Speaker
Description
By referring to the volume fracturing technology widely used in shale gas and other unconventional oil and gas resources with low-permeability, the segmented multistage fracturing technology of horizontal wells can be introduced to construct the EGS (Enhanced geothermal system) artificial reservoir. Since the EGS reservoir fracturing exhibits in a form of strong non-uniformity, a horizontal dual-well non-uniform multistage fracturing model is constructed. By adjusting the thickness and distribution types of heat transfer unit (HTU), several sets of cases are designed respectively to study the influence of HTU distribution characteristics on heat extraction performance of EGS using multistage fracturing in horizontal wells. In order to characterize the non-uniformity characteristic of HTU distribution, the new concept of preference thickness ratio is introduced. The results show that in non-uniform fracturing EGS reservoirs the production temperatures are not strictly positively correlated with the reservoir fracturing stage, and is also affected by the distribution characteristics of HTU. Moreover, the production temperatures are negatively correlated with the preference thickness ratio. In the EGS reservoir with non-uniform fracturing, the heat extraction performance can be enhanced by plugging the inferior HTU or strengthening the fracturing of the reservoir to make an homogeneous HTU. This study has certain guiding significance for the fracturing of reservoirs and the construction of artificial thermal reservoirs in EGS geothermal field.
