大张坨凝析气藏循环注气开发方案研究

大张坨凝析气藏位于大港油田板桥凝析油气田板中断块西部，１９７５ 年发现。为获得该凝析气藏的高采收率，进行了多年的开发方案综合研究论证。首先从地质特征、气藏测试、流体相态３ 个方面评价了大张坨凝析气藏，确定了循环注气开发所具备的基本地质条件和流体条件，应用多组分数值模拟技术，对合理井网、井距、注气开发方式和注入介质、循环注气速度和时间等进行全面研究，通过开发指标和经济指标综合优化，确定了二注三采循环注气、部分保持压力开发高凝析油含量气藏的开发方案。１９９５ 年现场实施方案，各项开发指标达到或基本达到方案预测，近４ 年来开发效果十分明显，证明方案的科学性和适用性，同时也证实：对于均质层状砂岩储集层、高凝析油含量、高反凝析液量的饱和凝析气藏，采用注气保持压力开发是一种高效的开发手段。大张坨凝析气藏的成功开发，将为国内凝析气藏的循环注气开发提供许多可借鉴的经验。图４ 表１（ 崔立宏摘）

Cyclic gas injection development plan for Dazhangtuo condensate gas reservoir.

In this project Dazhangtuo condensate gas reservoir is first evaluated from three aspects:geological characteristic, gas reservoir test and fluid phase behaviour and basic geological factors and fluid characteristic necessary for cyclic gas injection development are determined, then such aspects are fully studied as rational well pattern, well spacing, gas injection scheme, injection medium, cyclic gas injection velocity, injection time and so on using polycomponent numerical simulation technique. At last, the development plan for the condensate gas reservoir with high condensate oil content is determined, through synthetical optimization of development and economic indices. Two injection wells and three production wells are designed to implement cyclic gas injection and pressure is maintained partly. Having been implemented, each index of project achieves or basically achieves predicted one of program and development result is good. It proves that program is scientific and applicable, and at the same time it also proves that using injection gas to keep pressure is an effective development way about saturated condensate gas reservoir with homogeneous layer sandstones, high condensate oil content and high retrograde condensed liquid. It is successful that using cyclic gas injection to develop Dazhangtuo condensate gas reservoir. This makes condensate gas reservoir development effective and will provide many available experiences for developing domestic condensate gas reservoirs. This project was chosen as a national excellent development experimental program by China National Petroleum Corporation in 1997.