1625 results about "Seismic exploration" patented technology

A method for forming a prograde kinematic model allowing reproduction in 3D intermediate geometries of geologic objects of an underground zone such as a sedimentary basin, from an initial state to a current state. A representation of the current geometry of the geologic objects of the zone is formed by interpretation of acquired data obtained by seismic exploration, by in-situ measurements and by observations, then each geologic object is subdivided into layers separated by deformation interfaces. Each one of the layers is defined by means of a grid pattern into a series of hexahedral volume elements. Tectonic deformations are then applied separately and successively to each series of volume elements of a layer in relation to an underlying layer while conserving the thickness and the surface area of an intermediate neutral surface in each volume element. Then the tectonic deformations are iteratively modified until a geologic representation substantially in accordance with the known final state of the underground zone is obtained.

A method for use in seismic surveying includes determining the shape of a seismic cable during a seismic survey; determining the tension on the seismic cable at a plurality of points along the seismic cable; and predicting a current that will impact the seismic cable from the determined shape and the determined tension. The method may be practiced two-dimensionally in the context of a marine survey employing a towed streamer array or three-dimensionally in the context of laying an array of ocean bottom cables on the seabed. The predicted currents can, in some embodiments; be used to make steering corrections for the seismic cables.

A method and device for seismic exploration of a subsea geologic formation by pickups set on the sea bottom and intermittently connectable to active data acquisition stations (11) brought nearby. Permanent passive reception stations (1) comprising a heavy pedestal provided with housings for seismic pickups (geophones (6), hydrophone (7)) which receive acoustic or seismic signals from the underlying formation are arranged at the bottom of the water body. When collection sessions for the signals received by the pickups are scheduled, mobile active acquisition stations (11) connected to permanent passive reception stations (1) are positioned at the bottom of the water body. The signals picked up are then recorded, for the time required to carry out at least one session of acquisition and recording of the acoustic or seismic signals received by the passive stations in response to the emission of seismic waves by one or more seismic sources. The mobile active acquisition stations (11) are thereafter recovered at the surface and the records acquired by each one are transferred to a central collection laboratory.

A seismic exploration method and unit comprised of continuous recording, self-contained wireless seismometer units or pods. The self-contained unit may include a tilt meter, a compass and a mechanically gimbaled clock platform. Upon retrieval, seismic data recorded by the unit can be extracted and the unit can be charged, tested, re-synchronized, and operation can be re-initiated without the need to open the unit's case. The unit may include an additional geophone to mechanically vibrate the unit to gauge the degree of coupling between the unit and the earth. The unit may correct seismic data for the effects of crystal aging arising from the clock. Deployment location of the unit may be determined tracking linear and angular acceleration from an initial position. The unit may utilize multiple geophones angularly oriented to one another in order to redundantly measure seismic activity in a particular plane.

The invention belongs to the technical field of oil gas and coal-bed gas seismic exploration and development, and in particular relates to a reservoir sedimentary evolution analysis method in the exploration and development process. The method is used for providing reliable basic data for optimizing favorable target bed series and zone for oil gas and coal-bed gas exploration and development. In the method, sedimentary characteristics of reservoirs are analyzed by a three-dimensional seismic attribute data body, and high-resolution sequence stratigraphic principle and method, a seismic attribute analysis method and a pattern recognition method are applied; and a K-mean clustering algorithm is adopted, and the analysis process of sedimentary characteristics and sedimentary evolution of a sedimentary formation unit is performed under the control of a sedimentary isochronous interface. The method is used for assisting in reservoir sedimentary evolution research work in the exploration and development process of oil gas including unconventional oil gas, guiding the description of sedimentary characteristics of fine reservoirs of lithologic and stratigraphic trapped oil gas reservoirs, and providing the reliable basic data for optimizing the favorable target bed series and zone for the oil gas and coal-bed gas exploration and development.

The invention, which belongs to the oil gas and coalbed methane seismic exploration and development field, provides a stratification position flattening method-based ancient landform restoration method. The provided method comprises the following steps that: firstly, geologic stratification position defining is carried out; secondly, a geologic stratification position sequence is defined; thirdly, a small stratification is divided between two adjacent geologic stratification positions; fourthly, a maximum distance between two adjacent small stratifications between two adjacent geologic stratification positions at vertical direction is defined; fifthly, interpolation is carried out on channel data between the two adjacent small stratifications according to the maximum distance at the vertical direction and after the interpolation is completed, the distances at the vertical direction between the two small stratifications are equal, thereby completing stratification position flattening of the two small stratifications; sixthly, the step three and the step five are repeatedly carried out on all the two adjacent stratification positions so as to complete all the stratification position flattening; and seventhly, zero value filling is carried out on the truncation portion. The method can be implemented easily by a computer; and the actual effect required by the ancient landform restoration theory can be ensued.

A shorter spatial wavelength static correction method for exploration seismic data using first arrivals according to the invention includes the steps of: based on a quadratic curve fitting to the first arrivals, which are picked up from seismic wave records of receiver gathers after the field statics, obtaining the difference DELTAi,j between the observed first arrival time tij of the receiver point j with respect to the shot point i and the corresponding time value of the fitted quadratic curve; and forming the original matrix DELTA having mxn elements DELTAi,j, where n is the total number of shot points and m is the total number of receiver points of the line; substituting the elements of each row by the difference between the value of each element and the row average; and substituting the elements of each column by the difference between the value of each element and the column average; repeating the iteration until less than a predetermined error; the sum of the averages of the ith row for all iterations and the sum of the averages of the ith column for all iterations are the static correction value at the ith shot point and the static at the jth receiver point respectively. Said method is applicable to 3-D seismic survey by mean of using a formula of rij={square root}{square root over (DELTAxij2+DELTAyij2)} to transform 3-D seismic data into 2-D data, so that the 3-D seismic data processing is as simple as that of 2-D data.

The invention belongs to seismic data processing in petroleum geophysical exploration and geological engineering survey, and relates to near-surface velocity modeling and static correction in seismic exploration aiming at research and development of a shallow velocity model required for combined post static correction in a detector chamber of single-point high-density seism. A method for establishing a near-surface velocity model in high-density seismic static correction processing comprises the following steps of: supposing that the near-surface velocity is linearly increased along with the depth, calculating refracted wave velocity of different geophone offset from the travel time difference of primary waves of adjacent detection points of the high-density seism according to the physical property of the primary wave of the near-surface velocity field, establishing a near-surface ramp velocity field parameter according to the relationship between the geophone offset and the refracted wave, and further establishing the near-surface velocity model which can be directly used for static correction quantity calculation in seismic processing and also can be used as an initial model for tomographic inversion of near-surface velocity. The method has high calculation speed, and does not depend on the change of the initial position caused by a seismic focus.

The invention provides a method and device for predicating sand body thicknesses through logging constraint wave impedance inversion. The method includes the steps of acquiring corresponding seismic data and geological logging data after carrying out seismic exploration drilling sampling in a target exploration area, carrying out logging constraint wave impedance inversion on the target exploration area according to the seismic data with the geological logging data as constraint conditions to obtain a logging constraint wave impedance inversion model of the target exploration area, selecting a plurality of sampling points respectively and evenly for each sand group in the target exploration area on an inversion section of the logging constraint wave impedance inversion model to obtain sand body total wave impedance values of corresponding sand groups and sand body thickness relation curves of the corresponding sand groups through fitting, and obtaining the sand body thicknesses of the corresponding sand groups according to the relation curves. The method and device for predicating the sand body thicknesses through logging constraint wave impedance inversion improve reliability of sand body distribution and thickness prediction in stratums with complicated geological conditions, different reservoir stratum thicknesses and large physical property changes.

There is provided herein a system and method of seismic exploration that produces improved locations and timings for ocean bottom seismometers. The instant method utilizes linearized inversion in conjunction with a conventionally accurate clock to provide both time and positioning for each OBS unit with high accuracy as compared with the prior art approach. Inversion is one mathematical tool that effectively performs the requisite triangulation. Furthermore, the clock drift can be accounted for in the inversion scheme. The inversion not only determines the OBS position and shot timing errors, but also estimates the accuracy of the position and timing determination.

The invention provides a method for optimizing a design of a vertical seismic profile observation system for seismic exploration, which comprises the following steps: establishing a seismic geological model by known data; distributing more than two different observation systems; forwarding a response of a seismic wave field; calculating a position of a reflective spot, incident and reflection angles and length or ray impact frequency, and counting characteristic parameters again to construct an analysis map; and determining the optimal scheme for actual exploration according to a geological target. The method adopts multi-parameter analysis based on a spacial model, has strong rationality of results, adapts to details, can improve data acquisition quality, is suitable for homogeneous spaces and one-dimensional, two-dimensional or three-dimensional models, can be used for non-zero spacing, Walkaway and 3D-3C VSP exploration designs, and also can be used for analyzing VSP exploration designs of longitudinal waves, transverse waves and converted waves.

The invention provides a diffracted wave field separation method based on a Kirchhoff integral method. In seismic exploration, subsurface information can be inferred through responses of seismic waves to subsurface media; when a subsurface medium catastrophe happens, diffracted waves usually are response to the subsurface medium catastrophe. Main oil gas storage spaces in carbonate rock regions (such as Tarim and Sichuan) are secondary corroded holes and cracks, the sizes of the holes and the cracks are smaller than the wavelength of the seismic waves; the seismic response of the holes and the cracks is mainly diffraction, therefore the research on the diffracted waves has significant theoretical and practical meanings. However, in common deviation, the diffracted waves are converged to be one point on a profile and are submerged in a plurality of events and cannot be recognized. In a common reflection point (CRP) trace gather, since diffraction points and reflection points are the flattening of the events, the diffraction points cannot be recognized in the trace gather. Therefore, the invention provides a method for outputting an inclined angle trace gather through Kirchhoff deviation and hole diffracted waves and interface reflection waves can be rapidly and efficiently separated through obvious difference between the reflection waves and the diffracted waves in the inclined angle trace gather.

System and method for controlling an instrumented cable (30) towed in water, such as a marine seismic streamer and/or an instrumented towed cable array (streamer array), to which at least one instrumented cable (30), control devices (10, 20) are arranged to control the individual instrumented cables (30) both in shape and position in relation to other instrumented cables (30) and then counteract cross currents and/or other dynamic forces affecting a towed cable array behind a seismic survey vessel (50). The wings (12, 23) of the control devices (10, 20) are provided with acoustic transmitter/receiver means (14) and electronics for acoustic ranging, and the vessel (50) and one or more tail buoys (60) are provided with acoustic transmitter/receiver means (62) and electronics for acoustic ranging, and is provided with instrumentation for absolute position and velocity.

The invention relates to a multi-component converted wave static correction method by using surface waves, which comprises a step of solving stratigraphic classification and transverse wave velocity of a superficial layer through the extraction of the surface waves and the inversion of frequency dispersion curves based on Rayleigh surface waves in a shot record, so as to accurately calculate static correction quantity of detection points of converted waves. The test processing on two-dimensional three-component of a certain block in Daqing shows that a transverse velocity non-uniform body of the superficial layer generates a larger static correction time difference; and the processing on three-dimensional three-component data of a certain coal mine in Huainan shows that the static correction time difference of over 20 milliseconds can also occur due to the low and transversely non-uniform transverse wave velocity even in a flat plain terrain, and for a coalfield high-resolution seismic exploration to recognize minor faults of about 3 meters, the static correction time difference is a non-ignorable error. Application tests in three-component seismic data processing in two regions achieve a better processing effect and prove that the multi-component converted wave static correction method by using the surface waves is a feasible method.

Controller and method for adapting a frequency sweep for a vibro-acoustic source element that is configured to generate acoustic waves during a seismic survey. The method includes driving a seismic source element to generate a current frequency sweep; recording seismic data with plural seismic sensors in response to the current frequency sweep; selecting, during the seismic survey, a data subset of the seismic data, wherein the data subset has a size less than 10% of the seismic data; calculating with a processing device an attribute based on the data subset; and calculating a new frequency sweep based on the attribute.

The disclosure identifies method and apparatus for seismic exploration which may be used to provide improved positioning of land-based seismic sources in an array. Also described are methods which make use of the improved positioning to allow, in some examples, improved direction or distribution of the energy beam resulting from actuation of the sources. Some methods make use of the described techniques to steer the energy beam; and in some cases at each source or a distribution location, multiple shots will be taken to distribute the beam in multiple orientations relative to the central source point.