南海西部高温高压低渗油藏注气驱油效率实验研究

Experimental study on the efficiency of gas injection for oil displacement in high-temperature， high-pressure， and low-permeability reservoirs of the Western South China Sea

摘要:

鉴于南海西部高温高压低渗油藏注气开发的潜在可行性及提升油田开发效果的需求，本研究立足于室内实验，针对二氧化碳与烃类伴生气两种气体，在高温高压环境下进行了细管实验和长岩心驱替实验。通过对比分析两种气体的驱油效率，对其开发效果进行了系统评价。研究结果表明：在高温高压条件下注入CO₂驱油效率最高达88.8%，不同注入方式中气水交替驱油效率最高达87.4%，注气倾角对驱油效率的影响不大，为3.2%。烃类伴生气驱、CO₂驱可作为南海西部高温高压低渗油藏优选能量补充方式。

Abstract:

In light of the potential feasibility of gas injection for the development of high-temperature， high-pressure， low-permeability oil reservoirs in the western South China Sea and the imperative to enhance oilfield recovery efficiency， this study embarked on a series of laboratory experiments. These experiments were conducted with a focus on two gas types： carbon dioxide （CO₂） and hydrocarbon-associated gas. Under high-temperature and high-pressure conditions， fine-tube experiments and long-core displacement tests were meticulously carried out.A comparative analysis of the oil displacement efficiency of the two gases was undertaken， leading to a comprehensive evaluation of their development performance. The research findings indicate that under high-temperature and high-pressure conditions， CO₂ injection achieved a maximum oil displacement efficiency of 88.8%. Among various injection strategies， the alternating gas-water injection method yielded the highest displacement efficiency of 87.4%. The injection angle was found to have a maximum impact of 3.2% on the displacement efficiency. Hydrocarbon gas flooding and CO₂ injection technologies are deemed applicable to the high-temperature， high-pressure， low-permeability oil reservoirs in the western South China Sea.