skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Semiautomated method for cation-exchange capacity determination of reservoir rocks

Journal Article · · Soc. Pet. Eng. AIME, Pap.; (United States)
DOI:https://doi.org/10.2118/9873-PA· OSTI ID:5500259

The presence of significant amounts of clay in tight-gas sand formations makes the determination of cation exchange capacities (CEC) important for electric-log, self potential (SP), and gamma ray log interpretation. In the past, CEC measurements have been difficult and time-consuming to obtain. However, an automated method that avoids many difficulties of other techniques while determining the CEC's of many samples at one time has been described by Worthington. This work is a modification of the work done by Worthington. Easily assembled commercial equipment instead of specially built equipment is used to agitate rock samples contained in dialysis membrane bags during ion exchange with barium acetate solution and during washing of the samples to remove excess barium ions. Barium acetate is used as the source of barium ions instead of barium chloride, which is used in Worthington's procedure, to avoid corrosion of the stainless steel equipment. The amount of barium ions on the rock samples is then determined by conductometric titration with magnesium sulfate. The titration procedure is not automated. In addition, the use of the barium ion method was extended to samples with CEC values an order of magnitude lower than those determined by Worthington.

Research Organization:
U.S. DOE
OSTI ID:
5500259
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Vol. 23:2
Country of Publication:
United States
Language:
English