泥饼厚度对固井二界面胶结强度的影响  

The Influences of Mud Cake Thickness on Bonding Strength of the Cement-Formation Interface.

作　　者：杨宝林[1] 顾军[1] 郑涛[1] 秦文政[1] 陈雪峰[1] 

机构地区：[1]中国地质大学(武汉)资源学院

出　　处：《钻井液与完井液》2009年第1期42-43,46,共3页Drilling Fluid & Completion Fluid

基　　金：国家自然科学基金项目(50774071);国家高技术研究发展计划(863)项目(2007AA06Z205);湖北省自然科学基金项目(2007ABA096)

摘　　要：泥饼夹在水泥浆和地层之间,其质量会直接关系到固井二界面的胶结质量。用现场钻井液在自制的仿制井筒上形成不同厚度的泥饼,然后注入水泥浆养护一定时间,通过测出不同样品的二界面抗压强度,计算出二界面胶结强度。实验结果表明,随着泥饼的增厚,二界面胶结强度显著降低,根据拟合趋势线得出二界面胶结强度与泥饼厚度呈指数关系,当泥饼厚度达到5 mm时,固井二界面胶结强度将降为零。分析其根本原因在于,泥饼的内部结构并不是均一的,而是连续变化的,越靠近地层,泥饼越致密,泥饼的强度越大,与地层的胶结也越好,但是越靠近水泥浆,泥饼越疏松,孔隙度和渗透率越大,其强度越弱,二界面的胶结强度也就越小。Mud cakes being in between cement sheath and formation plays a great role in the bonding strength of the cement-formation interface.Mud cakes were formed in a artificial bore hole with field mud,and in this caked hole injected an amount of cement slurry.A bonding interface of cement-formation with mud cakes in between was formed after a period of aging time.Measurement of the bonding strength of the interface showed that with the increase of mud cake thickness,the bonding strength decreased.Trend line fit showed an exponent relationship between the bonding strength and mud cake thickness.Bonding strength became zero with mud cake thickness increased to 5 mm.It is considered that the structure of the mud cake is not uniform but various continuously,denser is the mud cake as it becomes closer to the formation on which it adhere.On the other hand,mud cake surface in contact with cement sheath is thin and loose,having a low strength,thus leading to a low bonding strength of cement sheath and mud cake,reducing the overall bonding strength of the cement-formation interface.

关 键 词：水泥浆 泥饼 胶结强度 固井质量 

分 类 号：TE256.9[石油与天然气工程—油气井工程]