Characteristics and recognition of existing states of oil and water in unconsolidated sandstone heavy oil layer:A case study of the heavy oil reservoir of Guantao formation in Zhanhua sag of Jiyang depression
GENG Bin
CAI Jingong
WANG Duanping
YAN Jianping
ZHOU Dezhi
CHENG Ziyan
BING Shaoxian
Abstract：To study the pore structure distribution and oil and water occurrence state in the heavy oil reservoir of Shengli Oilfield,core samples were selected as research objects from unconsolidated sandstone of the lower Guantao formation heavy oil reservoir in Zhanhua sag,Jiyang depression.The core micron scale CT scans was conducted,and the scanning images were calibrated to determine the distinction of grayscale threshold between different fluids by using the core residual oil saturation after dispersed oil and water correction.The characteristics of oil and water existing states in heavy oil reservoir was found to be different from traditional understandings.The results show that the water grayscale ranges from 4 000 to 4 800,while the oil grayscale ranges from 0 to 4 000.There are two other types of pores in core samples in addition to the oiliness pore with good connectivity.The oil and water are existing in the form of "separating water droplets" and "isolated oil droplets".The pore distribution and occurrence state of oil and water can explain the presence of water at the beginning of the production process.The oil saturation of heavy oil layer by logging interpretation is usually 5％ larger than the actual sealed core value.However,when the initial water content of a well,located in the lower parts of the heavy oil reservoir,is more than 40％,the exploited strata is not definitely close to the oil-water interface,which provides evidence for saturation correction using well logging interpretation and well arrangements in oil layers for further effective exploitation.
Keywords：unconsolidated sandstoneheavy oil reservoirsexisting states of oil and watersaturationCT scan
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 1126-1133 )