利用地震层速度和声波时差预测盖层封闭能力
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摘要
盖层封闭的最常见形式是毛管封闭和压力封闭。这两种形式的封闭能力与岩层的孔隙度、渗透率、砂泥岩含量比以及流体压力有密切关系。有鉴于此，可利用地震层速度和声波时差资料进行盖层封闭能力的预测。首先，运用拟合的经验公式计算岩层的孔隙度、剩余流体压力等物性参数；最后求取地层压力；然后进行盖层封闭能力的纵横向预测和评价。经与实测结果比较，盖层孔隙度的预测值绝对误差为－１３２～１３９，相对误差为３０７～１５４；突破压力的预测值绝对误差为－０２３～０６３ＭＰａ，相对误差为１８１～１２２７，均属允许范围。盖层封闭能力的纵横向预测结果都表明，由欠压实带形成的地层压力异常系统对油气的分布及运、聚、保起到了明显的控制作用。
The sealing capability of cap rocks is closely related to the porosity,permeability,the ratio of sand to mud contents and fluid pressure of the rocks.The sealing capability could be predicted by using seismic interval velotity and acoustic time.At first,fitted experiment formula is used to calculate some physical parameters such as porosity and residual fluid pressure,then calculate formation pressure,and finally predict and evaluate the sealing capabilities both laterally and vertically according to the calculated results.As compared with actual measured results,the absolute errors of the predicted porosity of seal rocks are-1.320/0～-1.390/0,their proportional errors are 3.070/0～15.40/0;and that the absolute errors of break out pressure are-0.23～0.63 MPa,their proportional error are 1.810/0～12.270/0.The results show that the abnormal formation pressune system resulted from uncompaction has obviously controlled the migration,accummulation,preservation and distribution of hydrocarbon.
The sealing capability of cap rocks is closely related to the porosity,permeability,the ratio of sand to mud contents and fluid pressure of the rocks.The sealing capability could be predicted by using seismic interval velotity and acoustic time.At first,fitted experiment formula is used to calculate some physical parameters such as porosity and residual fluid pressure,then calculate formation pressure,and finally predict and evaluate the sealing capabilities both laterally and vertically according to the calculated results.As compared with actual measured results,the absolute errors of the predicted porosity of seal rocks are-1.320/0～-1.390/0,their proportional errors are 3.070/0～15.40/0;and that the absolute errors of break out pressure are-0.23～0.63 MPa,their proportional error are 1.810/0～12.270/0.The results show that the abnormal formation pressune system resulted from uncompaction has obviously controlled the migration,accummulation,preservation and distribution of hydrocarbon.
引文
1DowneyMW．Evaluatingsealsforhydrocarbonacumulations．AAPGBul，1984，68（11）：1752～17602SchowoclterTT．Mechanicsofsecondaryhydrocarbonmigrationandentrapment．AAPGBul，1979，63（5）：723～7603真柄钦次．压实与流体运移（实用石油地质学）．陈荷立，邸世祥，汤锡元，等译．北京：石油工业出版社，1981．35～444庞雄奇，傅广，万龙贵，等．盖层封油气性综合定量评价．北京：地质出版社，1993．87～89
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