17 results about "Horizontal stress" patented technology

The invention discloses a fracture pressure prediction and internal friction angle joint inversion method for a heterogeneous stratum. The invention belongs to the technical field of petroleum engineering and artificial intelligence cross application, well depth is used as an independent variable, the minimum / maximum horizontal stress, pore pressure and cohesion are combined to construct well depth mixed input, only multi-scale periodic basis function transformation is carried out on the well depth, and a linear well depth channel is reserved; establishing a rupture pressure depth mapping model, introducing an augmented Lagrange physical constraint containing dual variables and a dynamic threshold, adaptively adjusting a physical weight according to a physical residual error and a threshold difference value, realizing dynamic balance of a rupture criterion and data fitting, and searching and optimizing a model topology by using a multi-target network structure; under a limited sample, a fracture pressure profile and a physically reasonable internal friction angle can be obtained at the same time, and the prediction precision and the physical consistency are improved.

The invention relates to the technical field of geotechnical engineering, in particular to a slip crack surface calculation method for a limited-width soil body in an active non-limit state. Comprising the following steps: step 1, determining a gradual exertion rule of a limited soil body internal friction angle and cohesion between the rigid gravity type retaining wall and an existing bedrock, a wall-soil external friction angle and wall-soil interface cohesion developing along with the displacement of the retaining wall, and establishing mathematical characterization of limited soil body non-limit state strength parameters developing along with the displacement of the retaining wall; step 2, establishing a relationship among the horizontal stress, the interlayer shear stress and the average vertical stress; step 3, establishing a balance equation of the rectangular area and the triangular area in the horizontal and vertical directions; 4, solving the slip crack surface inclination angle meeting the plastic upper limit theorem by adopting a numerical method; and 5, calculating the resultant force of the horizontal active soil pressure and the upsetting moment of the horizontal active soil pressure on the wall heel. The method provides a theoretical calculation basis for the design of the soil retaining structure under the working condition of the limited-width soil body.

The invention discloses a method for improving the fracturing crossing effect and the far-well end seam height, which comprises the following steps: determining a crossing position index according to a horizontal well track index, a reservoir minimum horizontal ground stress size index, a reservoir fracture toughness value index and a reservoir filtration coefficient index, selecting a crossing fracturing position, and segmenting to obtain a segmentation result; perforation, radial well guide reaming, fracturing and crossing of a reservoir where a horizontal well hole track is located and fracturing of a penetrated reservoir are carried out on the first crossing fracturing section; a multi-particle-size temporary plugging agent is added, the temporary plugging agent is pumped with medium-high displacement and high-viscosity fracturing fluid, normal-viscosity fracturing fluid is continuously injected in a high-displacement and step mode, and a propping agent is added in a step mode till a preset fracture height is reached; and a packing bridge plug is pumped to the position of the previous cross-layer fracturing section for the remaining cross-layer fracturing sections, setting is conducted, and cross-layer fracturing and pumping operation is repeated till cross-layer fracturing of all the sections is completed. The fracturing volume scale and the far-end crack height of the thin interbed horizontal well can be greatly improved.

The application discloses a shale formation compressibility analysis method and device, and relates to the technical field of oil and gas exploration and development, wherein the method comprises the following steps: determining a brittleness index according to clay mineral content and total organic carbon content; determining a horizontal stress difference index according to an in-situ horizontal stress difference, a maximum horizontal stress difference when a horizontal fracture network is formed by fracturing, and a minimum horizontal stress difference; determining a vertical stress difference index according to an in-situ vertical stress difference, a maximum vertical stress difference when a vertical fracture network is formed by fracturing, and a minimum vertical stress difference; determining a natural fracture index according to a natural fracture density, a natural fracture width, and an angle between a natural fracture direction and a vertical direction of the maximum horizontal stress; determining a bedding index according to a bedding density and a bedding width; and determining a compressibility index according to the brittleness index, the horizontal stress difference index, the vertical stress difference index, the natural fracture index, and the bedding index. The application can improve the precision of shale formation compressibility analysis.

This invention discloses a perforation method for preventing casing deformation by reducing reservoir stress differences, relating to the field of oil and gas extraction technology. The method includes the following steps: S1, acquiring reservoir and fracture information; S2, using the acquired information to determine the slip stress in natural fracture development zones, faults, or interlayers, and judging whether the slip stress reaches the slip condition. If so, proceed to step S3; otherwise, proceed to step S5; S3, using the acquired information, preset and adjust the location, fracture length, and net pressure of the anti-casing deformation perforation until the slip stress does not reach the slip condition; S4, pumping fracturing fluid into the anti-casing deformation perforation and sealing all perforation holes with temporary plugging material; S5, performing the main fracturing operation. This invention can reduce the horizontal stress difference in natural fracture or fault areas without sacrificing the reservoir stimulation effect, i.e., without changing the hydraulic fracture initiation location and fracture length in high-quality reservoir sections, by perforating and pumping in slip risk areas such as natural fractures or faults.

The application discloses a single-well fracture identification method based on rock mechanics and bi-directional constraint of ground stress. The single-well fracture identification method comprises the following steps: obtaining and analyzing core well data, special logging data and conventional logging data in a research area; calculating rock mechanics parameters and ground stress parameters according to conventional logging curves; determining a fracture development index, a horizontal stress difference and a stress heterogeneity coefficient of a fracture development position characterized by a rock mechanics level and a ground stress level; comparing the fracture development index, the horizontal stress difference and the stress heterogeneity coefficient with single-well fracture characteristic parameters and fracture development position characteristic parameters to obtain a parameter fluctuation interval of the fracture development position; screening wells with a single-well fracture development position to be predicted according to the parameter fluctuation interval of the fracture development position; and constructing a comprehensive fracture identification curve according to the screened fluctuation interval to predict the single-well fracture development position, thereby improving the precision of single-well fracture identification.

The present application relates to geotechnical engineering technical field, especially to a kind of active non-limit state under the calculation method of sliding surface of finite width soil body, comprising the following steps: step 1, determine the gradual development law of internal friction angle, cohesion, wall-soil external friction angle and wall-soil interface cohesion in finite soil body between rigid gravity retaining wall and existing bedrock with retaining wall displacement development, establish the mathematical representation of the strength parameters of finite soil body non-limit state with retaining wall displacement development;Step 2, establish the relationship between horizontal stress, interlayer shear stress and average vertical stress;Step 3, establish the balance equation of rectangular area and triangular area in horizontal and vertical directions;Step 4, solve the sliding surface inclination angle that meets the plastic upper limit theorem by numerical method;Step 5, calculate the horizontal active earth pressure resultant force, the overturning moment generated by horizontal active earth pressure on wall heel.The present application provides theoretical calculation basis for the design of retaining structure under the working condition of finite width soil body.

A horizontal-stress vector prediction method, which relates to the technical field of in situ stress prediction. The method comprises: calculating elastic parameters and anisotropic parameters of a target reservoir; using a horizon interpretation for the target reservoir as a constraint, and using the calculated elastic parameters and anisotropic parameters to calculate logging curves of Young's modulus, Poisson's ratio and the fracture density; on the basis of the calculated logging curves of Young's modulus, Poisson's ratio and the fracture density, constructing an initial azimuthal elastic impedance model; on the basis of the initial azimuthal elastic impedance model, inverting Young's modulus, Poisson's ratio and the fracture density; substituting into a prediction formula the fracture density and Poisson's ratio, which are obtained from the inversion, and the vertical principal stress of the target reservoir, and performing calculation to obtain the maximum and minimum horizontal stresses of the target reservoir; and on the basis of least-squares ellipse fitting, obtaining the directional distribution of the maximum and minimum horizontal stresses within the target reservoir, so as to realize quick, accurate and highly operable horizontal-stress vector prediction. The present invention further relates to a horizontal-stress vector prediction apparatus, a computer device, and a machine-readable storage medium.

The invention discloses a force measurement hole packer and a roof crack control fracturing method applying the force measurement hole packer, and belongs to the technical field of coal mining. The force measurement hole packer comprises an elastic sleeve, and a monitoring device is arranged on the outer side of the elastic sleeve and used for monitoring the vertical stress and the horizontal stress of a drill hole; the separation sleeve is arranged in the elastic sleeve, and a sealed injection molding area is formed between the inner wall of the elastic sleeve and the outer wall of the separation sleeve; the injection pressure pipe is communicated with the sealing injection pressure area, and the injection pressure pipe is used for enabling the elastic sleeve to expand; the fracturing pipe is arranged on the inner side of the separation sleeve; wherein after the vertical stress is larger than the horizontal stress and the vertical stress reaches a peak value and an inflection point appears, the injection pressure pipe injects pressure to the sealed injection pressure area, and the fracturing pipe injects water to fracture the drilled hole. According to the invention, pressure data can be accurately controlled, and fracturing crack controllability is realized.

The present disclosure relates to the technical field of oil and gas geophysical development, and particularly relates to a horizontal stress prediction method, device, equipment, medium and program. The method comprises: determining a target stiffness matrix of an orthotropic medium under the action of horizontal stress, the orthotropic medium being formed by two groups of mutually perpendicular cracks developed in an isotropic medium; determining a P-wave reflection coefficient equation of the orthotropic medium under the action of horizontal stress according to the target stiffness matrix; and determining the horizontal stress according to the P-wave reflection coefficient equation, the horizontal stress being used for shale gas exploitation. The P-wave reflection coefficient equation determined based on the target stiffness matrix can directly predict the horizontal stress and reduce errors in the process of predicting the horizontal stress, thereby improving the accuracy of predicting the horizontal stress.

The application discloses a volumetric fracturing compressibility characterization method, which comprises the following steps: measuring the horizontal stress of each well, calculating the stress difference coefficient D, observing the development degree K of the natural fracture of the reservoir at the well site, obtaining the elastic modulus and Poisson's ratio distribution of the reservoir section, calculating the rock brittleness index B from the elastic modulus and Poisson's ratio distribution, and finally calculating the compressibility index F according to the above three parameters, and selecting the reservoir area with the highest F value as the target sweet spot area of the volumetric fracturing reconstruction. The application solves the problem that the existing reservoir compressibility characterization method cannot accurately describe the reservoir compressibility by only using the brittleness index.

The application discloses a method for improving fracturing through-layer effect and far-well-end fracture height, which comprises the following steps: determining a through-layer position index according to a horizontal well borehole trajectory index, a reservoir minimum horizontal stress size index, a reservoir fracture toughness value index and a reservoir filtration coefficient index, selecting a through-layer fracturing position and segmenting to obtain a segmented result; performing perforation, radial well guiding reaming, reservoir fracturing and through-layer fracturing operation on a first through-layer fracturing segment; adding a multi-particle-size temporary plugging agent, pumping the temporary plugging agent with a medium-high discharge capacity and high-viscosity fracturing fluid, continuously injecting normal-viscosity fracturing fluid with high discharge capacity and step injection, and stepwise adding a proppant until a predetermined fracture height is reached; performing pumping and setting a bridge plug to a position of a previous through-layer fracturing segment on a remaining through-layer fracturing segment and setting the bridge plug, and repeating the through-layer fracturing and pumping operation until through-layer fracturing of all segments is completed. The application can greatly improve thin interbedded horizontal well fracturing volume scale and far-end fracture height.

The application discloses a repeated fracturing method for a high-water-cut horizontal well in a low-permeability reservoir, which comprises the following steps: performing a repeated fracturing seam design on the high-water-cut horizontal well, determining a high-water-yielding fracture of the high-water-cut horizontal well in a target block, determining a safety distance S of the high-water-yielding fracture and an adjacent fracturing fracture, performing the seam design according to the principle that the distance of the high-water-yielding fracture and the adjacent fracturing fracture along the wellbore direction is greater than the safety distance S, and determining the safety distance S according to the maximum horizontal stress direction of the target block, judging the predicted extension direction of the high-water-yielding fracture, and determining the safety distance S based on the included angle alpha between the extension direction and the wellbore. The method solves the problem that the existing repeated fracturing construction of the high-water-cut horizontal well in the low-permeability reservoir easily leads to water flooding.

The invention discloses a fracture pressure prediction method based on fracture toughness anisotropy. The method comprises the following steps: collecting elastic mechanical parameters, rock fracture mechanical parameters, geomechanical parameters, bedding occurrence parameters and borehole condition parameters of anisotropic stratum rocks; calculating an included angle between the bedding plane direction and the x-axis by using the geomechanical parameters and the bedding attitude parameters; calculating the flexibility matrix component of the rock under the xy rectangular coordinate by using the elastic mechanical parameters of the rock, and solving the root of the characteristic equation; and substituting the geomechanical parameters, the borehole condition parameters and the root of the characteristic equation into the fracture pressure prediction model under the four criterion conditions, and calculating to obtain the fracture pressure considering the fracture toughness anisotropy. The method overcomes the defect that the traditional fracture pressure prediction theory and method based on fracture mechanics neglect the fracture toughness anisotropy, and can accurately reflect the influence rule of bedding occurrence, anisotropy degree, well wall crack half length, borehole radius and horizontal stress ratio on the fracture pressure.

The application provides an experimental device and method for multi-crack stress distribution visualization. The experimental device comprises a photoelastic experimental mechanism, a three-way stress loading mechanism, a horizontal stress clamping mechanism and a crack body internal pressure maintaining mechanism. The horizontal stress clamping mechanism adopts four numerical control hydraulic clamping components which are uniformly distributed around the experimental specimen to maintain stress loading of the experimental specimen in two mutually perpendicular horizontal directions. The crack body internal pressure maintaining mechanism can maintain the internal pressure in the cracks of the experimental specimen. The experimental method adopts the experimental device for multi-crack stress distribution visualization to carry out experiments. The beneficial effects of the application include: the stress distribution and stress interference of multiple cracks under the conditions of triaxial stress and internal pressure in the cracks can be realized in indoor experimental research.

The invention provides a research method for an influence rule of a hydraulic fracture crossing behavior of deep shale and application, and belongs to the field of oil-gas field development. The method comprises the steps that a three-dimensional hydraulic fracture model considering the deep shale plasticity and bedding effect is established, basic cases are simulated, and a hydraulic fracture layer penetrating comprehensive control chart is obtained according to the simulation result. According to the method, a Mohr-Coulomb failure criterion representing rock plasticity is introduced, a three-dimensional hydraulic fracturing model considering deep shale plasticity and bedding action is established, and basic case simulation is performed by utilizing the established three-dimensional hydraulic fracturing model; meanwhile, the hydraulic fracture crossing behavior under the combined action of a plurality of geomechanical properties such as the rock matrix strength, the bedding interface strength, the horizontal stress difference, the vertical stress difference and the interlayer stress difference is considered, the fracture crossing behavior under the construction condition can be effectively judged, and therefore the transformation effect is improved.