渤南油田油藏应力敏感性研究

Sensitivity of the reservoir stress in Bonan Oilfield

对渤南油田三、四、五区的低渗透油田岩石进行了系统的岩性、物性分析,结果表明,岩石的低孔、低渗是由沉积作用和成岩作用共同控制。沉积水动力复杂多变,岩石埋藏深,压实作用强,对于粘土矿物含量较少的岩石往往发育石英胶结、石英次生加大和方解石胶结等成岩作用,对岩石的孔渗特性造成了破坏。此外,岩石中发育的潜在微裂缝和较多的应力软弱面,决定了低渗透油田岩石具有较强的应力敏感性。实验研究发现,随净上覆压力的增加,渗透率具有5种下降趋势。随着净上覆压力的增加和减少,不同岩性岩石渗透率的下降、恢复趋势和幅度也不同,其与岩石中粘土矿物含量、有无方解石胶结、颗粒的分选性密切相关。

The lithology and physical property of the Third Block, Fourth Block and Fifth Block of low permeability oilfield in Bonan Oilfield are analyzed systematically, the result show that the low porosity and low permeability of the rock are controlled together by sedimentary process and diagenesis. The sedimentary water force is complex and variable, the rock are buried deeply, the compaction is strong, the diagenesis （quartz cementation, quartz over- growth, and calcite cementation and etc） are usually developed for the rock which have a little content of clay min- eral, and the porosity and permeability of the rock are destroyed. Moreover, the potential microfraetures and superi- or stress planes of the weakness developed in rocks which made the rock have stronger stress sensitivity in low permeable sublayer oilfield. The findings show that the permeability has five types along with the increase of the over- burden pressure. Along with the increase and decrease of the net overburden pressure, the decrease trend and amplitude and resume trend and amplitude are also different. It is in close relationship with the clay mineral content, with or without calcite cementation and granular classification in the rock.