Characteristics and Evaluation of Extremely Shallow Oil Sand in a Heavy Oil Reservoir

Oil in extremely shallow layers gains more attention worldwide as oil price declines. Oil sand is abundant in shallow layers of Chunfeng Oilfield, from 0 m outcrop to 500 m depth. Most cores are so loose that they cannot effectively subject to experiment. To this effect, some special measures are taken to evaluate oil sand, including thermal property analysis, seepage flow analysis, and nuclear magnetic resonance (NMR) experiments. It is found that NMR and thermal properties are new and effective measures to evaluate oil sand in heavy oil reservoirs. Useful properties such as thermal and seepage properties and flushing efficiency are analyzed in this study. These oil sands are found to possess not only superb physical properties, but also excellent thermal conductivity, which is advantageous for common steam drives and steam-assisted gravity drainage. The experiments also prove that even after a lengthy time of steam drive, oil saturation still remains high. Extremely shallow oil sand shows very favorable...