塔河南部志留系柯坪塔格组层序地层及沉积相

STRATIGRAPHIC SEQUENCE AND SEDIMENTARY FACIES OF KEPINGTAGE FORMATIONIN THE SILURIAN AT THE SOUTH AREA OF TAHE OILFIELD

依据岩芯、露头、测井和地震资料,将塔河南地区志留系柯坪塔格组划分为SQ1、SQ2两个三级层序,主要为障壁滨海—浅海沉积体系。层序SQ1低位体系域(SQ1–LST)发育于柯坪塔格组下段,主要为中潮坪(混合坪)沉积,海侵体系域(SQ1–TST)发育于柯坪塔格组中段,主要为浅海陆棚沉积,高位体系域不发育;层序SQ2仅保留低位体系域(SQ2–LST),发育于柯坪塔格组上段,主要为低潮坪(砂坪)沉积。在此基础上,编制了塔河地区南部志留系柯坪塔格组不同体系域的沉积相平面分布图,为该区储层预测提供了依据。

Well S112-2 drilled in the south of Tahe Oilfield found commercial oil accumulation in the SilurianKepingtage Formation.Based on the crops,logging and seismic data,the Kepingtage Formation is divided intotwo third-sequences.The Silurian in the south of Tahe Oilfield develops coastal-offshore sediments with barriers.Accordingly,the Lower Member of the Kepingtage Formation corresponds to lower land systems tracts of SQ1(SQ1-LST),which mainly develops middle tidal flat(mixed flat)sediments;the Middle Member of the KepingtageFormation corresponds to transgressive systems tracts of SQ1(SQ1-TST),forming the offshore continental shelfsediments;the Upper Member of the Kepingtage Formation corresponds to the lower land systems tracts of SQ2(SQ2-LST),which forms primarily the lower tidal flat(sand flat)sediments.In the south of Tahe Oilfield,thestudy also compiles sedimentary subfacies distribution maps of the above three system tracts of the Silurian,whichprovides the basis for further reservoir prediction in the area.