Abstract:

Abstract: Physical simulation experiments were conducted based on the braided river sand deposit of the Daqing Oilfield unit PI23 as the background. Through six rounds of experiments, the five main microfacies types, i.e. the braided channel, the heart beach, the abandoned channel, the embankment deposit and the overbank deposit, and their distribution patterns were identified and analyzed. Among them, the braid channel and the heart beach deposits are widely developed, accounting for about 90% of the braided river deposits. Heart beach bar more developed in the middle and lower reaches of the river; the connectivity between the heart beach bars is of a higher degree and the mutually connected heart beach bars may account for 60 to 80 percent of the beach thickness. The connectivity in the lower part of the heart beach is good and in the upper part is poorer. At the same time, the correlation between the configuration parameters of sedimentary microfacies sand body and the model of physical parameters were established. The preliminary view is that the width to thickness ratio of the channel sand body is between 70 and 120, and the aspect ratio is between 3 and 5. The width to thickness ratio of heart beach bar sand body is between 80 and 100, and the aspect ratio is between 1 and 3. The distribution range of river face rate is 10%-11% with the trend of being gradually smaller upward. The distribution range of heart beach bar face rate is 9%-10% without obvious variation in the profile. The sandwich of the heart beach bar in the center part is approximately horizontal and in most cases the inclined angle is less than 3°. In the long axis direction, the sandwich on the meeting water side is little steep (<5°) while on the back water side is relatively flat. In the short axis direction, the sandwich is slightly inclined in two wings of the heart beach (<8°). The study is of great significance for forecasting the internal configuration parameters of the main sedimentary microfacies of braided river deposit in Daqing Oilfield.

Key words: braided river, configuration parameters, flume experiment, physical simulation