煤炭地下气化注入井压力控制

Pressure Control of Underground Coal Gasification Injection Well

煤炭地下气化具有煤炭清洁利用和低碳能源保障的优势,是煤炭清洁转化技术创新战略方向。而压力是影响煤炭气化的重要因素,为使煤炭气化在地下高效安全进行,需要对注入井的压力进行控制研究。为了实现对注入井压力的控制,建立了气化剂注入的流量压力仿真模型,对水力摩阻的部分影响因素进行分析,并调整生产参数,进行了压力控制研究。研究结果表明:(1)水力摩阻随井筒直径的增大而减小;水力摩阻随连续油管外径的增大而增大;水力摩阻随注水排量的增大而增大;(2)在10 MPa注入压力下调整环空中的注水排量由5.50 L/s改变为5.75 L/s时,井底压力由7.26 MPa降至6.11 MPa;(3)在8 MPa注入压力下调整连续油管中的注氧量由594.44 L/s改变为629.37 L/s时,井底压力由8.91 MPa降至8.87 MPa;(4)在8 MPa注入压力下调整生产井粗煤气的产出流量由800 L/s改变为900 L/s时,井底压力由8.94 MPa降至8.63 MPa。研究结果可为注入井的压力控制提供一定的指导。

Underground coal gasification has the advantages of clean utilization of coal and low carbon energy guarantee,and it is the strategic direction of clean coal transformation technology innovation.Pressure is an important factor affecting coal gasification.In order to make coal gasification underground efficiently and safely,it is necessary to control the pressure of injection wells.In order to control the injection well pressure,the flow pressure simulation model of gasifier injection was established,and the influence factors of hydraulic friction were analyzed,and the production parameters were adjusted to study the pressure control.The results show these as follows.The hydraulic friction decreased with the increase of wellbore diameter.The hydraulic friction increases with the increase of coiled tubing diameter.The hydraulic friction increases with the increase of water injection discharge.Under the injection pressure of 10 MPa,the bottom hole pressure decreased from 7.26 MPa to 6.11 MPa when the injection displacement of water in the adjusted annulus was changed from 5.50 L/s to 5.75 L/s.Under 8 MPa injection pressure,the bottom hole pressure decreased from 8.91 MPa to 8.87 MPa when the oxygen injection in coiled tube was adjusted from 594.44 L/s to 629.37 L/s.Under the injection pressure of 8 MPa,the bottom hole pressure is reduced from 8.94 MPa to 8.63 MPa when the output flow of crude gas is adjusted from 800 L/s to 900 L/s.The research results can provide some guidance for pressure control of injection well.