陕北西部地区裂缝性地层堵漏技术研究与实践

陕北西部地区钻井过程中漏失频发，吴起铁边城区域井漏问题尤为突出，漏失严重时导致填井或弃井，增加该区域钻井成本。通过对铁边城区域岩心特性分析和力学测试，该区域地层井漏原因主要由微裂缝扩展、延伸和对天然裂缝通道的勾通形成贯穿漏失通道引起。针对裂缝漏失特征，通过实验模拟，建立以刚性颗粒架桥、柔性变形材料充填以及纤维材料缠绕联结的裂缝堵漏配方，并分析其堵漏作用机理，室内承压可达7 MPa以上。现场应用该研究成果后，3次堵漏作业均能达到一次堵漏成功，地层承压能力当量密度提高0.22 g/cm3，达到很好的应用效果，为区域井漏预防和处理提供技术支撑。

Development and Mechanism Research on Novel Bloomless Shale Inhibitor HSH

Mud losses are frequently encountered in the west Shaanbei area, especially in Tiebian town of Wuqi County. Severe mud losses sometimes resulted in hole abandonment or sidetrack, hence high drilling cost in this area. By analyzing the characteristics of the cores taken from Tiebian town and performing mechanical testing on the cores, it was found that what caused the mud losses were mainly the inter-connected flow channels formed by propagation and extension of micro-fractures as well as the communication of natural fractures. Based on this understanding of the mud losses, a lost circulation control slurry was formulated with rigid particles (for bridging), flexible deformable agents (for packing) and fiber materials (for intertwined connection) through simulated experiment. In laboratory experiment the lost circulation control slurry was able to bear pressure of more than 7 MPa. Three times of trials of this slurry in field application were all succeeded in the first try, and the pressure bearing capacity (equivalent density) of the thief zones was increased by 0.22 g/cm3. The successful application of the lost circulation control slurry provided a technical support to the prevention and control of lost circulation in the area of application.