砾石充填这一有效的疏松砂岩油气藏防砂完井方式在水平井中的应用目前仅限于井筒或套管内充填。但近年来的一些有意无意的工程实践证明了水平井管外地层砾石充填的存在及其有目的实施的可能性。管外地层充填防砂效果好，更可贵的是可以最大程度降低完井表皮提高水平井产量。本项目将针对水平井管外地层砾石充填，开展前瞻性的应用基础理论研究。项目拟在前一项目研究基础上，考虑水平井沿井身轨迹分布的岩石特性参数及三维地应力的非均质性，通过数学模型和室内模拟实验，研究疏松砂岩水平井管外地层岩石在高压挤注条件下的破坏机理和模式（裂缝开裂延伸和塑性挤压破碎）及其判别方法；重点针对水平井管外地层塑性挤压破碎模式，开展管外地层砾石充填的实验模拟和数值模拟研究，建立复杂应力场下水平井管外地层砾石充填模拟的数学模型，开发模拟软件，模拟充填动态过程并预测最终充填结果。为管外砾石充填技术在疏松砂岩水平井中的应用提供前瞻性理论基础。

Gravel-packing is a well known effective sand cnontrol and well completion technology for unconsolidated sandstone reservoir, but its application in horizontal wells is limited to inside casing and wellbore gravel-packing. In recent years, some accidental site inside casing gravel-packing operations in horizontal wells indicate that the fact of outside casing gravel-packing in horizontal wells is subsistent and it's possibile to be implemented purposively. Outside casing gravel-packing means goog sand control effect and can also decrease horizontal well skin factor and improve well productivity. This project will perform the prospective application basic research of the issue of outside casing gravel-packing in horizontal wells. In this project, on the basis of another relative NSFC project completed before, the unconsolidated sandstone rock failure mode, which may concern one of fracture initiation and extension and another of plastic compaction breaking, and its diagnosis model will be focused on. Then, aim ate the rock failure mode of plastic compaction breaking, the study on numerical and experiment simulation of outside casing gravel-packing in horizontal wells will be performed to estiablish the numerical simulation model for horizontal well outside casing gravel-packing. The above study medthods involves matematical model and experimental apparatus and consider the heterogeneity of formation rock properties and 3-D stress field anlog horizontal wellbore trajectory. Finally, the corresponding visual simulation software package will be developed to visually simulation the whole packing process and predict the final packing parttern. This project and its implementation would provide prospective foundation for the real application of outside casing gravel-packing in horizontal wells.