准噶尔盆地西缘春光探区岩性油气藏成藏主控因素

Main Controlling Factors of Lithological Reservoirs in Chunguang Exploration Area,the Western Margin of Junggar Basin

准噶尔盆地西缘春光探区具有多层系立体含油特征,单个油气藏规模小、数量多且富集高产,主要发育有冲积扇-河流沉积体系和三角洲沉积体系,以岩性油气藏为主。油气源对比表明,西部稀油和中质油油藏主要为四棵树凹陷油源,东部稀油和稠油油藏主要为昌吉凹陷油源,不整合、厚砂层、断裂构成了春光探区油气运移的立体输导体系,冲积扇、辫状河和三角洲砂体提供了有利的储集空间。油气成藏具"多源供烃、断层纵向输导、毯砂横向输导、砂体尖灭带富集"特点,多源供烃是油气藏富集的基础,"多维度"输导体系是油气成藏的关键,砂体的展布控制着油气富集区带。

Chunguang Exploration Area in Western Margin of Junggar Basin is characterized of multiple series of petroliferousstrata, and reservoirs are mainly lithological type and have small size but are abundant and rich. The sedimentary facies of study area are alluvial fan-river sedimentary system and delta sedimentary system. The correlation between the crude oil and the hydrocarbon source rocks show that light and intermediate oil distributed at the western region are from Sikeshu sag source, and light and heavy oil distributed at eastern region are from Changji sag source. The complex migration system is composed of unconformity, thick sandstone bedding and faults. The sandstone body of alluvial fan, braided river and delta supply favorable storage space. Reservoir formation has the characters＂multiple sources for hydrocarbon generation, vertical and lateral migration process through faults and sandstone bodies and accumulating in sand spiking zone＂. The‘multiple sources＇ is the base of hydrocarbon enrichment; Multi-dimension migration system is key to the hydrocarbon accumulation; The distribution of sand bodies constrain petroleum enrichment zone.