Abstract:

The terrestrial gas reservoirs in the northeastern Sichuan region have reserves of over 100 billion cubic meters in the Xujiahe River. In the early stages, small?scale sand fracturing or acid fracturing were mainly used for production, but no significant breakthrough in productivity was achieved. Due to the tight and high fracture pressure of the Xujiahe reservoir, the construction displacement is limited, making it difficult to add sand and resulting in poor transformation effects. By conducting research on the guarantee technology for the operation of potential tapping wells, the Xujiahe potential tapping well wellbore treatment and fine pressure control technology have been developed, which has solved the problems of wellbore control and pressure control during construction operations caused by the coexistence of original test layers and large differences in ground pressure coefficients. The idea of tapping the potential of multiple layers in a single pipeline column has been proposed, forming a combination of large?diameter oil pipes and segmented fracturing pipelines with packers. The interactive operation of 140.0 MPa and 105.0 MPa wellheads meets the requirements of ultra?high pressure large?scale sand addition operations and later production. The application has been carried out in YB6, YL15, and YL171 wells, successfully achieving potential tapping operations in three old wells. A layer by layer fracturing of the four reservoirs was completed in the YL171 well using a single string, resulting in a production of 32 5000 cubic meters per day at a hydraulic pressure of 71.0 MPa.

Key words: Northeast Sichuan, Xujiahe River, Tapping potential wells, Ultra?high voltage, Fracturing string

摘要：

川东北地区须家河陆相气藏储量超1 000亿m³，前期主要采用小规模加砂压裂或酸压改造投产，未获得大的产能突破。由于须家河储层致密、高破裂压力导致施工排量受限，加砂难度大，改造效果差。通过开展挖潜井井筒作业保障技术研究，开发了须家河挖潜井井筒治理及精细控压技术，解决了原测试层共存、地压系数差异大导致井筒作业时井控难的问题以及施工作业承压问题。提出了一趟管柱多层挖潜思路，形成了大通径油管组合配套封隔器分段压裂管柱，140.0 MPa与105.0 MPa井口交互式作业可满足超高压大规模加砂作业以及后期生产要求；在YB6、YL15、YL171井应用，成功实现了三口老井的挖潜作业；在YL171井一趟管柱完成须四储层的分层压裂，在71.0 MPa的油压下日产量达到32.5万m³。

关键词: 川东北, 须家河, 挖潜井, 超高压, 压裂管柱