Abstract
A successful water injection pressure maintenance operation has been in progress in the Big Mineral Creek (Barnes sand) field, Grayson County, Tex., since Aug., 1962. The Barnes sand is typical of many fields in North Texas in that it is composed of several separate sand bodies operated as a single reservoir. one of the objectives, therefore, in planning the supplementary recovery operation was to insure maximum hydrocarbon recovery from each of the five sands which constitute the Barnes reservoir.
To insure this, a stage flood was initiated in which injection and production was confined to the lower sand member initially. When the flood front was sufficiently advanced, the next shallower zone was opened for production and injection. This procedure will be repeated until all five zones are effectively flooded out.
Introduction
The Big Mineral Creek (Barnes sand) field is typical of many fields in the North Texas area in that it is composed of a number of individual sand bodies which are in reality individual reservoirs and which have been grouped together and classified as a single field. This type of grouping did not offer any major production problems during the primary production portion of the reservoir's history. production portion of the reservoir's history. However, early in the life of the field it was realized that a pressure maintenance project would be desirable in the Barnes sand, and a plan of operation would be needed which would plan of operation would be needed which would maximize production from each individual sand member. Experience in other fields of this type had shown that, unless some type of selective injection was initiated, water breakthrough could occur in one of the minor sand intervals with better permeability. Corrective measures later in the life of the flood, if this sand was located in the center of the interval, could be costly.
GEOLOGY
The Big Mineral Creek area is located as shown in Fig. 1 on the west side of Marietta syncline and on the eastern flank of the Walnut Bend platform in Grayson County, Tex. This area is composed of a stratigraphic series of sandstone reservoirs which include the Barnes sand. The Barnes reservoir was established by field rules as a stratigraphic interval existing between the approximate depths of 4,900 and 5,200 ft. Contained within the Barnes interval are five correlative sand bodies that are lithologically characterized as fine to medium grained sandstones containing traces of chert. A type log of this interval is shown in Fig. 2. These zones comprise the basal portion of the upper Des Moines strata.
