62 results about "Siltstone" patented technology

A method of fracturing using deformable proppants minimizes proppant pack damage, without compromising the fracturing fluid's proppant transport properties during pumping, by use of deformable proppants. Selection of proppant is dependent upon the mechanical properties of the formation rock. The strength of the deformable proppant is dependent upon the modulus of the formation rock being treated such that the proppant is capable of providing, at the very least, a minimum level of conductivity in in-situ stress environments. The maximum elastic modulus of the deformable proppant is less than the minimum modulus of the formation rock which is being treated. The method is particularly applicable in fracturing operations of subterranean reservoirs such as those comprised primarily of coal, chalk, limestone, dolomite, shale, siltstone, diatomite, etc.

The invention discloses an experimental method for evaluating the oiliness of unconventionally-compacted shale reservoir stratums. According to the method, a closed coring saturation degree and fluorescent lamina technology can be used for effectively evaluating the oiliness of silty mudstones and siltstones; rock pyrolysis, laser co-focusing, a scanning electron microscope and an energy spectrum can be used for effectively evaluating the oiliness of the mudstones and the siltstones; technical indexes are matched with comprehensive application, mutual verification and mutual supplementation to effectively evaluate the microcosmic oiliness of the compacted and shale reservoir stratums. According to the experimental method, the method verification is carried out by taking a Qp1 well of an unconventional oil and gas exploratory well in the Daqing exploratory area as an example to, and new awareness can be obtained. The experimental method for evaluating the oiliness of the unconventionally-compacted shale reservoir stratums provides an experimental technology support to the seven-property evaluation of the oiliness of the unconventionally-compacted shale reservoir stratums and the exploration and development of unconventional oil and gas.

A Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill includes a horn actuator having high power piezoelectric materials and a flexure pre-stress to increase the actuators effectiveness. The drill is a low mass, low power, compact coring drill measuring 20-cm high by 7-cm diameter and having a total weight of 2 kg including drive electronics. Using an average power of 50-Watts, the drill basalt is expected to cut basalt at a rate of 0.2 cm / min down to depth of 10-cm and create cuttings and an intact core. The drill is expected to operate under different environments including Martian ambient (6 Torr and down to −50° C.), and liquid nitrogen temperatures (77 K) and low pressure (<<1 Torr) to simulate lunar polar and Europa conditions. Materials expected to be sampled include Kaolinite, Saddleback Basalt, Limestone, Volcanic Breccia, Siltstone, ice, permafrost and layered rocks with different hardness.

The invention discloses a particle diameter and rock property well-logging evaluation method under restraint of depositional microfacies, and belongs to the technical field of reservoir well-logging evaluation research. The particle diameter and rock property well-logging evaluation method is characterized in that mudstones are split through a well-logging data-well-logging curve, well-logging recognition on five particle diameter and rock property disclosed thick layers of coarse sandstones, sandy conglomerate, medium sandstones, fine sandstones and siltstones is performed in rock physical model-depositional microfacies well-logging evaluation units to determine heterogeneity of a low-permeability and compact sandstone reservoir; the rock physical model-depositional microfacies well-logging evaluation units are divided out from geologic origin, and innovation is obtained from well-logging recognition on thick layers and the rock property of low-permeability and compact sandstone reservoir; and well-logging data, well-logging information and analysis test data are integrated, so that mudstones split by the well-logging data-well-logging curve and different particle diameters and rock property recognized in the rock physical model-depositional microfacies well-logging evaluation units are combined to form the evaluation method.

A method of fracturing using deformable proppants minimizes proppant pack damage, without compromising the fracturing fluid's proppant transport properties during pumping, by use of deformable proppants. Selection of proppant is dependent upon the mechanical properties of the formation rock. The strength of the deformable proppant is dependent upon the modulus of the formation rock being treated such that the proppant is capable of providing, at the very least, a minimum level of conductivity in in-situ stress environments. The maximum elastic modulus of the deformable proppant is less than the minimum modulus of the formation rock which is being treated. The method is particularly applicable in fracturing operations of subterranean reservoirs such as those comprised primarily of coal, chalk, limestone, dolomite, shale, siltstone, diatomite, etc.

The invention discloses a field seal-storing method and device of a fine-grained rock core. The method comprises the steps of taking out a core, wiping off sealing liquid on the surface of the core, and removing the surface part, impregnated by the sealing liquid, of the core; tightly wrapping the core of the above step with plastic wrap; wrapping the plastic wrap with tin foil, and wrapping the tin foil tightly with polytetrafluoroethylene; loading an obtained sample into a heat-insulating cotton bag, and sealing for tightening; adding the sample of step D into thawed paraffin solution, taking out after a first preset time, and soaking in cold water; after a second preset time, taking out the sample from the cold water, and judging whether wax seal is complete; if yes, putting the samplein a sample bag. The method of the invention is suitable for long-range transportation and long-term preservation of samples and is applicable to the preservation of low-porosity low-permeability cores of mud shale, siltstone and the like.

The invention relates to potassium amino polymer strong-inhibition anti-collapse drilling fluid for an argillaceous siltstone stratum. The potassium amino polymer strong-inhibition anti-collapse drilling fluid is prepared from the following components in percentage by weight: 1-1.5 percent of a potassium-amino polymer, 1-1.5 percent of an acid soluble fluid loss agent G310-SJS, 1.0-2.0 percent of sulfonated bitumen, 1-2 percent of a blocking agent, 0.3-0.6 percent of high-viscosity polyanionic cellulose PAC-HV, 0.3-0.6 percent of low-viscosity polyanionic cellulose PAC-LV, or A weighting agent optionally added according to actual requirements and of which a pH value is controlled to be 9-10 by using a basicity control agent, and the balance of water. The potassium-amino polymer is adsorbed on the surface of rock debris at multiple points, and positive point groups are introduced in a certain proportion, so that the adsorption capability is high, the rock debris can be effectively coated, thereby being easily cleared away by using solid control equipment, the low solid phase of the drilling fluid can be realized; in addition, the polymer is high in adsorbability so that a hydrate adsorption layer of the polymer is formed on a well wall to constrain a clay intercalation, thus achieving the effect of stabilizing the well wall.

The invention, which belongs to the field of studying of the diagenetic numerical value simulation technology of the low-permeability-tight reservoirs, provides an analytical method for the evolutionhistory of 3D permeability of a sandstone reservoir. The method comprises the following steps that: well selection and data arrangement are carried out; a rock physics model including six types of lithofacies of coarse sandstone, medium sandstone, fine sandstone, siltstone, chiltern conglomerate and mudstone is established in a low-permeability-tight reservoir, and distribution of the six types oflithofacies at a target segment is evaluated by using combined scales of six kinds of welllogging curves; on the basis of a sandstone particle size, a rock density, and mineral constituents, six lithofacies types approximating geological actual situation are made; a porosity-depth and porosity- permeability mathematical equation based on magnetic resonance imaging and reservoir physical data is implanted and thus a 3D permeability evolution history of the six lithofacies types at the target segment is reproduced under the 3D burial history and thermal history constraints; and an overall 3D permeability evolution history of the target segment is evaluated by combining the percentage compositions of the six lithofacies types. Moreover, the consistency analysis of a practically measured permeability value and a simulated permeability value is carried out.

A Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill includes a horn actuator having high power piezoelectric materials and a flexure pre-stress to increase the actuators effectiveness. The drill is a low mass, low power, compact coring drill measuring 20-cm high by 7-cm diameter and having a total weight of 2 kg including drive electronics. Using an average power of 50-Watts, the drill basalt is expected to cut basalt at a rate of 0.2 cm / min down to depth of 10-cm and create cuttings and an intact core. The drill is expected to operate under different environments including Martian ambient (6 Torr and down to −50° C.), and liquid nitrogen temperatures (77 K) and low pressure (<<1 Torr) to simulate lunar polar and Europa conditions. Materials expected to be sampled include Kaolinite, Saddleback Basalt, Limestone, Volcanic Breccia, Siltstone, ice, permafrost and layered rocks with different hardness.

The invention relates to a sand consolidation and plugging removing treatment fluid for sand control of fine silt oil reservoir oil wells, a sand control treatment fluid system and a sand control method using the same, and belongs to the technical field of petroleum exploitation. The sand consolidation and plugging removing treatment fluid comprises the following components by mass: 8-12% of a sand consolidation and plugging removing agent, 0.5-1.5% of a drainage aid, 0.5-1.5% of a corrosion inhibitor, 1-2% of an iron ion stabilizer, 1-2% of mutual solvent, ammonium chloride and the balance ofwater. The sand control treatment fluid system is composed of a pretreatment liquid, a preflush, a treatment liquid and a replacement liquid, and the volume ratio is 4-6:1-2:2-3:1-2 in turn. The invention also disclose a sand control method using that sand control treatment fluid system. The synergistic effect of each component of the sand control treatment fluid system forms a bonding coating onthe surface of fine siltstone and clay grains, and sand is cemented and consolidated. After the implementation of this measure, the sand control and production increase effect is remarkable.

The invention discloses a waste slurry circulation method and system for shield in weathered argillaceous siltstone stratum tunneling. The method comprises the following steps of: 1, primary selectionof waste slurry: discharging the waste slurry to slurry-water separation equipment through a slurry discharging pump station and by means of the slurry discharging pipeline of a shield tunneling machine so as to subject the waste slurry to separation treatment; step 2, separation and dehydration by a primary cyclone separator; step 3, separation and dehydration by a secondary cyclone separator; step 4, dewatering by a horizontal spiral discharging sedimentation centrifuge; and 5, transferring treated usable slurry to a slurry pool of the shield tunneling machine by the horizontal spiral discharging sedimentation centrifuge to reuse the treated usable slurry. The system comprises slurry-water separation equipment, a primary cyclone separator, a secondary cyclone separator, a sedimentationtank, a horizontal spiral discharging sedimentation centrifuge, a clear liquid pool and a size mixing tank. Muck soil and muddy water are effectively separated through muddy water system equipment, separated mud indexes meet shield tunneling slurry indexes again, and therefore the purpose of recycling waste slurry is achieved.

The invention discloses a technology method using siltstone for manufacturing a stone pot. The purpose is to provide the technology method which is high in machined finished product rate and good in quality. The technology method includes the following steps that (1), according to pot shape designing, the pot shape is designed according to the stone grain of the siltstone, and drawing is performed; (2), according to blank manufacturing, the big siltstone is cut into small blanks according to designing requirements; (3), according to blank soaking, the blanks are soaked into cold water for two or more days; (4), the blanks are machined to be in a initial type to form a teapot semi-finished product; (5), according to spout forming, a carving machine is adopted for machining the shape of a spout; (6), the spout is got through; (7), a pot handle is formed; (8), according to manual machining and shaping, the stone pot is machined locally and manually until the stone pot is machined to be in a designed size and a designed shape; (9), according to grinding and polishing, the outer surface and the inner surface of a pot body are ground and polished, so that a smooth surface of the pot body is formed; (10), the product is detected, and if detected to be qualified, the product is packaged to be put in storage.

The invention belongs to the field of construction of infrastructure engineering technologies, and relates to an argillaceous siltstone tunnel excavation deformation monitoring method. The method comprises the following steps of: tunnel excavation, deformation point arrangement, deformation observation, data recording and calculation, and result analysis. In order to guarantee the safety of a tunnel during construction, deformation monitoring is smoothly carried out, the required operation is simple, the interference of a traditional monitoring mode on construction can be reduced, the investment of monitoring equipment and monitoring personnel can also be reduced, the cost is reduced, the monitoring efficiency is improved, and rapid and safe construction of engineering is ensured.

The invention provides stokehole modified steel slag and a preparation method thereof. According to the invention, steel slag which is discharged from converter steelmaking and has a temperature of 1400 DEG C or above is discharged to a slag tank, and meanwhile, a modifier (limestone powder, sandstone and fly ash) is mixed with the molten steel slag, wherein the particle size of the modifier is smaller than 0.15 mm, the modifier comprises, in percentage by weight, 1%-15% of the limestone powder, 1%-10% of sandstone powder and 1%-10% of the fly ash, and the total addition amount of the modifier is 5-25%; and the total content of CaO and MgO in the chemical components of the steel slag is less than 55%. The modified steel slag can be used as a cement admixture or a concrete admixture and is applied to cement or concrete. The modified steel slag is high in gelation activity, and the preparation method is simple to operate.

The invention provides a shield cutter head suitable for a soft and hard composite stratum and a tunneling method. The cutter head comprises a shield cutter head body (1), a cross-shaped main cutter beam (2), an auxiliary cutter beam (3), a center serrated cutter (4), a front hob (5), a cutter (6), an edge hob (7), an edge scraper (8), a fixed serrated cutter (9), a foam nozzle (10), a wear detection cutter (11), a wear-resistant steel plate (12) and other components. The cross-shaped main cutter beam is composed of a first cutter beam, a third cutter beam, a fifth cutter beam and a seventh cutter beam, and the auxiliary cutter beam is composed of a second cutter beam, a fourth cutter beam, a sixth cutter beam and an eighth cutter beam. The method comprises the steps of determining the starting torque of the hobs, selecting and setting the starting torque of the hobs as the starting torque of the hobs of the soft soil stratum, starting a foam system to spray a foam modifier, and pushing a tunneling face rock-soil body forwards by a shield. The opening rate of the cutter head reaches 43%, the cutter head is particularly suitable for tunneling of a typical gravel-argillaceous siltstone composite stratum, and the risk of mud pasting of the cutter head is reduced.

The invention discloses a predicating method for high-gamma sandstones in source rocks. The predicating method comprises the following steps: firstly, determining an average natural-gamma logging lower limit value and siltstones of the source rocks and an average natural-gamma logging upper limit value of sandstones, drawing up a radioactive contour map of the source rocks on a plane, and identifying an area with relatively high radioactive value and an area with a relatively low radioactive value; drawing up a sand thickness contour map on the plane according to the sand rock thickness identified by normal logging in the area with the relatively high radioactive value and the area with the relatively low radioactive value; predicating high-gamma sandstones in the area with the relatively high radioactive value according to the sand body formation causes and a distribution pattern on the plane. The predicating method is simple to operate, easy to popularize and use, great in economic benefit, and capable of quickly and effectively predicating a compact oil favorable area.

The invention discloses a sun-resistant anti-ageing glass container and a preparation method thereof. The glass container is prepared from the following raw materials in parts by weight: 33-46 parts of quartz powder, 8-14 parts of zinc borate, 14-26 parts of astrophyllite, 16-28 parts of monazite, 6-12 parts of bismuth vanadate, 22-34 parts of chalk powder, 4-7 parts of lanthanum hydroxide, 5-8 parts of strontium chromate, 3-5 parts of soda ash, 24-36 parts of gold tailings, 19-27 parts of siltstone, 4-6 parts of potassium pyrosulfate, 10-15 parts of nitronatrite, and 5-8 parts of an auxiliary agent. By adding bismuth vanadate, strontium chromate, zinc borate and other raw materials into the glass container, the glass container is enhanced in light ageing resistance and endurance, does not crack under long-term irradiation of daylight, and is durable. The glass container produced by employing the technology is resistant to light ageing, resistant to corrosion, resistant to impaction, high in mechanical strength, and greatly expanded in applicable scope.

The invention relates to a method for recognizing the petrographic rhythm change in the siltstone and mudstone alternate stratum through an imaging logging image. The method mainly includes the steps of firstly, reading RGB values of legend pixel points in the imaging logging image, and conducting interpolation to generate a normalized resistivity curve according to the number of the pixel points so that the different RGB values of each set can correspond to a specific resistivity value; secondly, reading the RGB values of the pixel points of the imaging logging image point by point, and calculating the quadratic sum of the RGB value of each the pixel point on the imaging logging image and the deviation of the RGB values of all the pixel points in a legend through the least square method, wherein the less the quadratic sum of the deviation is, the closer the RGB values of every two corresponding pixel points are; thirdly, searching the imaging logging image for the pixel point with the RGB value closest to the RGB value of each pixel point on the imaging logging image, and endowing the corresponding point on the imaging logging image with the resistivity value of the corresponding pixel point on the imaging logging image; fourthly, conducting solution line by line to obtain the arithmetic mean for the resistivity value of the imaging logging image so that the imaging logging image can be converted into a one-dimensional resistivity curve; fifthly, selecting wavelet package decomposition for the resistivity curve, and judging the petrographic rhythm change in the siltstone and mudstone alternate stratum through low-frequency components obtained through decomposition.

The invention relates to the field of analysis for chemical components, and in particular relates to a novel full-component granularity analysis method for siltstone particles. The method comprises the following steps of: analyzing a siltstone sample, judging the species of the siltstone sample, extracting an original sample from the classified siltstone sample, preparing an analysis sample through the original sample, adding clean water into the analysis sample, uniformly stirring the analysis sample and the clean water to form a turbid solution, adding the turbid liquid into a dispersing agent in a sample tank of a laser particle analyzer through a dropper, performing ultrasonic dispersion on the turbid liquid in the dispersing agent in the sample tank for certain time to obtain ultrasonic dispersion liquid, and performing granularity analysis on the dispersion liquid. According to the method, an analysis result obtained by the laser particle analyzer is accurate, and the granularity and the distribution of siltstone can be really reflected.

The invention discloses a method for predicting the brittleness of a compact oil reservoir. The method comprises the following steps: S01, adding an ellipsoidal pore with a fixed aspect ratio to a feldspar mineral; S02, calculating a bulk modulus and a shear modulus of a mixed mineral matrix by combining quartz minerals, carbonate minerals, and pyrite minerals; S03, on the basis of an SCA theory, mixing the feldspar mineral with the mixed mineral matrix based on a proportion to form a siltstone rock skeleton; S04, adding a micro crack into the rock skeleton by using a differential equivalent medium (DEM) model; S05, adding clay minerals into the rock skeleton in an inclusion body manner according to different mineral aspect ratios; and S06, calculating a speed, a Young's modulus, a Poisson's ratio and a brittleness index of the rock. According to the disclosed method, for the compact oil reservoir with low porosity, low permeability and internal complex structure, a brittle rock physics model is constructed by combining the SCA with the DEM model, so that the internal structure of the compact oil siltstone reservoir is described well.

The invention discloses a computing method for reflecting the overall splitting damage process of argillaceous siltstone. The computing method comprises the following steps: step S1, carrying out wavelet packet decomposition on acoustic emission signals emitted in the splitting evolution process of argillaceous siltstone so as to obtain an energy spectrum coefficient central frequency band F1 of a wavelet pocket; Step S2, computing the main frequency F2 of the acoustic emission signals; step S3, finally determining the optimal frequency band, namely the characteristic frequency band F according to the energy spectrum coefficient central frequency band F1 of the wavelet packet and the main frequency F2 of the acoustic emission signals, wherein F=F1UF2; and acquiring dynamic characteristics at different phases in rock failure and the cross-scale fracture process of rock according to the optimal frequency band. By adopting the technical scheme provided by the invention, fractional frequency study can be carried out on acoustic emission waveform in the splitting process of argillaceous siltstone, the acoustic emission information at different frequency bands and the sensitiveness of the fracture problem can be considered fully, and the acquired data are rich and high in reliability.

The invention discloses a watery argillaceous weak cementation siltstone tunnel construction method. The watery argillaceous weak cementation siltstone tunnel construction method comprises the following steps that (1) before excavation, precipitation is conducted on watery argillaceous weak cementation siltstone, wherein the precipitation comprises the steps of full-section light well point vacuum precipitation and deep well vacuum precipitation; (2) after precipitation is conducted on the watery argillaceous weak cementation siltstone, the watery argillaceous weak cementation siltstone is excavated according to the pre-designed shape and the pre-designed size of a tunnel, and the watery argillaceous weak cementation siltstone tunnel is formed. The watery argillaceous weak cementation siltstone tunnel construction method has the advantages that for the watery argillaceous weak cementation siltstone tunnel, full-section light well point vacuum precipitation and deep well vacuum precipitation are conducted before excavation is conducted, the content of water in a rock stratum is reduced, the self strength of the rock stratum is improved, the reinforcing effect of the rock stratum is ensured, and the fast construction of the watery argillaceous weak cementation siltstone tunnel is achieved.

The invention discloses a production method for wet processing of machine-made sand by using tunnel hole slag siltstone. The production method comprises the steps: a base material with the compressive strength of more than or equal to 80 MPa is selected; the base metal is crushed by a first crusher to obtain broken stones with the particle size being smaller than or equal to 100 cm; the broken stones are crushed by a second crusher to obtain particles, and the obtained particles are subjected to vibration screening to obtain particles with the particle size larger than 31.5 mm, particles with the particle size ranging from 5 mm to 31.5 mm and particles with the particle size smaller than 5 mm; the obtained particles with the particle size larger than 31.5 mm are crushed again through the second crusher, and then the operation is repeated; the obtained particles with the particle size ranging from 5 mm to 31.5 mm are crushed through a third crusher, the crushed particles are subjected to vibration screening, and the particles with the particle size smaller than 5 mm are obtained; and the obtained particles with the particle size of less than 5 mm are washed with water, the water-washed particles are fed into a water washing wheel through a chute, and dehydrating treatment is carried out. The method disclosed by the invention has the beneficial effects that the method disclosed by the invention is beneficial to control of the content of the machine-made sandstone powder, the controllable content of the sandstone powder can be ensured through water washing, and the strength and the working performance of the concrete can be effectively controlled.

The invention discloses a high fill quality control construction method for side slope embankment. The high fill quality control construction method comprises the steps that dredging and foundation treatment is performed on a newly added filling surface, and at the same time, dredging treatment is performed within a certain range outside a slope foot; the slope surface of an original filled body is subjected to bench excavation according to the principle of 1 to 2, and the newly added filling body is subjected to bench excavation when an original mountain body is steeper than 1 to 5; the newlyadded filling surface is subjected to tamping filling layered construction by adopting a tamping machine or a stamping mill, packing is siltstone stone or conglomerate stone, and if the newly added filling surface is narrow and small, filling construction is carried out by vibration rolling first until the newly added filling surface meets the construction conditions of the tamping machine or thestamping mill; and when a newly added filling body is originally provided with a drainage blind ditch, the drainage blind ditch is appropriately extended to a new slope surface according to the original direction and with the level not less than the original specification to ensure smooth drainage of the blind ditch. The high fill quality control construction method overcomes the defects of uneven settlement of foundations and deformation of side slopes.

The improved filler for the intermediary weathered argillaceous siltstone is characterized by being prepared from the following materials: intermediary weathered argillaceous siltstone fine aggregate,intermediary weathered argillaceous siltstone coarse aggregate, gravels, cement, quick lime and water. The mass part ratio of all the materials is 180:(240-260):(180-220):(50-100):(60-100):(110-150).The invention further provides a preparation method of the intermediary weathered argillaceous siltstone improved filler. The method can effectively overcome the defects of the conventional method for obtaining the backfill. The filler not only can improve the intermediary weathered argillaceous siltstone, but also is simple and feasible, convenient to operate and low in manufacturing cost.

The invention discloses a device and a method for manufacturing a non-diagenetic hydrate siltstone core. An experimental device constructs a core skeleton by utilizing a method of self-precipitation of silt particles, by a freezing mode, pore water is condensed into ice as a cement object to improve the strength of a core, after cutting is performed, the ice is converted into a hydrate at low temperature and high pressure environment, and a weakly cemented core containing the hydrate is finally formed. After the hydrate in the core is decomposed, the hydrate has the characteristics of recoverywithout cementation, low strength and no rock formation, and can better simulate a marine hydrate layer.

The invention discloses a cutterhead for shield tunneling of moderately-weathered argillaceous siltstone. The cutterhead comprises a cutterhead body, a cutterhead opening, a central heavy flat-tooth duplex hob, a cutter, edge heavy flat-tooth double-edged hobs, a front heavy flat-tooth double-edge hobbing cutter, an edge scraper, a gauge protection cutter and edge heavy flat-tooth double-edged hobs, wherein the cutterhead body is mounted on a driving device of a shield tunneling machine and in a disc shape; the cutterhead opening is formed in the cutterhead body and communicates with a soil cabin of the shield tunneling machine; the central heavy flat-tooth duplex hob is arranged on the cutterhead body; the cutter is arranged on the cutterhead body; the edge heavy flat-tooth double-edged hobs are arranged on the edge of the cutterhead body; the front heavy flat-tooth double-edge hobbing cutter is arranged on the cutterhead body; the edge scraper is arranged on the edge of the cutterhead body; the gauge protection cutter is arranged on the edge of the cutterhead body; the edge heavy flat-tooth double-edged hobs are arranged on the edge of the cutterhead body; and a cutting edge of the front heavy flat tooth double-edge hob is higher than a cutting material block of the cutter. According to the cutterhead for shield tunneling of the moderately-weathered argillaceous siltstone, the rock breaking effect in shield tunneling of moderately-weathered argillaceous siltstone is improved, and the wear resistance of the cutterhead can be enhanced.

The invention provides a protection method and a protection structure of a manual hole digging pile argillaceous siltsone stratum. The protection method of the manual hole digging pile argillaceous siltstaone stratum comprises the steps that a preset position of a to-be-constructed manual hole digging pile is positioned; a plurality of grouting holes having the same depth as that of the preset position are formed at the periphery of the preset position; and mortar is injected into the grouting holes, and thus a protection pile is formed. The invention conducts treatment on the surrounding argillaceous siltstone of the pile by adopting a method that mortar is grouted surrounding the manual hole digging pile, and accordingly the water stopping and foundation treatment effects are achieved. Step flow construction can be conducted in batches in the grouting process, the working efficiency is improved, and the construction period is ensured. The water permeability of argillaceous siltstoneis relatively low before being disturbed, the water stopping effect can be achieved by just injecting a small amount of mortar after grouting treatment is conducted, and the cost is low. The protection method solves the problem that a traditional steel protection cylinder is hard to press in and easy to tilt in the sinking process, and meanwhile the problem of hole collapse caused by a traditionalconcrete protection wall is avoided.

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.