鄂尔多斯盆地中新元古界拗拉槽特征及勘探潜力

鄂尔多斯盆地深层勘探程度较低，中新元古界是否存在拗拉槽一直存在争议。本文利用近年完成的高密度二维及“两宽一高”三维地震资料进行综合研究，明确了盆地自北向南发育贺兰拗拉槽、定边拗拉槽、晋陕拗拉槽、豫陕拗拉槽，拗拉槽平面呈北东向展布，向西南逐渐加深，最大深度可超过6 000 m；同时明确了中新元古界存在3种类型的油气藏，分别为以长城系暗色泥岩为源岩、砂岩为储层的岩性遮挡油气藏与断块油气藏，和以上古生界煤层为源岩、长城系砂岩为储层的上生下储气藏。三者的勘探有利区带分别为定边至乌审旗地区、黄龙—宜川地区、伊盟隆起与中央古隆起高部位。

Characteristics and exploration potential of the Mid-Late Proterozoic aulacogens in Ordos Basin

The degree of the deep exploration in the Ordos Basin was relatively low, and there had been controversy about the existence of the aulacogens in the Mid-Late Proterozoic. This article used the high-density two-dimensional seismic data and the“two width-one height”three-dimensional seismic data completed in recent years to conduct a comprehensive study and defined that Ordos Basin had Helan aulacogen, Dingbian aulacogen, Jin-Shaan aulacogen and Yu-Shaan aulacogen from the north to the south. Every aulacogen showed the north-west trending and gradually deepened to the south-west （where the deepest could exceed 6 000 m）. At the same time, the article defined that there were three kinds of reservoirs in Mid-Late Proterozoic. The dark mudstones deposited during Changcheng Period could be used as effective source rocks to form lithological shielding reservoirs and fault block reservoirs with the sandstones deposited during Changcheng Period and the gas generated from Palaeozoic coallayer could accumulated in the sandstone reservoirs deposited during Changcheng Period. The favorable area of the petroleum exploration included Dingbian-Wushenqi area, Huanglong-Yichuan area, the high parts of the Yimeng uplift and the central paleouplift.