松辽盆地梨树断陷金山气田沙河子组沉积相研究

SEDIMENTARY FACIES OF SHAHEZI FORMATION IN JINSHAN GASFIELD,LISHU FAULT DEPRESSION, SONGLIAO BASIN

针对金山气田储层岩性和沉积环境复杂多样等难点,通过开展地质录井和测井的观察、描述、解释与对比研究,依据主要含气层位沙河子组的岩石组合、沉积构造、剖面结构和测井相组合特征,综合研究认为金山气田沙河子组沉积期陡坡带发育水下扇沉积体系、缓坡带发育扇三角洲沉积体系。其中砾石坝、辫状水道为最有利的储集相带。纵向上,沙河子组沉积期由沙四段、沙三段→沙二段→沙一段,扇三角洲的主河道越来越发育,而且河道呈由东向西摆动。综合地质研究成果建立了金山气田沙河子组的沉积模式图。

In Jinshan oilfield, the reservoir lithology and depositional environment are very complex. A series of studies on geologic mud logging, and well-logging observation, description,and interpretation were carried on. Moreover, for the main bed of Shihezi Formation, its lithological association, sedimentary structure, profile structure, and logging facies association were explored. Results show that(1) during the deposition of Shahezi Formation, one dispositional system of underwater fan was developed at the steep slope belt whereas another system of fan delta was developed at the gentle slope belt, individually;(2)both gravel bar and braided channel are the most favorable sedimentary facies belts;(3)longitudinally, the main channel deposits are more developed gradually from Shahezi 4 and Shahezi 3 members to Shahezi 2 Member, further to Shahezi 1 Member;and(4)the channel swings from east to west. In addition, a depositional mode on Shahezi Formation is mapped out on the basis of comprehensive geological study.