帅页3-7HF页岩油小井眼水平井水基钻井液技术

Drilling Fluid Technology for Drilling the Slim Hole Horizontal Shale Oil Well Shuaye-3-7HF

帅页3-7HF井是部署于苏北溱潼区块的一口页岩油Φ118 mm小井眼侧钻水平井。在施工过程中面临着页岩地层井壁失稳、小井眼环空压耗大,易于漏失、水平井降摩减阻要求高、CO_(2)污染等诸多难题。通过研究,构建了页岩水基钻井液体系SM-ShaleMud-Ⅱ。室内评价表明,该体系具有优异的抑制能力、封堵性能和润滑性能,能够满足苏北页岩油长水平井对钻井液性能的要求。现场试验表明,页岩水基钻井液体系高温高压滤失量小于7 mL,体系黏附系数小于0.07,完钻起钻摩阻小于16 t,有效保持了阜二段页岩储层井壁稳定达110 h,改变水基钻井液对阜二段浸泡时间的认知。该井创页岩地层Φ118 mm小井眼裸眼段1948.66 m最长,水平段1361.66 m最长等多项记录,其施工经验可为后续超小井眼长水平井施工提供参考,也为页岩水基钻井液SM-ShaleMud-Ⅱ在苏北页岩油大规模应用奠定了基础。

The well Shuaiye-3-7HF is aΦ118 mm slim hole sidetracked horizontal shale oil well drilled in the Qintong block in northern Jiangsu area.Several problems were encountered during drilling,such as instability of shale formations,high pressure losses in the annular spaces,mud losses,higher requirement on friction reduction in drilling the horizontal section,as well as CO_(2) contamination etc.A water-based drilling fluid SM-ShaleMud-II for shale drilling was formulated in laboratory.Evaluation of this mud has shown that it has excellent inhibitive capacity,plugging capacity and lubricity,and is suitable for drilling the long horizontal section shale oil wells in the northern Jiangsu area.Field application has shown that the HTHP filter loss of the SM-ShaleMud-II drilling fluid was less than 7 mL,the adhesive coefficient of the mud was less than 0.07,and the overpull encountered during tripping out of hole after drilling to the total depth was less than 16 tons.The stability of the Fu-2 member,a shale reservoir section,was effectively maintained for 110 hours,greatly changed the past understanding of the length of time the Fu-2 member can be exposed to water-based drilling fluids.The length of theΦ118 mm slim hole was drilled to a length of 1,948.66 m,the longest open hole penetrating the shale formations in the area,and the length of the horizontal section is 1,361.66 m,the longest horizontal section in the same area.The experiences obtained in using this water-based drilling fluid have provided a good reference for subsequent slim hole long horizontal well drilling,and have paved the way for large-scale application of the SM-ShaleMud-II drilling fluid in shale oil drilling in the northern Jiangsu area.