Subsurface risks involved in a field development activity are best mitigated by establishing a narrow uncertainty band from all available subsurface data. Horizontal wells, based on their profile usually presents a set of ‘point’ data for a number of spatial location along the bore, however these information are usually not accurately captured in the development of a conceptual model.
This field study attempts to show the integration of data from horizontal wells, analogue and seismic in order to accurately predict facies/reservoir properties distribution and also look into the production potential of a newly drilled offshore production and injector wells.
The study area is situated in the deepwater South west of Niger Delta, Nigeria. An integrated approach which incorporates statistical and neural network seismic attribute analysis, horizontal well point properties, and analogue data to generate a robust depositional facies distribution was adopted in the static modelling. The facies model being an underlining step in distribution of reservoir petrophysical properties was then utilized to generate descriptive reservoir properties model that captures the subsurface heterogeneity of the "Zat" field. The correctness of this methodology is being substantiated by result culminated from other similar projects.
The depo-facies accurately captures the stratigraphic geometry and distribution of facies as seen by wells and seismic thereby leading to improved lateral and vertical facies predictions. So what you see is what you get! The interplay of along well-bore and three-dimensional prediction of sand intervals enables a better QC workflow for assigning petrophysical properties (e.g. porosity, permeability and water saturation) to the static model. The trend and connectivity of amalgamated channel bodies mimic to a greater extent the observed seismic and wellbore facies.
The resultant net-to-gross estimation of this approach compares better to the seismic data set prediction from inversion.