青海油田风西区块长水平段水平井钻井液技术

Application of Drilling Fluid Technology in Drilling a Long Horizontal Section Well in Block Fengxi in Qinghai

青海油田为实现稀井高产开发技术方案,在柴达木盆地大风山地区风西构造部署五口长裸眼水平井,并同时应用水基、油基钻井液进行施工对比,总结完善风西长裸眼长水平段水平井钻完井工艺技术模板。以优质复合盐水基钻井液在风西ⅠH1-5井的现场应用实例进行总结,并对相关钻井工艺技术应用、工程参数控制、流变性与携带等进行分析。风西ⅠH1-5井完钻井深为5478 m,水平段长2541 m,创青海油田水平段最长、油层钻遇率最高(100%)、水平井单趟进尺最多(1566 m)、水平段短程起下钻井段最长(达1000 m)、首次采用漂浮下套管技术等多项施工新纪录,该井的成功钻探对于超长水平段水平井的钻完井工艺在青海油田应用具有里程碑意义。与应用油基钻井液施工的邻井就钻井周期进行了对标分析,该优质复合盐水基钻井液施工井均优于油基钻井液施工井,对今后钻探长裸眼、长水平段水平井钻井液体系优选有较好的指导借鉴。

To obtain high production rate with less oil and gas wells,The Qinghai oilfield decided to drill five long open hole horizontal wells in the Fengxi structure which is located in the Dafengshan area in Qaidam Basin.Water-based and oil-based drilling fluids were to be used to drill these wells,and the results be compared to improve and perfect the technical prototype for future drilling and completion of long open hole and long horizontal section horizontal wells in the same area.This paper summarizes the field engineering of a high-quality compound saltwater drilling fluid on the well Fengxi IH1-5 and analyses are briefly conducted on the application,control of the engineering parameters,rheology and sand carrying capacity of the drilling fluid.The well Fengxi IH1-5,which is 5,487 m in depth,has a length of horizontal section of 2,541 m,the longest horizontal section in the Qinghai oilfield.This well has broken several records in this oilfield,such as penetrating the highest percentage of pay zones(100%),the longest footage(1,566 m)drilled in a single bit run,the longest horizontal section(1,000 m)in which short trips were performed,as well as the first application of casing floatation technology in casing running etc.The success of the drilling operation has milestone significance in applying the ultralong horizontal section well drilling technology in the Qinghai oilfield.Compared with the drilling operation of the offset wells drilled with oil-based drilling fluids,the use of this high-quality compound saltwater drilling fluid has gained better results in drilling than the oil-based drilling fluids previously used in other wells.The success gained in applying the water-based drilling fluid has provided a good guidance for optimizing the properties of water-based drilling fluids for horizontal wells with long open hole and long horizontal sections.