川西北部鱼洞梁飞一段储层特征

CHARACTERISTICS OF T_1f_1 RESERVOIRS AT YUDONGLIANG IN THE NORTH PART OF WEST SICHUAN

研究了川西北部鱼洞梁飞一段储层特征 ,获得三方面基本认识。①处于台地边缘滩高能滩体的高部位 ,纵向上由亮晶鲕 (豆 )粒灰岩和粉、细晶颗粒白云岩组成一逐步变浅的沉积序列 ,②孔隙发育程度高且多被沥青充填 ,为一古油藏破坏后的产物。孔隙演化主要经历了胶结和溶解各三期成岩作用 ,成岩早、中期受强烈的混合水白云化和大气淡水溶解作用改造而形成高孔白云岩储层。③古油藏成藏最突出的特点 ,一是经历了成岩早期的混合水白云化作用 ,二是两期溶解均有大气淡水的参与 ,三是在高孔阶段进油成藏 ,四是时空配置得当。

The first member of Feixianguan Formation, Lower Triassic (T 1f1) at Yudongliang of Jiangyou County is at the higher portion of high-energy beach body of the platform edge facies, it being composed of a regressive sequence of the sparry oolitic (pisolitic) limestones and silty-fine crystalline granular dolomites on the vertical. It is the result of an ancient oil reservoir's being destroyed because of its highly-developed and asphalt-filled pores. The diageneses suffered mainly by pore evolution include three stages of cementation and three stages of dissolution. During the early-middle stage of diagenesis, the high porous dolomite reservoirs were formed owing to the reformation of the intensive dolomization of mixed water and the dissolution of meteoric fresh water. The outstanding characteristics of forming the ancient oil reservoir include suffering the dolomization of mixed water m the early diagenetic stage; having the participation of meteoric fresh water in two stages of dissolution; reservoirmg during high porous stage ; and having an exact time-space matching relation. Such a reservoiring example provides new ideas and new target horizons for oil and gas exploration.