页岩气储层钻井液损害评价研究

Study on Drilling Fluids Formation Damage of Shale Gas Well

摘要:

延长油田页岩气储层埋藏较深，地质条件复杂，页理构造发育，岩石物性极差，页岩易膨胀、分散。由于孔缝并存，页岩气储层比砂岩油藏具有更严重的微粒运移损害、储层应力敏感损害、水锁损害等特性。鉴于延长页岩储层太过致密，不能用常规方法进行渗透率测定。通过采用人造裂缝法测定钻井液对储层裂缝的污染程度来表征钻井液对储层的损害率。经人造裂缝法测定，延长油田现场使用的白油基钻井液体系对页岩气储层的污染渗透率恢复率达到91.060%，初步证实该体系具有良好的储层保护效果，可在延长油田进一步推广使用并验证。

Abstract:

Yanchang oilfield shale gas reservoir is deeply buried with complex geological conditions, foliation structure development, poor physical properties of rock and shale easily expanses and disperses. Because of the coexistence of pores and cracks, the characteristics of the shale reservoir are worse than the sandstone oil reservoir, such as the particle movement damage, reservoir stress sensitivity damage, water blocking damage and so on. In view of Yanchang oil shale reservoir is too dense, the permeability measuring can not be made by conventional methods. The artificial fracture method was used to determine the pollution degree of drilling fluid to characterize the damage rate of drilling fluids to the reservoir. Measured by the artificial fracture method, the return pollution permeability rate is up to 91.060% with the use of white oil-based drilling fluids system in Yanchang oil field. It is preliminarily confirmed that this drilling fluids system has good effect in reservoir protection and can be further promoted and used in Yanchang oil field.