中文摘要：

深水地层上覆岩层压力低，钻井安全泥浆密度窗口窄，发生井下事故的风险更大，需要确定水平井眼的变形规律，减少或避免因疏松砂岩储层蠕变缩径造成的井下复杂情况和事故。荔湾3—1气田是我国第一个即将投入开发的深水油气田，利用分级加载的方式测试了荔湾3—1气田疏松砂岩储层的蠕变变形规律。应用拉格朗日元法进行数值模拟计算，得出了荔湾3—1气田疏松砂岩储层水平井井眼缩径变形随时间的的变化规律和控制井眼缩径率的钻井液密度图版，分析了水深对水平井井眼变形的影响。结果表明，在相同条件下，深水油气田因疏松砂岩储层蠕变缩径而影响水平井安全钻进的风险比陆地和浅水油气田更小。研究结果对确定深水水平井安全钻井周期和开展水平井极限延伸长度的研究具有指导意义。

英文摘要：

Comparing to common offshore drilling and onshore drilling, the deep water formation has lower overburden pressure, narrower safety window of mud density and greater risk of having down-hole accident. It is im- perative to study the under gauge deformation behavior of horizontal wells, which can avoid or reduce down-hole ac- cident caused by shrinkage of borehole in unconsolidated sandstone formation. LW3--1 gas field is the first deep water oil and gas field to be developed in China. The creep deformation law of unconsolidated sandstone reservoir in LW3--1 gas field was tested. The Lagrange Element Method will be used to do the calculation, from which the un- der gauge deformation with time of a horizontal well in deep water formation will be concluded, and the impact of deep water to deformation of a horizontal well is analyzed. The results show that, under the same condition, com- pared with common offshore drilling and onshore drilling, the risk of horizontal well drilling insecurity in deep water oil and gas field caused by unconsolidated sandstone creeping is lower. Derived from the study, will be a guide for studying and predicting safe drilling cycle of horizontal wells drilled in deep water oil and gas field and the horizon- tal length limit.