元坝地区须家河组三段钙屑砂体特征及成因

Features and Genesis of Calcarenaceous Sandbody of Member 3 of Xujiahe Fm in Yuanba

针对元坝地区须家河组三段有效储集体钙屑砂体研究较薄弱等问题,利用钻井、测井、分析化验等资料对钙屑砂体特征及其成因展开了研究。结果表明:须三段钙屑砂岩成分成熟度较低,其沉积具有交替与突变的特点;纵向上,钙屑砂体在须三中亚段最为发育,须三上亚段次之;平面上,钙屑砂体呈条带状、扇状由北西向南东厚度逐渐变薄;龙门山幕式造山运动控制着沉积环境和物源供给的幕式变迁,进而控制着钙屑砂体的沉积规模;热湿、温干交替变化的气候条件控制了钙屑砂体的发育时期。研究结果对预测须三段有利储集体具有指导意义。

A major breakthrough has been achieved in the hydrocarbon exploration of Member 3 of Xujiahe Fm. Considering the deficient study on calcarenaceous sandbodies of effective reservoir,the drilling,logging and laboratory test data are used to study the features and genesis of calcarenaceous sandbodies. Study shows that the Member 3 of Xujiahe Fm calcarenaceous sandbodies are featured by low compositional maturity,alternating and mutational sedimentary. Longitudinally,calcarenaceous sandbody is most developed in the middle part of Member 3 of Xujiahe Fm,and followed by the upper part. In the plane,the thickness of banded and fan-shaped calcarenaceous sandbodies increases from NW to SE. Longmenshan episodicorogeny controls episodic change of sedimentary environment and source supply,and then controls sedimentation scale of calcarenaceous sandbodies. The alternatinghot-wet,warm-dry climate controls the development stages of calcarenaceous sandbodies. This study could guide the prediction of favorable reservoirs of Member 3 of Xujiahe Fm.