一种页岩气井连通性评价的新型示踪剂应用研究

Evaluating the connectivity of shale gas wells by new rare element tracers

申宝剑 潘安阳 张俊 卢龙飞 钱门辉 陆双龙 杜明亮

SHEN Baojian PAN Anyang ZHANG Jun LU Longfei QIAN Menhui LU Shuanglong DU Mingliang

中国石化 油气成藏重点实验室, 江苏 无锡 214126 中国石化 页岩油气富集机理与有效开发国家重点实验室, 江苏 无锡 214126 中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 中国石化 科技部, 北京 100728 江南大学 化学与材料工程学院, 江苏 无锡 214122

SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China State Key Laboratory of Shale Oil and Gas Enrichment and Effective Development, Wuxi, Jiangsu 214126, China Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China Science and Technology Department of SINOPEC, Beijing 100728, China School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China

选取了3种在地层和压裂液中含量低、环保、稳定的稀土元素Pr、Yb、Sm与乙二胺四乙酸和吡啶二羧酸形成络合物，然后将其作为示踪剂应用于页岩气井连通性评价。在中国石化涪陵页岩气田焦页66号扩平台井组的中部气层两口井（焦页66-Z1HF和焦页66-Z2HF）中注入微量元素示踪剂，通过监测注入示踪剂井及其邻井返排液中是否有微量元素示踪剂来评估焦页66号扩平台压后连通性，进而探讨涪陵页岩气田下部、中部、上部气层立体开发的可行性。返排液监测结果显示，焦页66-Z1HF井偶见高含量Sm元素示踪剂（焦页66-Z2HF井注入剂），表明两口中部气层井间可能存在连通；下部气层监测井未见Pr，Yb，Sm浓度异常，说明其与中部气层未发生连通；上部气层监测井焦页5-S2井和焦页5-S3井返排液混样中监测到了高浓度Sm元素示踪剂，表明其与中部气层存在连通。研究初步验证了微量元素示踪技术是一项简单、有效的页岩气井连通性评价的示踪技术，可以方便、高效地判断页岩气井的井间连通情况，具有广阔的应用前景。

Three types of rare earth elements, Pr, Yb and Sm, in shale gas well and fracturing fluid, which showed a low content and are environmentally friendly and chemically stable, formed complexes with ethylenediamine tetra-acetic acid and di-picolinic acid, both of which were applied as tracers in the determination of the connectivity of shale gas wells. A case study was made in two shale gas wells (Jiaoye 66-Z1HF and Jiaoye 66-Z2HF) of the middle gas reservoir in the Jiaoye No. 66 extended platform well group in the Fuling shale gas field of SINOPEC. We first injected rare element tracer into the wells, and then evaluated the connectivity of the Jiaoye No. 66 extended platform after fracuring by monitoring whether there was rare element tracer in the tracer-injected wells and the flow-back fluid from adjacent wells, and finally discussed the feasibility of three-dimensional development of the lower, middle and upper gas layers of the Fuling shale gas field. The results of flow-back fluid monitoring showed that a high content of Sm tracer, which had been injected into well Jiaoye 66-Z2HF, was occasionally found in well Jiaoye 66-Z1HF, indicating that there might be a connection between the middle gas layers of the two wells. There is no abnormal Pr, Yb or Sm concentrations in the monitoring wells of the lower gas layers, indicating that they were not connected with the central gas layers. A high concentration of Sm tracer was detected in the mixed back-flow fluid samples of wells Jiaoye 5-S2 and Jiaoye 5-S3 in the upper gas layer, indicating that they were connected to the central gas layers. The present investigation has verified that rare element tracer technology is a facile and effective method for the connection determination between shale gas wells and has broad application prospects.

中国石化科技部项目 P20059-8

https://doi.org/10.11781/sysydz202105855