莺歌海盆地低孔渗储层测井相分类及渗透率评价方法研究

Research of Logging Facies Classification in Low Porosity and Low Permeability Reservoirs and Method of Permeability Evaluation in Yinggehai Basin

随着莺歌海盆地天然气勘探开发的不断深化,低孔低渗储层渗透率的精确确定成为东方气田群中深层储层测井解释评价亟待解决的关键问题。气田中深层储层岩石颗粒细且岩性复杂,导致常规的孔渗关系变化繁杂,用传统的岩心孔渗统计回归方法及常规测井解释方法计算的储层渗透率精度较低,存在一个数量级的误差。为提高低孔低渗储层渗透率精度,切实解决低孔低渗气藏勘探开发的实际问题,首先采用基于聚类分析方法的测井相分析技术对储层测井相进行分类,然后利用岩心孔渗、铸体薄片、激光粒度等试验分析资料对储层测井相进行标定及小类合并,使同类相具有更相似的岩石学特征,进而在测井相约束下,针对不同岩石物理相类型的储层分类建立渗透率计算模型。实际应用表明,该方法适用于东方气田群中深层储层测井渗透率的评价,能有效提高渗透率计算精度。

Along with the deepening of exploration and development of natural gas in Yinggehai Basin , the accurately determining the permeability in low porosity and low permeability reservoirs was the problem needed to be solved badly in Dongfang Gasfield.In the gasfield , particles were fine and lithology was complex in mid-deep reservoirs , by which the complicated conventional relationship was induced between porosity and permeability.Therefore the accuracy calculated by conventional core permeability statistical and regressive method and conventional logging methods was lower and the error was in a quantity degree.In order to increase permeability precision and resolve practical problems in exploratory development for low porosity and low permeability low porosity gas reservoirs and strictly solve the problems of exploration and development in low permeability low porosity gas reservoirs , logging facies were identified by using the logging analysis techniques based on cluster analysis method , and then the data of core porosity and permeability , casting thin section and laser grain , were used for calibrating the logging facies and combination of subdivision.Make sure the same electrofacies has similar petrological character.Finally , apermeability model is established according to different petrophysics and electrofacies types.Practical application results indicate that electrofacies assorting method is suit for permeability evaluation in Dongfang Gasfields and it can effectively improve precision of permeability evaluation.