Accelerated Whole-Core Analysis Optimization With Wellsite Tomography Instrumentation and Bayesian Inversion

摘要

Our previous work confirmed that Bayesian inversion enables whole-core tomography with sparse and noise-perturbed measurements, suitable for wellsite portable industrial scanners. The current study examines further potential of Bayesian inversion on-site X-ray computerized tomography (CT) in producing quantifiable digital representations of core samples. To that end, workflows using 3 D tomographic images depict (1) rock heterogeneity, (2) lithological changes, (3) bedding planes, (4) fractures and nodules, and (5) scale of heterogeneity by quantifying porosity regions. In so doing, this wellsite-based analysis aids in accelerating an informed assessment of whole round core and plug-sample locations for laboratory analysis. Additionally, earlier first-stage core analysis, promotes timely core-log integration and can significantly improve efficiency of subsequent laboratory sampling andanalysis programs. Considering carbonate core samples with complex pore topology, images stemming from Bayesian inversion yield estimates of image-detectable macroporosity within 8% relative to those from customary medical tomograms and depict similar distribution of vugs and angular bedding. Moreover, further appraisal of the performance of the proposed imaging technique, in the presence of multiphase saturation, considers a micro-CT of an oil-bearing carbonate after waterflooding. The intent is to confirm availability of a consistent CT method across scales, and its relevance to whole-core imaging in situations of sponge coring or filtrate invasion. At this scale, while images from Bayesian inversion generate coarsened pore networks, porosity and saturation estimates are within 2% compared to those from customary micro-CT.