基于修正Burgers模型的泥岩层套管形变影响因素分析

ANALYSIS OF INFLUENCING FACTORS OF CASING DEFORMATION IN MUDSTONE BASED ON MODIFIED BURGERS MODEL

地层含水饱和度的变化对于泥岩储层的蠕变特性有较大影响,尤其是注采过程中泥岩段套管产生形变从而导致套管损坏。本文在Burgers模型基础上加入含水饱和度元件,提高了瞬时蠕变阶段模型的精度,同时对实际油田某泥岩区块进行了比对,得出随含水饱和度增加,地层蠕变量增大,且瞬时蠕变阶段时间减小的结论,同时在蠕变条件下套管壁厚、水泥环弹性模量、地层含水饱和度均可大幅度影响套管变形,而套管尺寸对套管变形几乎无影响。本研究成果能够更加准确地计算地层不同含水量条件下泥岩蠕变的套管变形,对井筒的破坏进行有效的预防及控制。

The variation of formation water content has a great influence on the creep characteristics of mudstone reservoir, especially in the process of injection and production casing deformation in mudstone section can lead to casing damage. In this paper, a water-cut element was added on the basis of Burgers model to improve the accuracy of the instantaneous creep stage model. At the same time, a comparison was made on a mudstone block in an actual oil field. It was concluded that with the increase of water-cut, the formation creep variable increased and the time of the instantaneous creep stage decreased. At the same time, the thickness of casing wall, elastic modulus of cement ring and water content of formation can greatly affect the casing deformation under creep condition, while the casing size has almost no effect on the casing deformation. The research results can more accurately calculate the casing deformation of mudstone creep under different water content conditions, and effectively prevent and control the wellbore damage.