火成岩遮挡下储层展布特征及影响因素评价

Evaluation of reservoir distribution characteristics andinfluencing factors under the shielding of igneous rocks

黄河口凹陷A油田东三段发育辫状河三角洲沉积,东一、二段沉积时期,火山活动强烈,发育大套火成岩,针对上覆火成岩遮挡影响地震成像、火成岩分布影响储层预测等难点,通过开展井震精细标定、地震属性、地震相分析,并结合火成岩遮挡下的地震正演实验分析,建立水下分流河道、河口坝、前缘席状砂和前三角洲泥不同沉积微相识别标准,利用振幅属性研究定量刻画储层砂岩含量及展布,并分析储层平面非均质性影响因素,结果表明断层根部低洼区发育溢流相火成岩、火山通道周边发育侵入相火成岩及沉积相带变化导致储层砂岩含量降低。将该成果应用于地质精细建模中,优化15口开发井井位,平均提高单井砂岩钻遇率22.3%,通过模型预测,提高采收率1.2%。

The sedimentary system of Ed3 formation in A oilfield is braided river delta.Ed1 and Ed2 formation develop large set of igneous rocks because of strong volcanic activities.Aiming at the difficulties of seismic imaging quality and reservoir prediction effected by overlying volcanic rocks,identification standards of underwater distributary channel,mouth bar,frontal sheet sand and predelta mud are established through accurate well-seismic calibrating and analysis of seismic attributes and seismic facies.Sandstone percent content and distribution are predicted by study of seismic amplitude attributes.Three main factors controlling reservoir plane heterogeneity are summarized,which are overflow facies volcanic rocks in low position nearby faults,intrusive facies volcanic rocks around volcanic channel and reservoir sandstone content decrease caused by sedimentary facies belt change.The result is applied to fine geologic modeling.Well location optimization of 15 development wells is conducted,the average single well sandstone drilling rate is increased by 22.3%and recovery ratio is increased by 1.2%through model prediction.