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.

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.

scholarly journals Investigating seismic properties of the NEGIS onset region using ice-drilling noise as a seismic source

2021 ◽  
Author(s):  
Charlotte Schoonman ◽  
Olaf Eisen ◽  
Coen Hofstede ◽  
Nicolas Stoll ◽  
Steven Franke ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Ice Core ◽  
Seismic Source ◽  
Drilling Process ◽  
Seismic Velocity Structure ◽  
Seismic Surveys ◽  
Core Drilling ◽  
Seismic Properties ◽  
Ice Stream

<p>Investigating the physical conditions underlying and enabling fast glacier flow is crucial to understanding the future stability of ice sheets, as well as their impact on future sea-level rise. Seismic surveys have been widely used to measure material properties of the ice and substrate, including seismic velocity structure, anisotropy, and bed properties. While traditional seismic surveys rely on natural seismicity or man-made sources such as explosives, anthropogenic noise generated through ice-core drilling can also be used as a seismic source. Placing geophones around an ice-core drilling site therefore presents an exciting opportunity to complement and extend measurements from ice cores to the surrounding area.</p><p>Here, we present preliminary results from a seismic investigation conducted using noise generated by ice-core drilling activities at the East Greenland Ice Core Project (EGRIP) site. The EGRIP site is located near the onset region of the Northeast Greenland Ice Stream (NEGIS), which drains over 10% of the Greenland Ice Sheet. The ice-core drilling process creates a variety of semi-continuous (e.g., generator-induced) and impulsive (e.g., core break) seismic source signals. As drilling progresses through the ice column, the corresponding variation in seismic signals can be used to generate a vertical profile of seismic properties. In the summer of 2019, nine 3-component surface geophones were deployed at 0, 300, 750, 1500 and 3000 m distance from the drill site along two lines corresponding to the along- and cross-flow directions of the ice stream. The network recorded at a sampling frequency of 400 Hz for 28 days, during which drilling progressed between 1920 and 2110 m depth below the surface. Both continuous and impulsive sources related to the drilling process were recorded at all stations. Impulsive arrivals were identified using STA/LTA phase-picking across multiple components and stations. Because the depth of the drill head at any given time is known, the move-out of each event could then be used to determine the integrated seismic velocity structure along the source-receiver ray path.</p><p>Additionally, sporadic passive microseismic signals resulting from ice stream motion over the bed were observed at all stations. Both individually distinguishable icequakes and 3-5 minute-long “gliding” tremors were recorded, indicative of stick-slip motion at the bed of NEGIS. Further work will concentrate on modelling these tremors to resolve the shear modulus of the substrate, and on incorporating continuous drill-generated noise into our overall analysis. Our approach demonstrates the added value of opportunistic seismic networks as a complement to ice drilling operations.</p>

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.

RECENT DEVELOPMENTS IN BOREHOLE SEISMIC SURVEYS, OFFSHORE NORTHERN AUSTRALIA

1991 ◽  
Vol 31 (1) ◽  
pp. 250
Author(s):  
A. Sutherland ◽  
P.M. Smith
Keyword(s):  
Shear Wave ◽  
Seismic Data ◽  
Seismic Energy ◽  
Hard Water ◽  
Main Body ◽  
Northern Australia ◽  
Seismic Surveys ◽  
Sensor Module ◽  
Borehole Seismic

Offshore northern Australia has long been recognised as a region where the quality of seismic data is frequently adversely affected by several factors which include the following.The presence of a hard water bottom.The presence of carbonate units in the Eocene and Paleocene which are highly reflective and reduce the amount of seismic energy which penetrates to the deeper target horizons. These also produce interbedded multiples which are difficult to remove from the seismic data.Complex shallow faulting which causes ray path distortion and disperses the seismic energy.The confidence with which well data can be tied to the poor quality seismic data through well velocity surveys is further reduced by the complicated deeper faulting associated with the structures drilled and the low acoustic impedance contrast at the target horizon.Borehole seismic surveys provide the most reliable link between the subsurface intersected by a well and seismic data. The recent introduction of a new borehole seismic tool has improved the quality of Vertical Seismic Profiles (VSPs) acquired. This tool has three component geophones mounted in a sensor module which is isolated from the main body of the tool by springs which minimise the effect of source-generated noise.This reduction in sensitivity to the source-generated noise has allowed the introduction of more powerful source arrays to improve the signal to noise ratio. The use of source arrays has increased the bandwidth of the seismic impulse and decreased the effect of the bubble pulse.The quality of the horizontal component VSP data recorded using the new tool has also improved significantly and this has increased the possibility of detecting mode converted reflected and transmitted shear wave energy and the more accurate measurement of shear wave velocities.

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.

Novel Drill Bit Analysis to Delay and Mitigate Fixed Cutter Thermal Damage

2021 ◽  
Author(s):  
Sion Llywelyn Roberts ◽  
Michael James Bailey ◽  
Afshin Babaie Aghdam ◽  
Ahmed Suleiman ◽  
Ahmed Fathy
Keyword(s):  
Cooling Rate ◽  
Design Process ◽  
Thermal Damage ◽  
Drilling Process ◽  
Drill Bit ◽  
Operational Parameters ◽  
Thermal Index ◽  
Testing Phase ◽  
Index Analysis ◽  
Input Load

Abstract As oil and gas wells become deeper, drilling longer intervals is becoming a major milestone for drill bit companies, as the process comes with a variety of challenges affecting the durability of drill bits. Among the major challenges are thermal and impact damage in polycrystalline diamond compact (PDC) cutters, which can significantly affect the performance and longevity of a drill bit. While cutter technology development remains an important arena to address said challenges, there exists a need to also address these through the design process. This paper presents the development and deployment of a new drill bit analysis method that addresses thermal damage by optimizing the design, which has been field validated across the globe. The analysis involves estimating the thermal input load and the available cooling rate for every cutter on a drill bit during drilling conditions. The data is then used to optimize and apply changes to the design. The analysis considers all the critical and relevant operational parameters to calculate these indices. The outcome of the so-called thermal index analysis enables the design team to make informed decisions to improve the design of the drill bit and to minimize the extent of thermal damage in cutters. The improvements made in the design include changes in cutting structure to affect cutting forces and, eventually, the thermal input load during the drilling process. This stage in practice can bring down the temperature of the cutting edge by 20%, as calculated analytically. Another major change that can affect the results is hydraulic design of the bit, which includes the location of the nozzles as well as their orientation and size. In test cases, the cooling rate improved by 50% while keeping the same flow rate though the bit. Several field trials have validated the correlation of thermal index analysis to drill bit dulls. This analysis is now in the field evaluation and testing phase, where it is being used during the design process to improve bits with thermal damage. The field-testing phase has been primarily conducted in thermally challenging applications across the Middle East, North Africa region, and in West Texas.

scholarly journals Optimization of Drilling Process Parameters Via Taguchi, TOPSIS and RSA Techniques

2017 ◽  
Vol 62 (3) ◽  
pp. 1803-1812 ◽  
Author(s):  
K. Shunmugesh ◽  
K. Panneerselvam
Keyword(s):  
Process Parameters ◽  
Feed Rate ◽  
Research Work ◽  
Cutting Speed ◽  
High Strength ◽  
Drilling Process ◽  
Drill Bit ◽  
Influence Of Process Parameters ◽  
Light Trucks ◽  
Cfrp Composite

AbstractCarbon Fiber Reinforced Polymer (CFRP) is the most preferred composite material due to its high strength, high modulus, corrosion resistance and rigidity and which has wide applications in aerospace engineering, automobile sector, sports instrumentation, light trucks, airframes. This paper is an attempt to carry out drilling experiments as per Taguchi’s L27(313) orthogonal array on CFRP under dry condition with three different drill bit type (HSS, TiAlN and TiN). In this research work Response Surface Analysis (RSA) is used to correlate the effect of process parameters (cutting speed and feed rate) on thrust force, torque, vibration and surface roughness. This paper also focuses on determining the optimum combination of input process parameter and the drill bit type that produces quality holes in CFRP composite laminate using Multi-objective Taguchi technique and TOPSIS. The percentage of contribution, influence of process parameters and adequacy of the second order regression model is carried out by analysis of variance (ANOVA). The results of experimental investigation demonstrates that feed rate is the pre-dominate factor which affects the response variables.

Multiple Rock Breakdown in Electrodischarge Technology

2016 ◽  
Vol 712 ◽  
pp. 55-59
Author(s):  
Vladislav M. Vazhov ◽  
Sergey Y. Datskevitch ◽  
Mikhail Y. Zhurkov ◽  
Vasily M. Muratov ◽  
Arild Rødland
Keyword(s):  
Electric Discharge ◽  
High Voltage ◽  
Voltage Pulse ◽  
Rock Fracture ◽  
High Voltage Pulse ◽  
Electric Strength ◽  
Drilling Process ◽  
Drill Bit ◽  
Research Outcomes ◽  
Experimental Technology

The article covers the research of the electric strength and fracture of rocks that are undergone multiple breakdowns generated by electric discharge rock fracture and drilling technologies. The research outcomes allow proposing an experimental technology able to determine operating high voltage pulse values in the electric discharge drilling process where one should take into account such factors as the rock re-crushing and the drill bit shift cyclicity.

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