Formation Water Salinity and Its Exploration Application


Kinji Magara,
University of Texas

7th Formation Evaluation Symposium of the
Canadian Well Logging Society in Calgary, October 21, 22, 23 & 24, 1979



Formation water salinity of sedimentary rocks which were deposited under a marine environment is usually higher than that of sea water (35,000 ppm NaCl). The principal cause of increased salinity during burial and compaction is considered to be ion-filtration by clays or shales; the clays or shales expel water which is fresher than the original pore-water, leaving behind more salt ions in them, thus increasing the salinity.