Rock physics and pore pressure experts | fracture permiability | Ikon Science

Field planning

The placement of production wells, and the timing of their drilling, dictates the amount of hydrocarbons that will be produced in the ensuing years, and how much of the total reserves will be recovered. Complex reservoirs involving numerous bodies, associated with a complicated connectivity pattern, make this task all the more challenging.

Getting the picture right

The field development process relies on the available information from the discovery and appraisal wells, and the seismic data covering the area. The 3D model of the reservoir needs to be fully quantified with rock properties (porosity, permeability, lithology), fluid properties (pressure, saturation) and mechanical properties (stress). In the case of a compartmentalized reservoir connectivity becomes a major concern, as it dictates how much of the reservoir has been proven by appraisal drilling.

In areas subject to tectonic or other regional stress regimes, a full evaluation of the geomechanical elements affecting the reservoir, based on a geological interpretation of the existing wells, and where possible using image log analysis to refine the model, helps mitigate possible reservoir failures during development and production.

Regional map of overpressure in the Andrew Sandstone, Central North Sea. Hydrodynamic flow directions are at right angles to the contours in this laterally draining reservoir (from O’Connor and Swarbrick, 2008).

The Ji-Fi revolution in reservoir optimisation

Ji-Fi differs from other inversion methods in that it does not use existing wells as control points. Well data is involved in building the individual facies depth trends.  Thereafter the process is driven by seismic, depth trends and prior proportions. 

This has two crucial benefits:

  • Each existing well becomes a blind test to verify that the inversion is predicting the correct facies
  • The prediction of reservoir facies is unbiased by well locations or interpreter pre-conceptions. Therefore Ji-Fi predicts connectivity in a reliable manner

This information can guide the sequence of the development drilling program so as to minimise the number of wells and guide infill drilling.  

The iterative facies classification aspect of Ji-Fi produces more realistic and continuous geobodies than possible with traditional inversion classification approaches. Constraints may be imposed to optimise bedding and lateral continuity characteristics. With minimal refinement and QC, facies output is ready for immediate use in a reservoir model.