华庆探区长6_3储层破裂压力及裂缝开启压力估测与开发建议

Estimation of formation breakdown pressure and fracture open pressure of Chang 6_3 low permeable reservoir in Huaqing area and development suggestions

根据露头地层、钻井岩心及薄片等实物资料,结合古地磁岩心定向,对长63储层构造裂缝几何学等特征参数进行定量观测。结合储层现今应力状态数值模拟成果和岩石力学属性,对长63储层不同方向天然裂缝重新开启压力及储层破裂压力进行估算;预测储层裂缝开启压力和地层破裂压力分布,提出合理有效的注水压力范围。研究结果表明：长63储层破裂压力主要介于49.50-57.50 MPa之间,合理注水压力应控制在54.0 MPa以下,使得与现今最大水平主应力方向夹角小于40°的天然裂缝易开启,能有效地改善低渗储层渗流能力,提高石油高采收率。

On the basis of the observation of outcrops,drilling cores,thin-slices and the paleo-magnetic directions of the cores,detailed quantitative research was conducted on the tectonic fractures in Chang 63 reservoir,and the fracture essential characteristics in geometry were analyzed.Combining with the current stress field state,the fracture occurrence and their relationships,natural fracture open pressure in different directions were estimated in Chang 63 reservoir.Additionally,based on the reservoir rock mechanics and the distribution of the current stress field simulated by finite element models,oil-layer breakdown pressure was estimated.The plane distribution of the fracture open pressure and the oil-layer breakdown pressure were predicted.Simultaneously,reasonable and effective water-flood pressure in Chang 63 reservoir in Huaqing area was suggested.The results show that the oil layer breakdown pressure is 49.50 57.50 MPa,and the reasonable hydraulic pressure should be controlled under 54.0 MPa to open the natural fractures with an angle less than 40° with the direction of the maximum horizontal principle pressure,so as to effectively improve the vadose capacity of the reservoir and the recovery ratio.