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美国Amoco公司和巴西Lima等人分别在几口枯竭油井中进行了称为Ball Pump和Pig Lift的间歇球塞气举试验。实践证明，采用U型双管柱（一注一采），随注入气流投入球塞，在举升气液相间形成固体界面，有效地防止液体滑脱，其增油节气效果十分显著。我们开展的球塞连续气举实验也充分证实了这一结论。文章针对低压低效连续气举井普遍存在的液相滑脱损失严重的核心问题，提出了描述球塞连续气举系统举升管柱中气、液、球三相流动的理论和数值模拟方法。数学模型考虑了流体流动状态的瞬变性和气液两相流特性，模型的数值化处理采用长度和时间的有限差分方法。以川西南威远气田威100井为例，计算分析了举升过程中各物理量随时间的变化规律，对比分析了常规气举和球塞气举的滑脱损失，并对投球频率进行了优选。这一理论研究成果为开展新型球塞连续气举现场选井和工艺设计提供了必要的技术手段。

Numerical Simulation of New Continuous Pig Gas-lift Process

American Amoco Com. and Brazilian Lima Com. has conducted intermittent pig gas lift field trials in a few exhausted oil wells respectively. The practice proves that it makes production rate increase significantly using U shaped double strings (one for injecting and another for recovering), launching balls along with injected gas to form a solid interface between the up lifted gas and liquid phases, and to prevent liquid fall back effectively. The continuous pig gas lift tests we conducted also prove the results. Aiming to the key problem of severe slip loss in the continuous gas lift wells with low pressure and efficiency, the article proposes the theory and the numerical simulation method of 3 phase flow with gas, liquid and ball in the continuous pig gas lift system. The mathematical model considers the instantaneity of the fluid flowing state and the characteristics of 2 phase flow with gas and liquid. The digital process of the model uses the limited difference method of time and length. Taking well Wei 100 of Weiyuan gas field in southwest Sichuan as an example, the variation law of every physical items along with time is studied during the uplifting process. The slippage loss of the pig gas lift is compared with that of the conventional gas lift. And the ball launching frequency is optimized. The study results provide the necessary technical tools for well selecting and process design to expand the technology of the new continuous pig gas lift.