海洋天然气水合物开发产能及出砂研究

海洋天然气水合物多分布在深水非成岩储层,其开采过程中易出现泥砂运移（出砂）的情况且难以避免,然而出砂条件下的水合物产能估算偏差较大。本文通过室内海洋水合物降压开采出砂实验数据和海洋水合物试采公开资料,首次推导了出砂条件下现场尺度海洋水合物储层产能情况：在相当于1 200 m水深覆压、30.5 m厚的水合物细砂储层和7寸垂直井不防砂的情况下,得到最大产气速率4.63 ~ 14.1 m³/s,折合40.01×10⁴ ~ 121.84×10⁴ m³/d,综合出砂率0.16% ~ 10.74%;泥质储层在不防砂垂直井和水平井单个半径12 mm射孔下,其最大产气速率达到79.95×10⁴ m³/d和170 m³/d,但其综合出砂率是灾难性的。由于时空限制,产气速率、综合产能和出砂率还有很大提升空间,在平衡综合出砂率（控砂精度）和产气效率（产能）的情况下,有望达到产业化规模。本研究为合理估算出砂条件下的海洋天然气水合物产能提供支撑。

Study on Productivity and Sand Production of Marine Natural Gas Hydrate Development

Marine gas hydrates are mostly distributed in deep-water non-diagenetic reservoirs, and it is easy to conduct the migration of mud and sand (sand production) during the mining process. However, the deviation of hydrate productivity estimation in sand production conditions is large. In this paper, the capacity of marine hydrate reservoir was deduced for the first time under sand production condition at field scale through the laboratory sand production experimental data in marine gas hydrate depressurization exploitation and publicly information of marine hydrate field tests. With the overburden pressure, equivalent to 1 200 meters’ water depth in 30.5 m thick hydrate sand reservoir and 7" vertical wells without sand control, the maximum gas production rate reached 4.63-14.1 m³/s, equal to 40.01×10⁴-121.84×10⁴ m³/d, the comprehensive sand production rate was 0.16%-10.74%. The hydrate argillaceous reservoirs reached the maximum gas production rate of 79.95×10⁴ m³/d and 170 m³/d in vertical well and a radius 12 mm single horizontal well borehole without sand control respectively, but its comprehensive sand production rate was disastrous. Due to the limitation of time and space, there is still much room for improvement of gas production rate, comprehensive capacity and sand production rate. It is expected to achieve the industrial scale through balancing the relationship between comprehensive sand production rate (sand control accuracy) and gas production efficiency (production capacity). This study provides support for the reasonable estimation of marine gas hydrate productivity in condition of sand production.