Abstract:

The same stratum may reach the same embedding ending state through different burial traces. However, the preservation of porosity varies with each other, which highlights the influence of burial history. Based on the viscouselasticplastic stress strain model(Bingham model), we have rigorously deduced the functional relationship of porosity with burial depth and time. The essence of the porosity depending on burial depth and time is that the burial history of the stratum controls the variation degree of porosity. In order to fully testify this conclusion, we deduced the porosity function of burial time and depth for the four general types of subsiding basins, i.e., the accelerating, the constant speed, the decelerating and the early burial then standingstill type of basin. By comparison, it is concluded that the accelerating burial basin is the most favorable for the preservation of porosity, the decelerating burial basin is the worst for porosity preservation, and the constant speed burial basin is in the middle. This principle not only has been confirmed by the Beibuwan Basin and Zhujiangkou Basin in China, but also is statistically concordant with the porosity development in foreland basin, rift basin and craton basin that represent the three general types of basins mentioned above respectively.

Key words: burial depth, burial time, burial history, porosity, compaction