哈南油田保护储层钻井完井液新技术

Drilling fluid and completion fluid technology for formation protection in Hanan oilfield

针对二连地区哈南油田储层特性和使用的钾铵基钻井完井液体系特点,研究出一种新的保护油层封堵剂L-RP。加入L-RP后的钻井液能在一定深度内彻底封堵储层孔喉,减少钻井液及后续流体进入储层的量,降低外来流体对储层的污染,该封堵层经射孔后解堵,所以封堵层深度必须小于射孔深度,以便射孔后井筒与储层有较完善的连通,达到保护油层的目的。L-RP主要成分为磺化沥青和惰性粒子,与储层特性和钾铵基钻井完井液体系配伍性好。同时提出2项评价保护储层效果的参数:封堵效率和封堵深度,封堵效率应大于90％,封堵深度应小于1 cm。在哈南油田现场应用表明,保护油层封堵剂L-RP的保护油层效果良好,完善井达到了100％。

A new plugging agent for formation protection L-RP is developed based on the reservoir characteristics of Hanan oilfield in Erlian, and the methylamine based drilling fluid and completion fluid used in this area. By adding L-RP the drilling fluid can plug the pore throats of the formation completely in a certain depth, thus minimize the invasion of drilling fluid and subsequent fluids into the reservoir, and formation damages as well. The plugging layer is then removed by perforating, as the plugging length is shorter than the perforating depth, thus perfect communication can be established between the borehole and the formation. L-RP mainly consists of sulfonated asphalt and inert particles, which has good compatibility with formation characteristics and methylamine system. Two parameters for evaluating the formation protection results are proposed, i. e. , plugging efficiency and plugging depth. Specifically, the plugging efficiency should higher than 90% , and plugging depth less than 1 cm. Field using of L-RP in Hanan oilfield are successful, 100% of completely penetrating wells are achieved.