An essential step in vsp processing is the geometry input. Mcs survey located at the same site, which shared common source vibration points vps. Reflection seismology is similar to sonar and echolocation. Jan 20, 2008 this is a modeling example about how on vsps borehole seismic the upgoing and downgoing wavefields result in opposite positions on raw records. The purpose of this paper is to develop an optimization approach for vsp wavefield separation in the time domain. It was used in seismology for determining the mohorovicic discontinuity, and to discover the nuclei of earth. In this work we have proposed a new approach to spectral ratio method, where the seismic quality factor is estimated by nonlinear inversion of spectral ratios using levenbergmarquardt lm method. It is a simple system that provided invaluable benefits to the coal company. While a receiver may be moved a vertical distance of 200. The method requires a controlled seismic source of energy, such as dynamite or tovex blast, a specialized air gun or a seismic vibrator, commonly known by the trademark name vibroseis. Nonlinear approach to spectral ratio method for estimation of. In this paper, we propose a joint full waveform inversion method for surface, vsp and crosswell seismic data.
Seismic rays are used instead of the wave front to describe the wave propagation. The vsp provides information at an intermediate scale and also provides a calibration of the surface seismic method. Clearly, the frequency of the vsp is much higher than the seismic. A series of example of surface seismic with 3dvsp data spliced on the surface data, clearly link the fault detection on the borehole dataset and the surface 3d data. In particular, our 3d visualisation software allows the investigation of merged 3d vspseismic data from any perspective in. Borehole seismic data processing and interpretation. A vertical seismic profile vsp is recorded in essentially the same way as a checkshot survey. Constrained waveform inversion of colocated vsp and surface. Vertical seismic profiling vsp this technique is seldom used by itself, but rather is used to better interpret seismic reflection data. Vsps include the zerooffset vsp, offset vsp, walkaway vsp, walkabove vsp, saltproximity vsp, shearwave vsp, and drillnoise or seismic whiledrilling vsp. The vsp has four important roles to play in assessing the rock and fluids close to the borehole. This is a modeling example about how on vsps borehole seismicthe upgoing and downgoing wavefields result in opposite positions on raw records. The seismicvision service uses the latest qborehole integrated borehole seismic system technologya totalconcept approach in which borehole seismic interpretation experts use qtechnology singlesensor seismic hardware and software to deliver optimized and innovative solutions. Measurement of seismicwave travel time is one of the most common geophysical method.
Vsp measurements are much more closely spaced 50100 feet. The vsp has found a number of applications in the oil industry. The description of the geometry of refracted waves is more complex than that of reflected ones. Nonlinear approach to spectral ratio method for estimation. Thakur, ngri summary australia is the region to have large geothermal resources with the potential to provide cost effective lowemission energy for longer term. A series of such images are shown in figures 6 to 9.
The method includes the following steps that downlink waves in vsp data are separated, initial time of each vsp datum in the downlink waves of the vsp data is automatically picked up, amplitudes corresponding to the initial time of the vsp data are obtained, and a data. Vertical seismic profile vsp inversion for geothermal reservoirs sanjeev rajput, csiro p. In particular, our 3d visualisation software allows the investigation of merged 3d vsp seismic data from any perspective in slices through the x, y and z axes. A method for computation of velocity profiles by inversion of large. Seismic refraction method the first seismic method utilized in the field of exploration. Compared to conventional seismic methods, in which source and receiver are both on the ground, vertical seismic profiling vsp is designed with the source on the ground but the receiver in the.
Instructional material complementing fema 451, design examples seismic load analysis 9 2 topic objectives selection of method of analysis description of analysis techniques modeling considerations system regularity load combinations other considerations drift computation and acceptance criteria pdelta effects. Basic principles of the seismic method in this chapter we introduce the basic notion of seismic waves. Presented is how 3d vsp and surface seismic are being simultaneously acquired so as to use the vsp data to enhance the surface seismic project in. Vertical seismic profile vsp inversion for geothermal. Reflection seismology or seismic reflection is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the earths subsurface from reflected seismic waves. Introduction to seismic method linkedin slideshare. The 3d vsp survey is comparable to the surface seismic 3d survey except for the resolution difference, in addition to the areas that vsp fills in better than surface seismic in case of infrastructure difficulties, such as shallow gas which disrupts propagation of p waves. Advantages and disadvantages of surface and downhole. Conemounted accelerometers are used as the vsp receivers, and a sledgehammer against the cone truck baseplate is used as a source. The subject of vsp occupies several books and many research papers. In this study, we illustrate an analysis method for multicomponent vsp based on matrix operators in a convolutional model zeng and macbeth, 1993a, using a ninecomponent vsp shot at the conoco test facility in kay county, oklahoma. Seismic exploration is divided into refraction and reflection surveys, depending on whether the predominant portion of the seismic waves travel is horizontal or vertical. The method requires a controlled seismic source of energy, such as dynamite or tovex blast, a specialized air gun or a seismic vibrator, commonly known by the trademark.
An assumption behind this method, indeed all qestimation methods, is that the ability of the vsp sensor to record data is not affected by depth. The university of texas at austin, bureau of economic geology, report of investigations no. Both forward and backward wave propagations are calculated in the spacefrequency domain, and the gaussnewton method is used for accelerating the convergence rate. Current major constraints include dramatic reduction in acquisition time for cost effective operation in increasingly complex and harsh environments. Gochioco highresolution 3d surface seismic and coal geophysics program 2 written and archived. Constrained waveform inversion of colocated vsp and. Vsp data in comparison to other borehole seismic data.
Vertical seismic profiling the vsp can be used to gain insight into wavefield propagation lee and balch, 1983. This paper presents a case study relating to the 3d high resolution seismic acquisition currently in progress over the dukhan field in qatar. The continued interest in converted p to swaves pswaves and vertical seismic profiles vsps has resulted in the steady development of advanced vector wavefield techniques. Key formation tops are seen tracked across logs, real vsp with the same depth index the corridor stack time and seismic. High resolution, simultaneous vsp and land seismic. The efficacy of the proposed methodology has been tested on synthetic and real vsp datasets. Vsp data can be output in segy and displayed in a wide variety of formats and styles to illustrate any stage of the processing route. Receivers are located inside of the studied medium in a borehole while sources may be placed at any point on a surface. The spectral ratio method is the most commonly used approach to estimate the quality factor q from vertical seismic profile vsp data. Wavebywave extraction emil blias, revolution geoservices inc. For free space, the onedimensional wave equation is derived. Vertical seismic profile vsp data is generated by a surface source and recorded by. The major difference between a vsp and a checkshot survey is that vsp data are recorded at much smaller spatial sampling intervals than checkshots. Nearsurface vsp surveys using the seismic cone penetrometer.
Primarily, vsp data have been used to assist surface seismic interpretation through timetodepth values and. Pdf seismic inversion methods and some of their constraints. In geophysics, vertical seismic profile vsp is a technique of seismic measurements used for correlation with surface seismic data. Integrated welllog, vsp, and surface seismic analysis of nearsurface glacial sediments. The technique allows geophysicists to infer critical information that cannot be obtained otherwise. Seismic tomography is a method for finding the subsurface velocity distribution from a multitude of observations, such as vsp, crosswell, and surface seismic data. Vertical seismic profiling is a kind of transitive method inheriting some properties of both log and surface seismic surveys. The invention provides a surface seismic data amplitude compensation method based on vsp primary waves.
In his career willis has performed research and development in distributed acoustic sensing vsp technology, fracture identification using seismic data time lapse vsp, microseismics and surface seismic scattering, interferometric imaging, kirchhoff and reverse time depth migration. The defining characteristic of a vsp of which there are many types is that either the energy source, or the detectors or sometimes both are in a borehole. Willis is a chief scientific advisor in the borehole seismic group at halliburton. Evaluation of the vsp and seismic tomography methods in the tanna basin article pdf available in butsuritansageophysical exploration 466.
Vertical seismic profiling vsp is a measurement where the seismic source is still at the surface but the receivers are lowered down into a borehole slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. The fulldigital threecomponent vsp system is composed of digital exploring tubes, a data acquisition station, a control host and a storage battery, wherein the digital exploring tubes are arranged underground and sequentially connected end to end, and the data. The vsp traveltime tomography can provide valuable information about complicated geological structures and produce a suitable velocity model for depth migration imaging e. Vertical seismic profile vsp surveying is a vital tool in subsurface imaging and reservoir characterization. The method includes the following steps that downlink waves in vsp data are separated, initial time of each vsp datum in the downlink waves of the vsp data is automatically picked up, amplitudes corresponding to the initial time of the vsp data are obtained, and a data sequence is formed. Improving surface seismic resolution using vsp data 2 well has encountered pay sands within vadaparru shale. Geophysicists interpret surface seismic reflection data presented in time, and geologists construct models, drill wells, and acquire well logs in depth. An accurate velocity model of the subsurface is required to link the two types of data time and depth. Summary the spectral ratio method is the most commonly used approach to estimate the quality factor q from vertical seismic profile vsp data.
Purely defined, vsp refers to measurements made in a vertical wellbore using geophones inside the wellbore and a source at the surface near the well. The vertical seismic profiling vsp is a technique in which seismic signals generated at the surface of the earth are recorded by geophones at various depths in a borehole. Joint full waveform inversion of surface, vsp and crosswell. Basic source radiation patterns, free surface and seabed responses to p and swave arrivals are described as well as source, receiver, and vsp systems. Pdf evaluation of the vsp and seismic tomography methods in. Instructional material complementing fema 451, design examples seismic load analysis 9 17 1a, 1b stiffness soft story irregularity vertical structural irregularities irregularity 1a exists if stiffness of any story is less than 70% of the stiffness of the story above or less than 80% of the average stiffness of the three stories above. The total seismic wavefield is recorded in situ over a number of depth levels. Seismic attenuation estimation from zerooffset vsp data. Processing of a ninecomponent nearoffset vsp for seismic. Some history on vsp the vertical seismic profile vsp is a truly remarkable, versatile, and, unfortunately, underutilized innovationunderutilized perhaps because of its greater cost than the more routine check shot velocity survey and the possible overreliance within the industry on 3d surface seismic data. In the earth, seismic waves can propagate as longitudinal p or as shear s waves. Improving surface seismic resolution using vsp data. The seismic data used is a 2d section from a 3d volume available in the area.
The borehole camera method was the only nonseismic geophysical method published since it was a nonproprietary technology gochioco et. Cn104090299b surface seismic data amplitude compensation. The defining characteristic of a vsp of which there are many types is that either the energy source, or the detectors or sometimes both are in. Every point on the wave front is a source of a new wave that travels out of it in the form of spherical shells. On figure 8, the subtle fault located near the borehole. Check shot velocity survey measurements are typically taken every 250500 feet downhole and were designed to measure the downgoing waveforms used in velocity determination. Vsp acquisition geometry and first break picking the vista seismic processing package was employed for analyzing the data. Vertical seismic profiling vsp linkedin slideshare. Basic principles of the seismic method tu delft ocw.
Checkshots and vertical seismic profiles aapg wiki. Integrated welllog, vsp, and surface seismic analysis of. The determination of the seismic quality factor q from vsp. A vsp is a much more detailed survey than a checkshot survey because the geophones are more closely spaced, typically on the order of 25 m 82 ft, whereas a checkshot survey might. In vertical seismic profiling, both directly arriving and reflected signals are used. From the vsp, we can estimate the effects of the q and attempt to remove these effects from the surface seismic. A class of borehole seismic measurements used for correlation with surface seismic data, for obtaining images of higher resolution than surface seismic images and for looking ahead of the drill bit. Both forward and backward wave propagations are calculated in the spacefrequency domain, and the gaussnewton method is used for. It is commonly done with a string of hydrophones, 3component geophones or 3component accelerometers in a borehole and a surface seismic source located within a few.
A vertical seismic profile vsp stanford university. Cn104181579a fulldigital threecomponent vsp vertical. Mvsp is a new matlab tool with a graphical user interface gui for vsp shot modeling, data processing, and interpretation. The invention discloses a fulldigital threecomponent vsp vertical seismic profile system and a measuring method thereof. The well seismic is a zero offset vsp recorded from depth level 500m to 2375 m, using instrument dfs v, during the year 2005.
The wave phenomena occurring at a boundary between two layers are discussed, such as snells. Seismic inversion methods and some of their constraints article pdf available in first break 2210 june 2004 with 6,574 reads how we measure reads. Pdf evaluation of the vsp and seismic tomography methods. This technique eliminates the need to drill a borehole, thereby reducing the cost of the survey, and results in a less invasive means of obtaining vsp data. Unfortunately, vsps are costly and we rarely have them.