川东北元坝气田长兴组生物礁精细刻画及储层预测

Fine Characterization of Reefs and Reservoir Prediction of Changxing Formation in Yuanba Gas Field of Northeastern Sichuan Basin

四川盆地川东北元坝气田长兴组生物礁气藏是目前埋藏最深的气藏,埋深超过6000m。二叠系长兴组台地边缘生物礁礁体规模小、分布散,纵向发育多期,平面组合方式不一,储层薄、非均质性强、气水关系复杂。为实现水平井水平段长穿优质储层,提高开发效率,开展了生物礁精细刻画及储层预测:利用古地貌恢复和地震反射特征技术,结合三维可视化雕刻技术,刻画了生物礁及其内幕期次;运用地质统计学反演技术提高了储层预测的精度。结果表明,元坝生物礁沿台缘呈条带展布,不同礁带内部礁体发育单期或多期礁;优质储层主要发育于礁盖部位,预测结果与钻井揭示结果符合度较高,为元坝气田开发方案的编制和井位部署提供了技术支撑。

Reef gas reservoir of Changxing Formation was the deepest buried gas reservoir in the northeast Sichuan Basin,of which the buried depth was more than 6000m.The biological reefs of the Permian Changxing Formation were small scaled and scattered with multi-stage development vertically,plane combination style was different with thin reservoir,strong heterogeneity,complex relationship between gas and water.The key points included fine characterization of small reef body and thin reservoir prediction.From the development point of view,to realize the high quality reservoir in long horizontal section of horizontal wells,improve development efficiency,fine characterization of reefs and reservoir prediction were carried out.The reef and insider periods were studied by adopting Paleogeomorphic restoration and seismic reflection characteristics and combined with 3D visualization engraving technology.The accuracy of reservoir prediction was improved by geostatistical inversion.The results indicate that the reefs of Yuanba Gas Field are strip distribution along with the edge of the platform,the reefs are developed in single period or multi-periods in the inside of different reef zones.High quality reservoirs are mainly developed in the reef cover.The forecast results are in line with that of well drilling.It provides a technical support for the production planning and well location deployment in Changxing Formation of Yuanba Gas Field.