| Along with the development of exploration activity in middle-shallow layers in Songliao basin, the objects of exploration and development become complex and the difficulty is increasing. In order to ensure the continuous production of 40 million tons in Daqing oilfield, and realize the reserve-production balance, tight oil has become realistic exploration breakthrough goal. The object of study is Gao Taizi tight oil reservoirs in Qi Jia area. The reservoirs in Qi Jia area have characteristics of low porosity, low permeability, complex pore structure and high capillary bound water saturation.This thesis is based on rock physics experiment, coring, well testing and mercury penetration, the characteristics of reservoirs, physical property and pore structure are analyzed by histogram plots and pie-shaped plots. We understand that the lithology of Gao Taizi tight oil reservoirs mainly includes siltstone, calcicolous siltstone and shaly siltstone, and the reservoirs are tight which have low porosity and low permeability. We employ the core analysis data and logging data to establish models which can calculate the contents of shale, calcium, clay, quartz, illite and chlorite by multiple regression. We also introduce the concept of megaporosity and then multiple regression is used to establish reservoir parameter interpretation models to calculate porosity and permeability. Indonesia saturation equation is improved to apply in reservoirs, considering the effects of the shale and calcium on rock conductivity. Since pore structure is complex and micropore is developed, the tight oil reservoir classification standard is established in this paper which makes use of the methods of combination of macro-scale and the micro-scale parameters with production strength. The interpretation results are compared with in sealed coring well and well test results. The results show that log interpretation model is reasonable, and log evaluation accuracy for Gao Taizi tight oil reservoirs can be improved. |
PDF Full Text Request