青海南翼山E_3~2凝析气藏储层伤害研究

青海南翼山E32气藏是柴达木盆地一非常规裂缝性气藏。储层岩石渗透率主要受岩石裂缝控制。粘土含量高,在钻井、完井和其他各种作业过程中容易受到伤害。通过薄片分析、X-衍射、扫描电镜、压汞和室内各种静态伤害试验,研究了储层的储集空间、孔隙结构、粘土矿物种类以及敏感性等基本特征,分析了储层污染的潜在因素及伤害机理。研究结果表明,储层粘土矿物以伊利石为主,含量高达71.3％;孔隙结构以晶间孔、溶蚀孔为主,粒间孔极不发育;碱敏和压力敏感性是储层主要损害因素,从而为保护储层提供了必要的科学依据。

Studyon the formation damage mechanisms of Nanyi Mountain E_3~2 condensate gas reservoir in Qinghai.

Nanyi Mountain E32 gas reservoir in Qinghai is an unconventional fractured gas reservoir in Chaidamu Basin with high clay content. The permeability of formation rock is mainly controlled by rock fractures. So this pay -zone is subjected to damage in the course of operations such as drilling, completion and others. The basic characteristics of this pay -zone, including reservoir space, pore structure, types of clay mineral and sensi- tivity etc, are studied by means of slice analysis, X-ray diffraction, scanning electro-microscope, mercury injection and laboratory core static damage tests. The potential factors and mechanisms of formation damage are analyzed. The results show that the dominant clay mineral is illite with the content of 71.3% ; pore structure takes interctystal pore and dissolution pore as the main, and intergranular pore didn' t develop very much. Alkaline sensitivity and pressure sensitivity are main factors of formation damage. And all of these provide a scientific basis for formation protection in Nanyi Mountain E32 gas reservoir.