塔里木盆地大中型油气田形成及分布规律

目的 探讨塔里木盆地油气藏形成及分布规律,为油气田勘探部署提供依据。方法 运用石油地质综合研究方法,探讨了区域构造背景,有效烃源岩分布及其成熟度、储盖组合、后期构造变动等对塔里木盆地大中型油气田形成及分布的控制作用。结果 塔里木盆地油气分布十分复杂,油气藏形成及分布受多重因素控制;早期形成、长期继承发育的大型稳定古隆起及其斜坡以及前陆逆冲带第2,3排构造分别是大中型油气田形成的最有利地区;古隆起控油、斜坡富集以及隆起高部位油气易发生调整、斜坡部位有利于保存,是克拉通区油气藏形成和分布的重要特点;已发现的油气藏具有多期成藏、晚期调整的特点,早期形成的原生油气藏后期特别是晚喜山期普遍受到了调整改造,以克拉通区海相油气藏最为突出;保存条件对塔里木盆地油气藏形成与分布具有重要控制作用,特别是优质区域盖层的存在,是大中型油气田形成和保存的关键。结论 继承性古隆起与隐伏前陆逆冲带是塔里木克拉通区与前陆区寻找大中型油气田的最有利地区。

On the formation and distribution of mid-large oil and gas fields in the Tarim Basin

AimThe study is made to provide basis for petroleum exploration.MethodsThrough comprehensive study on petroleum geology,the controlling effects of regional tectonic background,effective source rocks and their maturation,reservoir-cap rocks association and later orogeny on the formation and distribution of mid-large oil and gas fields in the Tarim Basin are discussed.ResultsThe formation and distribution of petroleum accumulations in the Tarim Basin is very complicated and controlled by multiple factors. The large early formed, long developed, tectonically stable ancient uplifts and their slopes and the second and third foreland thrust belts are considered to be the major regions for the formation of mid-large oil and gas fields in the Paleozoic cratonic and Meso-Cenozoic foreland areas respectively. That oil and natural gas accumulations are controlled by ancient uplifs and riched in the slope areas and that the early formed hydrocarbon accumulations are easy to be adjusted in the top areas of the uplift and favored to be preserved in the slope areas are two important features of the cratonic petroleum distribution. And that multiple periods of accumulation and late adjustment is another important characteristic of hydrocarbon accumulation in the Tarim Basin. The earlier formed primary reservoirs are generally adjusted later particularly in the late Himalayan (Neogene), which commonly resulted in some secondary accumulations, a most typical phenomenon both in the Tarim craton and foreland areas. Therefore, preserving condition is critical to the formation of mid-large oil and gas fields, of which the excellent widespread cap rocks are most significant. Therefore, large early formed, long developed, tectonically stable ancient uplifts and their slopes are most favorable areas for marine petroleum exploration in the cratonic regions, whereas the second and third foreland thrust belts are those for petroleum exploration in the foreland regions such as the Kuche and Southwest Tarim foreland basins.ConclusionThe large early formed,long developed, tectonically stable ancient uplifts and the second and third foreland thrust belts are most favorable areas to search for mid-large oil and gas fields.