Evaluation of developing an enhanced geothermal heating system in northeast China: Field hydraulic stimulation and heat production forecast

In this work, the feasibility of using enhanced geothermal system correlation techniques (hydraulic fracturing and heat extraction) to develop medium-low temperature geothermal resources for heating purposes in northeast China is investigated. A detailed experiment on field hydraulic fracturing stimulation is conducted. Combining with numerical simulation approaches, heat production potential of this system is forecasted. Field hydraulic stimulation results indicate that the matrix acidizing treatment significantly limits near wellbore friction loss. For network fracturing treatment, however, the formation of branching fractures and its enhancing effects on reservoir flow conductivity needs to be verified by production tests in the future. The geometric dimension and flow conductivity of the induced fracture are determined by numerical simulation of hydraulic fracturing process. The accuracy of the numerical model is verified through matching well head pressure curve. Parameters including production flow rate, flow impedance, production temperature, heat extraction rate and energy efficiency are determined through the simulation results of heat production forecast. The results indicate that thermal energy production from the stimulated reservoir is satisfactory for heating purpose. However, water flow impedance maintains at a relative high level during production period. (C) 2014 Elsevier B.V. All rights reserved.