千米桥潜山构造油气藏成藏分析

千米桥潜山构造位于黄华坳陷板桥构造带。1998年钻于该构造的板深7井在奥陶系试油，获凝析油143．36t／d、气275309m3／d，这一成果标志着大港油田古潜山的勘探获得了重大突破。印支期—早燕山期的挤压逆冲使石炭-二叠系遭受剥蚀，奥陶系长期风化淋滤大量形成晶间溶孔，挤压逆冲还使奥陶系形成大量裂缝。晶间溶孔与裂缝的有机配合形成了有利的储集条件，这是形成千米桥潜山奥陶系油气藏的重要因素。千米桥潜山的油气主要来源于板桥凹陷沙三3段烃源岩。沙三3段烃源岩具有良好的成烃条件，并在沙一段沉积末期开始向千米桥潜山排烃。千米桥潜山圈闭形成时间早（印支期—燕山末期），上覆中生界、沙三段泥岩盖层厚度可达1300m，第三纪的构造断裂活动对潜山构造影响很小，有利于潜山油气藏的保存。图5（姜平摘）

A pool formation analysis for Qianmiqiao buried hill structure

Qianmiqiao buried hill structure is located in Banqiao structural belt in Huanghua depression. Well banshen 7 produces oil 143. 36t/d,and gas 275309m3/d, showing an important discovery for buried hill reservoir exploration in Degang oil field. Compressive thrust made Paleozoic and Ordovician formations denuded and aeoated and disolved, which formed fractures and dissolved pores, which are very important porosity spaces. It is also the most important situation that Qianmiqiao Ordovician buried hill reservoir formed as well. Correlating source rocks with oil shows that Qianmiqiao oil is from the third member of Shahejie oil source rocks. Oil migrated into Qianmiqiao buried hill trap at the end of the first member of Shahejie, which is later than the trap formation of Qianmiqiao buried hill. The thickness of shale cap of Mesozoic and Shahejie is over 1300m. The tertiary structural faulting had little influence on buried hill, which is favourable for conservation of Qianmiqiao buried hill reservoir.