Reservoir Properties and Their Effects on Waterfloods

Kansas Waterflood Symposium of the Society of Petroleum Engineers of AIME,19 November, Great Bend, Kansas The reservoir properties, both rock properties and fluid properties, are among the major factors affecting the success or failure of any waterflood project. Since this conference is primarily concerned with Lansing-Kansas City Limestone waterfloods, I will try to associate these properties with known properties of the Lansing-Kansas City Limestone. Porosity, being a basic reservoir property, bears a substantial influence on the secondary recovery of a waterflood. This factor is probably the easiest property to obtain, and therefore it is a more widely known property of the Lansing-Kansas City Lime. It can be easily obtained from either core analyses or log interpretations. The Lansing-Kansas City Limestone in most fields is a series of porous lime stringers with either shale or dense lime separating the porous stringers. Porosity development in the Lansing has been determined to be of various forms, that is, oolicastic, intergranual, vugular, etc. The porosity distribution or Lansing reservoirs is very irregular, because of its stratigraphy and variations in types of porosity. Core analyses of two Lansing producers, one in Stafford County and the other in Russell County, indicated these wide variances in porosity. The Stafford County well varied from 10 per cent to 31 per cent, and the Russell County well varied from 14 per cent to 28 per cent. Log interpretations of Lansing reservoirs in the same field in Barton County have indicated porosity variations from 10 to 18per cent. The ranges of porosity, as indicated by the three previous examples, indicate the necessity for accurately determining porosity, since the use of a" Rule of Thumb" could cause substantial errors in determining secondary recovery. An accurate porosity is also necessary to determine fluid saturations and primary recovery at the initiation of a waterflood.