Inversion of horizontal in situ stress field based on wide-azimuth seismic data

Abstract In situ stress is a significant rock mechanics parameter, which is widely used in many aspects of the petroleum industry. Horizontal in situ stress is an important part of in situ stress. Hence, how to obtain accurate information as to horizontal stress can vary with azimuth has been widely explored. A new prediction method for in situ stress on a horizontal plane is proposed here. This new method analyses the relationship between seismic data, fracture orientation and a horizontal in situ stress field. Through a series of actual data, it is found that azimuth seismic data and azimuth elastic modulus can effectively point out the direction of the horizontal stress. Meanwhile, the magnitude of horizontal stress is shown to be closely related to a combination of rock elastic modulus and seismic amplitude according to a further analysis of log and wide-azimuth seismic data. Under this premise, an objective function of horizontal in situ stress field inversion using azimuth seismic data is established. Finally, the inversion of a horizontal in situ stress field based on wide-azimuth seismic data is realized. This inversion method can simultaneously invert the maximum horizontal stress, minimum horizontal stress and their orientations, which optimizes the prediction process of a horizontal in situ stress field and establish a new method for the prediction of horizontal in situ stress fields. The application of actual data also verifies the prediction accuracy of this method.