筇竹寺和五峰—龙马溪组页岩地震岩石物理等效模型及等效孔隙纵横比的分析（英文）

发布时间：2018-07-04 10:32

本文选题：筇竹寺组页岩 + 五峰-龙马溪组页岩　；参考：《Applied Geophysics》2017年03期

【摘要】：四川盆地及其周缘地区的筇竹寺组和五峰-龙马溪组页岩是目前国内页岩气勘探的主要层位之一,但其地震弹性性质响应规律的区域性特征需要开展相关的实验和理论研究工作予以明确。本研究对干燥状态下的筇竹寺组和五峰-龙马溪组页岩的露头样品进行了超声波速度测试,系统地分析了地震弹性性质随页岩岩石学特征的变化规律。研究结果表明,孔隙度与粘土矿物含量呈正相关、与脆性矿物含量呈负相关;粘土、石英、长石和碳酸盐构成页岩岩石基质,与孔隙共同构成页岩岩石骨架,而干酪根和黄铁矿主要赋存于孔隙中,与页岩骨架的耦合较弱。通过将全部连通性孔隙近似等效于仅存在于骨架粘土矿物之内和采用Gassmann流体替换类似的思路处理干酪根和黄铁矿,可以较为简单地将自相容近似(SCA)理论、微分等效介质模型(DEM)和Gassmann方程组合起来构建研究区页岩的地震岩石物理等效模型。该模型通过关键参数等效孔隙纵横比(采用研究区样品平均值或者由碳酸盐含量进行估算)可以较为准确地预测筇竹寺和五峰-龙马溪组页岩的纵波速度,验证了等效模型的有效性和较广的适用性,可为筇竹寺组和五峰-龙马溪组页岩气储层的测井解释和地震"甜点"预测提供依据。
[Abstract]:The shales of Qiongzhusi formation and Wufeng Longmaxi formation in Sichuan Basin and its surrounding areas are one of the main strata of shale gas exploration in China at present. However, the regional characteristics of seismic elastic response need to be determined by relevant experiments and theoretical studies. The ultrasonic velocities of outcrop samples of Qiongzhusi formation and Wufeng Longmaxi formation in dry state were measured, and the variation of seismic elastic properties with the petrological characteristics of shale was systematically analyzed. The results show that porosity is positively correlated with clay mineral content and negatively correlated with brittle mineral content, clay, quartz, feldspar and carbonate constitute shale rock matrix, and together with pore form shale rock skeleton. Kerogen and pyrite mainly occur in pores, and the coupling between kerogen and shale skeleton is weak. By treating kerogen and pyrite using Gassmann fluid to treat kerogen and pyrite, it is easy to apply the theory of self-compatibility approximation (SCA) by approximating the total connected pores to the skeleton clay minerals only and using Gassmann fluid to replace the similar idea of kerogen and pyrite. The differential equivalent medium model (Dem) and Gassmann equation are combined to construct the seismic rock physical equivalent model of shale in the study area. The model can accurately predict the longitudinal wave velocities of Qiongzhusi and Wufeng Longmaxi formation shale by using the key parameter equivalent porosity ratio (using the average value of samples or estimating the carbonate content). The validity and wide applicability of the equivalent model are verified, which can provide the basis for logging interpretation of shale gas reservoirs in Qiongzhusi formation and Wufeng Longmaxi formation and prediction of seismic "dessert".
【作者单位】：北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室;地下信息探测技术与仪器教育部重点实验室(中国地质大学北京);
【基金】：sponsored by the National Natural Science Foundation of China(No.41274185 and 41676032)
【分类号】：P618.13;P631

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