Based on the ability of the fluid to freely fill the pretest chamber, a larger sample of formation fluid can be taken for analysis on the surface. The larger samples can range from 1 to 10 gal or more. Due to mud filtrate invasion, a large fraction (if not all) of the retrieved fluid may be mud filtrate. Proper analysis of the sample involves discriminating the filtrate from the native formation fluids. | Based on the ability of the fluid to freely fill the pretest chamber, a larger sample of formation fluid can be taken for analysis on the surface. The larger samples can range from 1 to 10 gal or more. Due to mud filtrate invasion, a large fraction (if not all) of the retrieved fluid may be mud filtrate. Proper analysis of the sample involves discriminating the filtrate from the native formation fluids. |