Evaluating the evolution of middle Miocene stratum in the North Eastern sub-trough, Nam Con Son basin to establish the input data for geochemical model

Abstract

Petroleum exploration was carried out very early in the Nam Con Son basin and at present, a lot of gas fields have been developed such as Dai Hung, Rong Đoi, Hai Thach, Moc Tinh, and Lan Tay. It is said that most structures in the North Eastern sub-trough were influenced by the North Eastern - South Western fault systems and inherited their trends from Early Miocene to Late Miocene. Paleotopography and paleoenvironment, especially at oil/gas migration and accumulation periods, are important factors contributing to the success of oil/gas exploration and production.

In this article, the authors focus on analysis and evaluation of the Middle Miocene unconformity in the North Eastern sub-trough, Nam Con Son basin. The results obtained by the authors on the basis of new seismic data interpretation and other studies indicate:

• The inversion in the Late of Middle Miocene resulted in a strong change of topography, with some areas being greatly different from the structural map of top Middle Miocene at present;

• The areal changes of inherited topography of Middle Miocene and Early Miocene are very strong;
• The paleotopography and the horizontal changes of topographic inheritance of the study area are important information for establishment of inputs for geochemical modeling.