水平井段内不同丰度天然气水合物固相颗粒的运移规律

发布时间：2018-06-10 20:41

本文选题：不同丰度 + 天然气水合物层　；参考：《天然气工业》2017年12期

【摘要】：在采用水平井对不同丰度天然气水合物(以下简称水合物)层进行钻进的过程中,含水合物的固相岩屑容易导致水平段固相颗粒沉积或黏附聚并,从而造成携岩不畅。为此,依据水平井多相流条件下的岩屑受力与运移规律及颗粒运移理论,建立了考虑水合物凝聚力条件下水平段岩屑滚动(正常钻进)和跃移(停泵沉砂)时钻井液临界返速模型并进行了数值模拟,分析了正常钻进和停泵条件下钻屑起动的影响因素和运移规律。结果表明:(1)起动临界流速随水合物丰度的增大而降低,该值在考虑水合物凝聚力条件下比不考虑该条件下要高,且水合物丰度越高水合物凝聚力的影响越明显;(2)水合物丰度小于85%时,起动临界流速随钻屑颗粒粒径的增大而增大,水合物丰度超过85%后,起动临界流速随钻屑颗粒粒径的增大而减小;(3)起动临界流速随钻井液密度、黏度的增大而减小;(4)相同条件下跃移所需临界返速约为滚动条件的1.28倍。结论认为,正常钻进条件下应考虑滚动模型,而停泵沉砂后再循环应考虑跃移模型的工艺思路,该成果对于优化水合物钻井施工参数以及降低钻井安全风险均具有重要意义。
[Abstract]:In the process of horizontal well drilling of gas hydrate with different abundance (hereinafter referred to as hydrate), solid rock cuttings containing hydrate can easily lead to solid phase grain deposition or adhesion and aggregation in horizontal section, resulting in rock carrying difficulty. Therefore, according to the cuttings force and migration law and particle migration theory under the condition of multiphase flow in horizontal wells, The critical return velocity model of drilling fluid for horizontal cuttings rolling (normal drilling) and jumping (stopping pump sinking) under the condition of hydrate cohesion is established and numerically simulated. The influencing factors and migration rules of drilling chip starting under normal drilling and pump shutdown are analyzed. The results show that the starting critical velocity decreases with the increase of hydrate abundance, which is higher under the condition of hydrate cohesion than that without considering hydrate cohesion. The higher the hydrate abundance is, the more obvious the effect of hydrate cohesion is on hydrate cohesion. When the hydrate abundance is less than 85%, the starting critical velocity increases with the increase of the particle size, and when the hydrate abundance exceeds 85%, the starting critical velocity increases. The critical starting velocity decreases with the increase of the particle size of drilling debris.) the critical starting velocity decreases with the density of drilling fluid and the viscosity of drilling fluid.) the critical return velocity required for jumping under the same conditions is about 1.28 times of that of the rolling condition. The conclusion is that the rolling model should be considered under normal drilling conditions, and the technological thinking of jump model should be considered in the recirculation after stopping pump sinking. This result is of great significance for optimizing the drilling parameters of hydrate drilling and reducing the drilling safety risk.
【作者单位】： "油气藏地质及开发工程"国家重点实验室·西南石油大学;中国海洋石油总公司;中海油研究总院;
【基金】：国家重点研发计划项目“海洋水合物固态流化测试新技术”(编号:2016YFC0304008) 国家自然科学基金重点项目“控压钻井测控理论及关键问题研究”(编号:51334003)
【分类号】：TE21

【相似文献】