59 results about "Pore fluid pressure" patented technology

The invention belongs to the field of rock permeability test, and discloses a device for testing rock permeability under different pore fluid pressure. The device is characterized by comprising a high-pressure gas source generating device, a back pressure control device and a data detection and display device, wherein the high-pressure gas source generating device is connected with the back pressure control device, and the data detection and display device is connected with the back pressure control device; and the back pressure control device comprises a needle-shaped throttling valve and a rock core holder, wherein the needle-shaped throttling valve is arranged at the outlet end of the rock core holder. The invention also discloses a method for testing the rock permeability under different pore fluid pressure. A back pressure valve in the prior art is replaced by using the needle-shaped throttling valve to adjust the pressure of the rock core in the rock core holder under different pore fluid, the device has good back pressure stabilizing effect, and meanwhile, the processing production technology for the throttling valve is mature and has low cost and strong adaptability.

The invention relates to a low-permeability reservoir bed starting pressure testing method which comprises the following steps of: placing a core with 0.8-1.5m in length in a core holder with multiple pressure testing points, and applying a confining pressure by simulating oil deposit conditions; vacuumizing the core, and filling the core with formation water until the original oil deposit pore pressure is achieved; setting the pressure of a return pressure valve to be with the pressure value of a designated testing pore fluid; setting the velocity of the formation water passing across a core chamber to be 0.1-1mL / min, gradually reducing the velocity to 0, and recording the pressure difference value between each pressure testing point and a fluid inlet; calculating the starting pressure gradient of the core by using the pressure difference data values between different pressure testing points and the fluid inlet. The calculation formula is GradP=(PAB / LAB+PAC / LAC+......) / n, wherein PAB, PAC ...... represent the pressure differences of section AB, section AC ...... of the core, and n represents the quantity of the pressure testing points. The low-permeability reservoir bed starting pressure testing method has small testing error and can be used for accurately testing the starting pressure under low-permeability reservoir bed oil deposit conditions by simulating oil deposit pressure conditions.

The invention relates to a method for determining formation fracture pressure gradient logging of a shale gas reservoir. The method comprises the following steps of calculating formation fracture pressure gradient of an objective layer of the shale gas reservoir by evaluating according to layers or according to certain step length in the layers; acquiring formation hole fluid pressure gradient of the objective layer through logging or well measuring information; acquiring the rock poisson ratio of the objective layer through logging or indoor core experimental analysis information; acquiring gas saturation through logging or well measuring information; acquiring overlaying formation lithology density through well measuring information; calculating the formation fracture pressure gradient FRAC of the shale gas reservoir according to the formula: FRAC=FPG+POIS / (1-POIS)*(DENb-Sg*FPG); and outputting a result according to a formula: FP=FRAC*H / 100. The method is applied to 32 shale gas wells in the Jiannan gas field of the middle yangtze region, the shale gas field of the Fuling region, the western Hunan region and the western Hubei region; and the error of a calculated value and the actually acquired formation fracture pressure gradient is &1t;10%.

The embodiment of the invention provides a method and device for acquiring a hydrofracture bursting pressure, wherein a stratum ground stress parameter, a pore fluid pressure value, a casing mechanical parameter, a cement sheath mechanical parameter and a stratum mechanical parameter are obtained; and under effects of a shaft fluid pressure and ground stress, a casing stress field distribution model, a cement sheath stress field distribution model and a stratum stress field distribution model are established respectively. According to the casing stress field distribution model, the cement sheath stress field distribution model and the stratum stress field distribution model which are already established, a well-circumference stress field model under a well-cased perforation completion condition can be established; and then, the hydrofracture bursting pressure can be acquired according to the well-circumference stress field model, hydrofracture theories and bursting norms. In comparison with existing methods for acquiring the hydrofracture bursting pressure, the method for acquiring the hydrofracture bursting pressure provided by the embodiment of the invention considers more comprehensive factors and is closer to actual well completion situations.

The invention relates to an evaluation method for describing the compressibility of a shale reservoir. The evaluation method comprises the following steps that material contents including a well-site design report of a well to be evaluated, well-logging materials and well-measuring materials of the well to be evaluated are collected; according to the collected materials, the shale reservoir and the vertical depth H of the middle of the shale reservoir are determined, the fluid pressure gradient (FPG) of a stratum pore of the shale reservoir is determined, and the density (DEN) of stratum rock overlaying the shale reservoir is obtained; according to the FPG and DEN, the largest horizontal crustal stress Kimax and the smallest horizontal crustal stress Kimin of the shale reservoir are calculated; and the diversity factor delta Ki of the horizontal crustal stress of the shale reservoir is calculated, the compressibility of the shale reservoir is evaluated, and an evaluation result is output. The diversity factor delta Ki of the horizontal crustal stress of the shale reservoir is calculated through parameters of the FPG, the DEN and the like, and the compressibility of the shale reservoir is evaluated according to the delta Ki. The evaluation method is applied in more than 300 wells among shale gas wells in areas such as the middle Yangtze area, the Jiannan gas-field and the like, and the verification coincidence rate of the staged fracturing effect is 97.1%.

The invention discloses an unsaturated soil multifunctional triaxial apparatus and a sample preparation device thereof. The triaxial apparatus comprises a rack, a pressure chamber, a precision volumechange measuring device, an axial load piston, an axial load sensor, a displacement sensor, an axial load and axial deformation rate control / data acquisition and processing system, a water-gas-circuitcontrol cabinet, a water supply device and a microcomputer. Suction can be conveniently applied or controlled, strain rate can be controlled to be constant, and deviator stress can also be controlledto be constant. A sample can be immersed in a certain stress state, after swelling / collapsibility / soaking deformation is stable, the suction is applied to perform drainage and dehumidification, the influence of drying and watering cycle under triaxial stress conditions on mechanical properties of soil is researched, pore air pressure is measured by a micro-sensor, triaxial shear test without drainage or exhaust can be performed, and the pore air pressure is accurately measured. Volume change measuring precision is high, errors are small, sample preparation is simple, convenient and rapid, thedry density of the sample can be accurately controlled, and sample preparation efficiency and the technical level of sample preparation are improved.

The invention relates to a method for predicting coal seam hydraulic fracturing permeability. The method comprises the following steps: (1) measuring original coal seam permeability k0 through a permeability test; (2) performing fitting on permeability test data in the fracturing process to obtain the permeability change rule k1 in the coal seam hydraulic fracturing process, and performing calculation to obtain the coal seam permeability k10 when hydraulic fracturing is completed; (3) performing fitting on permeability test data in the drainage process to obtain permeability change rule k2 inthe drainage process after coal seam hydraulic fracturing, and performing calculation to obtain the coal seam permeability k20 at the end of drainage; (4) obtaining permeability change rule k in the process of gas extraction after hydraulic fracturing of coal seams by taking account of gas adsorption expansion and pore fluid pressure, and performing calculation to obtain coal seam permeability indifferent gas pressures in the process of gas extraction after hydraulic fracturing. The coal seam permeability after hydraulic fracturing is quantitatively calculated, and the transformation of the coal seam hydraulic fracturing effect from qualitative analysis to quantitative analysis is achieved.

An electric booster according to the present invention comprises a booster piston disposed around an input piston so as to movable relative to the input piston. The booster piston and input piston also serve as a primacy piston of a tandem master cylinder. A brake fluid pressure is generated in the tandem master cylinder by an input thrust force provided from a brake pedal to the input piston and a booster thrust force provided from the electronic actuator to the booster piston. In this electric booster, a slide hole is formed through the secondary piston of the tamed master cylinder in the axial direction therefore, and a rod member is slidably disposed through the slide hole. When the fluid pressure is not increased in the primary pressure chamber, due to the fluid pressure in the secondary pressure chamber, the rod member comes to abut against the input piston, and a reactive force in the secondary pressure chamber is returned to the brake pedal.

The invention provides a method and a device for determining the stress sensitivity of reservoirs. The method includes determining body effective stress borne by rock frameworks of the to-be-detected reservoirs according to overburden pressures, porosity parameters and formation pore fluid pressures of the to-be-detected reservoirs; determining the types of the to-be-detected reservoirs according to physical property analysis results of the to-be-detected reservoirs; selecting corresponding stress sensitivity models according to the types of the to-be-detected reservoirs; combining the body effective stress and the selected stress sensitivity models with one another and determining the stress sensitivity of the to-be-detected reservoirs. The method and the device in an embodiment of the invention have the advantages that the stress sensitivity degrees of the reservoirs are determined by means of comprehensively utilizing processes for changing the formation pore fluid pressures and changing the overburden pressures, accordingly, the shortcomings due to the fact that the stress sensitivity degrees of existing reservoirs are determined by means of only changing existing formation pore fluid pressures or only changing existing overburden pressures can be overcome, the ultimately determined stress sensitivity degrees of the reservoirs are high in precision, and the method and the device have guiding significance in efficient development of oil and gas reservoirs.

A method of estimating at least one of stress and pore fluid pressure in an earth formation is disclosed. The method includes: discretizing a domain including at least a portion of the earth formation into a plurality of cells, each cell including a respective density value; dividing the domain into a first region and a second region, the first region including a surface of the earth formation; vertically integrating the respective density values in the first region; and estimating the total vertical stress for each cell in the first region and the second region by estimating a point load based on the respective density value.

A vehicular hydraulic system having a hydraulic pump and first and second hydraulic applications arranged in series. A dual relief valve defines first and second flow channels, a passageway and a bypass port. The first flow channel is disposed between the hydraulic pump and the first hydraulic application and the second flow channel is disposed between the first hydraulic application and the second hydraulic application. A first valve member controls fluid flow through the passageway and allows fluid flow from the first to the second flow channel through the passageway when fluid pressure within the first flow channel exceeds a first threshold pressure. A second valve member controls fluid flow through the bypass port and allows fluid flow from the second flow channel to a return line through the bypass port when fluid pressure within the second flow channel exceeds a second threshold pressure.

A method for conducting an earth reservoir process includes receiving a stress field of a reservoir that includes a pore pressure field for a rock volume, selecting a search radius extending from a grid cell of interest, and substituting a pore pressure from a plurality of surrounding grid cells within the selected radius for the pore pressure of the grid cell of interest and determining if a critical stress state exists for each of the substituted pore pressures. The method further includes determining a shortest distance to a grid cell in the plurality of surrounding grid cells having a pore pressure that yields a critical stress state when substituted in the grid cell of interest and conducting the earth reservoir process with earth reservoir process apparatus using a parameter related to the determined shortest distance.

This inventive method provides a novel way of modeling basins in planning the drilling of crude oil and natural gas wells by accounting for thermodynamic considerations in tracking the pore pressure of a location of interest. By plotting the energy gradients, heat flux, and thermal conductivity of the location of interest, the user can more accurately identify the location of the Top of Geopressure and additional pertinent information during the well drilling planning process that can reduce costs and increase the safety of the process.

The invention, which belongs to the field of rock reservoir engineering research, discloses a method for simultaneously testing the porosity and permeability of the porous rock under conditions of triaxial stress and pore pressure. According to the method, upstream and downstream motor servo pumps apply pore pressures to a reservoir rock sample in a triaxial stress state; fluid pressures in the pumps are set and fluid volume data in the pumps are obtained to realize testing the rock pore volume under the pore pressure condition. An injection pump and a collection pump are used for adjusting anosmotic pressure difference and the flow through the rock under the pressure difference is tested, so that the permeability under the stress state is obtained. According to the invention, with setting of different confining pressure conditions, biasing conditions and fluid pressure values at the upper and lower ends of the rock sample, the porosity and permeability values of the reservoir rockunder different stress and pore pressure conditions are tested simultaneously to provide technical parameters for controlling the exploration and injection process of the fluid substances in the deepporous rock reservoir.

The invention discloses a multi-field coupling monitoring and testing device for coal rock and belongs to the technical field of mining. The multi-field coupling monitoring and testing device comprises a base, a testing cavity body, an axial-pressure applying system, a confining-pressure applying system, a pore flowing-pressure simulation system, a temperature applying system, a charge acquisitionsystem, an acoustic emission signal acquisition system, a strain acquisition system and a data acquisition and analysis device, wherein the testing cavity body comprises a steel pressure-resistant cavity and a sealing flange disc, a transmission rod is arranged at the middle part of the sealing flange disc, and an upper pressing head and a lower pressing head are arranged in a sealed space formedby the steel pressure-resistant cavity and the sealing flange disc; the pore flowing-pressure simulation system comprises a first pore flow-pressure port formed in the upper pressing head, a second pore flow-pressure port formed in the lower pressing head, a first flowing-pressure transmission hole and a second flowing-pressure transmission hole formed in the sealing flange disc, a flow meter anda flowing-pressure applying system; the temperature applying system comprises an electric-control heating belt wound on the surface of a thermoplastic sleeve; and the axial-pressure applying system comprises an axial hydraulic cylinder and a pressure sensor.

The invention relates to the field of fluid pressure control, in particular to a fluid pressure adjusting mechanism. The fluid pressure adjusting mechanism comprises a machine body and a sliding cavity in the machine body. A valve and a sliding block slidably arranged on the right side of the valve are slidably arranged in the sliding cavity. A jacking spring is elastically arranged between the sliding block and the valve. The fluid pressure adjusting mechanism can be used for presetting the maximum water discharging pressure of equipment. The equipment can automatically adjust the water discharging pressure to a stable state in the operation process. Meanwhile, a pressurization device is arranged in the equipment, when the water inlet pressure is insufficient, inlet water can be pressurized, so that water discharging requirements of the equipment are met. A filtering plate is arranged in the equipment, and a filtering plate cleaning device is arranged at the same time, so that it is ensured that pipelines are not blocked, liquid is filtered, discharged water is cleaner, the functionality is strong, the stability is good, and production and popularization are facilitated.

The invention discloses a small hole expansion test device and a test method thereof. An expander is buried in saturated soft clay; and a plurality of earth pressure boxes and pore water pressure sensors are arranged in the plane on which the cross section of an elastic film of the expander is located at intervals in a radial direction. The radial expansion of the elastic film is realized by controlling the internal pressure of the closed space, so that the mechanical behavior of the small hole expansion is simulated. Meanwhile, a monitoring device obtains data of a hydraulic sensor, a pore water pressure sensor and an earth pressure box to obtain the internal pressure change of the closed space before and after the elastic film expansion, changes of pore pressures around the elastic filmand the changing condition of the radial stress; auxiliary measurement assisted by surface displacement measurement for reference is performed to obtain the displacement changing condition of the topof the saturated soft clay before and after the elastic film expansion; and then data that are obtained by testing and include the pore pressure, radial stress and surface displacement are analyzed and calculated to obtain a constitutive model being capable of explaining small hole expansion in saturated soft clay accurately in an assisted manner.

The present invention provides a soil layer response monitoring system which comprises a tubular mounting frame which is provided with a receiving cavity at a tube wall and a deformation measurement module which is connected to one end of the mounting frame to measure the deformation amount of a soil layer at a current position. The mounting frame is equipped with a temperature sensor which is installed in the receiving cavity and is used for measuring the temperature of the current position, a pressure sensor which is installed in the receiving cavity and is used for measuring the pressure of the current position, a concentration monitoring module which is installed in the receiving cavity and is used for detecting the concentration of the current position, and a signal transmitting unit which is used for transmitting each measurement signal to a control center. According to the system, the information of soil layer pore fluid pressure, temperature, sound waves, pore methane gas concentration, deformation response and the like in the exploration process of a natural gas hydrate under a seabed can be monitored in real time, a data support value can be provided for the aspects of making a natural gas hydrate exploration scheme, evaluating an environmental effect and the like, and a reference can be provided for the research and development of a related sea bottom measurement system.

The invention discloses a high-temperature and high-pressure coal-rock deformation detection system. The detection system comprises a coal-rock deformation test device and a gas collection and detection system. The test device comprises an upper axial pressure loading unit and a lower axial pressure loading unit which are capable of generating axial pressure on a coal-rock sample, and further comprises a confining pressure end cover, a confining pressure piston and a confining pressure head which are capable of generating confining pressure on the coal-rock sample; by accurately setting the axial pressure and the confining pressure and using a temperature meter to control temperature regulation of the coal-rock sample, accurate simulation of the coal-rock deformation stress-strain environment is achieved. The gas collection and detection system can collect mixed gas generated by the coal-rock sample during a deformation test in real time and conduct on-line analysis and detection; besides, gas with set pressure can be injected through a gas cylinder to simulate in-situ pore fluid pressure, and thus geological conditions are simulated more realistically. The test and detection system can obtain more complete coal-rock samples and is high in test precision, reasonable in structure, easy to disassemble and high in safety coefficient.

A valve provides multiple channels that allow alternating, or in some cases, simultaneous, fluid flow functions to a port of an instrument, without the requirement of manual manipulation of the valve by the user. A floating member such as a ball having magnetic affinity for a portion of the valve is positioned in a home, or normal, position by a magnetic field, where it remains until acted on by fluid pressure. The ball in the home position opens other channels of the device. Under fluid pressure in the channel in which the ball's home position is located, the ball is displaced, obstructing at least one of the other channels, while opening the channel to permit a fluid flow through the channel. When the fluid pressure in the channel is terminated, the ball returns to the home position, and other ports are opened.

The invention relates to a method for analyzing the preservation or not of early particle dissolution pores of a sandstone in the burial compaction process. The method concretely comprises the following steps: S1, preparing an earth surface modern deposit sample having the same structural fabric with a middle-deep stratum sandstone rock; S2, obtaining the real stratum water density of the actual stratum of the middle-deep stratum sandstone, the overlying stratum density, the earth temperature gradient and the earth surface average temperature, and calculating the pore fluid pressure, the static rock pressure and the stratum temperature meeting actual geologic conditions; S3, carrying out a mechanical compaction simulation experiment meeting the actual geologic conditions on the sample; S4,processing the sample after the experiment; and S5, analyzing the experiment sample and experiment data. The method can truly reflect the final preservation condition of the early particle dissolution pores after the modern earth surface deposit rich in the early particle dissolution pores is buried and compacted.

A multi-cone, multi-stage spray nozzle includes a nozzle body, a valve stem with a first valve head, and a second valve head attached to the first valve head. The first valve stem is biased into a closed position against a valve seat of the nozzle body by a bias device. The second valve head is continuously open. Upon the application of a first fluid pressure, which is less than a threshold fluidpressure, the bias device maintains the valve stem in the closed position while the second valve head is continuously open. And upon the application of a second fluid pressure, which is at least as great as the threshold fluid pressure, the valve stem moves to an open position while the second valve head remains continuously open.

The invention discloses a method for determining pore water pressure in a saturated soil layer under the load effect of an embedded anchor plate, which comprises the following steps: regarding the action of the embedded elastic anchor plate on a soil body as a uniformly distributed circular load which comprises effective stress and pore fluid pressure components; and giving a calculation formula of pore water pressure in a saturated soil layer with limited thickness on the rigid foundation under the load effect of the anchor plate. The invention considers the influence of the soil layer thickness, and obtains an existing half-space solution or a full-space solution through degradation processing; the anchor plate load is considered to be in the form of combination of three soil skeleton effective stress components and one pore water pressure, and can adapt to the situation of complex load combination.

The embodiment of the invention provides a crustal stress prediction method and device. The method comprises the steps: providing raw three-dimensional crustal stress distribution data of a work area;receiving a prediction moment and production data; determining the stratum pore fluid pressure of a well point location in the work area at the prediction moment based on the production data; determining the crustal stress of the well point location in the work area at the prediction moment based on the stratum pore fluid pressure and the raw three-dimensional crustal stress distribution data; determining the crustal stress at the prediction moment of the well point location in the work area based on the crustal stress of the well point location in the work area at the prediction moment, andthen obtaining the three-dimensional crustal stress distribution data of the work area at the prediction moment.