油区地热能开发新工艺的研究

Investigation on novel exploitation technology of oilfield geothermal resources

在油区地热资源开发过程中,应用井内换热和尾水回灌的对井供热系统可以提高地热资源开发效益、避免地热水资源浪费和实现可持续发展。文章使用了地热储二维分布模型和井筒传热模型,通过对地热储的数值模拟预测了尾水回灌过程中地热储的压力响应和冷却效应,通过对井筒的热力计算得到了井内换热器的最优设计方法。计算结果表明,地热储对尾水回灌的压力响应非常迅速,压力场能很快达到稳定;回灌冷水的影响区集中在回灌井的周围,冷区半径增长的速度越来越慢。井内换热器在最佳设置深度时,经济效益达到最大值;井内换热器设置深度不变,增大载热水的流量经济效益将增加,但是获得的热能温度下降。

During the exploitation of oilfield geothermal resources, the application of couple-well heating system can increase the exploitive profit, avoid the waste of geothermal water and achieve the purpose of sustainable development. The techniques of heat-exchanger in well-bore and exhaust water reinjeetion are applied to the system. In this paper, the distributed parameter model of geothermal reservoir and the heat transfer model of well-bore are adopted. The pressure respondence and cooling effect of geothermal reservoir are predicted with numerical simulation method when geothermal exhaust water is continuously reinjeeted into reservoir, and the optimal design method of heat-exchanger in well-bore is achieved. It is shown that the reservoir pressure field responds rapidly to the reinjection process and becomes stable quickly. The cooling-area locates mainly around the reinjection well and its radius increases less and less. The optimal depth of heat-exchanger in well-bore is acquired, which make economic profit reach the biggest value. The economic profit is directly proportional to the flux of transport-heat water under the conditions of fixed heat-exchanger depth, but the temperature of transport-heat water is inversely proportional to its flux.