Differentiation Characteristics And Main Controlling Factors Of Dissolution Modification In Sandy Conglomerate Reservoirs

As one of the important fields of global oil and gas exploration,glutenite reservoirs have attracted extensive attention from scholars at home and abroad.It is characterized by low porosity and low permeability.Because the glutenite reservoir has a near-source system,the development of the dissolution pores of the reservoir is relatively complex,and the dissolution rule is not yet clear.Therefore,the research on the differentiation characteristics of the glutenite reservoirs has been carried out.The cause analysis is the problem that this thesis needs to solve.In this paper,the sand conglomerate reservoir of Baikouquan Formation in the west slope of mahu depression in junggar basin is studied.On the basis of respecting the previous research achievements and drawing on the research experience of the neighborhood,based on the theory of petroleum geology,sedimentary petrology and reservoir geology.Through analyzing the outcrop observing and the core chip,combined with core and logging data,in turn,has carried on the sedimentary facies,reservoir petrology features,reservoir physical property,reservoir research of particle size.According to the four sections of study above,the micro-corrosion characteristics and genesis of glutenite reservoirs have been analyzed,and the following achievements and understandings have been achieved.The dissolution of the reservoir in the study area is mainly manifested in three aspects: sedimentary microfacies(subaqueous distributary channel,debris flow,fan channel),rock type,and different minerals(dissolution of feldspar and cementation of kaolinite).There are differences in these three aspects in different well zones,and even in the same well zone,with the different layers,the above three aspects also have certain differences.This shows the characteristics of the reservoir corrosion phenomenon.The contrast between the pore throat parameters(hysical properties,pore types,and different grain sizes)and sedimentary types indicates that the reservoir characteristics of the low heterogeneity in the subaqueous distributary channel are obviously better than that of the gravity flow breccia represented by the clastic flow.But the porosity of the gravity flow sand conglomerate is lower than that of the traction flow sand conglomerate.Although the overall dissolution of the study layer is strong,the dissolution of different rock facies is different.The dissolution of tractive current glutenite(in underwater distributary channels)is relatively strong,and the dissolution of gravity flows glutenite(in the detrital stream)is relatively weak.In Ma 18,Aihu 2 and Ma 1 well area,the reservoir space of gravity flows glutenite mainly consists of intergranular pores,the proportion of primary intergranular pores is low.Although there are some primary intergranular pores in tractive current glutenite,the dissolution pores are mainly dominated by intergranular poresStudies have shown that the Baikouquan Formation on the west slope of Mahu depression has a total of two signs of hydrocarbon charging in different periods,while the Ma 18 well area,Aihu 2 well area,and Mahu 1 well area have experienced erosion of acidic fluids,respectively.Its distribution in the sedimentary microfacies space is also different.In the interval,it is shown that the layer with strong dissolution in the Aihu 2 well area,the Ma 18 well area and the Mahu 1 well area is located in the Baiyi section.