--> Guided Sampling of Pore-Scale Imaging for Heterogeneous Mudrocks

AAPG Annual Convention and Exhibition

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Guided Sampling of Pore-Scale Imaging for Heterogeneous Mudrocks

Abstract

High-resolution microscopy enables the investigation of petrophysical properties of reservoir rocks at the pore scale, even in the case of mudrocks with pores as small as 1–10 nm across. However, tying these nanometer scale findings to longer length scales is challenging. Because of the heterogeneity of micro- and nano-scale rock properties for mudrocks, uninformed sampling can give results that are not representative at longer scales. A reasonable workflow strategy is to image samples at a course scale and then perform higher resolution imaging of representative zones. This has been proposed, and executed in limited cases, but doing so requires painstaking effort to track sample orientation and position in order to locate and image the targeted features manually. We have developed and demonstrate here a software platform that simplifies this critical task. Chiefly, the software platform is designed to use image data from any prior experiment to inform and guide targeted imaging for a subsequent experiment. We have identified and then implemented four key components to streamline this workflow. First, the system must manipulate and display disparate image data, which will likely come from a variety of microscopy techniques. Second, the platform must enable the user to properly register disparate image data to unify them in one common frame of reference. Third, the platform must be stage position-aware and capable of driving the stage to user-targeted areas of interest. Finally, the platform should present the high-resolution imagery in the context of the coarser data. Some of these requirements have been addressed individually, but they have never been integrated such that the coarse data can guide the high-resolution data collection. Prior to this work, an existing software platform could visualize various image types, and furthermore, it already had stage awareness. We demonstrate the addition of a highly flexible image registration tool that permits registration of 2D images, allowing translation, rotation, scaling, and shearing. We extended this to 3D with a common plane identification tool; once that plane is determined, the remaining alignment is carried out as a straightforward 2D registration problem. We demonstrate here this platform on various mudrock samples. We show integration of multiple imaging techniques for mudrocks spanning many orders of length scale (from mm to nm) and incorporating both 2D and 3D imaging and analysis.