基于微重力监测技术的地下储气库库容动用评价方法

Underground gas storage capacity utilization evaluation method based on microgravity monitoring technology

地下储气库(以下简称储气库)高速、频繁交替注采过程中的库容动用情况及圈闭动态密封性是储气库注采运行安全管理的重中之重。为了直观评价库容动用效果,以及高速往复注采过程中气水界面变化情况及圈闭动态密封性,以目前中国库容量最大、调峰能力最强的新疆H储气库为研究对象,在国内首次利用微重力监测技术在新疆H储气库西部气水混合区进行微重力监测现场试验,并评价储气库注采交互驱替过程中天然气富集区、气驱前缘及气水界面变化情况。研究结果表明:(1)利用微重力监测技术监测储气库注采层内因流体密度变化产生的重力异常,对储气库内流体的动态变化特征具有一定的指示性;(2)通过监测区微重力数据采集、注采层剩余重力异常提取与分析,可有效评价储气库注采层内流体富集特征;(3)采用层密度反演边缘检测技术,可辅助圈定储气库气水界面,评价注采交互驱替过程中气驱前缘的动态变化;(4)实际生产动态资料验证,该技术的评价结果与生产动态相吻合,说明微重力监测结果对储气库库容动用情况可进行有效判断。结论认为,微重力监测技术可直观评价储气库库容动用效果和气水边界变化情况,进而评价储气库高速往复注采过程中的圈闭动态密封性,对优化调整储气库注采运行政策、实现库容有效动用、提升储气调峰运行效率、保障注采运行安全具有重要的指导作用。

Storage capacity utilization and dynamic trap sealing capacity in the frequently alternative high-speed injection and production process of underground gas storage(hereinafter referred to as UGS)are of uppermost priority in the safety management of UGS injection,production and operation.In order to directly evaluate the utilization effect of storage capacity and the gas-water contact change and dynamic trap sealing capacity in the process of alternative high-speed injection and production,this paper takes Xinjiang H UGS which has the largest storage capacity and the strongest peak shaving capacity in China as the research object to to carry out the field test of microgravity monitoring by applying the microgravity monitoring technology for the first time in China in the gas-water mixed area of western Xinjiang H UGS.In addition,the changes of natural gas enrichment area,gas drive front and gas-water contact in the process of alternative injection and production are evaluated.And the following research results are obtained.First,the microgravity monitoring technology can be used to monitor the gravity anomaly caused by the density change of fluid in UGS injection and production reservoirs,which has a certain indication for the dynamic change characteristics of fluid in UGS.Second,the fluid enrichment characteristics in UGS injection and production reservoirs can be effectively evaluated by collecting the microgravity data of monitoring areas and extracting and analyzing the residual gravity anomaly of injection and production reservoirs.Third,the edge detection technology of layer density inversion can help to delineate the gas-water contact of UGS and evaluate the dynamic change of gas drive front in the process of alternative injection and production.Fourth,the actual production performance data verifies that the evaluation results obtained by this technology are consistent with the production performance,indicating that the microgravity monitoring results can provide an effective judgment on the utilization situation of storage capacity.In conclusion,the microgravity monitoring technology can directly evaluate the utilization effect of storage capacity and the change of gas-water contact,and then evaluate the dynamic trap sealing capacity in the process of alternative high-speed injection and production,which plays an important guiding role in optimizing and adjusting the operation policy of UGS injection and production,realizing the effective utilization of storage capacity,improving the operation efficiency of gas storage peak shaving,and ensuring the safety of injection,production and operation.