solid mixture into the basic solution with stirring, and stirring to dissolve the mixture so as to form the finished product. The protective solution is used during the process of workover operations such as well killing, well washing, sand washing, pump inspecting, electricity inspecting, electricity to pumping transferring, pumping to electricity transferring, blowing to pumping transferring, blowing to electricity transferring, pump upgrading, and pump depth deepening to protect the oil reservoir so as to prevent the oil reservoir from damages caused by workover fluid.

The invention discloses a solid free scale-preventing workover fluid suitable for sodium bicarbonate formation water. The fluid comprises the following components in percentage by weight: 56-97% of basic liquid, 0-12% of a weighting agent, 1.2-10% of a scale-preventing agent, 1.6-10% of a corrosion inhibitor and the balance of fresh water, wherein the density of the workover fluid is 1.20-1.55g / <cm3>; the basic liquid is an industrial calcium chloride solution with the saturated density of 1.40g / <cm3>; the weighting agent is zinc chloride; the scale-preventing agent is one of glacial acetic acid and formic acid; the corrosion inhibitor is imidazoline of quaternary ammonium salt. The density of the workover liquid disclosed by the invention can be randomly adjusted in a range from 1.20g / <cm3> to 1.55g / <cm3>. The workover fluid is particularly remarkable in scale preventing effect to sodium bicarbonate formation water, low in corrosivity to a sleeve of an oil pipe, good in compatibility with formation water, low in cost, low in damage, pollution-free, solid-free and good in mobility, and can meet the field construction demand.

The invention discloses frozen-soil hydrate deposit polyvinyl alcohol type drilling fluid, and relates to the field of natural gas hydrate exploitation. The drilling fluid is prepared from the following components: polyvinyl alcohol, sodium chloride, methyl alcohol, ethylene glycol, sulfonated phenolic resin SMP-2, potassium humate, xanthan gum, polyvinylpyrrolidone K30, polyoxyethylene and prepared water. The frozen-soil hydrate storage polyvinyl alcohol type drilling fluid can be used for frozen-soil-layer natural gas hydrate deposit drilling, and has the effects of no solid phase and low temperature resistance; a kinetic inhibitor and a synergist are added into the drilling fluid for compounding, so that relatively strong hydrate generation inhibition effect is achieved; and moreover, the drilling fluid is small in environmental harm by components, and has the advantages of being efficient, environmentally friendly, adopting cheap and easily available raw materials, and the like.

The invention discloses a natural gas hydrate storage compound drilling fluid for a frozen earth region and relates to the field of exploration of natural gas hydrate. The drilling fluid comprises thefollowing components: polyethylene glycol, sodium chloride, ethylene glycol, low viscosity carboxymethylcellulose LV-CMC, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, butyl cellosolve,tetracaproyl trimethyl ammonium bromide and prepared water. The drilling fluid can be used for drilling the natural gas hydrate storage drilling of a frozen layer, and plays roles of being free of solid phases and low-temperature resistant. By adding a dynamic inhibitor into the drilling fluid to be compounded with a synergist, the drilling fluid has a relatively high hydrate generation inhibiting effect, and the components of the drilling fluid are small in environmental damage, so that the drilling fluid has the advantages of high efficiency, environmental protection, low cost of raw materials, easily available materials and the like.

The invention discloses a compound drilling fluid for natural gas hydrate (NGH) reservoir in siltstone, and relates to the field of NGH exploitation. The drilling fluid comprises following components:sodium formate, sodium chloride, glycol, potassium chloride, potassium humate, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, ethylene glycol butyl ether, tetra-n-butyl ammonium phosphate, and make-up water. The drilling fluid is suitable for NGH drill wells in siltstone reservoir, is resistant to low temperature, and can inhibit and reduce the solid phase. The drilling fluid is compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluidhas the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention discloses a compound drilling fluid for natural gas hydrate (NGH) reservoir in a muddy siltstone stratum, and relates to the field of NGH exploitation. The drilling fluid comprises following components: sodium silicate, sodium chloride, glycol, potassium chloride, low viscosity carboxymethyl cellulose (LV-CMC), potassium polyacrylate, xanthan gum, polyvinyl caprolactam, ethylene glycol butyl ether, tetra-n-hexyl trimethyl ammonium bromide, and make-up water. The drilling fluid is suitable for NGH drill wells in muddy siltstone stratum reservoir, is resistant to low temperature, and can inhibit and reduce the solid phase. The drilling fluid is compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention discloses compound marine natural gas reservoir drilling fluid, and relates to the field of natural gas hydrate mining. The drilling fluid is prepared from the following components: sodium silicate, sodium chloride, ethylene glycol, potassium polyacrylate, low-viscosity polyanionic cellulose (LV-PAC), xanthan gum, polyvinylpyrrolidone K90, polyethylene oxide, mono-n-butyl glycol ether and prepared water, can be applied to drilling of natural gas hydrate reservoirs, and has the characteristics of no solid phase and low temperature resistance; a kinetic inhibitor and a synergist are added into the drilling fluid for compounding, so that the drilling fluid has a better hydrate generation inhibition effect; moreover, the drilling fluid components have little harm to the environment, so that the drilling fluid has the advantages of high efficiency, environmental friendliness, cheap and readily-available raw materials and the like.

The invention discloses a drilling fluid suitable for natural gas hydrate (NGH) reservoir in a frozen soil area, and relates to the field of NGH exploitation. The drilling fluid comprises following components: sodium formate, sodium chloride, methanol, glycol, low viscosity carboxymethyl cellulose (LV-CMC), potassium humate, xanthan gum, polyvinylpyrrolidone K30, polyvinyl methyl ether, and make-up water. The drilling fluid is suitable for drill wells in NGH reservoir in a frozen soil layer, does not contain any solid phase, and is resistant to low temperature. The drilling fluid is compoundedwith a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention discloses drilling fluid suitable for a marine natural gas hydrate reservoir, and relates to the field of mining of natural gas hydrate. The drilling fluid is prepared from the followingcomponents: sodium formate, sodium chloride, methanol, ethylene glycol, potassium chloride, low-viscosity carboxymethyl cellulose LV-CMC, potassium humate, xanthan gum, polyvinylpyrrolidone K30, polyvinyl methyl ether and prepared water. The drilling fluid disclosed by the invention can be used for drilling the marine natural gas hydrate reservoir and has solid-free and low temperature-resistantfunctions, the drilling fluid has a stronger hydrate generation inhibiting effect through adding a kinetic inhibitor and a synergist for compounding, components of the drilling fluid have small harm to environment, and the drilling fluid has the advantages that the efficiency is high, environmental protection is realized, raw materials are low in cost and easy to obtain, and the like.

The invention discloses an oil layer protective solution, which is composed of water, a tackifier, a filtrate reducer, an anti-swelling agent, a surfactant, and a bactericide. The protective solution utilizes a synergetic effect of the chemical agents mentioned above so as to realize multiple protective functions on oil layer. The preparation method of the oil layer protective solution comprises the following steps: adding a surfactant and a bactericide into clean water, stirring so as to prepare a basic solution; mixing a tackifier, a filtrate reducer, and an anti-swelling agent according to a ratio so as to make into a uniform solid mixture, then adding the solid mixture into the basic solution with stirring, and stirring to dissolve the mixture so as to form the finished product. The protective solution is used during the process of workover operations such as well killing, well washing, sand washing, pump inspecting, electricity inspecting, electricity to pumping transferring, pumping to electricity transferring, blowing to pumping transferring, blowing to electricity transferring, pump upgrading, and pump depth deepening to protect the oil reservoir so as to prevent the oil reservoir from damages caused by workover fluid.

The invention discloses a liquid capable of being simultaneously compounded with surface water and brine workover fluid and a preparation method thereof. The liquid is prepared from the following components in percentage by mass: 0 to 29% of weighting agent (sodium formate), 3% of antiswelling agent (potassium formate), 2% of chelating agent (ethylenediamine tetraacetic acid tetrasodium salt), andthe balance of fresh water, wherein the density of the liquid is 1.01 to 1.15g / m<3>. The liquid is compounded with the heavy sodium carbonate and calcium chloride surface water, and is also compounded with the workover fluid prepared from sodium chloride, calcium chloride and zinc chloride. The liquid has the advantages that the cost is low, the injury is weak, the pollution is avoided, the solidphase is avoided, the fluidity is good, and the like; the site construction requirements can be met.

The invention is a recycled solidfree micro-foam drilling fluid or a completion fluid, which comprises the following components in parts by weight: 1. 2-3 parts of recycled solidfree micro-foam composite treatment agent SD-LNA; 2. 0.5-1 part of low-density solidfree tackifier SD-LNV; 3 0.5-1 part of low-density modifier SD-LFD; 4. 0.5-1 part of low-density foam stabilizer SD-LFS; 5. 0.5-1 of low-density flow type modifier SD-LFR; and 6. 100 parts of water. According to a normal preparation method, the above substances are added into water successively, mixed and stirred evenly under normal temperature and normal pressure. The invention has the advantages of low density, high viscosity, small low fluid loss, good lubricating property, strong landwaste suspension property, easy maintenance, fine cleaning capability of wells, fine inhibitory capability on clay and shale, no micro-foam convergence, recycled use and the like, can be widely applied in engineering such as petroleum, geologic drilling and the like, is particularly applicable to construction technology of well drilling and well completion of low-pressure reservoir and exhausted reservoir.

The invention discloses a drilling fluid for natural gas hydrate (NGH) reservoir in a frozen soil layer, and relates to the field of NGH exploitation. The drilling fluid comprises following components: polyethylene glycol, sodium chloride, glycol, potassium humate, xanthan gum, polyvinylpyrrolidone K90, propylene glycol monomethyl ether, mono-n-butyl glycol ether, and make-up water. The drilling fluid is suitable for drill wells in NGH reservoir in a frozen soil layer, does not contain any solid phase, and is resistant to low temperature. The drilling fluid is compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention discloses a polyvinyl alcohol compound drilling fluid for natural gas hydrate (NGH) reservoir in a frozen soil area, and relates to the field of NGH exploitation. The drilling fluid comprises following components: polyvinyl alcohol, sodium chloride, methanol, glycol, sulfonated phenolic resin (SMP-2), potassium humate, xanthan gum, polyvinylpyrrolidone K-90, propylene glycol phenyl ether, polyvinyl methyl ether, and make-up water. The drilling fluid is suitable for NGH drill wells in a frozen soil layer, does not contain any solid phase, and is resistant to low temperature. The drilling fluid is compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention discloses complex marine natural gas hydrate storage drilling fluid, and relates to the field of natural gas hydrate exploitation. The drilling fluid is prepared from the following components: sodium formate, sodium chloride, ethylene glycol, low viscosity carboxymethyl cellulose (LV-CMC), potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, polyethylene oxide, propylene glycol monomethyl ether and prepared water. The drilling fluid can be used for marine natural gas hydrate storage and drilling, and has the effects of no solid phase and low-temperature resistance. Thedrilling fluid has higher hydrate generation and inhibition effects by compounding an added kinetic inhibitor with a synergist; in addition, the components of the drilling fluid have little hazard tothe environment and has the advantages of high efficiency, environment friendliness, low-priced and easily-obtained raw materials and the like.

The invention relates to drilling fluid for natural gas hydrate reservoir in argillaceous siltstone, which relates to the field of natural gas hydrate exploitation. The drilling fluid disclosed by theinvention consists of the following components: sodium silicate, sodium chloride, glycol, potassium chloride, low-viscosity carboxymethylcellulose LV-CMC, potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, propylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether and prepared water. The drilling fluid, which can be used in the drilling of natural gas hydrate reservoir in argillaceous siltstone, has low temperature-resistant, inhibiting and solid phase-reducing effects; by adding a kinetic inhibitor to be compounded with a synergist, the drilling fluid has a high hydrate formation inhibition effect, moreover, the environmental hazard of the components of the drilling fluid is low, and the drilling fluid has the advantages of high effectiveness, environment friendliness, cheap and easy-to-obtain raw materials and the like.

The invention provides compound polyvinyl alcohol drilling fluid applied to storage of hydrates in frozen soil layers and relates to the field of exploitation of natural gas hydrates. The drilling fluid comprises the following components: polyvinyl alcohol, sodium chloride, ethylene glycol, sulfonated phenolic resin SMP-2, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, ethylene glycoldiethyl ether, tetrahexamethyltrimethyl ammonium bromide and prepared water. The drilling fluid is capable of being applied to drilling with storage of the natural gas hydrates in the frozen soil layers, is free of solid phase and has resistance to low temperature; a kinetic inhibitor is added into the drilling fluid and is compounded with a synergist; the drilling fluid has an excellent effect of inhibiting generation of hydrates; meanwhile, the components of the drilling fluid are low in harm to the environment; and the drilling fluid has the advantages of high efficiency, environment friendliness and cheap and easily available raw materials.

The invention discloses marine hydrate storage polyvinyl alcohol type drilling fluid and relates to the field of natural gas hydrate production. The drilling fluid is prepared from the following components including polyvinyl alcohol, sodium chloride, methanol, potassium chloride, ethylene glycol, sulfonated phenolic resin SMP-2, potassium humate, xanthan gum, polyvinylpyrrolidone K30, polyvinyl methyl ether and prepared water. The drilling fluid can be used for marine natural gas hydrate storage drilling, has the effects of no solid phase and low temperature resistance, has stronger hydrate generation inhibition effect by adding a kinetic inhibitor for compounding with a synergist and has the advantages of high efficiency, environmental protection, cheapness and availability in raw materials and the like as the components of the drilling fluid are small in environmental harm.

The invention discloses complex frozen soil hydrate storage polyvinyl alcohol drilling fluid, and relates to the field of natural gas hydrate exploitation. The drilling fluid is prepared from the following components: polyvinyl alcohol, sodium chloride, ethylene glycol, sulfonated phenolic resin SMP-2, potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, polyethylene oxide, propylene glycol phenyl ether and prepared water. The drilling fluid can be used for frozen soil layer natural gas hydrate storage drilling, and has the effects of no solid phase and low-temperature resistance. The drilling fluid has higher hydrate generation and inhibition effects by compounding an added kinetic inhibitor with a synergist; in addition, the components of the drilling fluid have little hazard to the environment and have the advantages of high efficiency, environment friendliness, low-priced and easily-obtained raw materials and the like.

The invention discloses silty mudstone natural gas hydrate storage compound type drilling fluid, and relates to the field of natural gas hydrate exploitation. The drilling fluid is prepared from the following components: polyethylene glycol, sodium chloride, ethylene glycol, potassium chloride, potassium humate, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, polyvinyl methyl ether, tetrahexyltrimethyl ammonium bromide and prepared water. The silty mudstone natural gas hydrate storage compound type drilling fluid can be used for silty mudstone natural gas hydrate storing and drilling, has the effects of resisting a low temperature, inhibiting and reducing the solid phase; a kinetic inhibitor and a synergist are added into the drilling fluid for compounding, so that relatively strong hydrate generation inhibition effect is achieved; and moreover, the drilling fluid is small in environmental harm by components, and has the advantages of being efficient, environmentally friendly, adopting cheap and easily available raw materials, and the like.

The invention discloses marine facies natural gas hydrate storage compound drilling fluid and relates to the field of exploitation of natural gas hydrate. The drilling fluid is prepared from the following components: sodium formate, sodium chloride, methyl alcohol, ethylene glycol, potassium chloride, low viscosity carboxymethyl cellulose (LV-CMC), potassium humate, xanthan gum, polyvinyl caprolactam, propylene glycol phenyl ether, tetrahexamethyltrimethylammonium bromide and prepared water; the drilling fluid can be used for marine facies natural gas hydrate storage drilling and has the effects of no solid phase and low temperature resistance. By adding a kinetic inhibitor and a synergist for compounding, the drilling fluid has a stronger hydrate formation inhibition effect; in addition,the drilling fluid components have little damage to the environment; the drilling fluid has the advantages of high efficiency, environment friendliness, low-priced and easily-obtained raw materials and the like.

The invention relates to a compound drilling fluid for natural gas hydrate (NGH) reservoir in silt mudstone, and relates to the field of NGH exploitation. The drilling fluid comprises following components: polyethylene glycol, sodium chloride, glycol, potassium chloride, low viscosity carboxymethyl cellulose (LV-CMC), potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, polyvinyl methylether, and make-up water. The drilling fluid is suitable for NGH drill wells in silt mudstone reservoir, is resistant to low temperature, and can inhibit and reduce the solid phase. The drilling fluidis compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention provides compound drilling fluid applied to storage of natural gas hydrates in frozen soil areas and relates to the field of exploitation of natural gas hydrates. The drilling fluid comprises the following components: sodium formate, sodium chloride, ethylene glycol, low-viscosity carboxymethyl cellulose LV-CMC, potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, polyethylene oxide, polyvinyl methyl ether and prepared water. The drilling fluid is capable of being applied to drilling with storage of the natural gas hydrates in frozen soil layers, is free of solid phaseand has resistance to low temperature; a kinetic inhibitor is added into the drilling fluid and is compounded with a synergist; the drilling fluid has an excellent effect of inhibiting generation of hydrates; meanwhile, the components of the drilling fluid are low in harm to the environment; and the drilling fluid has the advantages of high efficiency, environment friendliness and cheap and easilyavailable raw materials.

The invention provides a drilling fluid for improving the sliding efficiency of highly-deviated large cluster wells and a construction method. The drilling fluid is composed of the following substances in percentage by mass: 5-10% of an inhibitor; 12-17% of a soluble weighting agent; 1.3%-1.85% of a tackifying fluid loss agent; and 0.1%-0.5% of a flow pattern regulator, with the balance being water. Non-soluble solid phase such as bentonite, limestone and barite is not added into the drilling fluid, and the density is increased through soluble composite salt; inorganic salt KCl is added into the drilling fluid to inhibit hydration of clay minerals so that rock debris particles are complete, and the sieving rate is high; as the drilling fluid has no solid phase, the friction resistance is lower than that of other drilling fluid systems, and sliding drilling is facilitated; a sliding drilling tool face is in place, a sliding drilling machine speed is high, and the sliding efficiency is high. The drilling fluid is recyclable, easy to control performance, free of solid phase, high in inhibiting performance, low in friction resistance, free of sticky support during sliding, effectivelyimproves the sliding efficiency of highly-deviated large cluster wells, and has extremely high applicability to field production.

The invention discloses a drilling fluid for marine natural gas hydrate (NGH) reservoir, and relates to the field of NGH exploitation. The drilling fluid comprises following components: sodium silicate, sodium chloride, glycol, potassium humate, potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, propylene glycol monomethyl ether, mono-n-butyl glycol ether, and make-up water. The drilling fluid is suitable for NGH drill wells in the sea, does not contain any solid phase, and is resistant to low temperature. The drilling fluid is compounded with a kinetic inhibitor and a synergist toinhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.

The invention provides compound type frozen soil natural gas hydrate reservoir drilling fluid and relates to the field of exploitation of natural gas hydrate. The drilling fluid is prepared from the following components: sodium silicate, sodium chloride, ethylene glycol, potassium humate, potassium polyacrylate, xanthan gum, polyvinylpyrrolidone K90, ethylene glycol ethyl ether, mono-n-butyl ethylene glycol ether and preparation water; the drilling fluid can be used for drilling the frozen soil layer natural gas hydrate reservoir and has solid-phase-free and low-temperature-resisting effects;a kinetic inhibitor and a synergist are added into the drilling fluid and are compounded so that the drilling fluid has a relatively strong hydrate generation inhibition effect; the components of thedrilling fluid have small dangers to environment and the drilling fluid has the advantages of high efficiency, environment protection, low-price and easy-to-obtain raw materials and the like.

The invention discloses a natural gas hydrate storage compound drilling fluid for a frozen earth region, relating to the field of exploration of natural gas hydrate. The drilling fluid comprises the following components: sodium formate, sodium chloride, ethylene glycol, potassium humate, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, ethylene glycol diethyl ether, tetracaproyl trimethyl ammonium bromide and prepared water. The drilling fluid can be used for drilling the natural gas hydrate storage drilling of a frozen layer, and plays roles of being free of solid phases and low-temperature resistant. By adding a dynamic inhibitor into the drilling fluid to be compounded with a synergist, the drilling fluid has a relatively high hydrate generation inhibiting effect, and the components of the drilling fluid are small in environmental damage, so that the drilling fluid has the advantages of high efficiency, environmental protection, low cost of raw materials, easily availableraw materials and the like.