Evolution and Reservoir Quality of C Carbonate in the Central Part of Nam Con Son Basin, Offshore South Vietnam

Abstract

Nam Con Son basin located offshore South Vietnam is predicted to contain 20% of the total hydrocarbon resources of Vietnam. Exploration has demonstrated discoveries in 3 types of reservoirs: pre-Cenozoic weathered and fractured basement, Oligocene and Miocene clastics, and Miocene carbonates. Recent acquired subsurface data have revealed the evolution and reservoir quality of C carbonate in Block 06-1 of central Nam Con Son Basin. Carbonate platform was initiated in Middle-Miocene and have been developed widely in Late Middle-Miocene to Early Pliocene. The C carbonate system started demising as an increase in clastic sediments from the western inland during the Early Pliocene period. In general, carbonate lithologies are dominated by coral, red algal and foraminiferal packstones, wackestones and grainstones. Vuggy and intercrystal are dominant pore types in investigated interval. Nevertheless, fracture pore was not well developed suggest the minor influences of tectonic activities on the development carbonate reservoir. The average porosity and permeability from routine core analysis is about 29% and 2900 mD respectively. Reservoir quality of C carbonate is classified as good to very good and it is strongly influenced by diagenesis processes such as dissolution and dolomitization. In which, dolomitization, recrystallization and cementation processes have reduced permeability of carbonate deposits. Dissolution and partly dolomitization have significantly enhanced the carbonate porosity. The presentation reviews the conducted studies aiming to contribute in establishing a predictive exploration model for the central part of Nam Con Son Basin. The challenges met in understanding the evolution and reservoir quality in the study area is also addressed to stimulate the discussion on the establishment of a more regional geological model.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018