为探究注采参数对松辽盆地干热岩物理力学及波动特征的影响,对不同注采参数下高温遇水冷却后花岗岩进行纵、横波波速测试试验和抗压强度试验。分别考虑注采参数(岩样温度、水温、高温遇水循环次数) 与岩样物理力学特征(外观形态、峰值强度、弹性模量、泊松比)、波动特征(纵、横波波速) 的关联性,建立不同注采参数下力学特征与波动特征拟合曲线,并研究搁置过程中不同岩样温度、不同水温条件下岩体物理力学及波动特征变化规律。研究发现:(1) 搁置初期,岩样温度越高,质量、纵、横波波速、弹性模量降幅越大;水温升高,质量、纵、横波波速、弹性模量降幅先增大后减小。(2) 对采热过程中岩体物理力学及波动特征影响由大到小的注采参数依次为靶区温度、注水循环次数、注水温度。提升岩样温度、增加注水循环次数,岩样力学与波动特征均逐渐下降,提高注水温度变化规律与其相反;经历600℃高温,岩样纵波波速、横波波速、峰值强度、弹性模量降幅分别达到53.44%、58.02%、66.56%、79.84%,高温遇水循环5 次
后降幅依次达到33.61%、33.63%、34.22%、56%。(3) 影响岩样力学与波动特征关联性的注采参数由大到小依次为岩样温度、高温遇水循环次数、水温。此研究能够为松辽盆地热采注采参数的选取提供一定参考。
In order to investigate the impacts of injection-production parameters on physico-mechanical and wave characteristics of hot dry rocks (HDR) in Songliao Basin, a uniaxial compressive test and wave velocity tests of longitudinal and shear waves of granite after high temperature treatments with subsequent water cooling under different injection-production conditions were performed. Considering the relationships between various injection-production parameters (rock sample temperature, water temperature, and cycles of high temperature with water) and granite physico-mechanical characteristics (shape, peak intensity, elastic modulus, and Poisson's ratio), and wave characteristics (longitudinal and shear wave velocity), we established the fitting curves of mechanical characteristics and wave characteristics under different injection-production conditions. Moreover, the variations of physico-mechanical and wave characteristics of granite under different rock sample temperatures and different water temperatures during the shelving process were studied. The results show that: (1) at the initial stage of shelving process, the higher the temperature of the rock sample was, the greater the magnitude of decrease in mass, longitudinal and shear wave velocity and elastic modulus can be. With increasing water temperature, the magnitude of decrease in mass, longitudinal and shear wave velocity, and elastic modulus first show an increase and subsequently a decrease; (2) among the injection and production parameters of the rock mass physical mechanics and wave characteristics on the temperature of the target area, parameters with the degree of influence from high to low are the target area temperature, the number of water injection cycles, and the water injection temperature. With the increase in the temperature of rock samples and cycles of high temperature with water, both the mechanical and wave characteristics of granite gradually decreased; while their variations can be opposite when the water injection temperature increases. After the treatment at the high temperature of 600℃ , the longitudinal wave velocity, shear wave velocity, peak intensity and elastic modulus of granite decreased by 53.44% , 58.02% , 66.56% , 79.84% , respectively. After 5 cycles of high temperature and water cooling treatments, the longitudinal wave velocity, shear wave velocity, peak intensity and elastic modulus of granite decreased by 33.61% , 33.63% , 34.22% , 56.00% , respectively. (3) The injection-production
parameters that affect the correlation between granite mechanics and wave characteristics, with the extent from large to small, are the temperature of the rock samples, cycle numbers of high temperature with water, and the water temperature. This study provides a useful reference for selecting injection-production parameters on thermal extraction in Songliao Basin.