温度对煤层气井固井二界面胶结强度的影响

mpact from Temperature on Cementation Strength of CBM Well Cement-Formation Interface

固井二界面胶结质量是煤层气井高效开采一个亟待解决的工程难题,温度是影响固井二界面胶结强度的一个重要因素。为此,基于取自沁水盆地HD012井的相关样品,实验评价了温度对固井二界面胶结强度的影响规律,并结合环境扫描电镜(ESEM)方法对比分析了不同温度条件下泥饼的断面特征和孔隙结构特征,进而探讨了温度对固井二界面胶结强度的影响机理。实验结果表明,在无泥饼条件下,固井二界面胶结强度,随温度升高而增大,而在有泥饼条件下,则随温度升高而减小;有泥饼存在时,温度升高,泥饼黏土颗粒结合水膜变薄,粒间作用力减小,泥饼中孔洞增大、增多,导致泥饼渗透性增大,固井二界面胶结强度降低。

The cementation quality of cement - formation interface is an engineering problem to be solved. The temperature is the key factor impacting cement - formation interface cementation strength. Thus, on the basis of related samples from the well HD012 in the Qinshui Basin, tested and assessed impact pattern of temperalure on cement - formation interface cementation strength. Combined with environmental scanning electron microscopy （ESEM） comparatively analyzed mud cake fracture surface features and pore geometry fea- tures, then discussed the impacting mechanism from temperature to cement - formation interface cementation strength. The result has shown that under without mud cake existed condition, cement - formation interface cementation strength increase with the increase of temperature, while under mud cake existed condition, decrease with the increase of temperature. When temperature build - up, mud cake clay particle bound water film attenuated, interparticle force decrease, and pores in mud cake magnified and increased thus caused mud cake permeability increase and cement -formation interface cementation strength lower down.