Book

Description

Gravity method is a technique that involves measurement of very small variations in the Earth's gravitational field, of order of a few parts per million or lower, caused by lateral variations in density. Although less well known than seismology, gravity method has its unique advantage and is widely used in applied geophysics and as well as in environmental research. Over the last decades, there has been tremendous progresses made in developing gravity technology. Among, the MEMS (Microelectromechanical systems) based gravity sensor is the latest in this long endeavour. Meanwhile, the development of data interpretation technology is continually expanding. Significant progress has been made in combining gravity data with other geophysical data, petrophysical data and reservoir parameters for forming integrated workflows. A long-standing challenge in widely using gravity is the inherently minute signal observable at a distance, such as from the surface above a deep target, due to the small changes in mass density. Thus, borehole-based gravimeter is preferred since the measurements can be made closer to the target mass. In conjunction with a collaborative program to develop a borehole deployable MEMS three-axis gravity sensor, we have collected in this book the recent several studies about the application of using the three-axis gravity signal strength produced by the dynamic processes in different types of reservoirs and demonstrate the capabilities and limitations of measuring a vector gravity field and its potential use within reservoir surveillance.