New Theory Systems of Base Level Cycle and Its Preliminary Application

Abstract

Base on water level theory, Octavian Catuneanu propose a four-division scheme to make sequence stratigraphy standardization. However, this scheme is simply a concession on different schools of sequence stratigraphy. It hasn't reached the target of multi-theory amalgamation theoretically. After deeply studied, the idea is proposed that base level cycle theory can be altered to get access to sequence stratigraphy standardization. The traditional base level and corresponding base level cycle theory has such defects as uncertainty of sequence order, base level cycle definition and poor operability et al. The new theory system on basic framework of base level cycle considers that base level has 3 movement status including ascending period of base level, descending period of base level and stable period of base level. The four kinds of dynamic process are put forward, which includes base level descending, base level tending to ascend, base level ascending and base level tending to descend. And the definition of base level oscillation sub-cycle is firstly put forward. The new suggestion is made that a base level cycle be a set of formation deposited from the descending to ascending stage of the base level, instead of from its ascending to descending stage. This cycle is made up of four sub cycles, which are descending sub base level cycle, tending to ascending sub cycle, ascending sub cycle and tending to descend sub cycle. Two neighbored base level cycles vertically are divided by the transition section of base level cycle. When the thickness of the transition section equals to 0, it becomes base level transition surface. The above concept and method system helps to resolve the contradiction between sequence division and partition of development layer series. It provides a new train of thought to establish isochronous stratigraphic framework. The construction of the new framework system makes high resolution sequence stratigraphy more easily to amalgamate with classic sequence stratigraphy. The new theory has been used in planning overall development programs of onshore Qin Oil field and offshore Peng oil field in eastern China (Qin is characterized of Paleogene fan delta, the other is Neogene fluvial facies) and obtained good effectiveness in practical application.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015