摘要
常用钻井液中所含的徽细粘土颗粒很容易侵入储层,使储层渗透率大大降低,对保护储层不利,尤其对保护酸敏性储层不利,因为酸敏性储层不能采用酸化的方法来恢复渗透率。因此,研制了一种新型的无粘土弱凝胶钻井液体系,用性能较好的聚合物(PF—Ⅵ)和交联剂(JLJ)作增粘剂,保证无粘土弱凝胶钻井液的粘度;辅以一定量的抑制剂、降滤失剂和润滑剂以防止储层中的粘土分散、膨胀。评价试验结果表明,使用BROOKFIELD DV—Ⅱ粘度计在0.3 r/min下(即剪切速率为0.0636s-1)测定该钻井液的粘度为40000-50000 mPa·s.可满足现场需要;与原油、盐相容性好,不会对储层造成伤害;加入一种氧化剂后,形成的弱凝胶能快速破胶降解;岩心渗透率的恢复值在80％以上。该钻井液在南海涠11-4-Al2b水平井及新疆TK431井的钻井过程中,都取得了很好的效果。
The fine clay particles in conventional drilling fluid invade into the formation easily, and decrease the formation permeability, thus causes formation damages, especially to acid sensitive formations, as the permeability cannot be recovered by acidizing. A new gel drilling fluid without clay has been developed, with a kind of polymer and crosslinking agent as viscosifier, and a certain amount of shale control agent, filtrate reducer and lubricating agent added into to prevent clay dispersion and .swelling. The viscosity of the drilling fluid measured is 40 000 to 50 000 mPa·s at 0. 3 r/min, and it has got good compatibility with crude oil and salt, thus results little formation damage. After completion, the weak gel can be quickly broken down by adding a kind of gel breaking agent, and the core permeability recovery reaches 80%. Satisfactory effects have been obtained when using the drilling fluid in the horizontal well Wei 11-4-A126 in offshore South China Sea and well TK431.
出处
《钻井液与完井液》
CAS
北大核心
2002年第1期10-12,共3页
Drilling Fluid & Completion Fluid
