随机分形体积压裂水平井CO2吞吐模拟

目前，非常规储层开采以水平井分段压裂技术为主，而体积压裂会在地下产生诱导裂缝并沟通天然裂缝形成复杂裂缝网络。为了更好地模拟页岩气在地下缝网中的流动情况，以组分模拟器为平台，基于双孔介质模型，结合随机分形几何系统，将复杂裂缝网络与页岩气数值模型耦合，来建立随机分形裂缝网络模型，并基于该模型进一步研究CO₂吞吐开采页岩气的5个方案。结果表明：CO₂吞吐能够显著提高页岩气的产量，注入压力和注入时间的增加均能提高最终采收率，后者在吞吐开采页岩气的过程中存在最优值，而注入时机过早或过晚都会使生产效果变差，在每个CO₂吞吐周期中存在一个最佳注入时机范围。分形裂缝网络模型为深入开展裂缝CO₂吞吐开采页岩气藏的模拟研究提供了一定的理论基础。

CO2 huff and puff simulation in horizontal well with random fractal volume fracturing

At present,the horizontal drilling with large-scale hydraulic fracturing is the main technology to mine shale gas while volumetric fracturing would induce cracks underground and communicate natural cracks to form complex fracture networks eventually. In order to simulate the seepage flow of shale gas in the complex fracture network and characterize the network on the shale gas model,a random fractal network model was established through a two-porosity component simulator combined with the random fractal geometry system. Based on the above model,five schemes for carbon dioxide stimulation to extract shale gas were further studied. The results show that CO₂ huff and puff can significantly increase the production of shale gas,and the increase of injection pressure and injection time can improve the ultimate recovery. The latter has the optimal value in the process of shale gas production,and too early or too late injection timing will make the production worse,and there is an optimal injection timing range in each CO₂ injection cycle. The fractal fracture network model provides a theoretical basis for further research on the simulation of fracture CO₂ huff and puff production of shale gas reservoir.