Deconvolution and Boosting Parameters for Obsolete Schlumberger Induction Tools

Barbara Anderson and Thomas D. Barber

INTRODUCTION (no abstract): There has been increasing interest in making processing algorithms for obsolete induction tools available to the general public. This interest is driven by the availability of modeling and inversion codes for older tools that require "raw" data, or by the need for accurate processing of modeled data. Processing algorithms have historically been kept as proprietary information by service companies. However, since today's array-type induction tools include comprehensive environmental corrections, there is no longer a need for the simple processing of old tools to remain proprietary. Although previous publications have described basic processing (Shen, 1989, Anderson and Barber, 1996), a complete description including all available variations has never been published. This note lists all of the processing parameters used on the deep induction (ID), medium induction (IM), 6FF40, and 6FF28 tools prior to the introduction of the Phasor Induction tool in the mid-1980s. In addition, simple formulas for the removal of this processing are given for those who need "raw" data for processing with more modern methods. The data files from the Phasor Induction tool include unprocessed raw data. No processing was done at all on the older 5FF27 and 5FF40 tools of the 1950s. The Phasor Induction raw data are available on the data tapes, as are data from the AIT-family of tools.

Jian-hua Zhang, Qi Hu, and Zhen-hua Liu

ABSTRACT Real invasion profiles are time dependent. Resistivity responses of dual-induction logs thus depend on time. If a well is logged at different times after drilling, the log responses will be different. Time-lapse induction logging modeling suggests a method to estimate true formation resistivity, and to estimate water saturation by history matching field well-log data as a function of time. The effects of two common mud systems, fresh mud on one hand and more-briny mud filtrate on the other, are illustrated with field applications.