摘要
过去对水泥浆失重机理的研究和解释都还很不够，看法也不一致，有碍气窜问题的彻底解决。近期的研究指出，候凝过程中水泥浆要经历从沉降不稳定体系到稳定体系的转化期，并提出了无滤失情况下转化期水泥浆中的固相沉积到井壁导致沉降失重的观点和固相结构在沉降中随着静切力的增长悬挂于井筒壁导致沉降—胶凝失重的观点。从上述两种失重观点出发，并以典型失重模拟实验为基础，分析了水泥浆在不同井斜的失重机理和规律，进一步证实了两种失重观点的正确性，得出几点结论：①井斜愈大，转化期愈短；②随着井斜角的增大，沉降失重对水泥浆转化期失重的影响增大，沉降—胶凝失重的影响减小；对垂直和小井斜角井眼来说，一般水泥浆在转化期以沉降—胶凝失重为主，对大斜度井和水平井眼而言，则以沉降失重为主；③在中等井斜角范围（４０°～６０°），水泥浆在转化期的平均失重速率将达到最大值。此时水泥浆有最大析水率，气窜也最容易发生。
In the past,the research and interpretation of the slurry weightlessness mechanism were quite rudimentary and there were many different views on it,which obstructed the gas channeling problem from thoroughly being solved.Recently,through our study it is pointed out that the slurry should undergo a transformation period from settling unstable system to stable one during waiting on cement,and the viewpoint that the solid phase in the slurry during the transformation period is deposited on the borehole wall under the condition of having no filter loss,which causes a settling weightlessness and the other viewpoint that in settling,along with the increase in gel strength the solid structure is hung to the borehole wall,which causes a settling jellification weightlessness,are proposed.According to the two weightlessness viewpoints mentioned above and in the basis of typical weightlessness stimulation experiment,the weigthlessness mechanism and law of the slurry under various hole deviations are analyzed and the correctness of the two weightlessness viewpoints is further verified.It is concluded that ① the larger the hole deviation,the shorter the transformation period;②along with the increase in hole deviation angle the effect of the setting weightlessness on the slurry weightlessness during the transformation period increases and the effect of the settling jellification weightlessness decreases;in regard to the vertical well and the well with small hole deviation angles,the settling jellification weightlessness occupies the principal position in the slurry during the transformation period in general,but in the case of the well with large hole deviation angles and the horizontal well,the settling weightlessness occupies the principal position;③in the range of middle hole deviation angles (40°～60°),the averrage weightlessness rate of the slurry during the transformation period will reach to the maximum.At this time,the slurry is of the maximum bleeding rate and gas channeling is easiest to form.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
1998年第4期55-58,共4页
Natural Gas Industry
关键词
大角度斜井
井斜
水泥浆
沉降机理
气窜
油田
High angle deviated hole,Hole deviation,Cement slurry,Settling mechanism,Gas channeling,Research.
