崂山隆起寒武系油气勘探前景预测——对比四川盆地和苏北盆地

OIL AND GAS PROSPECT OF THE CAMBRIAN AT LAOSHAN UPLIFT:A COMPARATIVE STUDY TO SICHUAN AND SUBEI BASINS

南黄海盆地是下扬子克拉通板块的主体,也是我国唯一尚未获得油气突破的海区。尤其是崂山隆起,目前只有1口钻井,勘探程度极低,制约了油气勘探的进程。然而,南黄海盆地的烃源岩、储层、盖层和成藏条件与四川盆地和苏北盆地存在着相似的地方。对比分析四川盆地和苏北盆地寒武系可以发现:2个盆地的烃源岩丰度高,厚度大,TOC平均含量分别达4%和3.32%,都是较好的烃源岩;储层以震旦系和寒武系白云岩为主,裂隙发育使储层具有较高的孔隙度和渗透率;成藏模式包括新生古储、古生新储和自生自储。在缺少资料的情况下,通过类比四川盆地和苏北盆地来推测南黄海崂山隆起寒武系的油气地质特征和油气勘探前景。对比分析认为,崂山隆起寒武系具有较大的油气勘探前景,应加快勘探进程。

As the main part of the Lower Yangtze Craton,the South Yellow Sea Basin has remained as the only area without breakthrough of oil and gas up to date.There is no conclusion being made for the region,especially for the Laoshan uplift,since there are lack of drilling wells.The oldest strata penetrated by drill hole so far are the Carboniferous,and the seismic exploration degree is low.In fact,there is no actual data enough to reach a conclusion on oil and gas potential.However,the South Yellow Sea Basin is similar to some extent to the Sichuan Basin and the Subei Basin in such aspects as hydrocarbon source rocks,reservoirs,cap rocks and accumulation mechanisms.By comparison,it is found that there are abundant and thick source rocks in the South Yellow Sea Basin.The average organic carbon contents are 4%and 3.32%respectively,which belong to the category of good hydrocarbon source rocks.In addition,there are widely distributed Sinian and Cambrian dolomite reservoirs,and the porosity and permeability of the reservoirs are rather high because of dolomitization and tectonic crackings.Moreover,there are three types of oil and gas accumulation models,i.e.the oil and gas generated newly and stored in the old,the oil and gas generated elderly and store in the new,and the oil and gas self generated and self stored.Of course,the Sichuan Basin has better preservation potentials comparing to the Subei Basin because of the influence of tectonic movement.With regard to the lower Paleozoic,the preservation conditions of the two basins are very similar indeed.By basin correlation,it is inferred that the oil and gas geological characteristics of the Cambrian on the Laoshan Uplift are comparable with the Sichuan Basin and the Subei Basin,and is a favorable target for further oil and gas exploration.