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 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 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.

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.

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.

A coal-rock multi-field coupling monitoring test device belongs to the technical field of mining. The coal-rock multi-field coupling monitoring test device includes a base, a test chamber, an axial pressure application system, a confining pressure application system, a pore flow pressure simulation system, a temperature application system, a charge collection system, an acoustic emission signal collection system, and a strain collection system. System and data acquisition and analysis device; the test chamber includes a steel pressure chamber and a sealing flange, a transmission rod is installed in the middle of the sealing flange, and an upper The pressure head and the lower pressure head; the pore flow pressure simulation system includes the first pore flow pressure port set on the upper pressure head, the second pore flow pressure port set on the lower pressure head, the first flow pressure port set on the sealing flange The pressure transmission hole and the second flow pressure transmission hole, flow meter and flow pressure application system; the temperature application system includes an electric control heating belt wound on the surface of the thermoplastic sleeve; the axial pressure application system includes 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 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 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.