适用于鄂尔多斯盆地天环塌陷西翼的体膨胀堵漏工艺

A Bulk Expansion Pressure-bearing Lost Circulation Process Suitable for Use in the West Wing of Tianhuan Collapse in Ordos Basin

长庆油田鄂尔多斯盆地天环塌陷西翼主要漏失层为洛河层及刘家沟组地层,漏层缝隙发育良好,地层水活跃,漏失速率为20~100 m^3/h,堵漏难度大。传统堵漏方法成功率低,难以有效封堵。针对大型漏失井,通过筛选堵漏材料,优选出体膨胀承压堵漏剂HSW-1,以此作为先导浆,在漏失层形成结构承压体,避免漏失点动水冲刷,后注入水泥塞达到堵漏目的。体膨胀承压堵漏剂遇水膨胀可达500~800倍,7 MPa压力下承压能力达11 MPa,耐温120℃,固化时间为2~6min。因HSW-1遇水膨胀和固化时间短的特征,研发出一种定点投送工具,以达到定点投送和定位候凝的目的,提高堵漏成功率。

In the west wing of the Tianhuan Collapse in Ordos Basin,Changqing Oilfield,mud losses have often been encountered when drilling to the Luohe Formation and Liujiagou group,in which fractures(both vertical and horizontal)are very developed and formation water is active.Rates of mud losses resulting from pressure differential are in a range of20-100 m3/h.Conventional methods seldom succeeded because of the difficulties in controlling this kind of mud losses.Many kinds of lost circulation material were tested in laboratory and a bulk expansion lost circulation material,HSW-1,was selected.In controlling mud losses,HSW-1 slurry was first spotted into the thief zone to form a pressure bearing barrier to protect the thief zone from being eroded by mud flow.Cement plug was then spotted into the thief zone protected by HSW-1 slurry to completely stop mud losses.HSW-1 when in contact with water will expand to 500-800 times o f its original volume,and the pressure bearing capacity of the set HSW-1 slurry is 11 MPa at test pressure of 7 MPa.HSW-1 works normally at 120℃and time for the HSW-1 to set is 2-6 min.A special tool has been developed for the targeted delivery of HSW-1 to the place where HSW-1 is required because of its short set time,and success rate o f mud loss control with HSW-1 can thus be increased.