Combined application of sub-bottom and single-channel seismic profiles to marine sand and gravel resource prospecting

The demand for marine sand and gravel is sharply increasing, which leads to the intensification of prospecting and exploitation offshore. As an important type of marine sand and gravel resources, extraction of buried marine sand and gravel has less environmental impacts. However, the prospecting of the buried sand and gravel deposits is relatively difficult. Single-channel seismic survey is commonly used to search for buried marine sand and gravel. It is advantaged by penetrating sand, whereas disadvantaged by multiple solutions. Sub-bottom profile has not been paid enough attention in previous marine sand and gravel investigations, due to the difficulties in penetrating sand. However, sub-bottom profile is easy to penetrate mud, and can be used to exclude the mud. In this paper, we propose a method by integrating sub-bottom and single-channel seismic profiles together. Mud could be easily recognized with the clear transparent or bedding structure on the sub-bottom profile, which could help avoiding the thick mud. Sand might be recognized by the medium-strong amplitude chaotic reflection on the single-channel seismic profile, which could guide to selecting the thick sand. Based on the understanding mentioned above, the method of "exclusion of thick mud by sub-bottom profile, identification of sand by single-channel seismic profile and verification by boreholes" is suggested for prospecting of buried marine sand and gravel so as to effectively improve the success rate of prospecting.