页岩微纳米孔缝封堵技术研究

发布时间：2019-01-16 03:55

【摘要】：在页岩气水平井钻井过程中,井壁失稳一直是困扰石油钻井的难题。一般页岩的水敏性影响并不突出,如何通过钻井液技术封堵页岩微细、微纳米孔缝,防止钻井液或者滤液进入地层,降低因水化或毛细管力对页岩地层造成的影响,防止页岩井壁坍塌从根本上解决页岩钻井中的井壁稳定问题。因此,有效的封堵便成了目前页岩水基钻井液研究的难点,也是本文研究的主要内容。在对国内外封堵技术及页岩地层井壁稳定钻井液技术调研的基础上,本论文开展了页岩封堵效果评价方法及封堵剂的优选研究。以理想填充与紧密堆积为理论基础,通过研究黏土含量、重晶石含量、粒径搭配、分散剂、结构型聚合物、温度及滚动条件等因素对泥饼渗透率的影响,制备出渗透率为4.78×104mD的评价泥饼；建立起了模拟页岩(超低渗透率10-3～10-4mD)纳微米孔缝封堵评价方法,标准评价筛选封堵剂,并分析了封堵作用机理。钻井液体系加入优选出的纳微米级封堵剂(YFD-1)后,降低泥饼渗透率的程度(封堵效果)与其对页岩坍塌压力的增量呈一一对应关系,泥饼渗透率降低越多,封堵效果越好,坍塌压力增量越小。进一步验证了用渗透率10-4mD的标准泥饼作为“岩芯”模拟纳-微米级孔、缝的超低孔超低渗页岩地层封堵评价方法是可行的。以延长页岩地质特征情况为依据,建立起延长陆相页岩气两性离子聚合物水基钻井液体系,体系添加纳微米级封堵剂后具有抑制性强、封堵能力强、润滑性好、流变性与失水造壁性好、抗土侵及抗盐抗钙能力强等优点。
[Abstract]:In the process of shale gas horizontal well drilling, sidewall instability has always been a difficult problem for oil drilling. In general, the water sensitivity of shale is not prominent. How to block shale micro-and nano-pore fractures through drilling fluid technology, prevent drilling fluid or filtrate from entering the formation, and reduce the influence of hydration or capillary force on shale formation, Preventing shale wall collapse fundamentally solves the problem of wellbore stability in shale drilling. Therefore, effective plugging becomes the difficulty of shale water-based drilling fluid research, and is also the main content of this paper. Based on the investigation of plugging technology at home and abroad and the drilling fluid technology of shale formation wellbore stability, the evaluation method of shale plugging effect and the optimal selection of plugging agent were carried out in this paper. Based on the theory of ideal packing and compact packing, the effects of clay content, barite content, particle size matching, dispersant, structural polymer, temperature and rolling conditions on the permeability of mud cake were studied. The mud cake with a permeability of 4.78 脳 104mD was prepared. A method for evaluating the plugging of simulated shale (ultra-low permeability 10-3~10-4mD) with nanometer-micron fractures was established. The plugging agent was screened by standard evaluation, and the mechanism of plugging action was analyzed. With the addition of excellent nano micron plugging agent (YFD-1) into drilling fluid system, the degree of mud cake permeability reduction (plugging effect) has a one-to-one relationship with the increment of shale collapse pressure, and the more mud cake permeability decreases, the more mud cake permeability decreases. The better the sealing effect, the smaller the increment of collapse pressure. It is further proved that it is feasible to use the standard mud cake of permeability 10-4mD as the core to simulate the nanometer-sized pore and the ultra-low porosity and ultra-low permeability shale formation plugging evaluation method. Based on the geological characteristics of Yanchang shale, an amphoteric polymer water-based drilling fluid system of Yanchang shale gas was established. The system has strong inhibition, strong plugging ability and good lubricity after adding nano-micron plugging agent. Good rheology and water loss wall-building, strong resistance to soil erosion and salt resistance to calcium, and so on.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE254

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