Abstract: A method of seismic analysis is disclosed for identifying subterranean features that in one embodiment uses a coherence analysis for improved seismic data interpretation such as improved accuracy of variables for use in velocity models. The method may be used while analyzing seismic data to produce an earth model wherein the analysis is preferably applied at each level for the model. In another embodiment of the present invention, the coherence analysis is applied as a function of the seismic processing sequence to improve the variables associated therewith. With respect to a subterranean location of interest, azimuth ordered gathers may be used to identify subterranean features such as fault/fracture patterns. In another embodiment, offset ordered coherence analysis is used to form an optimum stack at the subterranean location of interest.

Abstract: The invention relates to hydraulic fracturing of geological formations at selected levels of wells drilled for recovery of hydrocarbons. It resides in the addition of relatively small quantities of a bacterial cellulose to hydraulic fracturing fluids to improve their rheological properties. Proppant suspension is markedly improved and friction loss through well casings is significantly reduced, resulting in lower pumping energy requirements. Computer models also indicate that formation fractures will also be propagated for greater distances as will the propped portion of the fracture. Normally only about 5-15 lb of bacterial cellulose per 1000 gallons (0.60-1.8 g/L) of fracturing fluid is needed. A preferred bacterial cellulose is one made in agitated fermenters using mutation resistant strains of a bacterium from the genus Acetobacter.