Abstract:

Extensive mass transport deposits （MTDs） distributed in continental margin have became new filed of gravity flow exploration and development. In order to understand the sedimentary and distribution characteristics of the MTDs which deposited in depression and faulted basins, Songliao Basin and Erlian Bain are chosen as the research object. Based on integrated analysis of seismic, core and laboratory test data, sedimentary features and distribution pattern of MTDs were studied systematically. Gravity flow deposits can be divided into MTDs and turbidite. MTDs are different from turbidities in terms of sedimentary structure, concentration, flow pattern, rheology characteristics and seismic response. MTDs belong to laminar flow with solid and bingham fluid characteristics simultaneously and include movement and emplacement by elastic deformation and brittle deformation and plastic deformation. Besides the common massive sandstone, MTDs also form synsedimentary deformation structures or soft-sedimentary deformation structures, such as convolute bedding, slumping deformation structure, boudinage and microfaults, as well as shale boulder. Turbidite belongs to turbulence which forms grained beddings. Seismic profile reveals that thick layer of MTDs are characterized by chaotic, mounded, and transparent seismic reflection, and thin layer of MTDs have eye-shaped reflection structure. MTDs not only have the particle size distribution characteristics of gravity flow, but also have the particle size distribution characteristics of traction current. MTDs are more widely distributed than turbidite in the study area, have more layers and larger monolayer thickness, and have better reservoir performance. The study shows that MTDs are new areas for terrestrial lacustrine gravity flow exploration.

Key words: provenance analysis, source area, parent rock features, moving path, tectonic setting of source area, sedimentary basin