CT-Scan Image Processing for Accurate Pore Network Modeling and Core Samples 3D Printing: Polynomial Interpolation Geostatistical QC

摘要

3D-printed core-plug replicas have wide applications in oil and gas industry. We can use synthetic plugs for repeatable set of experiments in which pore network geometry is accurately described for experiments' simulation purposes. We can also eliminate the complex effects of rock compositions on flow/transport characteristics. That will enhance our understanding for the physics of fluid flow processes in porous media. It is challenging to ensure that synthetic core-plug is accurately duplicating the original core-plug. The pore network accuracy in the 3D-printed replicas is controlled by the computed microtomography (CT) images resolution (both planar and longitudinal), 3D-printing file generation steps, and 3D-printer resolution limitations. We generated a robust workflow by combining CT scanning, image processing tools, and 3D-printing technology to create accurate synthetic replicas for core-plugs. Geostatistical tools (multi-azimuth variograms) and image processing tools (polynomial interpolation) were utilized to tune XY and Z resolution of a CT scan for Berea sandstone core-plug to fit current 3D-printing technology requirements, reduce the needed processing computational power, and construct a 3D-printable continuous volume. Based on the generated conceptual volume, 3D-printed sandstone replica was created and presented a close agreement with the petrophysical and transport behavior (porosity and permeability) of the original Berea core-plug.