An apparatus that enables spot measurements of permeability variations along a core measuring 2 inches in diameter and 5.5 inches in length was developed. The apparatus is based on liquid injection at the rock surface and is referred to as the "Liquid Minipermeameter" (LMP). During the LMP measurements, full saturation of the rock sample is ensured by using a saturation bath. LMP measurements are also compared against air minipermeameter measurements. During liquid injection using the LMP, flow patterns were studied through the injection of colored liquids.
Various formation damage mechanisms on consolidated rocks using conventional coreflooding apparatus have been studied in conjunction with LMP measurements. LMP measurements were conducted before and after the formation damage experiments. The present paper includes an interpretation of a complex formation damage mechanism involving precipitation of gelatinous iron hydroxide. In this case, spot permeability measurements provide valuable information on the extent of damage as it is shown from LMP spatial variations.
Advantages of the LMP measurements arise as the measurements are not destructive for the rock sample and the rock heterogeneity is not excluded from the interpretation of the formation damage experiments. Compared to air minipermeameter the LMP shows better repeatability while drying of the rocks is not necessary.