注水排量对水平井造腔腔体形态影响实验研究

Experimental study on the influence of water injection displacement on the shape of the cavity built by horizontal well

针对国内盐穴储气库普遍存在的盐岩层厚度小、隔夹层厚度大的问题,提出采用具有造腔成本低、成腔率高的水平井多步法造腔技术。通过建立物理相似实验平台开展不同排量对水平腔体形态影响的实验,研究水平井造腔腔体形态扩展与排量的关系。结果表明:当排量为5~10 mL/min时,腔体发展呈现不均匀性,腔体最终呈“鞋”形态;当排量为20~30 mL/min时,腔体形成的顶部高度差较小,形状规则,呈圆柱形;造腔排量存在一临界值,该临界排量为20 mL/min,高于该临界值时,单位时间内的腔体累积产盐量随排量增大而减小,低于临界值时,腔体累积产盐量随着排量增大而增大。通过合理调配造腔参数,水平腔体最终呈“隧道”形。该研究对水平多步法造腔技术应用提供了一定理论基础并为水平井造腔在盐穴储气库规模化使用提供技术支持和借鉴。

The salt-cavern gas storages in China are generally characterized by thin salt rock layers and thick interlayers.To deal with this situation,this paper proposed a horizontal-well multistep cavity construction technology which has low cavity construction cost and high cavity formation rate.A physical similarity experimental platform was established to experimentally study the influences of different displacements on the horizontal cavity shape.And the relationship between the shape expansion of the cavity built by horizontal well and the displacement was studied.It is indicated that when the displacement is 5-10 mL/min,the development of the cavity is not uniform,and it is eventually in the shape of shoe.When the displacement is 20-30 mL/min,the cavity is in the regular shape of cylinder with smaller top height difference.There is a critical displacement of cavity construction,which is 20 mL/min.When the displacement is higher than the critical value,the cumulative salt production of cavity A per unit time decreases with the increase of the displacement;and when it is lower than the critical value,the cumulative salt production of cavity A per unit time increases with t he increase of the displacement.By adjusting the cavity construction parameters rationally,the horizontal cavity is ultimately in the shape of tunnel.The research results provide certain theoretical base for the application of horizontal-well multistep cavity construction technology and the technical support and reference for the large-scale application of horizontal-well cavity construction in salt-cavern gas storages.