Evaluation Of Chang 6 Reservoir And Prediction Of Favorable Areas In Huluhe Area, Ordos Basin

Reservoir is the main controlling factor of distribution range and enrichment degree of oil and gas reservoirs.Reservoir evaluation is the key link of exploration and development of oil and gas reservoirs.The result of reservoir evaluation will directly affect the effect of oil and gas reservoir development.In this paper,the Chang 6 reservoir group in Huluhe area is taken as the research object.By fully collecting drilling and logging data and combining with laboratory analysis,the main controlling factors of reservoir are analyzed,and the reservoir of Chang 6 reservoir in Yanchang formation is classified and evaluated,and the favorable areas are screened.Through the above research and analysis methods,the following main understandings and achievements have been achieved.(1)Chang 6 reservoirs in this area gradually shrink from Chang 63,Chang 62 to Chang 61,and their physical properties are poor.The area of reservoirs with relatively good physical properties is also gradually decreasing.The physical properties change rapidly in plane,the barriers develop and the reservoir heterogeneity is strong in the area.(2)Chang 6 reservoirs of the study area is in the late diagenesis stage A,and has undergone compaction,cementation and dissolution in buried diagenesis.The sandstone types of reservoirs are more common in feldspar sandstone and chock feldspar sandstone,while Chang 6 reservoirs mainly develop intergranular pores and Shirongkong.As the main laryngeal channel type of 6 reservoirs of Yan 'an group leader,the small larynx and neck larynx of pore shrinkage are studied.The average permeability of 6 reservoirs is 1.08?m2 and the average porosity is 10.2 %.Chang 6reservoirs generally belong to the ultra-low porous special low permeability reservoir.(3)Chang 6 reservoir in this area is divided into four types.The first type of reservoir is mainly fine-grained sandstone with good physical properties and oil-bearing properties.This type of reservoir develops in some horizons and parts of the study area,and has a small horizontal distribution.The second type of reservoir mainly distributes in the main belt of turbidite sand body.The pore types of reservoir mainly develop intergranular pore and feldspar dissolution pore,and the porosity and permeability of reservoir are relatively high,the average thickness of sand body is large,the heterogeneity is weak,and the reservoir is relatively good.The three types of reservoirs are mainly distributed in turbidite sand bodies.The pore types of reservoirs are mainly secondary dissolution pore,and the porosity and permeability of reservoirs are low.Four types of reservoirs are mainly distributed in the edge of turbidite body,with low porosity and permeability,thin average thickness of reservoir sand body,and strong heterogeneity of reservoir,which belongs to the worst reservoir type in the study area.(4)The productivity of a single well in the study area is influenced by many factors,such as porosity,permeability,effective thickness,oil saturation,acoustic time difference and resistivity.According to the result of comprehensive reservoir evaluation,the area of class I favorable area is 115 km2,class II favorable area is 190km2,and oil-bearing area of 11 class III favorable area is 372 km2.