Oil & Gas Exploration Target Evaluation In OML66 Block Of Nigeria

From the Eocene to the modern, the Niger Delta belongs to the continuous deposition of the regression phase, never happened huge tectonic disturbance, and it’s sedimentary environment has better consistency. From north to south, it is divided into five sedimentary belt. OML66 block is located in the coastal marsh deposition zone of the Niger Delta, it’s sedimentary setting is superior. It’s Work area has 100 km from west to east. The block is divided into Akata、Agbada and Beinin group from bottom to up, Agbada group is our research layer, it belongs to mutual successive deposition about sea and land from tertiary to Quaternary period during Cenozoic era.This paper bands seismic、logging、geological and other subjects together, through analysis of structural characteristics、seismic attributes、reservoir characteristics and research of sedimentary facies and sand body distribution, evaluates exploration potentiality comprehensively and points out four favorable exploration area.Through analysis of seismic data, we can draw a conclusion that the overall conformation of the block is a collapsed roof anticline complexed by fault. The region is divided into three tectonic belt: scroll anticline belt in the northern area, structure coordination belt in the central area, collapsed roof anticline belt in the eastern area.Sedimentary facies of the block is a regression model delta controlled by three factors commonly: rivers, waves and tides. Through comprehensive study of drilling、logging data and seismic attribute volume, we believe that the Agbada group belongs to delta front - former delta sedimentary system, with multiple source, sedimentary microfacies include underwater distributary channel、barrier bar、mouth bar and front sand sheet and etc.Through analysis of connectivity and flat distribution status of the sandstone, it is believed that the block has prolific sand body. Vertically, multiple phase channels overlay each other, reservoir is better in the superficial layer than that in the deep layer, the development degree of sandstone gradually changes for the better upwards, the sand thickness increases gradually, grain size also changes for the coarser, the ratio of sand layer and stratum also increases gradually. On Plane, controlled by sedimentation, sand bodys distribute in the form of zonated and banded, the two banded sand bodys of NNE in the east and NNW in the west are most obvious, the thickness of sand body is larger in the western and eastern area than that in the central area, and also richer in the northern region compared with the southern region. The interbedding of sandstone and mudstone also develops widely, stable mudstone is good regional cap-rock.Using the result of electric log interpretation and oil-well production test, the distribution rule of oil & gas is conducted. It is concluded that the accumulation model of the block is that oil & gas is generated from the deep source and gathers together in the superficial layer, frature is the major passage system, oil mainly accumulates in the high parts of the various local structures and distributes like "toothbrush" along the foot wall of the fault. The eastern anticline of the block has rich oil & gas, and oil & gas mainly concentrates in the reverse ridge fault-block、consequent ridge fault-block and fault-nose in the South Wing of the anticline, and the North Wing of the anticline has the similar structural and reservoir characteristics with the South Wing of the anticline, traps have big area and large reserves, sandstone develops widely, the reservoir combination is very favorable, so it can be used as development evaluation targets and favorable exploration targets. The north-west area of the block develops large traps with good succession from top to bottom, and the master control fault is activated for a long time and has big throw, furthermore,sandstone develops widely, but it is far from the K-K field drilled before, therefore, it can be used as the exploration vision targets. Structure coordination belt in the central region is located in the joint area of the seismic data, the degree of structure implementation is low relatively, so some risks for exploration can’t be avoided, and in this area, the development of sandstone isn’t so wide on the whole, therefore, it can be used as the risk exploration targets.