徐深气田兴城开发区火山岩储层发育控制因素分析

Study on control factors for forming volcanic reservoir in Xingcheng development area of Xushen Gas Field

利用岩心、薄片、分析化验、测井等资料,对徐深气田兴城开发区营城组一段火山岩储层进行了研究,结果表明:天然气主要产自溢流相的气孔流纹岩和爆发相的流纹质火山碎屑岩中,储集空间以气孔、粒间孔、斑晶溶孔、基质溶孔和构造裂缝为主。综合分析认为,储层的发育状况与构造活动、岩性岩相变化及成岩作用等因素密切相关。构造作用产生构造裂缝,形成有效的疏导体系;岩性岩相决定了原生孔隙的发育;成岩作用对原生孔缝进行了改造,其中压实、压溶、熔浆胶结和热液充填作用降低了储层的储渗能力,而溶解作用形成了大量次生溶蚀孔隙,使储层物性得到改善。不同岩性,其储层发育的主要控制因素不同。认识清楚储层发育的控制因素,对储层预测及今后气田的有效开发具有重要意义。

Xingcheng development area of Xushen Gas Field lies in Xujiaweizi Rift. Its reservoir is volcanic rocks of first member of Yingcheng Formation with characteristics of low porosity and permeability. The gas is mainly produced from rhyolite and volcanic rocks, and the main reservoir space includes stoma, intergranular pores, dissnlved pores in the crystals of feldspar, dissolved pores in the matrix and structural fissure. Comprehensive analysis shows that the control factors for forming volcanic reservoir include tectonic action, lithofacies and diagenesis. Tectonic action leads to formation of structural fissure, which becomes effective drainage system, lithnfacies decides the forming degree of original pores, and diagenesis modifies original pores and fissures. Lithology is different, and main control factor of reservoir forming is different.