New Method for Modifying Winland Equation Using Well Log Data, Case Study of Kangan and Dalan Formations, the Central Persian Gulf

Efforts have been dedicated to correlating pore throat sizes with petrophysical and geological parameters. Log data is helpful in examining and analyzing the degree of pore type, the presence of clay minerals as well as porosity and the density of the reservoir. This study aims to establish a relationship between pore throat sizes and well log data through regression analysis. Well-logging data are routinely accessible and can be compared with the core data.The research uses mercury injection capillary pressure, core samples, and well log data from three wells within a field in the central Persian Gulf region. Equations were developed to link data from various well logs and their combinations to pore throat sizes in the reservoir. To address with challenges, core plugs were categorized into more homogeneous groups using Winland and flow zone indicator rock typing methods. The Winland method revealed that equations within each rock type exhibited low R2 values due to significant porosity variations. Conversely, integrating data from all seven rock types yielded better fits as the diverse porosity values counterbalanced each other's effects. However, the flow zone indicator rock typing approach did not enhance results as it was designed for circular and cylindrical capillary tubes, making it less effective for developing complex equations in carbonate reservoirs. The findings underscore the significance of defining homogeneous units accurately, as this step is crucial for enhancing results and establishing robust relationships between pore throat sizes and well log data. By integrating data from various rock types and refining the approach to defining homogeneous units, the study demonstrates the potential for improving the accuracy and applicability of pore throat size predictions in carbonate reservoirs.