63results about How to "Stabilize the wellbore" patented technology

The invention discloses a strong-inhibition anticaving drilling fluid and application thereof. The strong-inhibition anticaving drilling fluid consists of 1000 parts of water, 20 to 60 parts of bentonite for drilling fluid, 5 to 20 parts of sodium carbonate, 5 to 20 parts of alkali, 10 to 20 parts of coating agent, 5 to 20 parts of flow pattern regulator, 5 to 20 parts of shale inhibitor, 10 to 30 parts of borehole stabilizer, 10 to 30 parts of plugging agent, 5 to 30 parts of lubricating agent, 5 to 40 parts of filtrate reducer, 1 to 10 parts of pH regulator, and a proper amount of salts and barite added according to the requirement. The strong-inhibition anticaving drilling fluid has the remarkable characteristics of properties of stabilizing a borehole, protecting an oil layer, improving the drilling speed, and preventing a balled bit and the like from approaching to oil-based drilling fluid.

The invention discloses a polyacrylamide inorganic nano composite material prepared by adopting a polymerization composite method of polyacrylamide and nano inorganic phase and a drilling fluid aid. The inorganic material is nano dispersed suspension formed by co-precipitation hydrothermal reaction and surface treatment reaction of laminated silicate, nitrate or the both. The suspension is mixed with acrylamide aqueous solution, cosolvent and complexing agent; and the mixture is polymerized under the initiation of persulfate and sulfite to form the polyacrylamide nano composite material with proper molecular weight, good water solubility and good tackifying effect, wherein the dimension of the inorganic phase is 30 to 70 nanometers. The drilling fluid prepared from the composite material has remarkable viscosity increment, good rheological property and filtration control, temperature and salt resistance and protection property on a reservoir layer, and improves the yield and recovery rate.

The invention discloses an uninterrupted circulating pup joint for petroleum well drilling and a continuous slurry circulation method, and the uninterrupted circulating pup joint comprises a pup joint body, an automatic central gate valve and a lateral normally-closed check valve, wherein the automatic central gate valve and the pup joint body are coaxially arranged; and the lateral normally-closed check valve is arranged on the side wall of the pup joint body below the automatic central gate valve. As the pup joint body structure with the combination of the large-drift diameter unobstructed automatic central gate valve and the triple lateral normally-closed single-flow valve is adopted, when a drill rod needs to be disassembled and assembled for making up, breaking out and pipe tripping, uninterrupted circulation of slurry is changed to be performed by the lateral normally-closed check valve, and pressure of the circulating slurry is utilized for automatically closing the automatic central gate valve above the lateral normally-closed check valve, thereby continuously maintaining the stability of the pressure of a borehole, effectively controlling the ECD (equivalent circulating density) value of annular space of the borehole, maintaining the stability of a well wall and the good effect of cleaning the borehole, preventing collapse and formation of a cuttings bed in the oblique well section and avoiding the collapse, clamping, leakage, blowout and other various complex situations.

The invention relates to a high-temperature-resistant plugging agent for a drilling fluid and a preparation method thereof. The high-temperature-resistant plugging agent is prepared from the following components by weight: 10 to 20 parts of a mineral fiber material, 10 to 30 parts of an asphalt particle, 20 to 30 parts of an inorganic elastic particle, 5 to 20 parts of fine rubber powder, 20 to 30 parts of ultrafine calcium carbonate and 0 to 5 parts of brown coal resin. The invention has the following beneficial effects: the plugging agent exerts a substantial plugging effect on holes and cracks and can form a plugging layer at a place near a borehole wall around a borehole in a short time, so invasion of solid particles and a filtrate is prevented, and borehole wall stabilizing and reservoir stratum protecting effects are exerted; and materials for preparation of the plugging agent are widely available, and the plugging agent has stable performance and adaptability to temperature, is environment friendly and can withstand a high temperature of 180 DEG C.

The invention discloses environmentally-friendly high-temperature-resistant synthetic base foam drilling fluid and a preparation method thereof. The drilling fluid comprises the following components in parts by weight: 1-3 parts of organic soil, 1-2 parts of high-temperature oil-based foaming agent, 1-3 parts of self-made high-temperature oil-based foam stabilizer and 92-97 parts of synthetic base liquid namely alpha-olefin. The dispersion medium of the synthetic base foam drilling fluid is foam liquid using alpha-olefin as the main component, the dispersed phase is air, and the drilling fluid is prepared through high-speed stirring. The drilling liquid system has stable performance, good heat resistance and antipollution capability and good compatibility to the reservoir; and the drilling fluid can be used in deep well underbalanced drilling and can be used to effectively inhibit the hydration and expansion of the shale, stabilize the well wall, prevent well leakage and protect the oil and gas formation. In addition, the synthetic base liquid namely alpha-olefin and the foaming agent are both non-toxic, are biodegradable and have no harmful effect on the environment.

The invention provides an environmentally-friendly strong sealing oil-based drilling fluid. The environmentally-friendly strong sealing oil-based drilling fluid is based on a base liquid, and comprises 10-20wt% of an aqueous solution of calcium chloride, 1-2wt% of a main emulsifier, 1-2wt% of an auxiliary emulsifier, 2-3wt% of a wetting agent, 3-5wt% of organic soil, 2-3wt% of calcium oxide, 2-4wt% of a sealing agent, 2-4wt% of a filtrate reducer, and 0-150wt% of a weighting material. The drilling fluid can effectively seal shale formation, improves the stability of a borehole wall, and reduces the pollution to environment; and the novel weighting material used in the invention has small influences on the rheological performance of the oil-based drilling fluid and reduces damages to reservoirs.

The invention discloses a continuous circulating system for realizing continuous circulation of slurry in the drilling process, comprising a hydraulic control device, a runner conversion device and a continuous circulating short-joint device. The system realizes control and conversion of slurry flowing pipelines by the hydraulic control device and the runner conversion device, and realizes continuous circulation of slurry by matching with a bypass structure of the continuous circulating short-joint device, so that the stability of the pressure of a borehole is maintained, the annulus backpressure value of the borehole is effectively controlled, the stability of the borehole wall and good effect for cleaning the borehole are maintained, and the runner conversion device and the continuous circulating short-joint device are mutually matched for working so as to realize continuous circulating operation of the borehole. The continuous circulating system is simple in structure, small in occupied space and convenient to operate and is especially suitable for being used in drilling on an offshore platform. In addition, the system can be concentrated in a system container after being disassembled, and the installation and the disassembly are convenient, so that the system is very important for simple operation on the offshore operation platform.

The invention discloses a polymer nanometer blocking agent for water-based drilling fluid and its preparation method, and belongs to the technical field of a drilling fluid function material. The polymer nanometer blocking agent for water-based drilling fluid is prepared from, by weight, 4-16 parts of emulgator, 2-14 parts of temperature sensitive monomer, 10-53 parts of hydrophilic monomer, 0.5-10 parts of hydrophobic monomer and 0.05-0.5 part of initiator. The polymer nanometer blocking agent is small in size, and can block micro and nano-sized holes of a shale well wall; through compressivedeformation property of the poymer, the compact blocking of the well wall hole can be realized; by means of the temperature response property of an intelligent polymer, the transformation from hydrophilia to hydrophobicity is realized in the well wall, and the zone closing to the well wall is transformed to be a hydrophobic environment, thus the diffusion and permeation of water in the water-based dirlling fluid towards the shale well wall is effectively stopped, thereby stabilizing the well wall and protecting reservoir, and providing an important technical guarantee for the development of the water-based drilling fluid system for shale development.

The invention relates to nanometer drilling fluid. The concentration of the nanometer drilling fluid comprises 900kg / m<3> of water, 40-50kg / m<3> of bentonite, 25-30kg / m<3> of nanometer emulsion JDL-3, 2-3kg / m<3> of cationic gel MMH, 3-5kg / m<3> of high molecular polymer PAM, 10-15kg / m<3> of sulfonated gilsonite FT-1, 15-20kg / m<3> of sulfonated phenolic resin SMP, 15-20kg / m<3> of salt and temperature resistant fluid loss agent LS-1, 10-15kg / m<3> of flow type regulating agent DS-2 and 8-10kg / m<3> of sodium hydroxide (NaOH). The nanometer drilling fluid has good colloid dispersivity and high heat stability, improves the rheology of the drilling fluid, increases the compactness of mud cakes, improves the thickness of the mud cakes, quickly forms a layer of nanometer film on a well wall, prevents the drilling fluid from invading stratums near the well wall and pressure from being transmitted and has good anti-caving performance and good storage layer protection performance.

The invention discloses a rapid drilling fluid, of which the component proportion according to mass parts comprises 3-5 parts of sodium soil, 0.2-0.3 part of organosilicate semipermeable membrane agent, 1-3 parts of modified starch filtrate reducer, 1.5-2.5 parts of sulfonated-methyl brown coal, 0.2-0.3 part of zwitterions encrusting agent, 0.2-0.5 part of rapid drilling agent and 90-100 parts of water. The rapid drilling fluid is water based drilling fluid by which drilling speed is greatly increases. Simultaneously, the drilling cost is low, no mud drum is produced in drilling process, and the drilling performance and the well wall are stable.

The invention discloses a chitosan and graphene oxide nano-hydrogel plugging agent and a water-based drilling fluid. The plugging agent used by the water-based drilling fluid is chitosan and grapheneoxide nano-hydrogel, and the chitosan graphene oxide nano hydrogel comprises synthetic raw materials: chitosan, clay minerals, graphene oxide and konjac oxide; the drilling fluid comprises the chitosan and graphene oxide nano-hydrogel disclosed by the invention. The chitosan and graphene oxide nano-hydrogel is used as a nano-blocking agent, the particle size of the chitosan and graphene oxide nano-hydrogel is approximately distributed between 20 nm and 45 nm, micro-sized and nano-sized pores in a shale well wall can be effectively blocked, and thus the well wall can be effectively stabilized,and collapse is prevented; the used water-based drilling fluid has good rheological property, stability, plugging property and the like under shale formation conditions.

The invention discloses an organic / inorganic nano composite gel plugging agent and an oil-based drilling fluid. A plugging agent used for the oil-based drilling fluid is organic / inorganic nano-composite gel, and synthetic raw materials of the organic / inorganic nano-composite gel comprise zirconium oxide powder, butyl oleate, N-isopropylacrylamide and stilbene. A cross-linking agent is divinyl benzene. The drilling fluid comprises the organic / inorganic nano composite gel provided by the invention. The organic / inorganic nano composite gel serves as a nano plugging agent, the particle size of the organic / inorganic nano composite gel is approximately distributed between 40 nm and 150 nm, drilling fluid filtrate can be effectively prevented from invading the stratum, accidents such as borehole wall collapse are prevented, the organic / inorganic nano composite gel is particularly suitable for nano plugging of shale strata, the principle of the preparation method is reliable, and the organic / inorganic nano composite gel has wide market prospects.

The invention relates to water-based drilling fluid for a shale horizontal well. The water-based drilling fluid comprises a reverse wetting agent. The invention further relates to a preparation method of the water-based drilling fluid.

The invention discloses a high-temperature-resistant filtrate reducer for drilling fluid. The high-temperature-resistant filtrate reducer is prepared from the following raw materials in parts by weight: 35-55 parts of synthetic resin, 15-25 parts of aldehyde ketone resin, 45-65 parts of sulfonated asphalt formed by sulfonating natural asphalt, 5-15 parts of an initiator B, 10-20 parts of nano calcium carbonate, and 60-80 parts of an alkene monomer polymer. The invention also discloses a preparation method of the high-temperature-resistant filtrate reducer. The preparation method comprises thefollowing steps: stirring the sulfonated asphalt and the alkene monomer polymer at 45-60 DEG C for 30-40 minutes; adding an initiator B, stirring the components for 2-3 hours, then adding nano calciumcarbonate, heating the mixture to 95-120 DEG C, then adding synthetic resin and aldehyde ketone resin, stirring the mixture, carrying out heat preservation reaction at 100-110 DEG C for 4-5 hours, and drying the reaction product to obtain the high-temperature-resistant filtrate reducer. The high-temperature-resistant filtrate reducer has the advantages of excellent filtration reduction performance, stronger crack plugging capability, stable mud rheological property, stable well wall and excellent high-temperature resistance and salt resistance.

The invention relates to a drilling fluid for drilling of a fractured igneous rock formation and a preparation method of the drilling fluid in the field of petroleum drilling. The drilling fluid is prepared from components in parts by weight as follows: 1,000 parts of water, 3-4 parts of drilling fluid bentonite, 2-3 parts of sodium carbonate, 2-3 parts of a polymer coating agent, 2-3 parts of potassium polyacrylate or a metal cation polymer, 5-10 parts of an organic amine inhibitor, 20-30 parts of an anti-sloughing reinforced wall fixation agent, 20-30 parts of sulfonated phenol formaldehyderesin, 5-10 parts of a sulfonate copolymer filtrate reducer, 20-30 parts of walchowite, 10-20 parts of an anti-salt and temperature-resistant fluid loss agent, 20-40 parts of superfine calcium carbonate, 50-70 parts of potassium chloride, 0-10 parts of an organic anti-friction compound and 10-20 parts of a nano-micro blocking agent, and the weight is increased to 1.30-1.85 g / cm<3> with a density weighting agent. The drilling fluid has good temperature resistance and lubricating property and excellent inhibition property and anti-sloughing wall fixation property and can effectively prevent thefractured igneous rock formation from collapsing; the rock carrying capability of the drilling fluid can be substantially improved, repeated grinding of larger falling blocks nearby a drill bit is prevented, the frictional resistance is reduced, the mechanical drilling speed is increased, and underground safety is guaranteed.

The invention relates to a compound saltwater drilling fluid for plugging fractures of a coal seam, and belongs to the field of petroleum drilling. The compound saltwater drilling fluid is characterized by comprising components in percentage by mass as follows: 6%-8% of calcium carbonate, 4%-6% of emulsified asphalt powder, 10%-12% of barite, 2%-4% of limestone powder, 3%-4% of carboxymethyl starch, 8%-10% of sodium formate, 4%-6% of industrial salt, 2%-4% of potassium chloride, 0.6%-0.8% of polyanionic cellulose and the balance of clear water, wherein emulsified asphalt, calcium carbonate, barite and limestone powder are generally termed as plugging materials. By means of the compound saltwater drilling fluid, the one-time success rate of well completion of an inclined shaft section is increased greatly, the collapse of the coal seam is greatly reduced, the construction period of the inclined shaft section is shortened, and the work efficiency is improved.

The invention provides a drilling fluid, a preparation method and an application thereof. The drilling fluid includes, by mass, 1-1.5% of a plugging agent, 7-9% of an inorganic salt inhibitor, 0.35-0.45% of an organic salt inhibitor, 1-1.5% of an acid dissolution fluid loss agent, 2.5-4.5% of an acid dissolution temporary plugging agent, 0.3-0.5% of xanthan gum, 0.3-0.6% of high-viscosity polyanionic cellulose, 0.3-0.6% of low-viscosity polyanionic cellulose, and the balanced being water. The drilling fluid solves the technical problems of low drilling speed, long drilling period, poor flowability, long soaking time of well wall in the drilling fluid and high reservoir damage degree since the reservoir is protected by increasing the density of the drilling fluid in the prior art.

The invention discloses a polyionic liquid nano hydrogel plugging agent and a water-based drilling fluid. The plugging agent used by the water-based drilling fluid is polyion liquid nano hydrogel, andthe polyion liquid nano hydrogel plugging agent is prepared by a step-by-step method; the drilling fluid contains 100 parts by weight of water, 1-10 parts by weight of bentonite, 0.2-1 part by weightof xanthan gum, 0.4-1.2 parts by weight of a salt-resistant filtrate reducer, 0.4-1.2 parts by weight of a temperature-resistant filtrate reducer, 4-10 parts by weight of potassium chloride, 10-20 parts by weight of a polyion liquid nano hydrogel plugging agent, 0.4-2 parts by weight of a lubricant, 20-50 parts of by weight calcium carbonate and 0.1-0.4 part by weight of sodium hydroxide. The polyionic liquid nano hydrogel prepared by the step-by-step method is used as a nano plugging agent, has a particle size distribution of approximately 30-200nm, and micro-sized and nano-sized pores in ashale well wall can be effectively plugged, so that the well wall is stabilized, and collapse is prevented.

Relating to the technical field of shale gas drilling, the invention discloses a water-based drilling fluid for stabilizing a shale gas stratum borehole wall and application thereof. The water-based drilling fluid comprises a nanofilm structure plugging agent, a waterproofing agent, a surface hydration inhibitor, polymeric alcohol, bentonite, polyanionic cellulose, a sulfonated lignite resin and water, wherein the waterproofing agent is N-perfluoroalkyl sulfonyl propyl triethoxysilane, and the nanofilm structure plugging agent includes a montmorillonite sheet, a structural unit shown as formula (1) and a structural unit shown as formula (2). The water-based drilling fluid provided by the invention shows good performance of inhibition, rheology and retarding of the shale compressive strength reduction when applied to stabilization of the shale gas stratum borehole wall.

The invention discloses an environment-friendly pseudo oil-based drilling fluid and a preparation method thereof. The drilling fluid comprises the following raw materials in ratio: 0.6-0.8 part of polyamine inhibitor, 12-15 parts of methyl glucoside, 2-3 parts of nano-emulsion, 0.2-0.4 part of high temperature protective agent, 0-30 parts of barite, 1-3 parts of bentonite, 0.1-0.3 part of sodium carbonate, 0.1-0.3 part of sodium hydroxide, 0.2-0.5 part of low viscosity parker, 0.1-0.2 part of zwitter-ion coating agent, and 80-100 parts of water. The preparation method comprises the following steps: 1) respectively adding sodium hydroxide and sodium carbonate in water, and stirring; 2) adding the bentonite in the water, stirring at high speed, and standing at normal temperature; 3) stirring the solution of the step 2), adding methyl glucoside in the stirring process, and continuously stirring; 4) orderly adding the zwitter-ion coating agent, the low viscosity parker, the high temperature protective agent, the polyamine inhibitor and the nano-emulsion in the solution in the step 3) at intervals of stirring; and 5) regulating the density of the drilling fluid.

The invention provides a drilling device and method. The device includes a continuous tube assembly and a drill bit, and the continuous tube assembly is provided with at least two fluid passages in communication with different fluid passages disposed on the drill bit. The device is capable of pumping drilling fluid of two different pressures into a rock formation, and the high pressure drilling fluid is mainly used for breaking rocks and cutting grooves on the rocks. After the low pressure drilling fluid and the high pressure drilling fluid meet, the drill bit can be cooled, a well wall can bestabilized, and the efficiency and capability of carrying rock fragments to the ground can be improved.

The invention provides a water-soluble organic salt weighting agent for drilling fluid for oilfields as well as a preparation method and application thereof. The method comprises the steps of preparing an organic acid mixture containing bromine atoms, wherein the organic acid mixture comprises C1-C6 organic acids; adding composite alkali containing NaOH, KOH, ammonia water, N(CH3)3 and epoxy chloropropane to the organic acid mixture, stirring the materials to react, and evaporating water until the product is pasty or half-dry, wherein the mass ratio of composite alkali to organic acids is (0.15-1.5):1; drying the product at 80-120 DEG C for 6-24 hours, and grinding the dried product, thus obtaining the granular product. The weighting agent can not only improve the density of solid-free water-based drilling fluid base fluid but also improve the inhibitive capacity of the drilling fluid.

The invention discloses an oil-based drilling fluid for protecting a shale gas reservoir, wherein the oil-based drilling fluid includes, in parts by volume, 70-90 parts of base oil and 10-30 parts of an aqueous phase; based on the total volume of the base oil and the aqueous phase, the oil-based drilling fluid further includes the components by the mass / volume ratio: 1-3% of a main emulsifier, 0.5-1.5% of an auxiliary emulsifier, 1-3% of lime, 1-3% of organic soil, 1-3% of a tackifier, 1-5% of a filtration loss reduction agent, 1-3% of a plugging agent, 3-8% of a reservoir protective agent, and 0-100% of a weighting agent, wherein the reservoir protective agent is a compound mixture of calcium carbonate, magnesium oxide and magnesium carbonate. The drilling fluid has relatively good inhibition and lubrication performance, and can protect the shale gas reservoir.

The invention provides a water-soluble organic salt weighting agent for drilling fluid for oilfields as well as a preparation method and application thereof. The method comprises the steps of preparing an organic acid mixture containing chlorine atoms, wherein the organic acid mixture comprises C1-C6 organic acids; adding composite alkali containing NaOH, KOH, ammonia water, N(CH3)3 and epoxy chloropropane to the organic acid mixture, stirring the materials to react, and evaporating water until the product is pasty or half-dry, wherein the mass ratio of composite alkali to organic acids is (0.2-2):1; drying the product at 80-120 DEG C for 6-24 hours, and grinding the dried product, thus obtaining the granular product. The weighting agent Weigh2 can not only improve the density of solid-free water-based drilling fluid base fluid but also improve the inhibitive capacity of the drilling fluid.

The invention discloses synthesis of temperature and pH dual-stimulation-responsive nano hydrogel and a water-based drilling fluid. A plugging agent used by the water-based drilling fluid is temperature and pH dual-stimulation-responsive nano-hydrogel, and the temperature and pH dual-stimulation-responsive nano-hydrogel is prepared from the following synthetic raw materials: nano-silica, a temperature-responsive monomer, a pH-responsive monomer, a cross-linking agent and an initiator. The water-based drilling fluid contains the temperature and pH dual-stimulation-responsive nano hydrogel disclosed by the invention. The temperature and pH dual-stimulation-responsive nano hydrogel is used as a nano blocking agent, the particle size distribution ranges from 20 nm to 75 nm, nano-sized pores in a shale well wall can be effectively blocked, and therefore the well wall can be effectively stabilized, and collapse can be prevented; and the water-based drilling fluid used in the invention has good rheological property, stability, plugging property and the like under the shale formation condition.

The invention discloses an uninterrupted circulating pup joint for petroleum well drilling and a continuous slurry circulation method, and the uninterrupted circulating pup joint comprises a pup joint body, an automatic central gate valve and a lateral normally-closed check valve, wherein the automatic central gate valve and the pup joint body are coaxially arranged; and the lateral normally-closed check valve is arranged on the side wall of the pup joint body below the automatic central gate valve. As the pup joint body structure with the combination of the large-drift diameter unobstructed automatic central gate valve and the triple lateral normally-closed single-flow valve is adopted, when a drill rod needs to be disassembled and assembled for making up, breaking out and pipe tripping,uninterrupted circulation of slurry is changed to be performed by the lateral normally-closed check valve, and pressure of the circulating slurry is utilized for automatically closing the automatic central gate valve above the lateral normally-closed check valve, thereby continuously maintaining the stability of the pressure of a borehole, effectively controlling the ECD (equivalent circulating density) value of annular space of the borehole, maintaining the stability of a well wall and the good effect of cleaning the borehole, preventing collapse and formation of a cuttings bed in the oblique well section and avoiding the collapse, clamping, leakage, blowout and other various complex situations.

A water-base wellbore fluid for use in subterranean wells that penetrate through a subterranean formation containing a shale which swells in the presence of water. The well bore fluid includes, an aqueous based continuous phase, and a shale hydration inhibition agent. One illustrative shale hydration inhibition agent is preferably the reaction product of a hydrogenation reaction of the product of the reaction of an aromatic amine with an aldehyde, preferably formaldehyde. Alternatively the shale hydration inhibition agent may be the reaction product of a hydrogenation reaction of the product of the reaction of aniline and formaldehyde. In one illustrative embodiment, the shale hydration inhibition agent is selected from the class of compounds known as polycycloaliphatic amines. The shale hydration inhibition agent may be present in the form of a free-base or preferably in the form of an acid salt of the disclosed amine compounds. The shale hydration inhibition agent is present in sufficient concentration to substantially reduce the swelling of shale drilling cuttings upon contact with the fluid.

The invention discloses a nano-plugging agent modified ketal, a preparation method thereof and an oilfield drilling fluid. The nano-plugging agent modified ketal with a nanoscale particle size is obtained by: subjecting ethyl acetoacetate ethylene glycol ketal, sodium chloroacetate and sodium hydroxide to hydroxymethylation reaction, and then performing cross-linking by a cross-linking agent. Thepreparation method is simple, the reaction process does not need nitrogen protection, and after adding the raw materials for reaction, the obtained product can be cooled directly without heating or drying. With good fluidity, the nano-plugging agent modified ketal has significant effect of plugging stratum microcracks, especially nano-microcracks, and after being added into oilfield drilling fluid, can effectively improve mud cake, stabilize the well wall and prevent collapse.

The invention discloses a flow pattern regulator for a drilling fluid. The flow pattern regulator comprises the following components in percentage by mass: 0.3-1% of a chemical modifier for natural asphalt, 0.1-0.7% of a synergist, 0.1-0.3% of a defoaming agent,0-0.4% of a tackifier and 0-0.2% of a filtrate reducer, with the balance being deionized water. The flow pattern regulator for the drilling fluid can reduce the percolation quantity of a high-permeability stratum, has a good plugging effect, is recommended to be added, reduces the filtration loss of the oil-based drilling fluid, stabilizes a well wall, prevents cracks from being opened, improves the oil wettability of a solid phase, improves demulsification voltage, enhances the performance stability of the oil-based drilling fluid,effectively plugs micron-sized cracks due to its micron-sized particle sizes, and has a good plugging-while-drilling effect.

The invention discloses a multifunctional drilling fluid additive. By 100 weight percentages, the components are: 10~30 wt. paraffin, 10~30 wt. white oil, 5~15 wt. non-ionic surface active agent, 0.02~5 wt. cationic surface active agent and water. The invention also discloses the method for preparation of the drilling fluid additive: mixing the paraffin and white oil into oil phase; mixing the non-ionic surface active agent and cationic surface active agent into mixed surface active agent; adding the oil phase and mixed surface active agent into the reactor, heating; then adding proper volume preheating water into the reactor till opaque viscous gel phase occurring in the architecture; agitating with rotary speed of 2000~3000rpm and keep the emulsifying temperature during reaction; adding the rest of water into the reactor and stop heating, agitating with 1000rpm, make the emulsion cool down to ambient temperature and get the paraffin pinpoint emulsion.