کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6410383 1629918 2016 19 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Optimal input experiment design and parameter estimation in core-scale pressure oscillation experiments
ترجمه فارسی عنوان
طراحی آزمایشگاه ورودی بهینه و ارزیابی پارامتر در آزمایشات نوسان فشار در هسته
کلمات کلیدی
طراحی آزمایش محدودیت های واریانس، برآورد کردن، رسانه های متخلخل،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی


- Optimal actuator signals are designed that minimise experiment times.
- An identifiability issue is revealed for an existing measurement methodology.
- Parameter estimates are guaranteed to be of a minimal quality.
- A new identification method delivers great experiment time reductions.

SummaryThis paper considers Pressure Oscillation (PO) experiments for which we find the minimum experiment time that guarantees user-imposed parameter variance upper bounds and honours actuator limits. The parameters permeability and porosity are estimated with a classical least-squares estimation method for which an expression of the covariance matrix of the estimates is calculated. This expression is used to tackle the optimization problem. We study the Dynamic Darcy Cell experiment set-up (Heller et al., 2002) and focus on data generation using square wave actuator signals, which, as we shall prove, deliver shorter experiment times than sinusoidal ones. Parameter identification is achieved using either inlet pressure/outlet pressure measurements (Heller et al., 2002) or actuator position/outlet pressure measurements, where the latter is a novel approach. The solution to the optimization problem reveals that for both measurement methods an optimal excitation frequency, an optimal inlet volume, and an optimal outlet volume exist. We find that under the same parameter variance bounds and actuator constraints, actuator position/outlet pressure measurements result in required experiment times that are a factor fourteen smaller compared to inlet pressure/outlet pressure measurements. This result is analysed in detail and we find that the dominant effect driving this difference originates from an identifiability problem when using inlet-outlet pressure measurements for joint estimation of permeability and porosity. We illustrate our results with numerical simulations, and show excellent agreement with theoretical expectations.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volume 534, March 2016, Pages 534-552
نویسندگان
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