Introducing a New Advanced Method to Predict Petrophysical Rock Types Using Multi-Well Flow Units - Using Integrated Core-Log Petrophysical Data for Identifying Additional Production Opportunities
Authors: Gunter Gary William , Sahar Mohamad Yacine , Viro Eduardo Jose , Negabahn Shahin , Watfa Mohamed 
Published: November 2020

Our new Petrophysical Rock Type (PRT) prediction method is based on Advanced Multi-Well Flow Units. The new PRT method uses a variation of the Multi-Component Stratigraphic Modified Lorenz Plot. The advantage is, the new method directly links PRT and flow units together at the field and well levels.

The advanced flow unit analysis is used for asset management, identifying and comparing completion zones, finding remedial opportunities, comparing petrophysical rock types from several approaches and aid geoscientist in identifying potential new well locations before building a 3-dimensional static model.

The new Multi-Well method includes core analysis, well performance data and well logs over the zone of interest. This method has been applied in conventional carbonates, sandstones, low permeability "tight" reservoirs and unconventional shales (gas or oil). A key reservoir characterization feature is the ability to determine petrophysical rock types directly using non-normalized total storage capacity, total flow capacity and bulk volumes of oil and water without using pore throat techniques.

Our PRT and Advanced Flow Unit workflow process includes the following steps; Determine total storage volume by integrating core and log data.Computed bulk volume water and hydrocarbon are determined by integrating core and log data.Flow capacity is determined by integrating conventional core analysis, special core analysis and well log data over the zone of interest and pressure analysis.Field or multi-well Composite Diagnostic Non-Normalized Modified Lorenz and Classic Lorenz plots are used to predict Petrophysical Rock Types per well using non-normalized data (total storage capacity vs. total flow capacity) as a function of depth.Determining field or multi-well Composite Diagnostic Non-Normalized Multi-Component Depth Domain Analysis plots include cumulative total storage capacity, cumulative total flow capacity, cumulative bulk volume water capacity and cumulative bulk volume hydrocarbon capacity. These plots are used to evaluate and compare well performance.Per well or composite Multi-Component Diagnostic Stratigraphic Modified Lorenz Plots are created as a function of depth and can be integrated with well test data or well performance data to provide another well evaluation tool for reservoir management.Slope analysis, slope difference and data smoothing are completed at the well level to automatically predict PRT. The results are compared to deterministic methods to access the quality of the PRT prediction.Slope analysis, slope difference and data smoothing are completed on a "super well or composite well" Classic Lorenz plot using results from high quality core-log integration analysis from multiple wells. The super well composite plot is used to predict the number of PRTs in a field for a zone.Resulting PRTs should be verified using the 10-Step process that we described in 2018 (SPE).

The benefits of this new method include, the field analysis and well-to-well comparisons of reservoir compartments and the petrophysical rock types identification using derivative analysis. Applying this multi-well method in mature fields provides a quick method of evaluating existing wells to identify bypassed hydrocarbon and zones that have a high probability of producing water. Potential infill drilling locations or zone recompletions can be evaluated before creating a detailed static or dynamic reservoir model. In the future these methods may be combined with "Artificial Intelligence or Machine Learning" using well monitoring data to identify anomalous performance.