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超浅疏松地层压实程度低,未压实的粉砂质泥岩具有一定的孔隙度,与泥质粉砂岩的电性特征相接近,不易区分.本文针对这一难题,提出了稳定泥质单元控制下的岩性划分技术.该技术的核心思想是:在测井曲线上将厚层稳定的泥岩段定义为泥质单元,将泥质单元所分隔的大套砂体部分定义为非泥质单元.在泥质单元内采用电阻率的回返率和自然伽马的交会识别泥质粉砂岩和粉砂质泥岩;在非泥质单元内,按照沉积韵律控制下电阻率曲线的相对变化来区分泥质粉砂岩和粉砂质泥岩.而针对不包含在任何韵律内的2种岩性,采用3参数、4种电测曲线交会分区识别.以密闭取心井岩性分析结果为标准,采用该套技术共解释岩性58层,误判4层,岩性判别总符合率达到93.1%.其中,判别泥质粉砂岩和粉砂质泥岩32层,符合率达到87.5%.
The degree of compaction of ultra-shallow and loose strata is low, and the uncompacted silty mudstone has a certain porosity, which is close to that of argillaceous siltstone and can not be distinguished easily.In this paper, aiming at this problem, Lithology division under the control of the technology.The core idea of this technology is: the logging curve will be thick and stable mudstone section is defined as muddy unit, the muddy unit is divided into large sand bodies defined as non-argillaceous Unit. Argillaceous silty sand and silty mudstone are identified within the shaly unit using the resistivity return rate and the gamma ray rendezvous; within the non-muddy unit, the relative change in the resistivity curve is controlled according to the depositional rhythm Muddy siltstone and silty mudstone, while for the two kinds of lithology not included in any prosody, three parameters and four kinds of electrical measurement curves are used for intersection identification.According to the results of lithology analysis of closed cored well, The set of techniques explained a total of 58 layers of lithology, misjudged 4 layers, the total coincidence rate of lithology identification reached 93.1%, of which 32 layers of muddy siltstone and silty mudstone were discriminated, the coincidence rate reached 87.5%.