The Concept of Progressive Property Modeling, a Sequential Technique to Enhance the Utilization of Seismic Inversion Products and Lwd Property Measurements from Horizontal Wells into Static Models

Abstract

To establish relationships between seismic derived acoustic impedance and LWD porosity measurements from several horizontal wells to be implemented into property modeling. This workflow is a sequential process that integrates property relationships from seismic scale to log scale using log data from a dozen of vertical wells and validate results at field scale with log data from about 50 horizontal wells. Overall process functions at grid-block scale in a 100x100mx1ft cell size following the four main phases. The first phase, involves exploratory data analysis and quality check. This is followed by a second phase of model building to concatenate all the required modeling steps. Third phase of model optimization explores the effect of all the parameters and data links defined in the process. Finally fourth phase involves validation to assess residual errors from the resulting porosity distributions and quantifying predictability of the model itself. A comprehensive and robust set of properties is generated by performing a recursive and convergent process of property modeling using lateral coverage from seismic inversion products and vertical resolution near well log scale. Independent analysis of different scales of porosity measurements are reconciled in this systematic approach by defining average distributions and descriptive statistics of reservoir properties at field scale. Variable data types, sample sizes and data resolution evolves across four different phases that integrates a holistic understanding of datasets in different dimensions. Quantitative analysis of seismic data ultimate correlates to a dense dataset from long horizontal wells. Final predictability of the model reaches a high confidence level (about 80% accuracy) when testing the predicted properties vs real measurements in about 50 horizontal wells. Multiple realizations of properties distribution matching all the available data is final output that provides a better understanding of reservoir property. This workflow allows total utilization of log data from horizontal wells into property distribution with no impact on overall statistics. No complex de-clustering operations are required as all the descriptive statistics are defined from vertical wells calibrated to core and seismic data. This methodology maximizes the value of LWD formation evaluation logs in property distribution, by combining the resolution of the logs along long horizontal wells with the strong lateral coverage of seismic inversion cubes.