Earth Sciences Division, MS 90-1116, 1 Cyclotron Road, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Proc Natl Acad Sci U S A. 2012 Dec 11;109(50):20254-9. doi: 10.1073/pnas.1105165108. Epub 2011 Jul 5.
In response to the urgent need for estimates of the oil and gas flow rate from the Macondo well MC252-1 blowout, we assembled a small team and carried out oil and gas flow simulations using the TOUGH2 codes over two weeks in mid-2010. The conceptual model included the oil reservoir and the well with a top boundary condition located at the bottom of the blowout preventer. We developed a fluid properties module (Eoil) applicable to a simple two-phase and two-component oil-gas system. The flow of oil and gas was simulated using T2Well, a coupled reservoir-wellbore flow model, along with iTOUGH2 for sensitivity analysis and uncertainty quantification. The most likely oil flow rate estimated from simulations based on the data available in early June 2010 was about 100,000 bbl/d (barrels per day) with a corresponding gas flow rate of 300 MMscf/d (million standard cubic feet per day) assuming the well was open to the reservoir over 30 m of thickness. A Monte Carlo analysis of reservoir and fluid properties provided an uncertainty distribution with a long tail extending down to 60,000 bbl/d of oil (170 MMscf/d of gas). The flow rate was most strongly sensitive to reservoir permeability. Conceptual model uncertainty was also significant, particularly with regard to the length of the well that was open to the reservoir. For fluid-entry interval length of 1.5 m, the oil flow rate was about 56,000 bbl/d. Sensitivity analyses showed that flow rate was not very sensitive to pressure-drop across the blowout preventer due to the interplay between gas exsolution and oil flow rate.
针对从 Macondo 井 MC252-1 井喷中估算石油和天然气流量的紧急需求，我们组建了一个小团队，并在 2010 年年中使用 TOUGH2 代码进行了两周的石油和天然气流量模拟。概念模型包括油藏和带有位于防喷器底部的顶边界条件的井。我们开发了一个适用于简单两相和两组件油气系统的流体性质模块（Eoil）。使用 T2Well 模拟了油和气体的流动，T2Well 是一个耦合的储层-井筒流动模型，与 iTOUGH2 一起用于敏感性分析和不确定性量化。根据 2010 年 6 月初可用的数据进行模拟估计的最可能石油流量约为 100,000 桶/天（桶/天），相应的天然气流量为 300 MMscf/d（百万标准立方英尺/天），假设井在 30 米厚的储层中开放。对储层和流体性质的蒙特卡罗分析提供了一个不确定性分布，长尾延伸至 60,000 桶/天的石油（170 MMscf/d 的天然气）。流量对储层渗透率最为敏感。概念模型不确定性也很重要，特别是对于开放到储层的井的长度。对于 1.5 米的流体进入间隔长度，石油流量约为 56,000 桶/天。敏感性分析表明，由于气体分离和石油流量之间的相互作用，流量对防喷器压降不太敏感。
