| The performance characteristics and the accurate prediction methods of overpressure in deep strata has become
a hot topic in oil and gas exploration and development. Based on a lot of relevant literature and patent works of formation
pressure prediction technology at home and abroad, the paper summarizes the challenges and problems in deep formation
pressure prediction, the new progress and shortcomings of deep formation pressure prediction technologies, and the future
research directions. The main understandings are as follows: (1) The classical pressure prediction theories and algorithms
effectively applicable to the shallow and middle strata can not be directly applied to the study of more complexive deep
formation pressure. (2) Due to the complex geological conditions, engineering difficulties, complex overpressure genetic
mechanism, and the lack of prediction algorithm in deep strata, there is still great challenges and problems although the
research based on porous elastic theory, petrophysical model, and tectonic pressurization has promoted the progress of
deep pressure prediction. (3) Different from the common overpressure causued by undercompaction, the overpressure in
deep strata is offen related to non-undercompacted mechanisms such as pressure transfer of structure and fault,
hydrocarbon generation, and caprock sealing, which is often characterized by the coexistence of multiple mechanisms in
the same areas and the various changes among different pressure systems. In order to accurately predict the deep
overpressure, the more adaptable models are needed including the improved classical methods and formulas facing to the
actual problems by analyzing the main and secondary overpressure mechanism. The seismic prediction technologies for
the deep formation pressure that adapt to the complex lithology, the coexistence of multiple overpressure mechanisms and
the variation of lateral pressure distributions, is the main research direction in the future. |
