渤海JZ区块变质岩潜山“坡积岩层”岩石特征及工程录井识别方法

Rock Characteristics and Engineering Logging Identification Method of “Slope Rock Stratum” in the Metamorphic Buried Hill of Block JZ in Bohai Bay Basin

摘要: 渤海JZ区块变质花岗岩潜山界面之上局部发育一套较薄的砂砾岩和砂岩(坡积岩层)。该坡积岩层厚薄分布不均，横向可对比性差，为现场钻井地质作业带来诸多问题。利用岩心、岩屑资料分析坡积岩的岩性特征，可分为长石砂岩和岩屑砂岩2种岩性，表明该坡积岩层应为2种不同成因形成的砂岩。通过分析工程录井参数与地层岩性的响应特征，应用钻井工程参数建立功指数和机械比能模型，结合其他录井手段，实现对潜山坡积岩的随钻实时判别。经过研究区多口井的实际资料处理与验证，随钻识别率高达86.7%，应用效果较好。

Abstract: There developed a suite of thinner sandy conglomerate and sandstones (slope rock stratum) over the interface of metamorphic granite buried hill in Block JZ of Bohai Bay Basin. The slope rock stratum was distributed with different thicknesses. Its lateral comparison was poor, by which problems were induced in drilling operations. The lithologic characteristics of the slope rock were analyzed based on core and cuttings data. The rock layer was divided into feldspathic sandstone and lithic sandstone, which indicated that the slope rock stratum was the sandstone of two different geneses. Based on analysis of engineering logging parameters and lithologic response characteristics of the formation, the parameters of drilling engineering are used to establish work index and mechanical specific energy models and combined with other logging means, the slope rock in the buried hill is identified in real-time while drilling. This method is used in several wells in the block with an identification rate of while drilling to 86.7%. It is proven that the method is effective.