Abstract

Study on igneous rock reservoir

Author(s): Zhaoyuan Shao, Ning Ning, Fang Zhao, Jiewen Sun

The characteristics of igneous rock reservoir are extremely complicated. It is difficult to develop effectively. In response to the reservoir characteristics, set the gas reservoir in southern Songliao Basin as an example. The experiments study on lithology of igneous rock reservoir, its permeability and pore characteristics were carried out to provide basis for the effective development of gas reservoirs. The results have shown the following points: the igneous rock reservoir has low porosity and permeability, The rock properties are mainly andesite, rhyolite and volcanic breccia and the main reservoir space types are apertures. The flow characteristic was related to the reservoir permeability and pore pressure. The reservoir which has the permeability higher than 0.05mD was prone to high speed non-Darcy effect. According to the experiment data, different flow regimes of permeability and pore pressure were divided. The threshold pressure gradient is existed in the watercut and dense igneous rock reservoir but the pore type and fracture type reservoirs have obvious difference. The differences were small when the water saturation was high. When the water saturation was lower than 65%, threshold pressure gradient of fracture type was much lower than the pore type. So for the high water saturation reservoir, fracturing should be used to change the seepage channel in order to lower the reservoir threshold pressure gradient