510 results about "Microseism" patented technology

A system and method monitor a hydrocarbon reservoir for drainage in volumetric three dimensions. Monitoring between wells is imperative for optimum reservoir management and is achieved by mapping the hydrocarbon fluid pathways in a producing reservoir. Unlike conventional 4D or time-lapse reflection seismic imaging systems that use a controlled active seismic source and records reflected seismic energy at receivers, the system and method exploit the minute vibrations, or micro-earthquakes generated in the reservoir layers that are induced by fluid movement. These microseisms are detected as the fluids move in the reservoir.

The invention belongs to the technical field of mineral resources, and particularly relates to a method for computing unsteady state output of a shale gas reservoir complex fracture network. The method comprises the following steps that S1, basic parameters of shale gas reservoir strata and shale gas are collected, and a shale substrate porous media capillary tube permeability model is established; S2, shale gas reservoir microseism fracture imaging data is collected, a box method is applied to acquire fractal dimensions, a two-dimensional discrete fracture network model is established, and animproved cubic law is adopted to calculate the complex fracture network permeability; S3, it is considered that a shale gas reservoir fracturing horizontal well outer region is a substrate area infiltration area and a shale gas reservoir fracturing horizontal well inner region is a complex fracture network area flow area, and a shale gas reservoir fracturing horizontal well steady-state productivity model is established; according to a shale gas pressure propagation radius equation and a shale gas reservoir material balance equation, a continuous quasi-steady method is applied to establish ashale gas reservoir fracturing horizontal well unsteady state model. The method for the computing unsteady state output of the shale gas reservoir complex fracture network has the advantages that theconsideration factors are close to the actual conditions of strata, and computed results are more accurate.

The invention discloses a high-precision pickup method of the first arrival of microseism. The high-precision pickup method comprises the steps that the signal to noise ratio of microseism data is increased through the higher moment method; according to the fact of whether the current microseism wave meets all the following constraint conditions, namely the relation between the magnitude of amplitude and space, the lineup apparent velocity and the polarization characteristics, whether the microseism wave is the first arrival of the microseism is judged; according to perforation data, actual event data and the change rule of constraint conditions, by the adoption of a statistical analysis method, the threshold value of the constraint conditions is determined; under the constraint of the amplitude and the apparent velocity, according to the temporal and spatial variation characteristics of the travel time first arrival of a microseism event, the change law of the energy, the apparent velocity and the relevant information of travel time first arrival points in a big fixed time window and a small sliding time window is utilized for automatic pickup of the first arrival of the microseism event by means of the repeated iteration method. Application effects of the actual data of different areas show that the high-precision pickup method of the first arrival of the microseism is high in adaptability and reliable in result.

The invention provides a shale gas reservoir fracture modeling method based on microseism monitoring data. The method comprises the steps that major fractures of a shale gas reservoir subjected to hydraulic fracturing are modeled to obtain a major fracture model by the adoption of a deterministic modeling method according to the time attribute of microseism event points in the microseism monitoring data in combination with original natural fracture information of the shale gas reservoir; on the basis of the major fracture model and within the effective reconstruction volume range for hydraulic fracturing, constraint conditions of space and geometrical parameters for accompanying fracture simulation in the hydraulic fracturing process are determined according to the density attribute of distribution of the microseism event points in the microseism monitoring data in combination with at least one of the direction attribute, the energy magnitude and the opening degree of the microseism event points, and accompanying fractures of the shale gas reservoir subjected to hydraulic fracturing are modeled by the adoption of a stochastic modeling method to obtain a shale gas reservoir facture basic model. By means of the shale gas reservoir fracture modeling method based on the microseism monitoring data, a complex fracture system of the shale gas reservoir can be depicted meticulously and effectively, and the actual fracture characteristics of the shale gas reservoir subjected to hydraulic fracturing can be reflected.

The invention provides a microseism focus positioning method based on a double-difference method, and belongs to the field of geophysical prospecting of petroleum. The microseism focus positioning method selects a perforation event as the main event, and picks the observation travel time for a microseism event, and can determine the relative distance between the perforation and the microseism event by calculating the residual error (double difference) between the observation travel time of the perforation and the microseism event and the theoretically calculated travel time difference. The microseism focus positioning method based on a double-difference method is high in operation speed and efficiency, and is easy for local convergence. As the microseism focus positioning method based on a double-difference method has the relative main event, the relative positioning accuracy is higher and the microseism focus positioning method is not limited by the spacial scale. The microseism focus positioning method based on a double-difference method offsets the error caused by changes of the speed of the near surface and the stratum speed, and can improve the positioning accuracy.

The invention provides a micro seismic event recognition method based on morphological filtering. The method comprises the steps of conducting spectral analysis on micro seismic data; rectifying a demodulator used for receiving micro seismic signals; selecting structural elements, combining opening operation and closing operation to form a morphological noise filter, and conducting the morphological filtering on the micro seismic data going through spectral analysis; calculating the energy ratio of a long-time window and a short-time window according to the data going through the morphological filtering, and comparing the energy ratio and triggering threshold to identify whether the demodulator has micro seismic events; and conducting microseism pickup according to the micro seismic events. According to the method, the signal to noise ratio of the data can be improved through preprocessing and further filtering treatment; the micro seismic events can be detected quickly and accurately by utilization of the energy ratio method, the fluctuation type of the micro seismic events can be identified through polarization analysis, and first arrival can be picked up accurately by utilization of self-adaptation threshold and the long-time and short-time window energy ratio method.

The invention discloses a recognition and interpreting evaluation method for shale reservoir fractured fractures. The recognition and interpreting evaluation method mainly comprises the steps of hydraulic fracture dynamic recognition of a shale reservoir under different stratum prestress conditions, three-dimensional natural fracture and hydraulic fracture network reconstruction and fracture network recognition and interpretation based on microseismic monitoring. The recognition and interpreting evaluation method achieves complex fracture network distribution form cognition and evaluation on the basis of hydraulic fractured fracture dynamic recognition and fracture comprehensive correction of microseismic monitoring interpretation to guide a fracture optimally designed fracture-microseism integrated fracture network prediction and evaluation technology and has important production significance for optimizing fracture construction parameters such as the fracture construction scale, the discharge capacity and the sand adding quality, reducing production cost and improving the fracture improvement effect.

The invention relates to the technical field of oil-and-gas-field geologic modeling, in particular to a shale-gas horizontal-well network crack modeling method based on microseism events. The method includes the steps that 1, data is prepared and imported; 2, a main crack model of shale-gas network cracks is established; 3, in combination with fractured microseism monitoring data, a gridding microseism-event density model and a network crack density model are generated; 4, a branch crack model of the shale-gas network cracks is established; 5, a contact crack model of the shale-gas network cracks is established; 6, the main crack model, the branch crack model and the contact crack model are combined to form a discrete crack model of shale-gas horizontal-well fractured network cracks. According to the shale-gas horizontal-well network crack modeling method based on the microseism events, by establishing the fractured crack models of different levels, the shale-gas horizontal-well complex network crack model is formed, has good fitting effects, and has relatively high practical significance to the development of shale gas.

The invention provides a method for recognizing and collecting microseism events in a well and belongs to the field of microseism monitoring. The method comprises the steps that (1) orientation rotation is conducted on each receiving point recorded in the even monitoring process; (2) for records obtained after rotation is conducted, a characteristic function value CFs of each receiving point at each moment is calculated; (3) an event superposition energy function L(t) is calculated through a time difference scanning technique; (4) the seism starting time ti of events is automatically detected through self-adaptive threshold values; (5) the peak value time of S waves of a set of events is collected and checked, and the jumping time of the S waves is collected and checked; (6) for each receiving point, a characteristic function value CFp is calculated for each time point within a fixed time interval Tspmax before the jumping time of the determined set of S waves; (7) the peak value time of each receiving point of P waves of the set of events is collected and checked, and the jumping time of the P waves is collected and checked.

The invention provides a high-precision automatic microseism P wave seismic phase first arrival pickup method. The method comprises the following steps of Hilbert conversion of a microseism signal, envelopment analysis of a Hilbert envelopment signal; pre-pickup of microseism P wave seismic phase first arrival, accurate calculation of the microseism P wave seismic phase first arrival and ending of automatic pickup of the microseism P wave seismic phase first arrival. The high-precision automatic microseism P wave seismic phase first arrival pickup method has the advantages of being good in anti-noise performance, high in calculation precision, high in algorithm real-time performance and the like, and has good technological value and application prospects.

The invention relates to a rock burst prevention method for deep tunnel excavation by adopting a TBM (Tunnel Boring Machine), aiming to solve the technical problem on lowering or eliminating the rock burst danger of the TBM in a strong-rock-burst tunnel section in an excavation process, improving the equipment utilization rate of the TBM and accelerating a construction schedule by means of pretreating a wall rock for the TBM to excavate. The rock burst prevention method for the deep tunnel excavation by adopting the TBM adopts the technical scheme comprising the following steps of: (a) excavating a pilot tunnel with the size smaller than the excavation contour line of the TBM in the strong-rock-burst tunnel section through which the TBM needs to pass for excavation by adopting a drilling and blasting method and monitoring microseisms before the TBM enters the potential strong-rock-burst tunnel section; and (b) releasing the stress of a strong-rock-burst part in the excavation process of the pilot tunnel and a part with potential rock-burst danger shown by microseismic monitoring. The invention is mainly used for deep hydraulic tunnels and deep traffic tunnels with high rock burst danger.

The invention relates to a novel modification system and process of a hot-dry-rock thermal reservoir, characterized by the combination of two stimulation measure processes, thermal stimulation and chemical stimulation. The process is characterized in that a naturally present fracture network is destructed by thermal stimulation to enhance permeability, partial minerals, scale and obstruction in shafts and fractures are dissolved by the chemical stimulation, and flow guiding capacity of the fractures is further improved. The repeating of the process enables a larger range of thermal reservoirs to be modified. By using the process, the problem of the prior art that after thermal stimulation, part of the fractures are closed along with the rise of the temperature of a cooling area and the problem that that a chemical stimulant disappears nearby an injection location during its excess speed of reacting with rock minerals at high temperature are solved, and the process enables greatly reduction in the risk of frequent microseism in a reservoir modification process when compared to traditional hydrofracturing. The process is widely applicable to the modification of hot-dry-rock thermal reservoirs.

The invention discloses a recyclable installation device of a microseism sensor and an installation method. The installation device includes a base, installation rods, an injection pipe, a rubber ring and a double sleeve. During installation, the microseism sensor is placed outside an installation hole. The microseism sensor is connected and fixed with the steel base through the installation rods and the double sleeve. The base is coupled with a rock body through cement mortar. Microseism signals are spread to the microseism sensor by the steel base through the installation rods. During recycling, screws on the double sleeve are screwed outside the installation hole so that the microseism sensor is recycled and the installation rods are rotated and pulled out outside the installation hole for recycling. The recyclable installation device of the microseism sensor and the installation method solve a problem that a microseism sensor is difficult to fix, maintain, protect and retract and are capable of receiving and acquiring vibration signals near any position and at the same time, positioning precision of a microseism source is ensured and the cost of microseism monitoring is saved. The recyclable installation device of the microseism sensor and the installation method are widely applicable to microseism monitoring of projects such as underground workshops, tunnels, slopes and roadways and the like.

The invention relates to a device for monitoring the stability of roof strata of a mine or concrete engineering in real time. The device mainly comprises a microseism signal conduction rod, a microseism signal sensing element and a microseism signal collection and analysis host computer. The microseism signal collection and analysis host computer is provided with a filter circuit for filtering the affection of ambient noise signal, a rapid data sampling circuit and a professional diagnosis and analysis software for analyzing the stability of the roof strata of the mine or the concrete structure in real time by utilizing artificial intelligence technology. The device is suitable for coal mines or other mines, can be used for the stability monitoring of underground construction which adopting concrete bar and concrete as the materials, such as metro stations or tunnels, and can also be used for the stability monitoring of dams, bridges, tall buildings and mountain landslides. Through a set of technology of digital filtering recognition and collection for the microseism signal, the recognition rate for acoustic signal released during rock breaking can be improved above 80 percent, and the purpose of monitoring the stability of the roof strata of the mine or the concrete structure is well completed.

The invention provides a microseism event positioning method. The method includes: utilizing a rule that any two waveforms are mutually correlated; calculating pickup first arrival time difference; utilizing weighted stacking of differences between the pickup first arrival difference among all wave detector pairs and calculated first arrival difference as a target function to perform optimized iterative positioning on a microseism event. By the method, the problem that low signal-to-noise-ratio coaxial axis is discontinuous can be effectively overcome; by utilizing weighted stacking of the differences between the pickup first arrival difference among all wave detector pairs and the calculated first arrival difference as the target function, N(N-1)/2 combinations of wave detectors can be provided for an observation system containing N wave detectors, so that massive information redundancy is provided, and positioning accuracy of the microseism event is improved.

The invention relates to a monitoring and early warning system and method, belongs to the technical field of coal mine monitoring, and particularly relates to a comprehensive monitoring and early warning system and method for floor water inrush in a coal mining working face. The comprehensive monitoring and early warning system and method mainly focus on real-time monitoring and graded early warning of a goaf part during the recovery process and after the recovery process of a mine coal mining face, based on a "lower three zones" theory, and a numerical simulation method is combined to determine monitoring positions, a microseism monitoring subsystem is used for monitoring the damage depth of a floor in the coal mining working face, a multi-frequency continuous electrical monitoring subsystem is used for monitoring the height of water table of confined water in the floor of the coal mining working face, the distance between the lowest point of floor damage and the highest point of height of water table of the confined water is calculated; a floor water inrush coefficient method is used for dynamically calculating the water inrush coefficient of the floor of the entire working surface; and the level of floor water inrush early warning is determined through different water inrush coefficients, early warning indication of stress and strain, early warning indication of water temperature and water pressure, and early warning is performed.

The invention discloses a micro-seismic multi-parameter early warning method for rock burst. The micro-seismic multi-parameter early warning method for the rock burst comprises the steps that a micro-seismic monitoring system is installed in a mine; the micro-seismic energy and the micro-seismic frequency are measured by means of the micro-seismic monitoring system in the mine, the total area A(t) of a fault, the quake absence b value and the Z-MAP value are calculated, and the four microquake signals are recorded; the obtained data are analyzed, and four evolution charts, namely the energy and frequency time sequence chart, the fault total area evolution chart, the quake absence b value evolution chart and the Z-MAP evolution value chart, are drawn; whether the situation that the mine earthquake frequency is reduced and the energy is increased, the situation that the fault total area value is abnormally high, the situation that the quake absence b value is abnormally low and the situation that the absolute value of Z is larger than two apprear in the same period of time is analyzed according to the drawn evolution charts, and if two to four of the four situations appear in the same period of time, it is judged that the situation of rock burst can occur. The micro-seismic multi-parameter early warning method for the rock burst has the advantage that the accuracy of early warning of rock burst is improved.

The invention relates to geophysical exploration microseism monitoring technology, in particular to a longitudinal and transversal wave time difference positioning method with computational efficiency improved greatly, combined with data base technology and under the condition that computational accuracy is guaranteed. The method comprises that (1) microseism happening space zone is established and grid subdivision is performed; (2) a forward modeling result of P wave or S wave of each grid is written to a data base by ray tracing algorithm; (3) combined with an azimuth angle of an actual microseism happening space, whether an azimuth angle of the i grid volume i (x, y, z) is in a range (theta m-theta', theta m+ theta') determined by the azimuth angle of a microseism event is judged and if the azimuth angle of the i grid is in the given azimuth angle range (theta m-theta', theta m+ theta'), a spatial point volume i (x, y, z, theta m +/- theta') where a microseism can happen is determined; and (4) in a microseism happening space zone volume, optimal seismic focus location search is performed on all grid points volume i (x, y, z, theta m +/-theta') with the azimuth angle located in the (theta m-theta', theta m+ theta') according to a formula. According to the microseism seismic focus positioning technology of the longitudinal and transversal wave time difference positioning method based on the data base technology, positioning accuracy can be satisfied and speed is greatly improved. The technology is initiate technology in seismic monitoring positioning technology.

The invention provides a microseism simulating and monitoring method and belongs to the micro-vibration generation and detection field. The method comprises the steps of pressurizing a fracturing fluid and injecting the fracturing fluid into a model to be detected; cracking the inside of the model to be detected by utilization of the fracturing fluid, wherein microseism signals are generated when cracks are produced; detecting the microseism signals via an accelerometer disposed on the surface of the model to be detected and also a laser doppler vibration meter disposed above the surface of the model to be detected and converting the signals into voltage signals; converting the voltage signals into digital signals; and finally storing, calculating and analyzing the digital signals by a computer to obtain information of the cracks. Through the method, microseism signals can be generated indoors through a micro-fracturing way and can be monitored, and water fracturing of field oil and gas wells and a three-dimensional microseism monitoring process can be simulated.

The invention relates to a wave packet superposition microseism ground location method. The method comprises the following steps of (a) dividing a model into a plurality of grids, and giving a threshold value for a number of iteration and an external enveloping superposition value; (b) selecting a detector, calculating a time for a microseism event in a designated grid to reach each designated detector, and correcting the time difference; (c) getting a root-mean-square amplitude of the corrected signal of the detector, solving external envelop, and adding the external envelops together to get an external enveloping superposition channel; (d) changing the grid, calculating the external enveloping superposition channel of the detector in a novel designated grid, traversing all grids to get the external enveloping superposition channel set; (e) picking up the microseism event on the external enveloping superposition channel set, and determining a position of the microseism; (f) calculating a signal-to-noise ratio of the picked microseism event; (g) repeating the steps of (b) to (f) until meeting the number of the iteration to obtain multiple microseism event positions, and counting the percentage of the times on each position in the total times; and (h) determining the microseism event exceeding the threshold value as a microseism valid event.

The invention discloses a microseism monitoring and positioning method based on full-waveform vector offset superposition. The purpose of monitoring and positioning microseisms is achieved by the data recorded by an earth surface three-component geophone through the method of vector superposition of the three components of P waves, SH waves and SV waves. The microseism monitoring and positioning method is suitable for detecting microseism signals, particularly, under the conditions that microseism energy is very weak caused by rock failure in the fracture improvement process and a traditional method loses efficacy, the effect of microseism detecting can be greatly improved, the defect that only microseisms with large energy can be detected in a traditional method is overcome, more microseisms with weaker signals can be detected, and the effect of fracture improvement can be more comprehensively monitored. According to the method, a good effect is achieved on monitoring of earth surface microseisms, very weak microseism signals can be detected, combined positioning of the P waves and the S waves can be conducted, and therefore the positioning precision is greatly improved.

The invention discloses a velocity model constructing and calculating method for ground monitoring microseism location, wherein the model is constructed based on a geophysical microseism linearization location method and an anisotropic average velocity model, in order to achieve construction and optimization solution of the three-dimensional anisotropic average velocity model, in comparison with the traditional laminated velocity model, the velocity model is closer to the actual simulation formation velocity so as to achieve a simple and reasonable calculating process, at the same time, through the velocity model constructing and calculating method, the laminated velocity model error caused due to ray tracing differentiation is also prevented; through the method, a residual vector between observation time and calculated travel-time difference of an appointed detector within a work area range and the optimization solution model are constructed, the least square solution of the velocity model can be obtained by iterating the model and inverted into the optimal velocity model, and crack events can be precisely located through the velocity model.

The invention discloses a hydrofracture focal mechanism inversion method and system, and the method comprises the steps: calculating the azimuths of all detectors relative to a hydrofracture focus according to the horizontal coordinates of all ground detectors; building a horizontal layered speed model through employing the interval transit time logging data of a hydraulic fracture well; calculating the take-off angle of each detector relative to the focus on the basis of the horizontal layered speed model, the focus positioning results, obtained through the processing of former microseism data, of a microseism event and the coordinate positions of the detectors; Determining the polarity of a first motion of a P wave according to the correlation coefficient of each recording channel to a standard channel; taking the azimuths and take-off angles of all detectors and the polarity of the first motion of the P wave as input, and obtaining the nodal plane solution of a fault corresponding to a minimum contradiction symbol ratio. The method achieves a high-efficiency and practical processing flow of the hydrofracture focal mechanism inversion through employing the information of the first motion of the P wave.