摘要
根据煤层气完井筛管受力特点建立了筛管受力的塑性铰模型,利用能量法推导出带有初始椭圆度筛管抗挤强度的计算公式,分析了相位角、射孔直径、射孔密度、初始椭圆度、径厚比和屈服强度等影响因素对筛管抗挤强度的影响规律,并对某煤矿使用的筛管抗挤强度进行了计算,与已有的实验数据和有限元计算结果进行了对比。计算结果表明:筛管抗挤强度的塑性铰模型具有很高的计算精度和准确度,可以满足工程实际需要;筛管抗挤强度随着射孔相位角、径厚比和初始椭圆度的增加而降低,随着屈服强度的增加而增加,相位角和椭圆度对筛管抗挤强度影响比较显著;在射孔直径小于12mm、射孔密度小于120孔/m时,筛管抗挤强度随射孔直径和射孔密度增加变化不明显。建议在实际煤层气完井筛管设计过程中,采用小相位角,严格控制初始椭圆度,适当增加射孔直径和射孔密度,以达到提高筛管抗挤强度和增加过流面积的目的。
The plastic hinge model of perforated liner casing was built up to calculate the collapse pressure according to the strength and deformation behavior of perforated liner casing subjected to external pressure. The calculation equa- tions of collapse pressure of perforated liner casing with initial ovalization were deduced by energy method. The influ- ences of phrase angle, diameter of perforation, shot density, initial ovalization, diameter-thickness ratio and yield stress on the collapse pressure of perforated liner casing were studied. The model and equations were used to calculate the collapse pressure of an actual perforated liner casing as example. The calculating results were compared with the test data in available literatures and FEM results. The research results show that the plastic hinge model is precise and cor- rect, which can satisfy with the actual engineering demands. The collapse pressure of perforated liner casing decreases with phrase angle, initial ovalization and diameter-thickness ratio increasing, and increases with the yield stress. The phrase angle and initial ovalization have greatly influence on the collapse pressure. The collapse pressure of perforated liner casing is slightly changed with the diameter and density of perforation when the diameter and density are smaller than 12 mm and 120 shots per meter, respectively. During the design of perforated liner casing, small phase angle and proper larger diameter and density of perforation are adopted and initial ovalization is constrained strictly in order to improve the collapse pressure and area of passage.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2010年第2期273-277,共5页
Journal of China Coal Society
基金
"大型油气田及煤层气开发"国家科技重大专项(2008ZX05017)
关键词
塑性铰模型
完井筛管
抗挤强度
初始椭圆度
相位角
plastic hinge model
perforated liner casing
collapse pressure
initial ovalization
phrase angle
