Abstract: A method for compressing seismic data to reduce data storage and transmission requirements applies wavelet transforms to digitized trace sequential data obtained from plural arrays of multiple acoustic sensors. The wavelet transforms are applied in at least three dimensions, and, in the case of underwater exploration, four dimensions. The transformed data is ordered and quantized to increase the number of zero data values, and the quantized data is compressed using rim-length encoding and entropy coding. The entropy coded data is stored for later retrieval or transmitted to a remote location. The retrieved or received data is decompressed, dequantized and inverse wavelet transformed to construct a representation of the original data. The compression can be selected to be in excess of 100:1 to significantly reduce the data storage and transmission requirements without significant degradation of the reconstructed data.

Abstract: Apparatus for clarifying produced water. A flotation chamber has a produced water inlet, a clean water outlet, and is segmented into a plurality of cells by baffles. An oil overflow compartment is in fluid communication with the upper portion of the chamber. Produced gas is introduced into each cell of the flotation chamber by porous sparger tubes creating bubbles of 100 to 1000 microns in diameter. The bubbles rise through the water removing any suspended oil particles. The gas exits through a gas outlet. The removed oil collects on the liquid surface of the produced water and overflows to the overflow compartment. Oil is removed from the overflow compartment via an oil outlet.

Abstract: Minerals in a subterranean formation are dissolved by treating them in the presence of an organic acid with a fluoride-containing compound having a concentration in the range of from 0.007 N to 0.05 N. The hydrogen ion concentration can be less than 0.02 N, preferably less than 0.004 N. The fluoride-containing compound can be hydrofluoric acid. Alternatively, the minerals can be treated by applying alternating stages of a solution of fluoride salt, such as ammonium fluoride or ammonium bifluoride, and an organic acid, such as acetic acid. The treatment can be done in a formation at a temperature of at least 350.degree. F.