中国石油大学学报（自然科学版）2017，Vol.41Issue(6)：108-116,9.DOI:10.3969/j.issn.1673-5005.2017.06.013
中等强度砂岩饱水力学参数变化试验及动态出砂规律
Experimental study on mechanical properties of medium strength sandstone saturated with water and its dynamic sanding behaviors
摘要
Abstract
In order to quantify the effect of water saturation on sand production, a series of core tri-axial testing was performed u-sing 27 cores from a medium strength sandstone reservoir in an oilfield abroad, in which different water saturating time and water saturation at various surrounding pressure were applied for the measurement and analysis of the failure strength, elastic modulus, Poisson ratio, cohesive force and internal friction angle of the rock samples. The variations of rock strength at different water satu-ration conditions were revealed in the experiments. Based on the experimental data, an empirical ultimate strength exponential model was fitted to quantify the relationship of rock strength and water saturating conditions. The results indicate that the failure strength of the rock samples and elastic modulus decrease obviously with water saturating time varying from 0 to 50 d, and can drop to 70% of their initial value under water saturating time of 50 d and surrounding pressure of 40 MPa. With water saturation chan-ging from 0 to 100%, the compressing failure strength, elastic modulus and cohesive force decrease dramatically at the early stage,then slowly to a stable state, the final dimensionless strength ratio of which is about 72%. The empirical model can be further used for the prediction of dynamic sanding behaviors. The increasing water saturation to 0. 85 can cause a reduction of the critical san-ding pressure drawdown (CSPD) by 25%-30%. Meanwhile, a 30% reduction of the reservoir pressure can lead to 10%-11% de-creasing of the CSPD. The increase of water saturation and reduction of reservoir pressure in the Iraq reservoir studied can be the main inducing conditions for sand production in the process of future production.关键词
中等强度砂岩/饱水度/饱水时间/力学强度参数/三轴破坏试验/动态出砂预测Key words
medium strength sandstone/water saturation/water saturating time/rock mechanical parameters/tri-axial fail-ure test/dynamic sanding prediction分类
能源科技引用本文复制引用
董长银,周崇,钟奕昕,王鹏,崔明月,曾思睿,尚校森..中等强度砂岩饱水力学参数变化试验及动态出砂规律[J].中国石油大学学报（自然科学版）,2017,41(6):108-116,9.基金项目
国家自然科学基金项目(51374226,51774307) （51374226,51774307）
国家重点研发计划项目(2017YFC0307304) （2017YFC0307304）
