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塔里木盆地下古生界在地质历史中相当长的时间处于深埋藏环境,明确深埋藏阶段白云岩形成/改造过程及其对储层的影响,对深层白云岩油气勘探有重要意义。以塔里木盆地台地相区寒武系和下奥陶统蓬莱坝组白云岩为研究对象,以岩石学和地球化学为主要手段,取得2点认识:一是下古生界绝大多数白云岩在浅埋藏阶段及以前就已经形成,进入深埋藏阶段,受残余蒸发卤水和热液2类流体的影响局部发生白云岩化,形成中—粗晶它形白云岩;二是深埋藏白云岩化作用通常表现为早期形成白云石的重结晶,晶体变大,加之较高的地层温度会造成白云石的过度生长,所以会堵塞原有的孔隙,是一种破坏性的成岩作用。
The Lower Paleozoic in the Tarim Basin has been in a deep burial environment for a long time in the geological history. It is of great significance to clarify the formation and remodeling process of the dolomite in the deep-burial stage and its influence on the reservoirs, and to explore the oil and gas in the deep dolomites. Taking the Dolomites of the Cambrian and the Lower Ordovician Penglaiba Formation in the Tarim Basin, Tarim Basin as the research objects, taking petrology and geochemistry as the main measures, we get two points: First, most of the Lower Paleozoic dolomite Shallow burial stage and before it has been formed, into the deep burial stage, by the residual evaporation of brine and hydrothermal fluids two kinds of local occurrence of dolomitization, the formation of medium-coarse crystalline dolomite it; the second is the deep burial dolomitization Usually appears as the early formation of dolomite recrystallization, larger crystals, combined with the higher formation temperature will cause dolomite overgrowth, it will plug the original pores, is a destructive diagenesis.