廊固凹陷沙三段深层砾岩体油藏成岩作用与储层孔隙关系研究

廊固凹陷沙三段深层砾岩体油藏埋深在3500m以下，砾石成分以元古界灰岩为主，成岩作用强烈，属晚成岩期。成岩作用主要有3种：压实、胶结和溶解。溶解作用使砾岩体储集层次生孔隙发育，渗透能力提高，是形成深层砾岩体油藏的必要条件。在高温条件下灰岩的溶解度低于云岩的溶解度，因而云岩砾岩储集层孔隙度较灰岩砾岩储集层发育，油气成藏条件明显优于灰岩砾岩储集层。

Relation of diagenesis and pores in conglomerate reservoir of deep Sha 3 formation of Langgu sag

Conglomerate reservoir in deep Sha 3 formation of Langgu sag was buried below 3 500 m. The conglomerate is mainly Proterozoic limestone showing striking diagenesis of late genetic stage. The diagenesis was mainly compaction , cementation and dissolution. It was dissolution that resulted in developed secondary pores and improving of permeability of conglomerate reservoir, and was a necessary condition of forming deep conglomerate reservoir. At high temperature, the solubility of limestone is lower than that of dolomite, therefore the porosity of dolomite conglomerate reservoir is more developed than that of limestone, and reservoir forming conditions were also better than that of limestone conglomerate reservoir.