A Study on the Acquisition Technology for Weak Seismic Signals From Deep Geothermal Reservoirs

There are rich geothermal resources widely distributed in China. After years of continuous exploration and production, most of the shallow geothermal resources have been explored. At present, the exploration mainly focuses on deep geothermal resources. Among many geophysical exploration methods, seismic survey is the most effective means of geothermal resource exploration and production. The weak seismic reflection signal, low S/N ratio and poor imaging of thermal reservoirs due to their seismic geological conditions restrict the production and utilization of deep geothermal resources. In this paper, we considers based on the analysis of the geophysical characteristics of the thermal reservoir that the shielding effect of the strong wave impedance interface between the thermal reservoir and the caprock, the small reflection coefficient inside the thermal reservoir and the serious absorption and attenuation of seismic waves by high-temperature fluids such as hydrothermal fluids and steam in the thermal reservoirs are the main causes of the weak seismic waves in deep thermal reservoirs and proposes a series of seismic data acquisition technologies based on the high-precision vibroseis low-frequency shooting, high-sensitivity geophones long-spread receiving and small-bin size high-fold technologies. They are applied in the seismic acquisition of hot dry rocks (HDR) in Gonghe Basin, Qinghai and have a very good application effect.