昭通地区页岩气水平井钻井难点与对策分析

Horizontal-well drilling challenges and solutions for shale gas, Zhaotong area

在昭通页岩气示范区勘探开发过程中,虽然机械钻速逐年上升,钻井周期逐年缩短,但仍存在机械钻速上升不明显、卡钻、井漏复杂频发等难点。因此提高机械钻速、降低复杂时效仍是目前钻井的首要任务。针对问题提出实施措施:①强化钻井参数、优选钻头型号、开展难钻地层提速攻关试验措施,提升机械钻速;②分析卡钻原因,提出优化钻井液性能、优化施工参数、优化钻具组合的防治卡钻方法;③统计分析井漏原因和防治措施,针对不同漏失类型,提出堵漏措施。钻井机械钻速有所上升、钻井复杂得到了很好的治理。昭通页岩气水平井钻井难点分析与对策实施对今后水平井的提速提效有非常好的借鉴作用。

In the exploration and development process of Zhaotong Shale Gas Demonstration Area, the rate of penetration (ROP) increases year by year whereas the drilling cycle comes down every year;however, there are still some challenges, such as subtler ROP increase, pipe sticking, and frequent complexity and circulation loss. Therefore, improving ROP and reducing time efficiency are still critical. And some solutions were proposed, including,(1) to optimize drilling parameters and drill bit types, to carry out some study on ROP improvement measures, and to test in hard-to-drill formations to finally improve ROP;(2) to analyze the causes of pipe sticking, and put forward pipe-sticking prevention methods of optimizing drilling-fluid performance, construction parameters, and bottomhole assembly;(3) to carry on some analysis on circulation-loss causes and preventive measures, and propose corresponding plugging measures. After applying these solutions to this demonstration area, ROP was improved greatly and drilling complexity was well treated. In conclusion, all these analysis and solutions are of great significance to further ROP and efficiency improvement for horizontal-wells drilling in Zhaotong Shale Gas Demonstration Area.