Palynostratigraphic Evaluation of Depositional Environment in Well E001 Niger Delta

Palynological investigation was carried out on E001 well to interpret the lithofacies and biostratigraphy with the aim of establishing the palynological zones and the consequent age, environment of deposition and paleoclimatic conditions of the rock sediments in the well, using visual microscopic observations to determine their lithological character and palynologic content of the sedimentary succession. E001 well is located on latitude 4° 31′ 16.58″N and longitude 8° 18′ 24.96″E onshore Niger Delta. The analysis of this study was carried out on 50 ditch cutting samples composite at 60ft interval ranging from a depth of 3480 to 6420ft. From the well logs, three lithofacies were delineated and stratified from shale to sandstone. The shale is fissile and dark brown, followed by the siltstone which are poorly sorted, and the sandstones are poorly to well sorted, rounded to well-rounded and fine to coarse grained, the presence of this lithofacies unit indicates that the well section penetrated the Agbada Formation. The Palynologic content recovered were fairly diverse as six (6) zones were erected from base to top which are Acrostichum aureum (Zone I), Zonocostites ramonae (Zone II), Pachydermites diederixi (Zone III), Granulatisporites spp. (Zone IV), Verrucatosporites alienus (Zone V), and Psilatricolporites crassus (Zone VI). These Miospore zones was compared with P820 palynological zones of Evamy et al. 1978 to assign a late Miocene age for the sediments. The paleoenvironmental conditions fluctuates between mangrove setting to freshwater conditions, based on the presence of continental-derived miospores such as Zonocostites ramonae, Psilatricolporites crassus, Acrostichum aureum, Retibrevitricolporites obodoensis, Pachydermites diedirixi, ctenolophonidities costatus. Analysis of the paleoclimatic conditions show that 60% of the total miospores are freshwater, 30% are mangrove, 1% Brackish water and 5% Marine environment. The Palynomorph Marine Index (PMI) also validates the depositional environment which transits from brackish water environment at the upper unit of the well to Fresh water and mangrove environment from the middle to the lower part of the well.