复杂砂砾岩体岩性定量识别技术

Quantitative lithology identification technology of complex sand-conglomerate bodies

复杂砂砾岩体的岩性多样,缺少效果较好的岩性定量识别方法,为此,通过对大量岩性和测井信息进行比较和定量分析,形成了一套复杂砂砾岩体岩性定量识别的新型实用技术。以CH油田近物源砂砾岩扇体为研究对象,首先利用岩心、粒度分析及铸体薄片等资料精确落实部分岩性,并在此基础上建立交会图图版来确定关键岩性的测井响应值;其次利用阵列感应曲线区分泥岩、泥质砂砾岩和砂砾岩这3种岩性;再利用密度曲线进一步区分出砂岩、砾岩、泥质砂岩和泥质砾岩;最后利用三孔隙度(密度、声波时差、中子)及波阻抗等曲线区分出灰质砂岩与灰质砾岩,进而定量识别出复杂砂砾岩体的7种主要岩性。从识别结果上看,正确率总体在75%以上。

The lithologies of complex sand-conglomerate bodies are various, and effective lithology identification method is still lacked. Through comparing many lithologies and well logging data, a new quantitative lithology identification technology was formed. Near source sand-conglomerate bodies in CH Oilfield were taken as the study case. Firstly, some lithologies were accurately identified with cores, grain size and cast slice data, and the critical log values of key lithologies were determined based on cross plots. Secondly, sandstone, conglomerate, and sandy conglomerate were iden- tified with the array induction log curve. Thirdly, sandstone, conglomerate, muddy sandstone and muddy conglomerate were further identified with the density log curve. Finally, limy sandstone and limy conglomerate were identified with the critical values of three-porosity curves （DEN, A C, CNL） and wave impedance log curve, and altogether 7 kinds of litho- logics were identified in complex sand-conglomerate bodies. Judging from the results, the correct rate is more than 75%.