In evaluating the process of rock deformation as a result of fluid withdrawal, two approaches prevail: macromechanical and micromechanical methods. In the oil and gas industry, the macromechanical method assesses the formation compaction arising from hydrocarbon production under reservoir field scales. The micromechanical method examines the origin of formation compaction arising from hydrocarbon production under micro-pore scale. The primary purpose of this micromechanical approach is to determine the critical pore strains subjected to the specified rock deformation and fluid drawdown that may lead to excessive reservoir compaction that is detrimental to the stability of subsurface structures (such as generating excessive sand production). This paper proposes the alternative conceptualization and formulation of pore volume reduction under both hydrostatic and uniaxial strain loading conditions. The result can be calibrated by the conventional pore volume compressibility (PVC)/compaction experiments. Furthermore, the proposed method considers the simplified concepts of pore volume reduction and solid volume reduction under the simple loading conditions amenable to laboratory testing techniques. The collective solutions yield the pore volume reduction in the form of reservoir porosity change that becomes a useful assessment to the planned reservoir production rate, and associated reservoir compaction, which is particularly important to the production in soft rock reservoirs where the reservoir compaction is often too significant to be manageable. The application of the developed critical pore strain in relation to bulk compressibility and PVC along with the variation of pore pressure and in-situ stress under the uniaxial strain testing conditions is illustrated in a simple case study.

You can access this article if you purchase or spend a download.