非均质高温油藏非混相水气交替实验研究

Immiscible water-alternating-gas experiments in high-temperature heterogeneous reservoir

张立娟¹ 岳湘安¹ 杨志国² 乔美桦¹ 柳宗权³

中国石油大学（北京）石油工程学院，北京 102249 哈里伯顿（中国）能源服务有限公司，天津 300457 中国石化中原油田分公司石油工程技术研究院，河南 濮阳 457001

College of Petroleum Engineering, China University of Petroleum, Beijing 102249, China Halliburton Energy Services Ltd., Tianjin 300457, China Petroleum Engineering Institute, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China

水气交替（WAG）注入是抑制气驱中气窜问题的有效方法之一。文中利用人造岩心模型，针对一类纵向非均质高温油藏，开展了烃类气体（HC）、N2和CO2非混相WAG注入的模拟实验。实验结果表明，气体类型和岩心的纵向非均质性对WAG注入的开采特征和驱油效果有显著的影响。纵向渗透率级差为5的驱油实验显示，HC与N2非混相WAG开采特征相似，但是与CO2非混相WAG相比，有3个明显不同的开采特征：见气早；在第1周期注气后和第2周期注水前，存在一个快速增油期；增油期间含水率下降快且波动大。随着岩心非均质性的增强，3种气体非混相WAG提高采收率的效果均不同程度下降。HC非混相WAG随岩心纵向非均质性的变化相对不敏感，当渗透率级差为15时，可以在水驱基础上提高采收率15百分点以上。对于以正韵律为主要沉积特点且非均质性在一定范围内的高温油藏，HC非混相WAG注入可作为一种油藏水驱后有前景的提高采收率方法。

WAG (water-alternating-gas) is one of effective technique to reduce gas channeling. Immiscible WAG experiments were conducted through heterogeneous core model with hydrocarbon gas (HC), N2 and CO2 respectively, with the aim to simulate WAG injection in high-temperature heterogeneous reservoirs. Results show that gas type and vertical heterogeneity have significant influences on WAG′s production performance and displacement effects. In core flooding experiments with vertical permeability ratio of 5, HC-WAG flooding and N2-WAG flooding are similar in production characteristics; three distinct characteristics are found different from that of CO2-WAG: gas is produced early, there is a fast oil increment phase, which occurs between the first cycle gas injection and the second cycle water injection, water-cut reduces rapidly and fluctuates greatly within the fast oil increment phase. Recovery factors of three gas-WAG decline to some degree with increasing heterogeneity. Compared with N2 and CO2, hydrocarbon gas by WAG injection has less sensitivity to vertical heterogeneity and its recovery factor is above 15% after water flooding. HC-WAG can be used as one of potential techniques for high-temperature fining upward reservoir with vertical heterogeneity within a certain range after water flooding.

10.6056/dkyqt201506021