Abstract: The magmatic rock buried-hill gas reservoir in the central uplift zone of northern Songliao Basin is one of the important areas for risk exploration of deep natural gas, and the characteristics and controlling factors of high-quality reservoirs are still unclear, thus severely restricting the gas reservoir exploration process. Based on the drilling, logging, seismic data and analytical test data, this paper analyzes in detail the reservoir characteristics of magmatic rock buried-hill and the controlling factors of high-quality reservoirs in the central uplift zone. The research results show that the magmatic rock buried-hill in the central uplift zone can be vertically divided into weathered accumulation layer, weathering-leaching layer, fracture layer and tight magmatic rock layer, showing the characteristics of reservoirs with low-porosity and ultra-low permeability. The reservoir spaces include the intergranular dissolution pores, intragranular dissolution pores, quartz primary intergranular pores, structural fractures and micro-fractures. The micron and nanoscale pores communicating with micro-fractures can provide storage space for natural gas. The NNW-, NNE-, NE- and NW-trending fractures are mainly developed in the study area, with the medium to high dip angles. Granite and cataclastic granite reservoirs have relatively good physical properties, well-developed fractures, and high degree of fracture opening, and are the dominant lithologies of magmatic rock buried-hill reservoir in the central uplift zone. The controlling factors such as multi-stage structural superposition, weathering leaching, organic acid dissolution, and structural high locations have controlling effects on the development of high-quality reservoirs in magmatic rock buried-hill of the central uplift zone of northern Songliao Basin. The research results provide a reference for promoting the natural gas exploration and development in magmatic rock buried-hills.

Key words: magmatic rock buried-hill, high-quality reservoir, controlling factors, central uplift zone, northern Songliao Basin

摘要： 中央隆起带岩浆岩潜山气藏是松辽盆地北部深层天然气风险勘探的重要领域之一,但其优质储层特征及控制因素尚不清晰,严重制约了气藏的勘探进程。利用钻井、测井、地震资料以及分析化验数据详细分析了中央隆起带岩浆岩潜山的储层特征及优质储层的控制因素。研究结果表明:中央隆起带岩浆岩潜山在垂向上分为风化堆积层、风化淋滤层、裂缝层和岩浆岩致密层;储层属于低孔、超低渗储层;储层的储集空间类型为粒间溶蚀孔、粒内溶蚀孔、石英原生晶间孔以及构造裂缝和微裂缝,与微裂缝沟通的微米—纳米级孔隙可为天然气的聚集提供储集空间;裂缝走向主要为NNW向、NNE向、NE向和NW向,裂缝倾角以中—高角度为主;花岗岩和碎裂花岗岩储层的物性相对较好、其裂缝发育、裂缝开启程度好,是中央隆起带岩浆岩潜山成储的优势岩性;多期构造叠加作用、风化淋滤作用和有机酸溶蚀作用,以及构造高部位等因素,控制了松辽盆地北部中央隆起带岩浆岩潜山优质储层的发育。研究为推进岩浆岩潜山的天然气勘探开发提供了依据。

关键词: 岩浆岩潜山, 优质储层, 控制因素, 中央隆起带, 松辽盆地北部