In The Area Of Songliao Basin In Gaotaizi Reservoirdiagenesis Research

摘要

Qijia region is located in the northern Song Liao Basin in the central depression area, Gaotaizi reservoir is a typical tight reservoir, the study of the effects of diagenesis on reservoir properties are conducive to further exploration development. The rock types of Gaotaizi reservoir is mainly lithic arkose. The maturity of element is low, mainly fine-grained. Primary pores are less, secondary pores are mainly intragranular dissolution pores. The average porosity of Gaotaizi reservoir is about 13.34%, the average permeability is 27.41×10~(-3)um~2. On the basis of including vitrinite reflectance, the highest pyrolysis temperature, the transformation of clay minerals of Illite/montmorillonite mixing layer, rock features, authigenic mineral assemblage of sandstone, Gaotaizi reservoir is belong to middle diagenesis. The types of diagenesis which affect development of reservoir are including: compaction, dissolution, cementation, metasomatism and Pressolution. According to the objective study of diagenesis types and the judgement of diagenetic stage, the area is divided into four kinds of diagenetic facies: forced compaction diagenetic facies, illite cement diagenetic facies, carbonate cementation diagenetic facies, feldspar dissolution diagenetic facies. The influences of diagenesis acting upon reservoir physical property are three ways: mechanical compaction, the deposit of calcite cementation, authigenic quartz and filaments illite and the inject of oil and gas destory the reservoir porosity; The chlorite cladding protects the reservoir; dissolution due to oragnic acid improving reservoir properties by the formation of secondary porosity to increase reservoir space.