Estimation of Weight and Torque on Bit: Assessment of Uncertainties, Correction and Calibration Methods

2014 ◽  
Author(s):  
Eric Cayeux ◽  
Hans Joakim Skadsem
Keyword(s):  
Sampling Rate ◽  
Physical Processes ◽  
High Sampling Rate ◽  
Calibration Methods ◽  
Weight On Bit ◽  
Surface Measurements ◽  
Rock Interface ◽  
The One ◽  
Torque On Bit ◽  
Downhole Measurements

The efficiency of a drilling operation is to a great extent governed by how well one is able to optimize the rate of penetration (ROP) throughout each stage of the operation. ROP optimization normally involves balancing drilling speed on the one hand with acceptable wear to the drill bit on the other. The bit lifetime is largely determined by the mechanical conditions at the bit-formation rock interface and the weight on bit (WOB) and torque on bit (TOB) provide important information related to the working condition of the bit. The accuracy of WOB and TOB measurements can thus become a determining factor for the overall drilling efficiency. Due to the low bandwidth of downhole mud pulse-based telemetry systems, the WOB and the TOB are generally derived from surface measurements, i.e. from the hook load and the top-drive torque. Field experience indicates that a WOB derived from surface measurements can be of limited accuracy, such as when surface measurements suggest a negative WOB even though the ROP is positive, or when high sampling rate and high precision downhole measurements confirm a large discrepancy between the memory recorded downhole data and the estimated values based on the measurements made at the level of the hoisting equipment and the top-drive. The reason for these inconsistencies is simply that there are numerous physical processes taking place between the bit and the surface measurements that are normally not accounted for when WOB and TOB are estimated. This paper reviews and analyses the sources of these deviations and models the physical processes in order to quantify the precision for which the WOB and the TOB can be ascertained using solely surface measurements. Methods are also proposed that compensate for certain side effects by utilizing real-time torque and drag and hydraulic calculations.

scholarly journals Calibration for Sample-And-Hold Mismatches in M-Channel TIADCs Based on Statistics

2019 ◽  
Vol 9 (1) ◽  
pp. 198 ◽  
Author(s):  
Xiangyu Liu ◽  
Hui Xu ◽  
Yinan Wang ◽  
Yingqiang Dai ◽  
Nan Li ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Sampling Rate ◽  
Analog To Digital ◽  
Sample And Hold ◽  
High Sampling Rate ◽  
Calibration Methods ◽  
Input Signals ◽  
Calibration Algorithm ◽  
Signal Simulation ◽  
Time Interleaved

Time-interleaved analog-to-digital converter (TIADC) is a good option for high sampling rate applications. However, the inevitable sample-and-hold (S/H) mismatches between channels incur undesirable error and then affect the TIADC’s dynamic performance. Several calibration methods have been proposed for S/H mismatches which either need training signals or have less extensive applicability for different input signals and different numbers of channels. This paper proposes a statistics-based calibration algorithm for S/H mismatches in M-channel TIADCs. Initially, the mismatch coefficients are identified by eliminating the statistical differences between channels. Subsequently, the mismatch-induced error is approximated by employing variable multipliers and differentiators in several Richardson iterations. Finally, the error is subtracted from the original output signal to approximate the expected signal. Simulation results illustrate the effectiveness of the proposed method, the selection of key parameters and the advantage to other methods.

Intelligent Displacement Measuring System for Rock Stratum

2011 ◽  
Vol 103 ◽  
pp. 583-586
Author(s):  
Feng Ling Li ◽  
Jian Hua Rong ◽  
Yu Ping Zhang
Keyword(s):  
Civil Engineer ◽  
Real Time ◽  
Sampling Rate ◽  
Measuring System ◽  
Displacement Sensor ◽  
Rock Stratum ◽  
Baud Rate ◽  
Real Time Clock ◽  
High Sampling Rate ◽  
Displacement System

Measuring rock stratum displacement in dam grouting process is very important. A new displacement system is designed, comprising a programmable microcontroller Atmega16, a new grating capacitive displacement sensor(GCDS), DS1302 real time clock chip and announciator etc. The system has high sampling rate of 9600 baud rate and can trap the displacement equal to 0.001 millimeter in one second. Equipped with mechanical conveyance system, the system can be applied to the civil engineer. The experiment results show the instrument can measure accurately the displacement value and alarm geologic disaster in time, which can conduct continuous and accurate monitoring and provide operation decisions for dam engineers.

scholarly journals An Automatic Method for Detection and Update of Additive Changes in Road Network with GPS Trajectory Data

2019 ◽  
Vol 8 (9) ◽  
pp. 411 ◽  
Author(s):  
Tang ◽  
Deng ◽  
Huang ◽  
Liu ◽  
Chen
Keyword(s):  
Road Network ◽  
Sampling Rate ◽  
Quality Data ◽  
Automatic Method ◽  
Trajectory Data ◽  
The Road ◽  
High Sampling Rate ◽  
Map Generation ◽  
Gps Trajectory Data ◽  
Gps Trajectory

Ubiquitous trajectory data provides new opportunities for production and update of the road network. A number of methods have been proposed for road network construction and update based on trajectory data. However, existing methods were mainly focused on reconstruction of the existing road network, and the update of newly added roads was not given much attention. Besides, most of existing methods were designed for high sampling rate trajectory data, while the commonly available GPS trajectory data are usually low-quality data with noise, low sampling rates, and uneven spatial distributions. In this paper, we present an automatic method for detection and update of newly added roads based on the common low-quality trajectory data. First, additive changes (i.e., newly added roads) are detected using a point-to-segment matching algorithm. Then, the geometric structures of new roads are constructed based on a newly developed decomposition-combination map generation algorithm. Finally, the detected new roads are refined and combined with the original road network. Seven trajectory data were used to test the proposed method. Experiments show that the proposed method can successfully detect the additive changes and generate a road network which updates efficiently.

All-optical parallelization for high sampling rate photonic ADC in fully digital radar systems

2010 ◽  
Author(s):  
Paolo Ghelfi ◽  
Lingmei Ma ◽  
Xiaoxia Wu ◽  
Minyu Yao ◽  
Alan E. Willner ◽  
...  
Keyword(s):  
Sampling Rate ◽  
Radar Systems ◽  
High Sampling ◽  
High Sampling Rate ◽  
All Optical

scholarly journals High sampling rate thermistor string observations at the slope of Great Meteor Seamount

Ocean Science ◽  
2005 ◽  
Vol 1 (1) ◽  
pp. 17-28 ◽  
Author(s):  
H. van Haren ◽  
R. Groenewegen ◽  
M. Laan ◽  
B. Koster
Keyword(s):  
High Frequency ◽  
North Atlantic Ocean ◽  
Sampling Rate ◽  
Very High Frequency ◽  
High Sampling ◽  
High Sampling Rate ◽  
In Situ Calibration ◽  
Great Meteor Seamount ◽  
Very High

Abstract. A high sampling rate (1 Hz) thermistor string has been built to accommodate the scientific need to accurately monitor high-frequency and vigorous internal wave and overturning processes in the ocean. The thermistors and their custom designed electronics can register temperature at an estimated precision of about 0.001° C with a response time faster than 0.25 s down to depths of 6000 m. With a quick in situ calibration using SBE 911 CTD an absolute accuracy of 0.005° C is obtained. The present string holds 128 sensors at 0.5 m intervals, which are all read-out within 0.5 s. When sampling at 1 Hz, the batteries and the memory capacity of the recorder allow for deployments of up to 2 weeks. In this paper, the instrument is described in some detail. Its performance is illustrated with examples from the first moored observations, which show Kelvin-Helmholtz overturning and very high-frequency (Doppler-shifted) internal waves besides occasionally large turbulent bores moving up the sloping side of Great Meteor Seamount, Canary Basin, North-Atlantic Ocean.

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