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KAPPA Consortium on Unconventional Resources – Draft – 7
th
Feb 2011
p1/10
KAPPA Consortium
On Unconventional Resources
Draft project document – 7
th
February 2011
A - Introduction
Unconventional resources that include
shale gas, CBM, shale oil and hydrates,
are a hot topic today, with an explosion
of publications and initiatives across our
industry. Easy oil and gas reserves are
now, in the main, owned by National Oil
Companies (NOC’s). Unconventional
resources and deepwater are therefore
the two main options that remain open
to international operators. Even NOC’s
are taking an active interest in
unconventional resources for domestic
consumption.
At KAPPA we focus on the use of dynamic data. For shale gas, dynamic data is a critical piece
of the puzzle, as this impacts reserve booking and production forecasting. In the last three
years KAPPA has developed dedicated analysis tools and models based on the hypotheses
accepted by the industry.
The results are presented in a WEB publication: ‘
The Analysis of Dynamic Data in Shale Gas
Reservoirs (Parts 1 and 2)’
.
At the cornerstone of the KAPPA work is a numerical model, which includes most of the
common hypotheses. Specialized plots and analytical models complement this model.
The solutions presented by some of the other protagonists in the industry have been
somewhat different. Some technical groups are indeed offering numerical alternatives, but in
most cases the focus is placed on specialized plots and the desorption mechanism. The main
tool is a square root plot to assess the linear flow orthogonal to the fractures. A material
balance plot is also used when apparent Pseudo-Steady State (PSS) is reached in the
Stimulated Reservoir Volume (SRV).
These tools are useful to arrive at a first approximation of the parameters. What is more
questionable is to use these results, straight lines and simple analytical models, to run long
term production forecasts. It is not valid to simply extrapolate transients, and approximating a
fractured horizontal well by a single longitudinal super-fracture is plain wrong. Such methods
do not take into account the complex geometry of the flow and the nonlinearity of the
diffusion. The latter, to us, is the main issue in this kind of production environment.
In this document and annex we describe the current approach by KAPPA. We list, without
going into detail at this stage, what needs to be done in order to reach a minimum objective:
to be able to simulate events before they occur, and not look back with regret at deviations
and try to justify them after the fact.
We then present the rationale for a consortium on shale gas which will then be extended to
other unconventional resources such as CBM, Shale Oil and Hydrates.