歧口凹陷深层储层控制因素与有效储层下限分析

Reservoir Controling Factors for Deep Clastic Reservoir and Analysis on Lower Limits of Effective Resrvoir in the Qikou Sag

歧口凹陷中深层碎屑岩储集性能总体为中-低孔~中低-特低渗型,深层（大于3500 m）储层中,低孔低渗储层占85%以上,储集空间类型主要为次生孔隙。虽然中深层储集体由于埋藏压实作用的影响,总体储集性能（尤其深层储层）偏差,但在沉积、压力、成岩等多因素的共同影响下,仍发育异常孔隙而成为有效的油气储集空间。有效储层是指在现有工艺条件下能够采出具有工业价值产液量的储集层,其下限具有动态变化的特点。以产液层孔隙度8.0%,产气层孔隙度7%作为当前勘探技术条件下划分深层有效储层的底界限,歧口凹陷勘探深度石油是4550 m,天然气大于5800 m,在渤海湾盆地内勘探深度较大。

The middle- deep clastic reservoir of Qikou Sag are medium- low in porosity and medium- low to ultra low in permeability on the whole,in deep reservoir（ deeper than 3500m）,the percentage of reservoir in low porosity and low permeability is higher than 85%,the main reservoir types are secondary pores. Although reservoirs are affected by compaction,which led to bad reservoir property,the abnormal pores were developed to provide reservoir space for oil and gas because of the common influence of sedimentation,pressure and diagenesis. The effective reservoir is a kind of reservoir in which well yield with industrial value can be obtained in the current process,the lower limits are dynamically changed. Taking the producing fluid reservoir with porosity of 8% and producing gas reservoir with porosity of 7% as the lower limits of deep effective reservoirs in the current process,in Qikou Sag,the exploration depth for oil is 4550 m; depth for gas is deeper than 5800 m,showing the deeper exploration depth in Bohai Bay Basin.