基于压力监测的水平井临界出砂预警模型——以新疆H储气库为例

新疆H储气库作为中国最大的气藏型砂岩储气库,调整方案采用水平井整装部署,单井具有强注强采和大排量吞吐的特点,若生产压差过大,会破坏岩石骨架,携带出的砂粒冲蚀生产管柱甚至堵塞井筒导致气井停产,影响储气库的整体调峰能力。开展基于压力监测的水平井临界出砂预警模型研究,利用适用于H储气库的物质平衡方程、状态方程和流动方程,建立水平井动态生产压差监测模型;同时开展水平井临界出砂压差现场测试,确定岩石坚固程度判断指标“C”公式模型以预测临界出砂压差,二者结合形成水平井动态出砂压差预警模型,模型压力与实测压力吻合率超93%。不仅可以实现对水平井动态生产压差的实时监测,还为水平井最大调峰能力评价和后续调峰配产奠定了基础。

Early Warning Model for Critical Sand Production in Horizontal Wells Based on Pressure Monitoring: A Case of H Gas Storage in Xinjiang

For H gas storage in Xinjiang, the largest gas-reservoir-type sandstone underground gas storage in China, the adjustment plan adopts full arrangement with horizontal wells. The single well is characterized by intensive injection and production as well as large-displacement huff and puff. If the production pressure difference is too large, the rock skeleton may be damaged, and the sand carried out may erode the production string or even block the wellbore, causing production suspension of gas wells and affecting the overall peak-shaving capability of the gas storage. This paper discusses the early warning on critical sand production in horizontal wells based on pressure monitoring. Based on the material balance equation, state equation and flow equation applicable to the H gas storage, a dynamic production pressure difference monitoring model of horizontal wells was established. Meanwhile, the field test on critical sand production pressure difference of horizontal wells was carried out, and the criterion “C” formula model determining rock solidity was defined to predict the critical sand production pressure difference. Finally, an early warning model for critical sand production in horizontal wells based on pressure monitoring was established. The coincidence between the model-derived pressure and the measured pressure exceeds 93%. The model can realize the real-time monitoring of the dynamic production pressure difference in horizontal wells and also lay a foundation for the evaluation of maximum peak-shaving capacity and subsequent peak-shaving and production allocation of the gas storage.