Seismic‐while‐drilling by using dual sensors in drill strings

Geophysics ◽  
2004 ◽  
Vol 69 (5) ◽  
pp. 1261-1271 ◽  
Author(s):  
Flavio Poletto ◽  
Massimo Malusa ◽  
Francesco Miranda ◽  
Umberta Tinivella
Keyword(s):  
Drill String ◽  
Reflection Coefficients ◽  
Drill Bit ◽  
Seismic Signals ◽  
Signal Distortion ◽  
Inverse Filtering ◽  
Numerical Examples ◽  
Transmission Coefficients ◽  
Dual Sensor ◽  
Additional Noise

Drill‐string waves can be successfully used as reference pilot signals for drill‐bit seismic‐while‐drilling (SWD) purposes. The seismic signals obtained by correlating pilot and geophone measurements are disturbed by the drill‐string reverberations because the pilot waves are reflected at each interface between string sections with different acoustic impedances. Inverse filtering of these reflections, using a reference‐pilot deconvolution calculated in the presence of additional noise, may cause signal distortion. To overcome this problem, we consider using dual‐sensor measurements in the drill string to remove the reflections of the drill‐bit waves in the acquisition phase and to improve pilot deconvolution. We measure acceleration and strain of drill‐string dual fields, which have opposite reflection coefficients and, in a string of constant elastic properties, the same transmission coefficients. These quantities are scaled to fit the amplitude of the direct arrivals, summed to remove the reflections in the drill string and in the rig, and may be deconvolved by Einstein deconvolution to characterize the reflection coefficient between the drill bit and the formation. Synthetic numerical examples and real measurements acquired downhole in a location close to the bit show that upgoing and downgoing drill‐string pilots can be separated using dual fields and jointly used to improve the SWD seismograms.

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.

The First Multilateral Well in Eastern Siberia on the Separated Oil Reservoirs

2021 ◽  
Author(s):  
Ruslan Fanisovich Gataullin ◽  
Stanislav Evgen’evich Ter-Saakov ◽  
Evgenij Vladimirovich Nikulin ◽  
Dmitriy Pavlovich Stifeev ◽  
Alexey Vyacheslavovich Filatov
Keyword(s):  
Low Frequency ◽  
Cost Effective ◽  
Drill String ◽  
Hole Drilling ◽  
Drill Bit ◽  
Eastern Siberia ◽  
Water Contact ◽  
Bottom Hole ◽  
Drilling Technology ◽  
Equipment Failures

Abstract This article describes engineering and technology solutions developed to successfully construct unconventional and unique horizontal well at the field of Eastern Siberia targeted to two isolated formations with an option to shut-off top Botuobinsky horizon after gas breakthrough and produce oil from underlying Ulakhansky bed further on. As oil-water contact in the lower part of Ulakhansky horizon makes fracturing the well inexpedient, multi hole drilling technology was implemented enabling drainage of the reserves that are far from the main borehole. The main objective of this well is to deplete Botuobinsky horizon subsequently shutting it off and continuing to recover petroleum reserves from Ulakhansky pay zone. Constructing such well is cost-effective, as it requires drilling only one intermediate casing interval instead of two. Accumulated experience of drilling and completing multi hole wells was used to ensure successful well construction; also, geological and stratigraphic data as well as possible complications while drilling Botuobunsky and Ulakhansky formations were analyzed in-depth. The following appliances were selected to meet the objective: –Bottom-hole equipment enabling drilling abrasive formations under conditions of high vibrations;–Special line of drill bits to ensure high ROP and successful sidetracking without additional tripping;–RSS with 152.4 mm drill bit. The goal set by the operating company was achieved through multi-faceted approach to performing the task, efficient cooperation of engineering technical services and continuous monitoring of output data while drilling. All that combined delivered the results listed below: –Sidetracks were carried out in an open horizontal hole without cement plugs and additional tripping for drill bit or BHA.–Minimized bottom-hole equipment failures under condition of increased high-frequency vibrations from bit while drilling hard formations due to implementation of modular PDM with data-transmitting channel.–Minimized bottom-hole equipment failures under condition of increased low-frequency vibrations from drill string with Hard Bending due to improved BHA design and optimized drilling parameters selection.–Liner was effectively run to Botuobinsky and Ulakhansky reservoirs with an option to shut-off the former after depletion and gas breakthrough. This well is the first one targeted at two isolated formations in East Siberia.

Torsional Vibrations and Nonlinear Dynamic Characteristics of Drill Strings and Stick-Slip Reduction Mechanism

2019 ◽  
Vol 14 (8) ◽  
Author(s):  
Jialin Tian ◽  
Genyin Li ◽  
Liming Dai ◽  
Lin Yang ◽  
Hongzhi He ◽  
...  
Keyword(s):  
Torsional Vibration ◽  
Nonlinear Dynamic ◽  
Drill String ◽  
Drilling Process ◽  
Drill Bit ◽  
Torsional Vibrations ◽  
Reduction Mechanism ◽  
Nonlinear Dynamic Model ◽  
Stick Slip ◽  
Research Results

Torsional stick–slip vibrations easily occur when the drill bit encounters a hard or a hard-soft staggered formation during drilling process. Moreover, serious stick–slip vibrations of the drill string is the main factor leading to low drilling efficiency or even causing the downhole tools failure. Therefore, establishing the stick–slip theoretical model, which is more consistent with the actual field conditions, is the key point for new drilling technology. Based on this, a new torsional vibration tool is proposed in this paper, then the multidegree-of-freedom torsional vibrations model and nonlinear dynamic model of the drill string are established. Combined with the actual working conditions in the drilling process, the stick–slip reduction mechanism of the drill string is studied. The research results show that the higher rotational speed of the top drive, smaller viscous damping of the drill bit, and smaller WOB (weight on bit) will prevent the stick–slip vibration to happen. Moreover, the new torsional vibration tool has excellent stick–slip reduction effect. The research results and the model established in this paper can provide important references for reducing the stick–slip vibrations of the drill string and improving the rock-breaking efficiency.

Interaction of plane electromagnetic waves with a moving compressible plasma fluid

1969 ◽  
Vol 47 (4) ◽  
pp. 375-387 ◽  
Author(s):  
H. Fujioka ◽  
F. Nihei ◽  
N. Kumagai
Keyword(s):  
Electric Field ◽  
Electromagnetic Waves ◽  
Surface Charge Density ◽  
Magnetohydrodynamic Wave ◽  
Reflection And Transmission ◽  
Numerical Examples ◽  
Compressible Plasma ◽  
Transmission Coefficients ◽  
Moving Interface ◽  
Magnetoacoustic Waves

The problem of reflection and transmission of plane electromagnetic waves by a semi-infinite compressible plasma fluid moving parallel to its own interface with vacuum is investigated. Solutions are obtained for both incident E wave and H wave. It is found that (i) for the case of incident E wave which excites only two distinct magnetoacoustic waves, the reflection and transmission coefficients add to unity; however, (ii) for the incident H wave which excites only the transverse magnetohydrodynamic wave, both coefficients do not add to unity in general, because of the interaction of the electric field of the transmitted wave with surface charge density at the moving interface. Other interesting features due to the movement of the medium are discussed, and a few numerical examples are given.

Numerical modeling and interpretation of drillstring waves

Geophysics ◽  
2001 ◽  
Vol 66 (5) ◽  
pp. 1569-1581 ◽  
Author(s):  
Flavio Poletto ◽  
Massimo Malusa ◽  
Francesco Miranda
Keyword(s):  
Signal Processing ◽  
Numerical Modeling ◽  
Boundary Conditions ◽  
Transmission Line ◽  
Reflection Coefficients ◽  
Drill Bit ◽  
Noise Sources ◽  
Numeric Modeling ◽  
Joint Contribution ◽  
Group Velocities

Drill‐bit seismic and pilot seismograms contain drillstring periodicities from signal and environmental noise sources. These coherent components are similar in seismic‐while‐drilling correlations, and their joint contribution may cause distortions in signal processing. Numeric modeling of the drillstring transmission line is used to correctly interpret the axial and torsional events with similar propagating modes of signal and noise. The reflection coefficients are computed for drillstrings of arbitrary materials, and their average mechanical features are related to the axial and torsional group velocities obtained by the dispersion equations. Fitting of the periodical components in the real seismograms is used to automatically correct the drill‐bit pilot delays and to estimate the surface and downhole boundary conditions.

scholarly journals Characterization of a Pulsating Drill Bit Blaster

2016 ◽  
Author(s):  
Nicholas J. Thorp ◽  
Geir Hareland ◽  
Brian R. Elbing ◽  
Runar Nygaard
Keyword(s):  
Drilling Fluid ◽  
Fluid Pressure ◽  
Pressure Oscillation ◽  
Drill String ◽  
Operating Conditions ◽  
Drill Bit ◽  
Pulsation Frequency ◽  
Design Changes ◽  
Weight On Bit ◽  
Fluid Pulsation

The drill bit blaster (DBB) studied in this paper aims to maximize the drilling rate of penetration (ROP) by using a flow interrupting mechanism to create drilling fluid pulsation. The fluctuating fluid pressure gradient generated during operation of the DBB could lead to more efficient bit cutting efficiency due to substrate depressurization and increased cutting removal efficiency and the vibrations created could reduce the drill string friction allowing a greater weight on bit (WOB) to be achieved. In order to maximize these mechanisms the effect of several different DBB design changes and operating conditions was studied in above ground testing. An analytical model was created to predict the influence of various aspects of the drill bit blaster design, operating conditions and fluid properties on the bit pressure characteristics and compared against experimental results. The results indicate that internal tool design has a significant effect on the pulsation frequency and amplitude, which can be accurately modeled as a function of flowrate and internal geometry. Using this model an optimization study was conducted to determine the sensitivity of the fluid pulsation power on various design and operating conditions. Application of this technology in future designs could allow the bit pressure oscillation frequency and amplitude to be optimized with regard to the lithology of the formations being drilled which could lead to faster, more efficient drilling potentially cutting drilling costs and leading to a larger number of oil and natural gas plays being profitable.

scholarly journals Sonic Drilling with Use of a Cavitation Hydraulic Vibrator

2021 ◽  
Author(s):  
Yuriy Zhulay ◽  
Olexiy Nikolayev
Keyword(s):  
Drill String ◽  
Drill Bit ◽  
Vibration Frequencies ◽  
Drilling Speed ◽  
Temporary Reduction ◽  
Inertia Effects ◽  
Hard Rocks ◽  
Mud Pressure ◽  
State Pressure ◽  
Mud Flow

Sonic drilling is a soil penetration technique that strongly reduces friction on the drill string and drill bit due to liquefaction, inertia effects and a temporary reduction of porosity of the soil. Modern studies to assess the effect of the vibration frequency of the drill bit on the rock fragmentation in experimental and theoretical works on drilling various rocks by the sonic method have shown that vibration frequencies of ~ 1.4 kHz are the most beneficial for ensuring the maximum drilling speed in hard rocks. The above frequencies of excitation of vibrations of the drill bit can be achieved by using a cavitation hydrovibrator. The cavitation hydrovibrator is the Venturi tube of special geometry that converts a stationary fluid (flushing mud) flow into an oscillatory stalling cavitation flow and hydrovibrator structure longitudinal vibrations. The drill bit vibration accelerations are realized in such a drill string, leading to the destruction of rock. Efficient removal of rock particles from the bottomhole is achieved due to high-frequency shock self-oscillations of mud pressure exceeding the steady-state pressure at the generator inlet. The cavitation hydraulic vibrator lacks the main disadvantages of submersible hydraulic hammers.

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