Abstract:

 In order to characterize the pore structure of reservoir rock really, accurately and intuitively, different rock cores are scanned by CT imaging technology and the 3D digital cores are reconstructed. Then the model of pore network is extracted by maximal ball algorithm form the 3D digital core. And finally the reservoir properties and pore structure parameters are characterized quantitatively. This method of pore structure characterization has a good result after it is applied in Sangonghe Formation of 116 well field in Mobei oilfield. Our research indicates that the pore type here is mainly intergranular pore, emposieu pore and a little intercrystal pore. The average pore radius is 33.11 μm and the throat radius is 1.47 μm. The small throat is the main reason of low permeability in this area. Compared with the result of NMR Coates model, digital core can give a more accurate permeability result. The pore structure of digital core has a good concordance with mercury penetration result. However, the digital core method can identify the pore and throat respectively and it is more vivid, more direct, more accurate with little sample broken. So it is more applicative for pore structure characterization.

Key words: CT scanning, digital core, pore network, maximal ball algorithm, pore structure