让纳若尔低渗薄油层水平井LWD钻井实践与认识

哈萨克斯坦让纳若尔油田Дю区块油藏渗透率低,仅为10 mD,属于特低渗透率油藏,同时该地区油层薄,仅为2~3 m,已钻直井单井产能低,多年来一直未能得到有效开发。为挖掘剩余油潜力,开发低渗难动用储量,同时为提高低渗油藏开发效率,尝试应用水平井钻井技术,并结合导眼钻井、LWD地质导向、地质录井等关键技术,顺利钻成H5147井和H4061井2口水平井,有效保证了水平井段中靶率和油层钻遇率,最终获得较高的单井产能,单井初期日产分别达到89 t和91 t,达到直井初期产能的3倍。其中,导眼钻井有效确定油层深度与厚度,LWD地质导向和地质录井则保证了井眼轨迹在油层中穿行。2口井的产能效果证明了水平井及配套钻井技术在Дю区块的适用性和必要性。

LWD drilling practice and understanding in low-permeability thin reservoir horizontal wells of Zhanarol Oilifeld

In Zhanarol Oilfield in Kazakhstan, the reservoirs in Дю Block are in low-permeability, only 10 md, belonging to extra-low permeability reservoirs; meanwhile, the oil reservoirs in this Block are thin, only 2-3 m; the drilled vertical wells have low capacity, so the oilfield has not be effectively developed for many years. In order to tap the remaining oil potential, develop the low-permeability hard-to-produce reserves and also improve the development efficiency of low-permeability reservoirs, the horizontal well drilling technology was tried, and two horizontal wells-H5147 and H4061 were successfully drilled together with critical techniques like pilot hole drilling, LWD geo-steering and geological logging, etc. which effectively ensured the target hit rate of the horizontal section and encountering rate of oil reservoir and finally obtained high single well productivity. The initial daily productions of single wells were 89 t and 91 t respectively, about three times of initial production of vertical well. Among the techniques, the pilot hole drilling effectively determined the depth and thickness of oil reservoir; LWD geo-steering and geological logging ensured that the wellbore trajectory was within the oil reservoir. The productivity of the two wells shows the applicability and necessity of horizontal wells and drilling technology in Дю Block.