Application of a stochastic network pore model to oil-bearing rock with observations relevant to oil recovery

✍ Scribed by R. Mann; G.P. Androutsopoulos; H. Golshan

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 878 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(81)85013-0

✦ Synopsis

Mercury porosimeter experiments have been traditionally used to investigate the pore structure of oil bearing rocks, although interpretation based upon the oversimplified parallel-bundle model is inadequate to explain many practical aspects of oil recovery. A technique for stochastically assigning the sizes of tubular pore segments placed in a network configuration of interconnected pores has been used to model pore structure and a trial and error procedure has been devised which gives directly the size distribution of segments comprising the network which will exactly reproduce any observed mercury porosimeter penetration curve. The theory is applied to porosimeter tests on a core sample from the Agha Jari Field (Iran).' It is evident that the pore size distribution function according to a network interpretation comprises a very much greater proportion of larger pores than is inferred from the parallel bundle model. This distortion of the pore size distribution is shown to arise from the inaccessibility of larger segments when surrounded by small pores, a phenomenon that cannot be represented by the parallel-bundle approach. As a quantified inrerconnecting pore model, the network analysis has potential for investigating oil retention mechanisms in a reservoir, and the probable micro-scale water displacement behaviour of the pore network deduced to represent the core sample is described. Low recovery factors seem to be related to water flowing oreferentiallv throuah oathwavs made of larger pores. Entrapment is then likely in large pores _ . _. _ isolated by surrounding smaller ones.