复合堵漏材料优化实验研究及配方评价新方法

针对复合堵漏过程中存在对堵漏材料选择的盲目性、堵漏配方的经验性以及堵漏工艺的随意性。对常见堵漏材料进行了常压条件下膨胀性、高温高压条件下膨胀性和吸水量的系统评价。结果表明,常用堵漏剂在水中浸泡8 h,膨胀基本完成。封堵调剖剂和海带不但体积膨胀率大,吸水量也多。常温封堵实验表明,配方中加入CMC胶液对封堵有利;新型堵漏仪的研制和应用不仅能充分模拟漏失地层。试验后还可以剖开试验岩心,观察分析堵漏材料沿程分布特点和“平衡区域”的位置。平衡区域是成功堵漏中的重要特征,其规律为当堵漏效果好时,平衡区域向堵漏泥浆入口端移动,堵漏效果不好时,平衡区域向出口端移动,甚至不能形成平衡区域。有平衡区域形成,说明堵漏配方与漏层相适应,否则要对配方进行调整;该技术在现场堵漏应用试验中效果较为显著。

EXPERIMENTAL RESEARCH ON COMPOUND LCM OPTIMIZATION AND A NEW METHOD FOR FORMULA EVALUATION

Considering the blindness in selecting LCM materials, experience-dependent when formulating LCM fluids, and randomness when deciding the LCM procedures, a systematic evaluation is conducted on the expansion and water absorption capabilities of the common LCM materials under both normal pressure and HPHT conditions. The results show the common LCM materials complete expansion within 8 hours when they were dipped in the water; the profile control agent and kelp not only have a high volumetric expansion rate, but also have a high water absorption capability; the plugging experiment at room temperature indicates that it's favorable for lost circulation control if CMC is added in the formula; and the development and application of a novel lost circulation simulator can simulate the thief zone fully and can cut the core into half after test to observe the LCM distribution along the path and the location of the "balance region". The balance region is an important feature of a successful plugging operation. The region will move toward the plugging fluid inlet if the plugging is efficient, or move toward the plugging exit or won't appear if the plugging is not effective. So the presence of balance region is an indicator to show the plugging formula is suitable for the thief zone. Otherwise, the formula has to be changed. This technology has obtained remarkable results in field tests.