Determine minimal layered-velocity model for downhole microseismic monitoring by total variation (TV) regularization

Jiang，Xingda1; Zhang，Wei2

10.1190/segam2017-17750372.1

2017-08-17

1052-3812

1949-4645

SEG Technical Program Expanded Abstracts

2893-2897

We propose a new method to simultaneously determine number of layers, layer velocity value, and layer depths of the velocity model using total variation (TV) regularization for downhole microseismic monitoring. To derive a good velocity model for locating events, the layered-velocity model is usually initially created from the sonic logging curves, then the layer velocity values are calibrated by the perforation shot or string shot data while the depths of layers are fixed. To avoid possible errors caused by wrong layer-depths in the initial velocity model from the sonic logging curve, we use a uniform but fine interval layer model as the initial velocity model. Based on the fact that the velocity values in layers are different, we use the differential arrival times to invert the velocity values in each fine interval layer under TV regularization. Even though the number of layers is significantly increased by using fine interval, the TV regularization helps to preserve sharp interfaces in piecewise-constant structure and produces an equivalent layered-model with minimal number of layers. Synthetic tests show that the velocity structure is recovered well for noise-free data. For data with noise, we still can get an equivalent velocity model which can result in a good event location. Numerical test also reveals that if the initial velocity model has wrong number of layers or wrong layer depths, our method can get a better model than the traditional approach.

通讯

英语

EI

20215311407815

Acoustic logging ; Microseismic monitoring ; Numerical methods

Earthquake Measurements and Analysis:484.1 ; Acoustic Properties of Materials:751.2 ; Numerical Methods:921.6 ; Acoustic Variables Measurements:941.2

2-s2.0-85120175380

Scopus

1.School of Earth and Space Sciences,University of Science and Technology of China,China
2.Department of Earth and Space Sciences,Southern University of Science and Technology,China

Jiang，Xingda,Zhang，Wei. Determine minimal layered-velocity model for downhole microseismic monitoring by total variation (TV) regularization[C],2017:2893-2897.