长庆致密气超长水平段水基钻井液技术

2020年长庆气田在致密气井区先后完成了3口超长水平段水平井，水平段长度分别为3321、4118和4466 m，均使用水基钻井液完成施工，不断刷新亚洲陆上最长水平段记录。超长水平段给降摩减阻、钻屑清洁、泥岩防塌等工作带来极大难度，针对这些难点并结合地层岩石结构特点进行了针对性的技术攻关，形成了超长水平段井眼净化、井眼稳定等技术和CQSP-RH水基钻井液体系，现场应用效果良好，水平段井壁保持稳定，完钻钻具下放摩阻控制在500 kN左右、套管摩阻控制在350 kN以内，顺利完井。随着长庆油气田开发力度的加大，为了动用水源保护区、林区并提高单井产量，长水平段井的开发成为必然，这些井的顺利完成，为油气田的后续开发带来了极大的示范作用 

Water Base Drilling Fluid Technology for Ultra-Long Horizontal Drilling in a Tight Gas Well in Changqing Oilfield

Changqing Oilfield has in the year 2020 drilled three wells with ultra-long horizontal sections in its tight gas well block, the lengths of the horizontal sections are 3321 m, 4118 m and 4466 m, respectively. These long horizontal sections were all drilled with water base muds, and each of the horizontal lengths has consecutively set a new record of the longest horizontal section of onshore wells in Asia. Long horizontal section drilling was faced with challenges such as friction reduction, hole cleaning and borehole wall stabilization. Specific studies were conducted to deal with these difficulties based on the structures of the formation rocks. As a result, a CQSP-RH drilling fluid and technologies for hole cleaning and wellbore stabilization in ultra-long horizontal well drilling were presented. Field application of the technologies and the CQSP-RH drilling fluid has produced good results, the horizontal section of the well was stable during drilling. When running the drill string into the hole, the friction of the drill string encountered was controlled at 500 kN in the open hole, and 350 kN in the cased hole. The well was successfully completed. With more and more development activity in Changqing oilfield going on, long horizontal well drilling technology has to be adopted to develop the water resource conservation and the forest regions and to increase the production of a single well. The successful drilling of these wells has provided a model and an arsenal of technologies for the subsequent development of the oil and gas field.