From 1991 to 1996, sand consolidation by use of high-pH steam was tested successfully in 13 vertical and 7 horizontal wells in the Wilmington field, California. By not running gravel packs, U.S. $90,000 was saved per vertical well and U.S. $150,000 was saved per horizontal well. An experimental study to understand and optimize the process indicated that sand consolidation did not occur for 7-pH steam but that sand consolidation did occur for 12-pH steam. Photomicrographs showed both needlelike and equidimensional sodium aluminum silicate crystals being formed between the consolidated sand grains.