Improving Accuracy of Checkshot Time-Depth by Applying Advanced Model-Based Correction for Rig-Source Survey on a Highly Inclined Well

2021 ◽  
Author(s):  
The Nguyen ◽  
Jakkarin Iamboon ◽  
Piyanuch Nampratchayakul ◽  
Nirut Tongpan ◽  
Ye Yint Htun ◽  
...  
Keyword(s):  
Least Square ◽  
Seismic Exploration ◽  
Earth Model ◽  
Travel Times ◽  
Advanced Technique ◽  
Actual Measurement ◽  
Model Based ◽  
Standard Geometry ◽  
Advanced Model ◽  
Geometry Correction

Abstract In seismic exploration, checkshot survey is an important method to obtain accurate time-depth profile for depth-to-time or time-to-depth conversion. However, the standard geometry correction for a rig-source survey in a high-inclination well will not provide a reliable time-depth result due to ray-bending effect. The objective of this study was to enhance the accuracy of the time-depth velocity by utilizing an advanced technique called model-based correction or pseudo walk-above simulation. To obtain model-based vertical times, a flat-layered velocity model was built by using the checkshot velocities as initial guess. The model was then inverted to match the observed checkshot travel times, which were the actual measurement of travel path from source to receivers. The model was iterated to minimize the residual between the observed and modeled travel times in a least-square sense. A pseudo walk-above checkshot simulation was run on the inverted model by positioning the sources exactly on top of the receivers to get the vertical times, which were used for the final time-depth relationship and further image processing. The residual times of less than 1 millisecond (ms) were observed between the actual measured transit times and modeled travel times from a fixed source to the receivers in the inverted model. This demonstrated the inverted model was realiable to use for obtaining more accurate vertical time-depth through pseudo walk-above checkshot simulation. This optimal inverted model was considered as the best estimation of the true earth model in this case. A comparison of modeled vertical times estimated through the pseudo walk-above simulation and calculated vertical times using standard geometry correction were done. The difference between the two scenarios was 6 ms one-way time (OWT) demonstrated the reduction of 6 ms uncertainty of using the advanced model-based correction versus the standard geometry correction. In short, the advanced technique delivered more reliable time-depth velocity information to reduce depth uncertainties for drilling operation. The walk-above or vertical incidence checkshot survey, which required boat and navigation system, was unable to acquire in a highly deviated well due to very bad weather conditions. The rig-source survey was carried out instead of employing the walk-above survey in this project. The standard geometry correction using simple trigonometry was not able to provide the correct vertical times. The advanced model-based correction was the optimal solution to improve the accuracy of checkshot time-depth velocity data.

Model-based control of the substrate concentration in an aeration basin using the wastewater level

1998 ◽  
Vol 37 (12) ◽  
pp. 335-342 ◽  
Author(s):  
Jacek Czeczot
Keyword(s):  
Substrate Concentration ◽  
Consumption Rate ◽  
Least Square Method ◽  
Estimation Procedure ◽  
Adaptive Controller ◽  
Open Loop ◽  
Least Square ◽  
Substrate Consumption ◽  
Model Based ◽  
Effluent Flow Rate

This paper deals with the minimal-cost control of the modified activated sludge process with varying level of wastewater in the aerator tank. The model-based adaptive controller of the effluent substrate concentration, basing on the substrate consumption rate and manipulating the effluent flow rate outcoming from the aerator tank, is proposed and its performance is compared with conventional PI controller and open loop behavior. Since the substrate consumption rate is not measurable on-line, the estimation procedure on the basis of the least-square method is suggested. Finally, it is proved that cooperation of the DO concentration controller with the adaptive controller of the effluent substrate concentration allows the process to be operated at minimum costs (low consumption of aeration energy).

Fitting Spherical Surface and Evaluating Sphericity Error Based on the Minimum Zone Principle

2014 ◽  
Vol 687-691 ◽  
pp. 1373-1376 ◽  
Author(s):  
Lei Zhang ◽  
Li Li Liu ◽  
Chuan Hui Huang ◽  
Xing Hua Lu ◽  
Gen Sun
Keyword(s):  
Mathematical Model ◽  
Spherical Surface ◽  
Least Square ◽  
Model Based ◽  
Minimum Zone

To address the fitting spherical surface and evaluating sphericity error, a mathematical model based on the minimum zone principle is presented. And the presented model is answered by GA. An example shows the performance of the proposed method by comparison with the methods based on the least square principle.

A new analytical method for finding the upper mantle velocity structure from P and S wave travel times of deep earthquakes

1969 ◽  
Vol 59 (2) ◽  
pp. 755-769
Author(s):  
K. L. Kaila
Keyword(s):  
Velocity Structure ◽  
Focal Depth ◽  
Least Square ◽  
Travel Times ◽  
S Wave ◽  
The Earth ◽  
Straight Line ◽  
Wave Travel ◽  
Deep Focus ◽  
Mantle Velocity

abstract A new analytical method for the determination of velocity at the hypocenter of a deep earthquake has been developed making use of P- and S-wave travel times. Unlike Gutenberg's method which is graphical in nature, the present method makes use of the least square technique and as such it yields more quantitative estimates of the velocities at depth. The essential features of this method are the determination from the travel times of a deep-focus earthquake the lower and upper limits Δ1 and Δ2 respectively of the epicentral distance between which p = (dT/dΔ) in the neighborhood of inflection point can be considered stationary so that the travel-time curve there can be approximated to a straight line T = pΔ + a. From p = (1/v*) determined from the straight line least-square fit made on the travel-time observation points between Δ1 and Δ2 for various focal depths, upper-mantle velocity structure can be obtained by making use of the well known relation v = v*(r0 − h)/r0, h being the focal depth of the earthquake, r0 the radius of the Earth, v* the apparent velocity at the point of inflection and v the true velocity at that depth. This method not only gives an accurate estimate of p, at the same time it also yields quite accurate value of a which is a function of focal depth. Calibration curves can be drawn between a and the focal depth h for various regions of the Earth where deep focus earthquakes occur, and these calibration curves can then be used with advantage to determine the focal depths of deep earthquakes in those areas.

Model-Based EEG Analysis: Proposal and Verification of Mathematical Model for Application to Neurotechnology

2019 ◽  
Author(s):  
Kenyu Uehara ◽  
Takashi Saito
Keyword(s):  
Mathematical Model ◽  
Binary Classification ◽  
Least Square ◽  
Mental Condition ◽  
Support Vector ◽  
Model Parameters ◽  
Eeg Analysis ◽  
Analysis Method ◽  
Model Based ◽  
Proposed Model

Abstract We have modeled dynamics of EEG with one degree of freedom nonlinear oscillator and examined the relationship between mental state of humans and model parameters simulating behavior of EEG. At the IMECE conference last year, Our analysis method identified model parameters sequentially so as to match the waveform of experimental EEG data of the alpha band using one second running window. Results of temporal variation of model parameters suggested that the mental condition such as degree of concentration could be directly observed from the dynamics of EEG signal. The method of identifying the model parameters in accordance with the EEG waveform is effective in examining the dynamics of EEG strictly, but it is not suitable for practical use because the analysis (parameter identification) takes a long time. Therefore, the purpose of this study is to test the proposed model-based analysis method for general application as a neurotechnology. The mathematical model used in neuroscience was improved for practical use, and the test was conducted with the cooperation of four subjects. model parameters were experimentally identified approximately every one second by using least square method. We solved a binary classification problem of model parameters using Support Vector Machine. Results show that our proposed model-based EEG analysis is able to discriminate concentration states in various tasks with an accuracy of over 80%.

Advanced Model-Based Disturbance Compensation Control Using Proportional-Integral-Observer

2005 ◽  
Author(s):  
Idriz Krajcin ◽  
Dirk So¨ffker
Keyword(s):  
State Feedback ◽  
Dynamical Behavior ◽  
State Feedback Control ◽  
Disturbance Compensation ◽  
Proportional Integral ◽  
Compensation Control ◽  
Model Based ◽  
Simulation Results ◽  
And Control ◽  
Advanced Model

This contribution presents a state feedback control and a new disturbance compensation method using the Proportional-Integral-Observer (PI-Observer). For a suitable class of systems the observer estimates the unmeasured states as well as unknown inputs acting on a structure using a small number of measurements. Here, the observer is applied to elastic structures where the PI-Observer can be used for model-based diagnosis and control. An extended disturbance compensation is proposed to improve the dynamical behavior, to decouple the effect of disturbances on defined outputs using the PI-Observer. The observer and the control are applied to an all side clamped elastic plate. The performance of the control is illustrated by simulation results.

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