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青海省柴达木盆地是中国石油天然气股份有限公司的重要气区之一,其中涩北气田是青海气区天然气开发的主战场,占青海油田盆地总探明地质储量的93.3%,占盆地总探明可采储量的94%。涩北气田属于第四系生物成因气藏,为一完整、无断层发育的背斜构造,属于湖泊沉积相,主要发育有滨、浅湖亚相,滩砂、坝砂和泥滩沉积微相;储层具有高孔隙度、中-低渗透率的特点;岩性以含泥粉砂岩和泥质粉砂岩为主,夹少量细砂岩,碎屑颗粒胶结程度低,欠压实,易松散,盖层为泥岩层;气田具有含气井段长、气层多且薄、气水层间互、地层胶结疏松和气水界面复杂等特点,国内外类似气田罕见,涩北气田已被列为我国五类难开采气田之一。
Qinghai Qaidam Basin is one of the important gas areas for PetroChina Company Limited. Sebei gas field is the main battlefield for natural gas development in Qinghai gas area, accounting for 93.3% of the total proved geological reserves in Qinghai gas field, Proved recoverable reserves of 94%. The Sebei gas field belongs to the Quaternary biogenic gas reservoir and is a complete and faultless anticline structure. It belongs to the lacustrine sedimentary facies and is mainly characterized by foreshore, shallow lake subfacies, beach sand, dam sand and mudflat sedimentary microfacies The reservoirs are characterized by high porosity and medium-low permeability. The lithology is dominated by silt-bearing siltstones and muddy siltstones with a small amount of fine sandstone. The degree of cementation of clastic particles is low, compacted, and loose, The caprock is a mudstone layer. The gas field has the characteristics of long gas bearing section, more and thinner gas layers, mutual interaction of gas and water layers, loose cementing of strata and complex gas-water interface. Similar gas fields are rare in China and abroad. The gas field in Sebei has been listed as China’s fifth One of the hardest-hit gas fields.