论文成果

Laboratory study on sand production in moderately consolidated sandstones

摘要:Sand production has long been recognized as a major problem during the extraction of oil/gas from weak sandstone reservoirs. It has been well accepted that sand production is almost inevitable in poorly consolidated and unconsolidated sandstones due to the extremely low strength and the focus is on effective sand control methods, while sand production is seldom in competent sandstones due to the high strength. For moderately consolidated sandstones, no such rule of thumb exists and a lot of efforts have been devoted to finding a method for predicting the onset and the rate of sand production in moderately consolidated sandstones. In this paper, we report the results of a series of laboratory experiments on sand production in moderately consolidated sandstone outcrops of uniaxial compressive strengths about 20MPa. Hollow cylinder specimens with outer diameter of 96 mm and inner diameter of 20 mm were prepared, and loaded with various levels of confining pressures. Radial inward flow was realized to model the seepage force and to carry the sand out of the sample, and the produced sand was continuously collected during the experiments. After the experiments, the grain size distribution of the produced sand was measured and compared to that of the original constituent grains. Furthermore, X-ray CT scanner was used to inspect the failure patterns on the surface of the inner hole after the experiments. The experimental results demonstrated the primary role of confining pressure on sand production in moderately consolidated sandstones, i.e. sand production only occurs when confining pressure is high enough. X-ray CT scanning figures showed classic breakouts on the surface due to the shear failure. Correspondingly, seepage force from the radial inward flow was found to be secondary compared to the confining pressure, since the amount of sand produced and the size of the failure zone was almost independent on the radial flow rate. The median grain size of the produced sand was measured to be 2~3 times of that the original constituent grains. It was also evidenced that Drucker-Prager model was suitable for predicting the onset of sand production in moderately consolidated sandstones.
Copyright 2019 ARMA, American Rock Mechanics Association.

发表日期:2019-01-01

期刊分区(SCI为中科院分区):无

收录情况:EI(工程索引),国际学术会议论文集

发表期刊名称:53rd U.S. Rock Mechanics/Geomechanics Symposium

参与作者:刘小刚,马英文,刘宝生,李志恒,闫新江

第一作者:刘伟

论文类型:会议论文

论文概要:刘小刚,马英文,刘宝生,李志恒,闫新江,刘伟,Laboratory study on sand production in moderately consolidated sandstones,53rd U.S. Rock Mechanics/Geomechanics Symposium,2019,

论文题目:Laboratory study on sand production in moderately consolidated sandstones