矿物岩石
礦物巖石
광물암석
JOURNAL OF MINERALOGY AND PETROLOGY
2001年
1期
23-27
,共5页
鄂尔多斯盆地%塔巴庙%奥陶系%气源追踪
鄂爾多斯盆地%塔巴廟%奧陶繫%氣源追蹤
악이다사분지%탑파묘%오도계%기원추종
鄂尔多斯盆地北部塔巴庙地区奥陶系天然气的赋存分布以风化壳最具工业价值,另一类尚待进一步勘探研究的天然气则分布于奥陶系内部或盐下。对这两种分布形式的天然气,在通过天然气组分、同位素以及相伴生的凝析油化学特征研究对比的基础上,与其可能来源的烃源岩层即上覆石炭系煤系烃源岩和奥陶系碳酸盐岩烃源岩的生源地化特征相对比,结果表明塔巴庙区块北部以鄂5鄂8井为代表的奥陶系风化壳工业性天然气具有双重母质的混合型天然气特征,即来源于上古生界煤成气和下古生界油型气;该区南部以伊24井为代表风化壳非工业性天然气则来源于奥陶系典型腐泥型成因的有机质;对于奥陶系内部或盐下天然气显示而言,均属单一海相碳酸盐岩来源的油型天然气。因此,奥陶系风化壳相对发育与生烃气强度中心相叠合的区域是当前在勘探上古生界时兼顾下古生界天然气的最佳地区。
鄂爾多斯盆地北部塔巴廟地區奧陶繫天然氣的賦存分佈以風化殼最具工業價值,另一類尚待進一步勘探研究的天然氣則分佈于奧陶繫內部或鹽下。對這兩種分佈形式的天然氣,在通過天然氣組分、同位素以及相伴生的凝析油化學特徵研究對比的基礎上,與其可能來源的烴源巖層即上覆石炭繫煤繫烴源巖和奧陶繫碳痠鹽巖烴源巖的生源地化特徵相對比,結果錶明塔巴廟區塊北部以鄂5鄂8井為代錶的奧陶繫風化殼工業性天然氣具有雙重母質的混閤型天然氣特徵,即來源于上古生界煤成氣和下古生界油型氣;該區南部以伊24井為代錶風化殼非工業性天然氣則來源于奧陶繫典型腐泥型成因的有機質;對于奧陶繫內部或鹽下天然氣顯示而言,均屬單一海相碳痠鹽巖來源的油型天然氣。因此,奧陶繫風化殼相對髮育與生烴氣彊度中心相疊閤的區域是噹前在勘探上古生界時兼顧下古生界天然氣的最佳地區。
악이다사분지북부탑파묘지구오도계천연기적부존분포이풍화각최구공업개치,령일류상대진일보감탐연구적천연기칙분포우오도계내부혹염하。대저량충분포형식적천연기,재통과천연기조분、동위소이급상반생적응석유화학특정연구대비적기출상,여기가능래원적경원암층즉상복석탄계매계경원암화오도계탄산염암경원암적생원지화특정상대비,결과표명탑파묘구괴북부이악5악8정위대표적오도계풍화각공업성천연기구유쌍중모질적혼합형천연기특정,즉래원우상고생계매성기화하고생계유형기;해구남부이이24정위대표풍화각비공업성천연기칙래원우오도계전형부니형성인적유궤질;대우오도계내부혹염하천연기현시이언,균속단일해상탄산염암래원적유형천연기。인차,오도계풍화각상대발육여생경기강도중심상첩합적구역시당전재감탐상고생계시겸고하고생계천연기적최가지구。
In Tabamiao area of northern Ordos Basin, natural gas is widespread in Ordovician.However, the commercial gas is mainly produced from the weathered crust lying at the top of Ordovician. In order to track the origin of gas in Ordovician,associated condensate and indigenous gas in Ordovician carbonate source rock in upper and lower Paleozoic were correlated from such geochemical characteristics as component, compounds and isotope.Detailed study showed that (a) the commercial gas in Ordovician weathered crust in northern Tabamiao was originated mainly from coal-bearing source rock in upper Paleozoic, (b) the non-commercial gas in Ordovician in southern Tabamiao is formed on the spot, and (c) the gas below salt bed in Ordovician is also formed on the spot. The author suggested that both Ordovician weathered crust and upper Paleozoic are the superior objects for gas exploration in northern Tabamiao and upper Paleozoic is the only one of object for gas exploration in southern Tabamiao.