牙哈凝析油气田注气监测技术

牙哈凝析油气田是我国最大的实施循环注气开发的凝析气田，在注气开发过程中缺乏有效的注入气推进前缘动态检测技术。微地震技术通过检测注气过程中孔隙流体压力变化和微裂缝的张开与扩展时产生的微震波，利用摩尔-库仑理论和断裂力学准则描述注气过程中地层渗流场的变化，通过拾震器提取微波信号，然后转化成地层波速场，动态监测气驱前缘、注气波及范围、优势注气方向、注气波及区面积等。YH23-1-8井是塔里木油田第一口实施微地震注气前缘检测技术的注气井，对其监测结果进行解释，表明该井气驱前缘注气宽度为1 km，气驱波及长度为2 km，气驱波及面积为108.8×10⁴ m²，在平面上气驱前缘呈“菱形”分布。根据解释结果可以判断周围采气井的见效程度，为下一步调整注采参数提供了技术依据。

GAS INJECTION MONITORING TECHNOLOGY OF YAHA CONDENSATE GAS FIELD

The Yaha condensate gas field is exploited by implementing cycle gas injection to largest degree in China. However, in the process of gas injection exploitation, the effective dynamic detection technology on the advancing front of input gas is seriously required. Through detecting the pressure changes of pore fluid in the process of gas injection and microseismic waves produced by the opening and extension of the microcrack, taking advantage of Mohr Coulomb theory and criterion of fracture mechanics to describe the changes of formation seepage field, using  seismic geophone to extract microwave signals and then transforming them into formation wave velocity field, micro seismic technique dynamically monitors the gas displacement front, gas injection scope, direction of principal injected gas and gas injection area, etc. The well YH23-1-8 is the first gas injection well implementing micro seismic injection gas front detection technology in the Tarim oilfield. By interpreting the monitoring results of this well, it showed that the width of gas displacement front is 1 km, gas drive sweep length is 2 km, gas drive sweep area is 108.8×104 m2 and the gas displacement front occurs in diamond distribution on plane. Based on the interpretation results, the effective degree of the peripheral gas recovery wells can be predicted. Meanwhile, technical basis for further adjusting the injection production parameter is provided.