薄油层水平井连续密闭取心工具的研制与应用

Development and Application of Continuous Closed Coring Tools for Horizontal Wells in Thin Reservoirs

为定量评价大庆长垣油田薄差油层水驱效果及剩余油分布情况,探索最大程度挖掘薄差油层剩余潜力方法,通过分析薄油层水平井连续密闭取心技术难点,研制了不同规格薄油层水平井连续密闭取心工具。将该工具与井下钻具配合形成增斜、稳斜和降斜等3种钻具组合,通过LWD随钻监测,实现薄油层水平井连续取心的同时调整井眼轨迹。大庆杏6-20-检平647井的应用结果表明,该工具可将井眼轨迹精准控制,且现场定向与密闭取心完美结合,首次在油层有效厚度仅0.6~1.0 m的靶体中连续取心315.54 m,取心收获率99.76%,密闭率97.10%,创造国内首口薄油层水平井连续密闭取心最长记录,取得了良好的应用效果。该工具的研制成功可为大庆长垣油田三类油层的有效开发提供一定的帮助。

In order to quantitatively evaluate the water flooding effect and remaining oil distribution in thin and poor reservoirs in Daqing Changyuan Oilfield, and to explore the method to maximize the remaining potential of thin and poor reservoirs, the technical difficulties of continuous closed coring in horizontal wells in thin reservoirs were analyzed. Based on this, closed coring tools with different specifications were developed for horizontal wells in thin reservoirs. Combining with the BHA, three types of drilling assembly were developed, namely inclination-increase type, inclination-stabilization type and inclination-decrease type. By means of LWD monitoring while drilling, continuous coring from horizontal wells in thin reservoirs was completed and meanwhile the wellbore trajectory was adjusted. The application results of Well Xing 6-20-Jianping 647 in Daqing Oilfield show that, this coring tool performs well in precise control of wellbore trajectory and closed coring simultaneously. For the first time, 315.54 m of continuous coring was completed in the target with only 0.6~1.0 m effective thickness, with coring harvest rate of 99.76% and closed rate of 97.10%. It created the longest record of continuous closed coring from thin reservoir horizontal wells for the first time in China and achieved good application results. The research results could provide some references for the effective development of three types of reservoirs in Daqing Changyuan Oilfield.