A Resume of the Application of Gravel Packing to Oil Wells in California

Abstract

The production of sand in an oil well increases operating costs because ofabnormal wear in subsurface equipment, the necessity for frequent cleanouts, and the need for a means of disposing of the sand. Moreover, removal of sandfrom the zone can bring about the creation. of cavities from which bodies offormation, sand or shale, may slough into the hole, endangering the shutoff, impeding production or collapsing the liner. The procedure known as gravelpacking is attracting attention as a means of controlling these factors andcontributing to the productive life of a well. That gravel packing is nowsubstantially beyond the preliminary stage on the Pacific Coast is reflected inthe 191,000 bbl. of oil produced monthly by the 66 gravel-packed wells in 11 different producing sectors. Reasons for Gravel Packing Gravel packing, if properly carried out, can be expected to provide the following benefits:Prevent the movement of sand and thus eliminate sand production and sandfills, and prevent the formation of cavities.Provide a practical, relatively inexpensive, large-diameter hole, which willprovide well-known theoretical advantages.Support the walls of the hole by completely filling the space between theliner and the formation, regardless of its irregularities, and afford a supportfor liners.Provide for more efficient pumping operations in wells by:possiblyutilizing the gravel as a gas trap in pumping gaseous fluids,allowing deepsubmergence of the pump into the oil zone. In a conventional well-that is, where the liner is set in an open hole-? eventhough perforation sizes are chosen according to known rules based on analysisof sand grains from samples from the zone, there is likely to be someproduction of sand. T.P. 1079