Fluid Injection in Deformable Geological Formations by Benjamin Loret

Author:Benjamin Loret
Language: eng
Format: epub
ISBN: 9783319942179
Publisher: Springer International Publishing

6.8.7 Transport of Fines in the Existing Porosity Versus Backward Erosion

Transport of fines in the existing or evolving porosity in the suffusion process is in a sense the opposite of transport of proppant in the porous network of oil rocks. The porous network is formed by the coarse particles, assumed not to be (strongly) affected by suffusion. On the other hand, the channels in between the coarse particles may be partially filled with fines, clogged by diffusing fines or progressively cleared of eroded fines. Ideally, a pure suffusion process assumes that the fines do not participate to bear the load, in the sense that their erosion should not lead to deformation. In this sense, the dissolution of salt substituting fines in the experiment of Meijer et al. (2012) should not generate deformation. To that end, their initial percentage of salt, namely 23%, should be reduced.

In general, however, fines may participate to the solid skeleton and their removal changes the stiffness, strength and generates deformation. In fact, one may expect that their contribution to the mechanical properties depends significantly on the stress. Similarly, while flowing through the porous network, proppant does not contribute to bear the load but it does when the fluid pressure is decreased and channel walls tend to come in contact, which in fact is their raison d’être.

Erosion of the coarse particles corresponds to another type of process where the existing porous network is altered: both mechanical and transport properties are modified. Still, stronger changes take place during backward erosion or piping which can be seen as a sort of subsurface erosion, where both fines and coarse particles are washed out backward, deeper, and deeper in the structure.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.