The use of drill‐bit energy as a downhole seismic source

Geophysics ◽  
1991 ◽  
Vol 56 (5) ◽  
pp. 628-634 ◽  
Author(s):  
J. W. Rector ◽  
B. P. Marion
Keyword(s):  
Seismic Energy ◽  
Seismic Source ◽  
Drilling Process ◽  
Drill Bit ◽  
Data Set ◽  
Pilot Signal ◽  
Data Volume ◽  
Vsp Data ◽  
Borehole Seismic ◽  
Incoherent Noise

A new wellbore seismic technique uses the vibrations produced by a drill bit while drilling as a downhole seismic energy source. The technique is described as “inverse” VSP because the source and receiver positions of conventional VSP are reversed. No downhole instrumentation is required to obtain the data and the data recording does not interfere with the drilling process. These characteristics offer a method by which borehole seismic data can be acquired, processed, and interpreted while drilling. Interchanging the conventional VSP source and receiver positions improves the efficiency of recording multioffset surveys for imaging a 3-D data volume in the borehole vicinity. The continuous signals generated by the drill bit are recorded by a pilot sensor attached to the top of the drillstring and by receivers located at selected positions around the borehole. The pilot signal is crosscorrelated with the receiver signals to compute traveltimes of the arrivals and to attenuate incoherent noise. Deconvolution and time shifts of the pilot signal compensate for the effects of propagation from the drill bit to the top of the drillstring. By repeating this process for an interval of the well, a VSP‐equivalent data set is generated. Results from a test well demonstrate that the processed drill‐bit data are comparable to conventional VSP data.

The use of an active drill bit for inverse VSP measurements

1989 ◽  
Vol 20 (2) ◽  
pp. 343 ◽  
Author(s):  
J.W. Rector III ◽  
B.P. Marion ◽  
R.A. Hardage
Keyword(s):  
Seismic Energy ◽  
Seismic Source ◽  
Drilling Process ◽  
Drill Bit ◽  
Seismic Surveys ◽  
Reference Trace ◽  
Vsp Data ◽  
Sensor Signals ◽  
Borehole Seismic ◽  
Reference Sensor

Vertical Seismic Profiling (VSP) is often used to provide high resolution seismic images near a wellbore. A new borehole seismic technique, the TOMEX� survey (Rector, et al., 1988), uses the vibrations produced by a drill bit as a downhole seismic energy source to produce inverse VSP data. No downhole instrumentation is required to acquire the data, and the data recording does not interfere with or delay the drilling process. Hence, there is no loss of rig time in performing the survey. These characteristics offer a method to acquire SWD (seismic-while-drilling) borehole seismic surveys. In addition, 3-D imaging around a well can be obtained at significant savings compared to conventional offset VSP imaging. The continuous signals generated by the bit during drilling are monitored with a reference sensor attached to the top of the drillstring, and the reference sensor signals are crosscorrelated with signals from surface-positioned geophones to produce inverse VSP data. Deconvolution and time shifts are then performed to remove the effects of recording the source reference trace at a location that is a considerable distance from the source. Results from tests demonstrate that these processed drill-bit source data are virtually identical to conventional forward VSP data. In using the drill bit as a downhole seismic source for inverse VSP, many of the limitations of conventional VSP are overcome. Several applications for VSP that were previously considered to be prohibitively expensive are now feasible. Furthermore, this seismic-while-drilling technique offers the potential for the explorationist to make real-time drilling decisions at the well site.

Orbital vibrator seismic source for simultaneous P‐ and S‐wave crosswell acquisition

Geophysics ◽  
2001 ◽  
Vol 66 (5) ◽  
pp. 1471-1480 ◽  
Author(s):  
Thomas M. Daley ◽  
Dale Cox
Keyword(s):  
Seismic Energy ◽  
Seismic Source ◽  
P Wave ◽  
S Wave ◽  
Circularly Polarized ◽  
S Waves ◽  
Polarized Waves ◽  
Coordinate Rotation ◽  
Processing Algorithms ◽  
Borehole Seismic

A recently developed borehole seismic source, the orbital vibrator, was successfully deployed in a crosswell survey in a fractured basalt aquifer. This seismic source uses a rotating eccentric mass to generate seismic energy. Source sweeps with clockwise and counter‐clockwise rotations are recorded at each source location. Because this source generates circularly polarized waves, unique processing algorithms are used to decompose the recordings into two equivalent linearly oscillating, orthogonally oriented seismic sources. The orbital vibrator therefore generates P‐ and S‐waves simultaneously for all azimuths. A coordinate rotation based on P‐wave particle motion is used to align the source components from various depths. In a field experiment, both P‐ and S‐wave arrivals were recorded using fluid‐coupled hydrophone sensors. The processed field data show clear separation of P‐ and S‐wave arrivals for in‐line and crossline source components, respectively. A tensor convolutional description of the decomposition process allows for extension to multicomponent sensors.

Combined surface and borehole seismic imaging in a hard rock terrain: A field test of seismic interferometry

Geophysics ◽  
2013 ◽  
Vol 78 (3) ◽  
pp. B103-B110 ◽  
Author(s):  
Charles Hurich ◽  
Sharon Deemer
Keyword(s):  
Field Test ◽  
Seismic Imaging ◽  
Hard Rock ◽  
Seismic Interferometry ◽  
Borehole Data ◽  
Data Set ◽  
Directional Bias ◽  
Vsp Data ◽  
Borehole Seismic ◽  
Seismic Images

Seismic images are inherently directionally biased by the source-receiver geometry. This directional bias is particularly problematic for seismic imaging in hard rock terrains where structural dips may have any orientation with respect to the surface. We tested a technique for partially mitigating directional bias by combining surface and borehole seismic data and evaluated the results of a first field test of the technique. In this technique, surface data acquired using standard 2D acquisition procedures were combined with borehole data derived from a walk-away vertical seismic profile (VSP). The VSP data were transformed into the borehole datum using seismic interferometry. The interferometry created virtual shot records comprising sources and receivers in the borehole. The virtual shot records were then processed, using standard common midpoint techniques, resulting in an image from the borehole datum. The combination of the surface and borehole data increased the range of illumination angles resulting in seismic images that included reflections from structures with a wider range of dips than is available to surface profiling alone. The field test demonstrated that the surface and borehole data provide complementary information, which is more than either data set alone can provide. The test also verified the robustness of the virtual source technique even when the original VSP data are highly contaminated by high-amplitude tube waves. These results demonstrated that the combined imaging approach has significant potential for application in the polydeformed hard rock domains often encountered in minerals exploration.

Borehole seismic‐source radiation in layered isotropic and anisotropic media: Real data analysis

Geophysics ◽  
1995 ◽  
Vol 60 (3) ◽  
pp. 748-757 ◽  
Author(s):  
Wenjie Dong ◽  
M. Nafi Toksöz
Keyword(s):  
Body Wave ◽  
Transversely Isotropic ◽  
Seismic Source ◽  
Real Data ◽  
Wave Radiation ◽  
Data Set ◽  
Transversely Isotropic Media ◽  
Isotropic Media ◽  
Local Geology ◽  
Borehole Seismic

The source and receiver boreholes in crosshole seismology are usually considered unimportant except for their effects on body wave radiation and reception patterns. We present counter examples by analyzing a real crosswell data set from Buckhorn, Illinois, using computer simulations. The algorithm used is a combination of the boundary element method (for the source borehole) and the borehole coupling theory (for the receiver borehole) in transversely isotropic media. We find that most of the strong events in the data are inexplicable unless both boreholes are included in the modeling. The importance of the boreholes stems from the local geology which consists of highly contrasted sedimentary rocks. At a high‐contrast interface, wave conversion is no longer a negligible secondary effect. In fact, converted waves can be stronger than the primaries.

Automated arrival-time picking using a pixel-level network

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. V415-V423
Author(s):  
Yuanyuan Ma ◽  
Siyuan Cao ◽  
James W. Rector ◽  
Zhishuai Zhang
Keyword(s):  
Seismic Data ◽  
Arrival Time ◽  
Spatial Information ◽  
Training Data ◽  
Convolutional Network ◽  
Data Set ◽  
Arrival Times ◽  
Data Volume ◽  
Borehole Seismic ◽  
Arrival Time Picking

Arrival-time picking is an essential step in seismic processing and imaging. The explosion of seismic data volume requires automated arrival-time picking in a faster and more reliable way than existing methods. We have treated arrival-time picking as a binary image segmentation problem and used an improved pixel-wise convolutional network to pick arrival times automatically. Incorporating continuous spatial information in training enables us to preserve the arrival-time correlation between nearby traces, thus helping to reduce the risk of picking outliers that are common in a traditional trace-by-trace picking method. To train the network, we first convert seismic traces into gray-scale images. Image pixels before manually picked arrival times are labeled with zeros, and those after are tagged with ones. After training and validation, the network automatically learns representative features and generates a probability map to predict the arrival time. We apply the network to a field microseismic data set that was not used for training or validation to test the performance of the method. Then, we analyze the effects of training data volume and signal-to-noise ratio on our autopicking method. We also find the difference between 1D and 2D training data with borehole seismic data. Microseismic and borehole seismic data indicate the proposed network can improve efficiency and accuracy over traditional automated picking methods.

An integrated surface and borehole seismic case study: Fort St. John Graben area, Alberta, Canada

Geophysics ◽  
1993 ◽  
Vol 58 (11) ◽  
pp. 1662-1675
Author(s):  
Ronald C. Hinds ◽  
Richard Kuzmiski ◽  
Neil L. Anderson ◽  
Barry R. Richards
Keyword(s):  
Seismic Data ◽  
Seismic Profile ◽  
Well Log ◽  
Data Set ◽  
Seismic Control ◽  
Subsurface Geology ◽  
Vsp Data ◽  
Borehole Seismic ◽  
Sandstone Facies

The deltaic sandstones of the basal Kiskatinaw Formation (Stoddard Group, upper Mississippian) were preferentially deposited within structural lows in a regime characterized by faulting and structural subsidence. In the Fort St. John Graben area, northwest Alberta, Canada, these sandstone facies can form reservoirs where they are laterally sealed against the flanks of upthrown fault blocks. Exploration for basal Kiskatinaw reservoirs generally entails the acquisition and interpretation of surface seismic data prior to drilling. These data are used to map the grabens in which these sandstones were deposited, and the horst blocks which act as lateral seals. Subsequent to drilling, vertical seismic profile (VSP) surveys can be run. These data supplement the surface seismic and well log control in that: 1) VSP data can be directly correlated to surface seismic data. As a result, the surface seismic control can be accurately tied to the subsurface geology; 2) Multiples, identified on VSP data, can be deconvolved out of the surface seismic data; and 3) The subsurface, in the vicinity of the borehole, is more clearly resolved on the VSP data than on surface seismic control. On the Fort St. John Graben data set incorporated into this paper, faults which are not well resolved on the surface seismic data, are better delineated on VSP data. The interpretive processing of these data illustrate the use of the seismic profiling technique in the search for hydrocarbons in structurally complex areas.

Seismic-while-drilling drill-bit source by ground force: Concept and application

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. MR167-MR178
Author(s):  
Flavio Poletto ◽  
Francesco Miranda ◽  
Biancamaria Farina ◽  
Andrea Schleifer
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
Complex Impedance ◽  
Seismic Source ◽  
Drill Bit ◽  
Pilot Signal ◽  
Effective Removal ◽  
Source Signal ◽  
Diffusion Phase ◽  
Drilling Conditions

For four decades, the use of the drill-bit seismic source has been evaluated extensively and investigated for seismic-while-drilling (SWD) purposes. After an initial diffusion phase, however, the routine application on drill-bit reverse vertical seismic profiling (RVSP) has declined because of issues related to variability in the signal-to-noise ratio of drill-bit signals obtained with different drilling conditions. Consequently, additional efforts have been dedicated to improving the recording of reference signals. Recent technology developments enable direct ground-force pilot measurements at downhole positions close to the bit, which enable reliable estimations of the far-field drill-bit-radiated signature. The knowledge of the ground force below the source in the near-field is a key aspect not only for the exploitation of the drill-bit source but also for conventional seismic vibrator sources. The SWD deconvolved results obtained by the ground force are different from those obtained by recording only motion vibration, such as acceleration. The ground force and particle velocity are linked by a complex impedance in the near-field, and together they provide dual measurements. In addition, the ground force provides signals with effective coupling conditions at the bit-rock interface in the presence of the drill-bit displacement action with penetration during rock fracturation. The analysis of the impedance at the bit source includes the drillstring reflections, which are observed in the reference drillstring pilot signal and are simulated by using an appropriate mechanical model. The processing of real seismic signals with different approaches by deconvolution and correlation using ground-force and motion signals produces improvements in the extraction of the source signal, with effective removal of the undesired pilot wavefields, and with cleaner estimations of the drill-bit seismic wavefields in a crosswell survey.

Machinability study and optimization of CNC drilling process parameters for HSLA steel with coated and uncoated drill bit

2021 ◽  
Author(s):  
Nitin P. Sherje ◽  
Sameer A. Agrawal ◽  
Ashish M. Umbarkar ◽  
Prashant P. Kharche ◽  
Dharmesh Dhabliya
Keyword(s):  
Process Parameters ◽  
Hsla Steel ◽  
Drilling Process ◽  
Drill Bit

Study of stick–slip suppression and robustness to parametric uncertainty in drill strings containing torsional vibration tool using sliding-mode control

2021 ◽  
pp. 146441932110452
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai
Keyword(s):  
Torsional Vibration ◽  
Complex Dynamics ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Drill String ◽  
Lumped Parameter Model ◽  
Drilling Process ◽  
Drill Bit ◽  
Stick Slip ◽  
Drilling Operations

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety of drilling operations. To suppress the stick–slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of the 4-degree of freedom lumped-parameter model. In the design of the model, the tool is approximated by a simple torsional pendulum that brings impact torque to the drill bit. Furthermore, two sliding mode controllers, U1 and U2, are used to suppress stick–slip vibrations while enabling the drill bit to track the desired angular velocity. Aiming at parameter uncertainty and system instability in the drilling operations, a parameter adaptation law is added to the sliding mode controller U2. Finally, the suppression effects of stick–slip and robustness of parametric uncertainty about the two proposed controllers are demonstrated and compared by simulation and field test results. This paper provides a reference for the suppression of stick–slip vibration and the further study of the complex dynamics of the drill string.

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