Application of Seismic Sedimentology in Tight Sandstone Reservoirs in Zhengning Area

In the Zhengning area of Ordos Basin, the underwater distributary channel deposits of the delta front are developed in the He8 segment of Shihezi Formation, and several exploration wells have obtained natural gas discoveries in this area. However, the overall thickness of this set of tight sandstone is thin and its lateral variation is fast. Finding the distribution rules of sandstone is of great significance for gas exploration and development in this area. In the case of low drilling density, seismic sedimentology methods are applied. Determine the optimal parameters for phase conversion through forward modeling. The seismic event axis after − 70° phase conversion has a good correspondence with sandstone, and the converted data slices and amplitude attributes reflect the general distribution range of sandstone. Determine the response characteristics of sandstone through time-frequency analysis. High frequency band above 35 Hz was found to be sensitive to thick sandstone, and single frequency volume slices obtained through spectral decomposition reflect the location of thick sandstone. Three main river channels and several sand body distribution centers were identified in the target layer. The coincidence rate between the predicted results and the completed exploration well is more than 80%, and the effect has been verified, which can effectively guide the follow-up exploration work.