Energy Efficiency Anlysis For Unconventional Natural Gas Development In China And Evaluation Of Non-pipeline Natural Gas Tansportation Options

As natural gas is more and more widely used in China, domestic conventional natural gas output can not keep pace with its demand. Unconventional gas resources have been held great expectations in improving the domestic natural gas supply chain as they are abundant in China. To achieve this goal, conducting a rational evaluation on their development value and selecting optimized transportation option for gas fields with different scales are very important and urgent.EROI(energy return on investment) analysis method was built to evaluate the development value of unconventional gas in China from the perspective of energy efficiency. The results show that the four typical unconventional gas reservoirs(Fuling shale gas field, Sulige tight gas field, Qinshui coalbed gas field and Shenhu hydrate reservoir), are of high energy efficiency, which is higher than that of conventional oil and gas except Shenhu hydrate reservoir. Compared comprehensive energy efficiency, tight gas should be given priority when developing unconventional gas, followed by coalbed gas, shale gas and hydrate. Besides, to achieve the average energy efficiency of conventional oil and gas development, the wellhead ultimate recovery of these four unconventional gas resources must reach 1.4×107 m3、0.7×107 m3、5.9×107 m3 and 47.3×107 m3, respectively. The existing gas price subsidy policy for unconventional gas is disadvantage for technological progress, supporting policies focused on technology research on unconventional gas development should be built. In addition, in order to improve the energy efficiency of unconventional gas development, complete regulation system for the venting and flaring of methane and EROI energy audit system in the unconventional gas development process should be established as soon as possible.A systematic method for analyzing and selecting the best non-pipeline transportation option from LNG road, railway or water transportation and CNG, ANG or NGH road transportation was established, which considers feed gas rate, transportation diatance, prices of feed gas and commodity gas as uncertain. Besides, a comparative study for the six options was performed. The results show that NGH technology has no competitiveness while under the existing technical level, CNG and ANG technology display almost the same ENPV(expected net present value) within the whole scope of the transport distance and gas reservoir capacity, both of them are suitable for the short distance transportation within 110 km, and CNG scheme is better. LNG water, railway and road transportation options display obvious advantages after the transport distance is beyond 110 km, the economic transportation distance can reach 3570 km, 1750 km and 760 km, respectively. For coastal and riverside city, LNG water transportation option is the best one, LNG railway transportation option will be preferred if water transportation is infeasible, followed by LNG road transportation.