Fine Characterization Of The Chang 6 Reservoir In North Block Of Tanjiaying Oilfield

The Sixth Member of the Yanchang Formation(Chang6 reservoir)in North Block of Tanjiaying oilfield has been taken as the research object in this thesis.This block currently has problems of poor water driving,rapid water seepage and ineffective water injection in some wells.In order to improve the well productivity and the development effect,on the basis of the original geology,the data of core,well logging,logging and dynamics data have been used to accurately describe the reservoir in a detailed way than before,which including the stratigraphy subdivision,structural characteristics,sedimentary facies,sand body distribution,reservoir characteristics,oil reservoir characteristics and reserve recalculation.The main understanding and conclusions are as follows.According to the characteristics of sedimentary cycle,lithology,well logging and marker layer of Chang6 reservoir,the composition of the Chang 6 reservoir is Chang 61-1,Chang61-2,Chang62'1,Chang62-2,Chang63 and Chang64.The study area is delta front subfacies deposition,and the main microfacies are underwater distributary channel,distributary bay and channel flank.Among them,the underwater distributary channel deposition is the most developed,and its sand bodies are important oil and gas reservoir.The tectonic pattern is EW-NE distribution,and local micro-structures such as small depressions,small trenches,small synclines and small nose-shaped trenches are distributed side by side gradually decreasing from east to west.The pore types of the Chang 6 reservoir are mainly intergranular pore,followed by feldspar dissolution pore and turbidite dissolution pores,few debris dissolution pore develop.The rock type is fine-grained feldspar sandstone,containing a small amount of coarse sandstone and siltstone,The sorting of debris particles is medium-better.The cementing type is mainly porous cementing,and the particles are mainly in line contact.Average porosity of the Chang6 reservoir in study area is 9.2%,average permeability is 0.73mD,The Chang 6 oil layer group is a tight sandstone reservoir with ultra-low porosity and ultra-low permeability.The Chang62 stratigraphy subdivision in the study area is relatively well connected,locally connected,distributed in a band shape,with good oil-bearing properties and strong heterogeneity,and is the main stratum of the study area.The Chang 64 stratigraphy subdivision has poor connectivity and poor heterogeneity.The study area has no boundary water and no bottom water,belonging to elastic-dissolved gas flooding lithologic reservoir.The sand body of the Chang 62-2 stratigraphy subdivision has a wide spread area and good oil content.Tight sandstone reservoirs are close to high-quality source rocks,and the reservoir formation conditions are superior.The main controlling factors for oil and gas accumulation in the study area are jointly controlled by sedimentary microfacies and high-quality reservoirsAccording to the characteristics of the reservoir,the reservoir of Chang 6 oil layer group in the study area is divided into three categories:?,?,and ?.On the basis of reservoir evaluation,the favorable area selection criteria are established,and the favorable area ?,?and III reservoirs are selected as Further exploration provided the basis.