济阳坳陷桩海地区下古生界白云岩储集空间形成机理

白云岩是济阳坳陷下古生界潜山的主要储集类型之一，不同成因白云岩的非均质性差别很大，致使油气产量稳定性存在差异。根据白云岩岩石学与地球化学特征分析，将桩海地区白云岩划分为微晶云岩、微晶泥云岩、膏云岩和粉一细晶云岩4种类型。前3种类型的白云岩为准同生白云岩化成因，主要发育构造作用和岩溶作用形成的构造裂缝或构造溶蚀裂缝；后1种类型白云岩为埋藏白云岩化成因，主要发育晶间或粒问孔，是成岩过程中文石或方解石粒屑被白云石粒屑交代后体积缩小而形成的。晶问或粒间孔是油气产量较为稳定的内幕型储层的主要储集空间类型。

The forming mechanism of dolomite reservoir space of Lower Paleozoic in Zhuanghai region, Jiyang Depression

The dolomite was one of the major reservoirs of Lower Paleozoic buried hill in Jiyang Depression. The heterogeneity of dolomites with various geneses was much different,which resulted in the difference in stability of oil and gas production. According to the analysis of dolomite lithology and geochemical char-acteristics, four types of the dolomite in this area were divided, that is, dolomicrite, microcrystaJ argillaceous dolomite, plaster dolomite and powder - aplite dolomite. The dolomites of the first three types were formed by means of penecontem-poraneous dolomization, during which fractures or dissolution fractures were formed due to tectonic movement and karstifica-tion. Dolomite of the last type with intergranular pores were formed through dolomitization during burier time. The arago-nite or calcite particles were replaced by the dolomite through metasomatism in the diagenetic process, and thus the volume was diminished. The intergranular pores were the primary reservoir spaces with more stable oil - gas production.