A novel SEM technique allows the observation of the same pore on a core face after each step in a series of dynamic flow tests. It requires no conductive coating and facilitates core flow using a one inch (25.4 mm) diameter plug. Three separate studies were undertaken in which the procedure was used to observe the effects of drilling mud invasion, waterflooding, and matrix acidization on individual grains and pores. In the drilling mud study it was found that 2% HF removed most of the siderite weighted mud, but that mud residue and etching of the framework grains resulted in a lowered overall permeability. When seawater replaced formation water during the laboratory waterflood, there was an increase in permeability due to ionic stabilization of clays and the washing out of other loose fines. In the matrix acidization study. 10% HCI created wormholes in a fractured dolomite at elevated temperature and pressure.
Rothbard, D. R.; Skopec, R. A.; Bajsarowicz, C. J.; and Fate, T. H.
"Scanning Electron Microscope Evaluation of Drilling Damage and Acid Treatment using Uncoated Core,"
Scanning Microscopy: Vol. 1
, Article 7.
Available at: https://digitalcommons.usu.edu/microscopy/vol1/iss2/7