Desk study 3D acoustical tomography

In order to be able to develop an acoustical measurement technique for measuring gas fractions and bubble size distributions in a mud depot, a desk study has been done. The results of the study are presented. In the first part of the report an overview of the theory for the propagation of sound waves in gassy sediment, taking into account the sediment properties, gas fraction and bubble size of the gas, is given. An overview is given of a number of measurement systems presented in literature, used to detect the presence of gas in a muddy sediment.The systems presented are back scatter systems. They are not able to quantify the amount of gas present in the sediment or to predict the bubbel size distribution. The outline of a measurement system which is capable to measure the gas fraction in the depot as function of the position is presented. The system presented is a transmission system, which, if necessary, can be combined with a reflection system.