单井热吞吐开采南海神狐海域天然气水合物数值模拟

以国土资源部广州地质调查局2007年5月在南海北部神狐海域SH7站位的钻探、测井数据为基础，建立了实际水合物藏分层地质模型，主要包括上盖层、水合物层和下盖层，其中上、下盖层均为可渗透的沉积物。本文利用单一水平开采井，进行了热吞吐法开采水合物的数值模拟。给出了选取合理的注入速度和生产速度的准则。模拟结果表明，开采过程中水合物分解区域主要集中在开采井周边区域，在注热阶段和生产阶段，地层中的水合物分别经历合成和分解两种过程，期间有明显的盐水浓缩和稀释效应。在本文条件下，利用单一水平井热吞吐法不能经济有效地开采该区域的天然气水合物，有待于利用其他更高效的水合物开采方法。

Numerical simulation for gas production from hydrate accumulated in Shenhu Area, South China Sea, using huff and puff method

In this work, the gas production potential from hydrates at the SH7 drilling site of the Shenhu Area by means of the huff and puff method using a single horizontal well was estimated.3 dimensional numerical model was established based on currently available data from site measurements.The hydrate accumulations in Shenhu Area are similar to Class 3 deposits (involving only a HBL), and the overburden and underburden layers are assumed to be permeable.The simulation results indicate that the hydrate dissociated zone expands around the well, and the hydrate formation occurs during the injection stage of the huff and puff process.Reasonable injection and production rates should be adopted to avoid the over pressurization and depressurization during each huff and puff cycle.Thermal stimulation is shown to have an effect over a limited range around the well. The gas production rate and gas to water production ratio in the Class 3 hydrate deposit at site SH7 in Shenhu Area in this work is not suitable for commercial production.