抗高温井下交联固结堵漏技术在塔河油田的应用

Application of High Temperature Downhole Crosslinking Solidification Technology for Mud Loss Control in Tahe Oilfield

塔河油田奥陶系碳酸盐岩缝洞地层埋深超过6 000 m,地层温度可达130℃;由于地层压力亏空严重,建立循环的漏失压差超过10 MPa;缝洞漏层还存在连通性好、地层水矿化度高的特点。针对漏层高温、高压差、高矿化度的特点,提出采用井下交联固结堵漏技术解决深井缝洞的漏失难题。通过室内评价表明,井下交联凝胶材料SF-1在地层高温、高Ca2+环境中可发生交联反应并迅速增稠,黏度在10 000 m Pa s以上,滞留性强,且抗温达130℃。后续注入的化学固结堵漏材料HDL-1可与滞留在通道中的SF-1进一步反应,凝固形成封堵强度在15 MPa以上的致密封堵塞。该技术在塔河油田TH12179CH井奥陶系漏层一次堵漏成功,为深井缝洞性恶性漏失提供了一种有效的堵漏方法。

Depleted fractured Ordovician carbonate formations in Tahe Oilfield were buried at 6,000 m, with formation temperature of about 130 ℃. When lost circulation occurred, mud circulation can be re-gained with bottom hole pressure exceeding 10 MPa.These fractured formations had high channel connectivity and high salinity formation water. A downhole crosslinking solidification technology was developed to deal with lost circulation in these formations. In laboratory experiment, the crosslinking gelling agent SF-1 had its viscosity soared to above 10,000 m Pa s at high temperature(130 ℃) and high calcium environment, and stayed in place long enough for the mud loss to be stopped. HDL-1, a lost circulation material followed SF-1 reacted with SF-1 in the hole to form a dense plug being able to stand pressures up to 15 MPa, ensuring the efficiency of lost circulation control. This technology was successfully applied in the Well TH12179 CH in Tahe Oilfield, where severe lost circulation always occurred.