Keywords
Abstract
In the recent years, 1992-2000, a scientific well log analysis software has been developed by the Formation Evaluation Group of PRC. The objective was to cope with quantitative well log analysis of the Libyan Oil Sector from the very beginning, 1959.
In the early wells, only gamma ray (GR), neutron, and resistivity (plus SP) logs were available, which restricted the capabilities of the software to provide only porosity (Φ), shaleiness (V_sh), and fluid saturations (S_w & S_o).
In recently drilled wells, a rich suite of well logs have been measured: GR, (sometimes SGR), Φ, Pu, Pe, At, Cal; Induction or Laterolog resistivities (SP), and sometimes MSFL. This collection gives an ample chance to derive sophisticated rock composition and determine a large number of petrophysical rock properties at fair accuracy even for reservoir simulation.
The software is flexible since it can suit both old and recent logging conditions; a high integration is involved because all the evaluation techniques are calibrated to core investigations, well test results, and production history data; the software is statistical & probabilistic since it is mathematically overdetermined.
The basic feature of the software is the application of multiporosity (3 - 5 porosity components) rock models with more efficient fluid saturation models which distinguish between saturations of the different porosity components.
An example of practical application is presented in the Palaeozoic fractured/vuggy Gargaf sandstone of Belhedan oil field (well V26).
A second stage of the FlexInLog software development will start in 2002, which will involve the application of some novel logging techniques, such as Sonic Array Tool, MicroImages of the wall of borehole, etc.