Abstract: The present invention comprises a data delivery system for delivering oilfield data from an acquisition site to a remote delivery site comprising a central data hub computer that processes a workflow order for controlling delivery of the oilfield data, a data acquisition site computer that transmits oilfield data over a first communications network to the central data hub in near real-time in response to the workflow order and a data server that receives data from the central data hub over a second communications network. The data server communicates with multiple remote delivery site computers for the simultaneous display of oilfield data in near real-time at the multiple delivery site computers in response to the workflow order.

Abstract: Methods and apparatus for generating an error bar (variance) log for a formation parameter are disclosed. According to the method, acoustic waveforms are detected at a plurality (M) of detectors which are a function of a source signal which has interacted with the formation and noise, and the detected waveforms are sampled and processed in order to obtain a semblance or a normalized mean square error. Using the semblance or the NMSE which is related to the semblance, a signal to noise ratio 2E/N.sub.0 can be found by recognizing that the semblance function has a non-central beta distribution whose mean is a function of the signal to noise ratio 2E/N.sub.0, the time-bandwidth product N, and M. The signal to noise ratio is then used to find the Cramer-Rao lower bound which is taken as an estimate of the variance. An error bar log is formed by repeating these steps at a plurality of locations along the borehole.

Abstract: Methods for determining an optimal frequency band for processing of flexural waves according to bias-corrected STC or QSTC are disclosed. A preliminary estimate of the formation shear slowness S and a determination of the borehole diameter D are first obtained, and the flexural waves are processed in a frequency band having a center frequency f.sub.c which is a function of preliminary estimate of S and the product of that estimate of S and diameter D. Where the preliminary estimate of S indicates a slow formation, f.sub.c is chosen as 0.6/SD. Where the estimate indicates a fast formation, f.sub.c is chosen as 0.2/SD. In other or all formations, a smooth function such as [0.2+((0.8/.pi.) arctan ((S-100)/100))/SD] can be used to choose the center frequency. Alternatively, if errors in the environmental parameters can be estimated statistically, they can be used to select an optimum center frequency. Once f.sub.

Abstract: A borehole correction software of a multipole sonic well tool adapted to be disposed in a borehole determines a true, corrected value of shear wave slowness from a measured uncorrected shear wave slowness value by first building a look up table comprising hole diameter, measured synthetic shear wave slowness and correction factor, and using the table in a system including the look up table and a multiplier to determine a bias, which bias is subtracted from the measured uncorrected shear wave slowness to produce an output medium reflecting a true, corrected value of shear wave slowness. The measured uncorrected shear wave slowness values are input to the look up table. For a given hole diameter, the measured uncorrected shear wave slowness is matched to a measured synthetic shear wave slowness, and a value of correction factor is determined from the table. The correction factor is multiplied by the measured uncorrected shear wave slowness, via the multiplier, and a bias figure is determined.