Positioning drill-bit and look-ahead events using seismic traveltime data

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. F79-F90 ◽  
Author(s):  
Jo Eidsvik ◽  
Ketil Hokstad
Keyword(s):  
Velocity Model ◽  
Drill Bit ◽  
Surface Sampling ◽  
Data Set ◽  
Norwegian Sea ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Look Ahead ◽  
Sampling Locations ◽  
Dense Sampling

We study seismic traveltime measurements acquired in the borehole, including vertical seismic profiling, seismic measurements while drilling, and drill-bit noise generated data. These traveltime data are used to assess informative parameters, including drill-bit position, distance to drilling target, and parameters of the velocity model. First, we analyze seismic traveltime data using a simple hyperbolic traveltime equation for rays between surface sampling locations and the drill bit. Second, we describe a model for estimating both the position of the drill bit and the relative distance to geologic interfaces ahead of the bit. Finally, we present a dynamic Bayesian strategy for real-time prediction of drill-bit positions, velocity parameters, and distances to geologic markers. Walk-away vertical seismic profiling data from the Norwegian Sea are used to demonstrate our methods. For this data set, we pick five key reflectors ahead of the drill bit. The deepest reflector is estimated to be [Formula: see text] ahead of the drill bit, using seismic traveltime data alone. The effects of aperture and surface sampling locations are large on our estimates and their associated uncertainties, and we observe that large offset is preferable to dense sampling in terms of positioning accuracy.

scholarly journals Reference P-wave velocity in coal seams at great depths in Jastrzebie coal mine

2019 ◽  
Vol 133 ◽  
pp. 01011
Author(s):  
Jakub Kokowski ◽  
Zbigniew Szreder ◽  
Elżbieta Pilecka
Keyword(s):  
Wave Velocity ◽  
Coal Mine ◽  
Velocity Model ◽  
P Wave ◽  
Coal Seams ◽  
Data Set ◽  
Seismic Profiling ◽  
Reference Velocity ◽  
P Wave Velocity ◽  
Geological Conditions

In the study, the determining of the reference velocity of the P-wave in coal seams used in seismic profiling to assess increases and decreases in relative stresses at large depths has been presented. The seismic profiling method proposed by Dubinski in 1989 covers a range of depth up to 970 m. At present, coal seams exploitation in Polish coal mines is conducted at greater depths, even exceeding 1200 m, which creates the necessity for a new reference velocity model. The study presents an empirical mathematical model of the change of the P-wave velocity in coal seams in the geological conditions of the Jastrzebie coal mine. A power model analogous to the Dubinski’s one was elaborated with new constants. The calculations included the results from 35 measurements of seismic profiling carried out in various coal seams of the Jastrzebie mine at depths from 640 to 1200 m. The results obtained cause changes in the result of calculations of seismic anomalies. Future validation of the proposed model with larger data set will be required.

Prediction ahead of the bit by using drill‐bit pilot signals and reverse vertical seismic profiling (RVSP)

Geophysics ◽  
2002 ◽  
Vol 67 (4) ◽  
pp. 1169-1176 ◽  
Author(s):  
Massimo Malusa ◽  
Flavio Poletto ◽  
Francesco Miranda
Keyword(s):  
Numerical Model ◽  
Low Cost ◽  
Drill Bit ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Zero Offset

Surface drillstring axial pilot signals are used to predict reflections ahead of the drill bit. We show that part of the drill‐bit signal propagates downward in the formation, reflects upward by a seismic interface, and is then transmitted to the drillstring and the surface pilot sensors. These reflections are interpreted in drill‐bit pilot signals by means of a numerical model of the drillstring coupled to the formation at the bit–rock contact. The result is an additional, low‐cost, reverse VSP (RVSP) in the zero‐offset approximation. These while‐drilling results are integrated with conventional drill‐bit RVSP measurements and compared with other geophysical and well results.

Analysis and removal of multiply scattered tube waves

Geophysics ◽  
2000 ◽  
Vol 65 (3) ◽  
pp. 745-754 ◽  
Author(s):  
Gérard C. Herman ◽  
Paul A. Milligan ◽  
Qicheng Dong ◽  
James W. Rector
Keyword(s):  
Wave Field ◽  
Large Amplitude ◽  
Data Set ◽  
Impedance Function ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Total Data ◽  
Vsp Data ◽  
Tube Wave

Because of irregularities in or near the borehole, vertical seismic profiling (VSP) or crosswell data can be contaminated with scattered tube waves. These can have a large amplitude and can interfere with weaker upcoming reflections, destroying their continuity. This type of organized noise cannot always be removed with filtering methods currently in use. We propose a method based on modeling the scattered tube‐wave field and then subtracting it from the total data set. We assume that the scattering occurs close to the borehole axis and therefore use a 1-D impedance function to characterize borehole irregularities. Estimation of this impedance function is one of the first steps. Our method also accounts for multiply scattered tube waves. We apply the method to an actual VSP data set and conclude that the continuity of reflected, upcoming events improves significantly in a washout zone.

VSP traveltime inversion for linear inhomogeneity and elliptical anisotropy

Geophysics ◽  
2004 ◽  
Vol 69 (2) ◽  
pp. 373-377 ◽  
Author(s):  
Michael A. Slawinski ◽  
Chad J. Wheaton ◽  
Miro Powojowski
Keyword(s):  
Statistical Analysis ◽  
Least Squares ◽  
Field Data ◽  
Velocity Model ◽  
Western Canada ◽  
Velocity Dependence ◽  
Traveltime Inversion ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Good Agreement

To account for measured vertical seismic profiling (VSP) traveltimes, we study a velocity model described by three parameters. We assume that the velocity increases linearly with depth and is given in terms of parameters a and b, whereas the anisotropy is the result of elliptical velocity dependence and is given in terms of parameter χ. Using this model, we formulate an analytical expression for traveltime between a given source and a given receiver. This traveltime expression contains the three parameters that are present in the velocity model. To obtain the values of a, b, and χ, we use least‐squares fitting of this traveltime expression, with respect to measured traveltimes. This process of obtaining the parameters is exemplified by a study of traveltime data acquired with a two‐offset VSP in the Western Canada Basin. Having obtained a, b, and χ, we perform a statistical analysis, which shows good agreement between the field data and the modeled data. Furthermore, it shows that the elliptical velocity dependence, although small, is statistically significant.

Correlation between seismic diffractions extracted from vertical seismic profiling data and borehole logging in a carbonate environment

2015 ◽  
Vol 3 (2) ◽  
pp. T121-T129 ◽  
Author(s):  
Alexander Klokov ◽  
Damir Irkabaev ◽  
Osareni C. Ogiesoba ◽  
Nail Munasypov
Keyword(s):  
Joint Analysis ◽  
Seismic Attribute ◽  
Data Set ◽  
Borehole Logging ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Fluid Saturation ◽  
Attribute Analysis ◽  
Vsp Data ◽  
Tectonic Dislocations

Seismic diffractions may play an important role in seismic interpretation because they characterize geologic objects that might not be visible for conventional seismic attribute analysis. Diffractivity may be caused by, and consequently may define, tectonic dislocations (faults and fractures), lithologic variations, and fluid saturation within rocks. We have tied seismic diffractions extracted from vertical seismic profiling (VSP) data and borehole logging, from which we recognized the reasons that were responsible for diffractivity of the strata. First, we processed a multisource multicomponent VSP data set to extract seismic diffractions and constructed diffraction images of the strata for all three of the VSP data components. Then, we performed joint analysis of well logs and diffractions to obtain petrophysical attributes associated with diffraction images. We divided the rock succession into several units, which have different diffraction properties. We identified compacted rock, alternating intervals, isolated fractured zones, and fluid-saturated layers.

First-break vertical seismic profiling tomography for Vinton Salt Dome

Geophysics ◽  
2006 ◽  
Vol 71 (3) ◽  
pp. U29-U36 ◽  
Author(s):  
Hua-wei Zhou
Keyword(s):  
A Priori ◽  
Salt Dome ◽  
Data Set ◽  
Velocity Anisotropy ◽  
Seismic Profiling ◽  
Velocity Models ◽  
Vertical Seismic Profiling ◽  
Vsp Data ◽  
Multiscale Inversion ◽  
Sonic Logs

Building laterally depth-varying velocity models for vertical seismic profiling (VSP) imaging is challenging because of the narrow ray-angle coverage of VSP data, especially if only first arrivals are used. This study explores the potential of a new deformable-layer tomography (DLT) for building velocity models with a VSP data set acquired over the Vinton salt dome in southwestern Louisiana. The DLT method uses first breaks to constrain the geometry of velocity interfaces from an initial model of flat, constant-velocity layers parameterized using a priori geologic and geophysical information. A progressive multiscale inversion loop gradually updates the interface geometry. The final solution model, containing 3D geometry, is well supported by resolution and reliability tests and closely matches the long-wavelength trends of area sonic logs. The presence of velocity anisotropy is also indicated.

Identification of structures inside basement at Soultz-sous-Foret (France) by triaxial drill-bit vertical seismic profiling

Geothermics ◽  
1999 ◽  
Vol 28 (3) ◽  
pp. 355-376 ◽  
Author(s):  
Hiroshi Asanuma ◽  
Hakusei Liu ◽  
Hiroaki Niitsuma ◽  
Roy Baria
Keyword(s):  
Drill Bit ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling

A new approach to offshore drill‐bit reverse vertical seismic profiling (RVSP)

Geophysics ◽  
2002 ◽  
Vol 67 (4) ◽  
pp. 1071-1075 ◽  
Author(s):  
Flavio Poletto ◽  
Giuliano Dordolo
Keyword(s):  
Drill Bit ◽  
New Approach ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling

scholarly journals Seismic-While-Drilling in Kuwait Results and Applications

GeoArabia ◽  
1996 ◽  
Vol 1 (4) ◽  
pp. 531-550
Author(s):  
Osman S. Khaled ◽  
Alaa M. Al-Ateeqi ◽  
Andrew R. James ◽  
Richard J. Meehan
Keyword(s):  
Real Time ◽  
Seismic Source ◽  
Extensive Study ◽  
Drilling Process ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Look Ahead ◽  
Drilling Technique ◽  
Oil Company

ABSTRACT During early 1994, Kuwait Oil Company and Schlumberger completed an extensive study of the Seismic-While-Drilling technique in two development wells in the Raudhatain field of North Kuwait. Seismic-While-Drilling records the energy radiated from a working drillbit (utilized as a seismic source), with receivers placed at the surface. This technology provides well seismic information such as checkshot and look ahead Vertical Seismic Profiling services at the wellsite, in real-time. The technique does not interfere with the drilling process nor does it require deploying any downhole hardware. The result of the study is that the Seismic-While-Drilling technique can work successfully in the Raudhatain field.

Sign in / Sign up

Export Citation Format

Share Document