四川盆地长兴组遂宁高带礁滩体储层预测方法

目前针对礁滩体的识别与储层预测总体以礁滩体的井震响应特征、沉积或古地貌背景以及地震解释三方面入手，综合模型正演、地震相分析、地震属性分析、古地貌恢复及地震反演等技术，根据地震反射特征、地震属性(振幅、频率、相位)及波阻抗的变化识别礁滩体。上述方法对厚度较小、地震波形特征不明显的礁滩体的识别效果较差，且受二维地震资料的采集年代、位置、线间距、处理参数等因素的限制，对钻井资料以及地震资料品质要求较高。为此，以长兴组地层展布—礁滩体展布—礁滩体储层分布逐级递进的研究思路，基于前人研究成果，针对四川盆地上二叠统长兴组遂宁高带礁滩体，分两步预测礁滩体储层分布：首先识别礁滩体，通过分析礁滩体地震响应特征，结合地震相识别、古地貌恢复等明确礁滩体展布特征；其次预测礁滩体储层，运用正演模拟分析礁滩体储层的地震响应特征，结合地震属性分析与地震反演准确预测遂宁高带礁滩体储层分布。预测结果表明，遂宁高带礁滩体规模较大，共发育三排礁滩体，呈北西—南东向雁列式展布，其储层发育程度受古地貌和礁滩体距武胜—蓬溪台凹的距离共同控制，自南西向北东逐渐发育，且礁滩体非均质性较强，储层分布不均匀。

Reef-bank body reservoir prediction method for Suining high zone in Changxing Formation,Sichuan Basin

At present, the identification and reservoir prediction of reef-bank bodies are generally based on well-seismic response characteristics, sedimentary or paleogeomorphic background, and seismic interpretation. The reef-bank bodies are identified according to the changes in seismic reflection characteristics, seismic attributes (amplitude, frequency, and phase), and wave impedance by using technologies such as forward modeling, seismic facies analysis, seismic attribute analysis, paleogeomorphic restoration, and seismic inversion. However, the above methods have poor identification effect on reef-bank bodies with small thickness and unobvious seismic waveform characteristics and have high requirements on the quality of drilling and seismic data due to the limitation of acquisition time, location, line spacing, processing parameters, and other factors of two-dimensional seismic data. Therefore, this paper carries out a study following the sequence of Changxing Formation distribution, reef-bank body distribution, and reef-bank body reservoir distribution and predicts in two steps the reef-bank body reservoir distribution in Suining high zone in Changxing Formation of Upper Permian in Sichuan Basin based on previous research results. First, the reef-bank body is identified, and the distribution characteristics of the reef-bank body are defined by analyzing the seismic response characteristics of the reef-bank body and utilizing seismic facies identification, paleogeomorphic restoration, etc. Second, the reef-bank body reservoir is predicted, and the distribution of the reef-bank body reservoir in Suining high zone is accurately predicted by analyzing the seismic response characteristics of the reef-bank body reservoir through forward modeling and employing seismic attribute analysis and seismic inversion. The prediction results show that the reef-bank body in Suining high zone is large in scale, with three rows of reef-bank bodies developed, and these reef-bank bodies are distributed in echelon from northwest to southeast. Furthermore, their reservoir development is jointly controlled by the ancient landform and the distance between the reef-bank body and the Wusheng-Pengxi Sag, and the reservoir gradually develops from southwest to northeast. In addition, the heterogeneity of the reef-bank body is strong, and its reservoir distribution is uneven.