济阳坳陷沾化凹陷古近系沙四段现今压力场特征及其与油气分布的关系

利用实测压力数据和通过平衡深度法计算的压力值,恢复了沾化凹陷单井压力剖面,划分了单井纵向压力变化序列类型,指出沾化凹陷古近系沙河街组存在正常压力-过渡压力型、过渡压力-异常高压型的2种不同类型的次洼。压力场的纵向叠置决定了油气的分布,沙河街组四段油层与压力场耦合关系可以总结出:异常高压型油层、压力过渡型油层、正常压力型油层3种耦合模式,而研究表明压力与岩性双重封堵的模式对沙四段高产油层的形成最为有利。过渡压力-异常高压型次洼中-深部正常压力带和压力过渡带是获得沙四段高产油层的有利区带。

Characteristics of the present pressure filed in the Paleogene Sha-4 Member of Zhanhua sag,Jiyang depression and their function to the distribution of oil and gas pools

The measured pressure data and pressures calculated with balanced depth method are used to reconstruct pressure profiles and classify vertical pressure variation sequences in single well in Zhanhua sag.Two different types of sub-sag,i.e. sub-sags with normal-transitional and transitional-abnormal pressure,are recognized in the Paleogene Shahejie Formation in the sag where the vertical superimposed pressure field controls the distribution of oil and gas pools.There are three modes of coupling relationships between the reservoirs in the 4th member of Shahejie Formation(Es4) and the pressure fields: abnormal-pressure reservoirs,transitional-pressure reservoir,and normal-pressure reservoirs,among which the mode that oil with double lithologic and pressure seal are the most favorable to the formation of high yield reservoirs.The middle-deep normal pressure zone and transitional pressure zone in sub-sag of transitional-abnormal pressure are potential plays for the disco-very of high yield oil layers in the Es4.