High-Resolution Characterization of Carbonate Source Reservoir Heterogeneity for Enhanced Production Optimization

Abstract

Carbonate source rock reservoirs often exhibit pronounced lamination, resulting in fine-scale facies and rock property variations that are not adequately captured by open hole logs. Precise characterization of reservoir heterogeneity across multiple scales is essential for accurate hydraulic fracture design, landing zone optimization, and ultimately enhancing well productivity. This paper presents a comprehensive workflow that utilizes specialized core-logging equipment to precisely define the thinly layered nature of the cored section, enabling centimeter-scale resolution analysis of vertical heterogeneity. The acquired data allow us to define distinct rock classes with unique and characteristics behaviors, based on multi-dimensional data patterns that mirror their unique and characteristic behaviors in rock properties. The rock classification facilitates the quantitative definition of vertical heterogeneity, capturing the fine-scale property variations within the core section. It also informs the selection of core samples for laboratory rock property characterization, ensuring that the representation of the observed variability is maximized. By integrating the multidimensional core-logging data with the discrete laboratory rock property results, we construct centimeter-resolution petrophysical and geomechanical models that result in higher fidelity reservoir characterization of thinly layered carbonate source reservoirs and more representative numerical simulations, thereby enhancing our ability to optimize hydraulic fracturing and well productivity. The workflow also includes upscaling the resolution of downhole wireline log measurements, utilizing image log measurements as structural constraints to the process, thereby enabling the derivation of high-resolution petrophysical and geomechanical properties in non-cored sections of the same well and in neighboring wells without core data. The study revealed cyclic reservoir and mechanical property variability, particularly in intervals with higher organic content, which were critical for understanding productivity, evaluating the in-situ stress, and for hydraulic fracture modeling. This level of detail in reservoir characterization is not achievable when using conventional resolution wireline logs.