海上稠油油藏温敏凝胶改善气窜实验研究*

Experimental Research on the Control of Gas Channeling by Thermo-sensitive Gel on Offshore Heavy Oil

孙永涛 李兆敏 林 涛 孙玉豹 刘海涛 宋宏志 李松岩

SUN Yongtao LI Zhaomin LIN Tao SUN Yubao LIU Haitao LIN Tao SONG Hongzhi LI Songyan

针对海上稠油油田多元热流体吞吐过程中出现的气体窜流问题，以精制棉花、环氧丙烷、氯甲烷为原料，制 备了温敏凝胶，评价了温敏凝胶的黏度、耐盐性能、封堵性能和封堵有效期，并利用大型二维物理模拟实验装置 开展了温敏凝胶治理气窜的模拟实验。研究表明，随着温度的升高，温敏凝胶溶液黏度先逐渐降低，但是当温度 超过70℃后温敏凝胶溶液黏度逐渐增大，而当温度达到80℃时，温敏凝胶溶液形成不可流动、强度很大的凝胶。 该温敏凝胶的耐盐性能良好，用含1000 mg/L的Ca2+ 的水溶液、1000 mg/L的Mg2+ 的水溶液和50000 mg/L的氯化 钠溶液配制质量分数为1.5%的温敏凝胶溶液，在80℃下均能成胶。向水测渗透率为1.59 μm2 的填砂管注入温敏 凝胶，在80℃下成胶后水驱1.0 PV的渗透率为0.0040 μm2，封堵率为99.74%，而且经过40 mL/min的高强度水驱 30 PV后，填砂管渗透率保持率为95.28%，表明该温敏凝胶具有很高的封堵强度且封堵有效期长。注入的温敏 凝胶主要进入高渗通道，被后续注入的多元热流体加热后成胶，起到封堵高渗通道、有效延缓气窜的作用。原有 的高渗通道被温敏凝胶封堵后，后续注入的多元热流体被迫发生绕流，扩大了波及范围，采收率由36.1%提高至 45.3%。南堡35-2油田现场试验结果表明，温敏凝胶可以封堵住了前两轮次注多元热流体期间形成的窜流通道， 有效延缓气窜的发生，在25 d的注多元热流体作业期间未发生气窜，注入压力比气窜前提高2.0 MPa，临井气量 未见明显上升，生产未受到影响。图12表3参13

In order to resolve the problem of gas channeling in offshore horizontal wells during multi-component thermal fluid （MCTF）huff and puff，a thermo-sensitive gel（TSG）was prepared using the refined cotton，propylene oxide and methyl chloride as main raw materials，and the viscosity，salt resistance，plugging properties and effective period of the TSG was evaluated and an experiment simulating the plugging effect of the TSG was conducted using a large two-dimensional physical modeling system. The results showed that with the increase of temperature，the viscosity of the TSG solution decreased gradually，but increased when the temperature exceeded 70℃. TSG solution formed a non-flowable and strong gel when the temperature reached up to 80℃. The TSG had good salt resistance，as 1.5% TSG solution prepared with 1000 mg/L Ca2+ aqueous solution，1000 mg/L Mg2+ aqueous solution or 50，000 mg/L sodium chloride solution could become gel at the temperature of 80℃. The plugging rate of TSG was tested to be 99.74% using a sand packed tube，as the permeability of the sand packed tube was 1.59 μm2 before TSG injection and turned out to be 0.004 μm2 after TSG injection at 80℃ followed by 1.0 PV water drive. The permeability retention rate of the sand packed was 95.28% after 30 PV water drive at a rate of 40 mL/min，indicating that the TSG had a strong plugging strength and a long effective-period. The result of simulation experiment showed that TSG solution tended to enter and plug the high permeability channel，then it gelled under the heating effect of MCTF injected later，which inhibited the occurrence of gas channeling. MCTF was forced to bypass the high permeability channel plugged by the TSG，which expanded sweep area and improved oil recovery from 36.1% to 45.3%. Field application in NB35-2 showed that the injected TSG had plugged the high permeability channel formed in the first two rounds of huff and puff，and the connected well was not affected during the whole injection stage of 25 days，and injecting pressure increased by 2 MPa.

10.19346/j.cnki.1000-4092.2020.02.015