辽中地区钻井井漏主控因素及对策

Main control factors and countermeasures of lost circulation in drilling

辽中地区地质特征复杂,属释压-增压组合型走滑派生构造。区域内断层发育,导致钻井过程极易发生漏失,严重制约煤田的高效勘探开发。为明确地区内井漏的主要控制因素,通过用地震及测井数据的方式将漏失井和未漏失井地质及工程因素的差别进行分析,认为辽中地区井漏的地质因素主要是走滑断层及其调节断层与高渗透砂岩的共同作用;工程因素主要是井轨迹平面与断层的夹角大小。因此提出待钻井漏风险分析方法及防漏对策并推广应用,成功规避高风险井漏的发生。

The central Liaoning has complex geological features and belongs to a combined strike-slip derivative structure of pressure release-pressurization.Faults are developed in the area,which leads to easy lost circulation during drilling,seriously restricting the efficient exploration and development of coal fields.In order to clarify the main control factors of lost circulation in the area,by analyzing the difference between the geological and engineering factors of lost wells and non-lost wells and using seismic and logging data,we believe that the geological factors of lost circulation in central Liaoning are mainly strike-slip faults,the adjustment fault and the high permeability sandstone act together;and the engineering factor is mainly the angle between the plane of the well trajectory and the fault.The risk analysis method of lost circulation for to-be-drilled well and the anti-leakage countermeasures are proposed and applied,which successfully avoids the occurrence of high-risk lost circulation.