Moreover, the offset provides higher chances of converting p waves into s wave. The simplest type of acquisition would be to use a single coincident source and receiver pair and profile the earth along a line as shown in the adjacent figure. The contents of this chapter are fundamental to seismic processing. Below the depth of the drill hole, the walkaway vsp velocities are significantly lower than those determined by. Proposal for acquiring zerooffsetvertical seismic profile. Subsurface geology and velocity structure of the krafla high. Simultaneous vertical seismic profiling in two wells and. Automatic gain correction 200 ms operator length applied. Units in the velocity model are based on lithologic boundaries interpreted as seismic horizons and.
The seismic data used is a 2d section from a 3d volume available in the area. Vsps include the zero offset vsp, offset vsp, walkaway vsp, walkabove vsp, saltproximity vsp, shearwave vsp, and drillnoise or seismic whiledrilling vsp. Zero offset, walkaway vsp processing and avo gather creation sequences. During zvsp surveys, an airgun array is deployed adjacent to the drillship, while receivers are placed temporarily anchored in the wellbore. F17f25 march 2005 with 218 reads how we measure reads.
The first two components of this survey were a high resolution zerooffset vertical seismic profile vsp krau. Due to its geometry, a vsp survey is used principally to calibrate surface seismic data by giving an accurate depthtime measurement to geological features. Vertical seismic profile an overview sciencedirect topics. We proposed to acquire a single zero offset vertical seismic profile vsp in one of the scientific observation holes sohs on the island of hawaii. To date, a pp wave corridor stack and vspcdp mapping have been completed and are correlated to synthetic seismograms. The method is based on the correspondence principle. Appendix d marine mammal monitoring and mitigation plan. We proposed to acquire a single zerooffset vertical seismic profile vsp. Zero offset vsp in vertical and deviated wells, offset vsp, walkaway vsp. Raytracing modeling for borehole seismic acquisition design. Improving surface seismic resolution using vsp data 2 well has encountered pay sands within vadaparru shale.
In many cases, vertical seismic profiles vsp must be conducted with the source placed at considerable distance from the well. Halliburton borehole seismic services bhs can help enhance reservoir characterization with customized, reliable, highresolution images provided by far offset, walkaway and 3d vertical seismic profiles vsp. The source for the detailed zero offset vsp was located 32 m away from the, 100 mm diameter fibreglass reinforced plastic frp, water monitoring well m345408. Noisy seismic travel time data units of s from equallyspaced every 20 m seismometers deployed in a m deep vertical seismic profile experiment the same geometry as in example 4. Ep0202745a2 method for moveout correction and stacking. The joint inversion problem is solved by the damped leastsquares method, and the inversion result is successful using synthetic data. Geophysics a conventional vertical seismic profile in which the energy source is positioned directly above the receivers, typically very close to the wellbore. Pdf comparison of seismic attenuation models using zero. Zero offset vertical seismic profiling zvsp to correlate with surface seismic survey in identifying multiple reflections and true primary reflections presence in the given surface seismic data. Sidebyside comparisons of these data sets are shown at several steps in the processing flow to help understand the.
Vertical seismic profiling synonyms acquisition techniques. Analysis of multicomponent walkaway vertical seismic. Subsurface geology and velocity structure of the krafla. Measurement of the first compressional wave arrival and later arrivals are associated with field reflected waves. Interpretations of key seismic reflectors in the black warrior basin are presented based on a synthetic seismogram, checkshots, a zero offset vsp, and a wellconstrained well seismic tie. Sidebyside comparisons of these data sets are shown at several steps in the processing flow to help understand the advantages of each of these data types. Checkshots and vertical seismic profiles aapg wiki. Seven offset source seismic profiles were also made, using a vibroseis source. Integrated ditch cuttings, wireline and zero offset vertical seismic profile analysis. The standard borehole seismic imaging tools such as accelerometers and geophones are now being replaced by the fibreoptic fo acquisition for basic surveys such as zero offset vertical seismic profiles zvsps and checkshots. In this technique, a source is positioned at the surface near the well. Within this study we present results from an integrated analysis of the downhole volcanic stratigraphy from the k18 borehole within the krafla caldera based on combined wireline, ditch cuttings, and zero offset vsp vertical seismic profile analyses.
Regional support in latin america for vertical seismic profile vsp data planning, processing and interpretation, including. This kind of surveys is similar to the zero offset, except the source is further away from the well bore. To transform reflection times into vertical incidence times, 2 steps are performed. A moveout correction process and stacking velocity estimation process to permit stacking of vertical seismic profile vsp data is disclosed wherein the primary reflection time is determined by using the twoway travel time, the root mean square velocity of acoustic pulses in the formation and the first arrival time of direct path acoustic pulses. The complete package halliburton uses the latest technology in data acquisition coupled with advanced. Seismic displays visualization is key to seismic data analysis 3d displays are mostly done interactively using workstations in this plot.
At the completion of each well a zero offset vertical seismic profile zvsp likely will be conducted. In this work, we propose an approach to invert vertical seismic profile corridor stacks in bayesian framework for look. Normal moveout corrections, based on the velocity model from the zero offset vsp, were applied during processing of the offset seismic profiles. Vertical seismic profiling vsp types planning and acquisition processing reading.
Analysis of multicomponent walkaway vertical seismic profile data. The acquisition of the zero offset vertical seismic profiling zvsp and borehole data was done in well. Calculation of zerooffset vertical seismic profiles. Threecomponent 3c zero offset vertical seismic profile zvsp and offset vertical seismic profile ovsp data was integrated with surface seismic data and openhole logs to characterize seismic reflectors and successfully identify and improve delineation of channel type reservoirs in a deviated well in the llanos basin, colombia. The vsp however, is also in twoway time on the vertical axis.
U k orizons g etermination via vpvs and qfactor g ata. The well seismic is a zero offset vsp recorded from depth level 500m to 2375 m, using instrument dfs v, during the year 2005. Case history seismictrak service identified target ahead of. A vertical seismic profile experiment carried out at ocean drilling program site 891 ties the regional seismic reflection. Lawton summary zerooffset vertical seismic profiles vsps were acquired at a coalbed methane test site using three different sources. Summed raw vertical component data recorded for minip zerooffset vertical seismic profile at red deer. Proposal for acquiring zerooffset vertical seismic profile. We should take into account the mutual interactions between the intrinsic and scattering attenuation. Radiation from seismic sources in cased and cemented boreholes. An important method in oil and gas exploration is vertical seismic profile vsp to estimate rock properties in drilling well. Comparison of seismic attenuation models using zerooffset vertical seismic profiling vsp data article pdf available in geophysics 70. Proposal for acquiring zerooffsetvertical seismic profile in. Analysis of multicomponent walkaway vertical seismic profile data bona wu, don c.
Vsp vertical seismic profile shows a geophone measurements at different depths in the well which are sent to receptors on the surface. In addition to tying well data to seismic data, the vertical seismic profile also enables converting seismic data to zero phase data and distinguishing primary reflections from multiples. 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. Proposal for acquiring zerooffset vertical seismic. Analysis of zero offset vertical seismic profiling data. Determinationof multiplesin surface seismic data using. Zero offset vertical seismic profiling, mamuniyat formation, murzuq basin, libya. The offset increases the volume of subsurface imaged reflectors which increase the correlation with surface seismic data. A conventional vertical seismic profile in which the energy source is positioned. Next, it is explained how to obtain a re ectivity pro le from raw vsp data. Dedicated module for vsp survey geometry calculation and assignment, properly accounting for borehole deviations.
Most vsps use a surface seismic source, which is commonly a vibrator on land and an air gun in offshore or marine environments. Case history seismictrak service identified target ahead. In order to overcome this limitation, we propose a novel method for separating intrinsic and scattering attenuation for zero offset vertical seismic profiling vsp data. In the more general context, vsps vary in the well configuration, the number and location of sources and geophones, and how they are deployed. Subsurface geology and velocity structure of the krafla high temperature geothermal field, iceland. Hall abstract a multicomponent walkaway vsp data processed for pp and ps imaging as well to study the avo response. Afterwards, deconvolution of the data migration is carried out to obtain the final image.
There are numerous methods for acquiring a vertical seismic profile vsp. The objective of the vsp is to define the pwave velocity structure around the hole and to test the applicability of the vsp technique in an soh. In geophysics, vertical seismic profile vsp is a technique of seismic measurements used for correlation with surface seismic data. A migration step is strongly advisable in the case of 12 3 45 6 vertical seismic profiling, figure 1 common acquisition geometries for vertical seismic profiling vsp. This is because of the coincident raypaths that traverse a given rock layer, ensuring that the only path difference between two reflected waves one from the top of the interval and one from the. Because this particular vsp used an offset source, we have created. These vertical seismic profile data were processed to reveal reflections originating from the 85.
While a receiver may be moved a vertical distance of 200. Seismic, migration algorithm, or a combination of the two. A vertical seismic profile vsp is a measurement in which the seismic waves are recorded by geophones secured in a borehole for a seismic source at the surface of the earth. Introduction the murzuq basin is located in southwestern libya figure. Proposal for acquiring zerooffset vertical seismic profile in soh, hawaii. Reprints were made with permission from the respective publishers.
Improving surface seismic resolution using vsp data. Vertical seismic profile with the radexpro software, you can efficiently process zerooffset, faroffset and walkaway 2d vsp data. Zero offset vsps a have sources close to the wellbore directly above receivers. A vertical seismic profile vsp is recorded in essentially the same way as a checkshot survey. Carlos andres ramirez technical sales advisor wireline. Zerooffset vertical seismic profiles of coalbed methane strata.
Integrated ditch cuttings, wireline and zero offset vertical seismic profile. In the most common type of vsp, hydrophones, or more often geophones or accelerometers, in the borehole record reflected seismic energy originating from a seismic source at the surface. A vertical seismic profile vsp was made, using a vibroseis source, in a well in austria owned by oem vag. This allows a direct correlation of surface seismic data as well as synthetic data to the well logs in depth. In october 2006, threecomponent zero offset vertical seismic profile data were acquired from a deviated well in the flin flon mining camp in manitoba, canada, using a dynamite source.
We present a 1d viscoelastic waveform inversion scheme for determining the quality factor q from the normalincidence surface seismic and zero offset vertical seismic profile vsp data simultaneously. Vertical seismic profile with the radexpro software, you can efficiently process zero offset, far offset and walkaway 2d vsp data. Beyond the vertical profile todays borehole seismic methods create new opportunities for investigating formations penetrated by a borehole. Methods there are different techniques or processing steps applied when carrying out zero offset vertical seismic profile. Zero offset vertical seismic profile vsp measurements provided a more detailed interval velocity profile realtime surface seismic vsp calibration placed bit on surface seismic for look ahead capability background and challenges llog exploration offshore, l. Zerooffset vertical seismic profiles of coalbed methane. The vertical seismic profile vsp is a technique based on the register of acoustic travel time recording the duration of the passage. Vertical axis is the twoway reflection travel time, horizontal axes give the collocated sourcereceiver coordinates, color represents reflection amplitudes the colorcoded upper surface is the water bottom. Proposal for acquiring a zero offset verticalseismic profile in soh gregory moore and gerard fryer we proposed to acquire a single zero offset verticalseismic profile vsp in one of the scientific observation holes sohs on the island of hawaii. Determinationof multiplesin surface seismic data using zero. Ep0202745b1 method for moveout correction and stacking. 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. The board, in consultation with the operator, may request the operator to acquire a vertical seismic profile vsp, where it would. We note that the gamma ray and sonic logs are in depth 600m1800m as is the horizontal scale of the vsp.
This invention relates to a method for moveout correction and stacking velocity estimation of offset vertical seismic profile data. Twenty four hydrophones deployed were in m345408 over a fixed depth range from 120 m to 350 m below surface. The geometry of a zero offset vertical seismic profile vsp makes it an ideal survey to use for the calculation of q using the spectral ratio method. Impulse responses including nearfield terms have been obtained in closed form for the zero offset vertical seismic profiles generated by a horizontal point force acting on the surface of an anelastic halfspace. When the source is at a considerable horizontal distance of the well head, the result is an offset vsp.