Mesozoic bottom boundary in Yakela Faulted upliftt is an important unconformity developed for a long geologic time

and its overlying and underlying formations are quite different in deformation manner.Based on interpretation of 3D seismic data in the Yakela faulted uplift

combining with well data

regional geology and regional strata distribution characteristics

the types of unconformities related to this reflector can be divided into nonconformity

truncation unconformity

overlap unconformity and karst unconformity according to their formation mechanisms and main factors controlling geometry.The nonconformities mainly occur in the eastern and western parts

where the pre-Mesozoic deposits were denuded completely.The monocline area

fold area and fault-fold area of truncation unconformity exsit in the middle and western parts of the Yakela faulted uplift from west to east.The overlap unconformity distributes along south climb of the Yakela faulted upliftt.The karst unconformity mainly distributes in the central and western parts

where the upper Palaeozoic was eroded completely and carbonates expose.The unconformities are of great significance for hydrocarbon accumulation as they can act as migration pathway

improve reservoir conditions and create lots of traps.Comprehensive analysis of the characteristics and distribution patterns of various unconformities in this area reveals that they are the results of tectonic deformations strong in the east and weak in the west of the Yakela faulted uplift.