Iron Control In Fracturing Operations

Iron control studies over the last 30 years have dealt primarily with iron control in acidizing operations. In fracturing operations, iron control has received much less consideration. Certain hydrocarbon producing zones contain iron compounds in both the rock composition and formation water. Fluids used in fracturing operations may be incompatible with the formation water or rock itself, if iron is present in them. Special consideration should be given to the design of fracturing fluids and fracturing techniques so that iron problems will be minimized. This paper presents: (1) data and treating information on 3 formations (Clinton Sandstone in Ohio, Granite Wash in Oklahoma, Limy Sand in Texas) that contain iron in the formation rock and formation water and were treated with an iron control fracturing procedure. (2) the new iron control fracturing procedure that helps maintain iron in solution and helps provide compatibility of the fracturing fluids with the formation. (3) treating techniques to control iron problems and (4) field results from jobs that utilized the modified fracturing fluid and procedure. Sharp production decline curves have plagued operations in the formations listed. The Clinton Sandstone, Granite Wash, and Limy Sand formations have responded well to fracturing treatments; however, in many instances the production increases have not been sustained as long as desired. Iron, a constituent of the reservoir rock, may well be a primary factor in this problem. Utilization of iron control additives and treating techniques as applied to the formations encountered in Pennsylvania, Michigan, Illinois, Indiana, Kentucky, West Virginia, Tennessee, Alabama, Texas, and Oklahoma should be considered for improving cleanup operations, production stimulation and rate of production decline in the same or similar formations in other areas.