Analysis Of Inter-well Sand Body Connectivity And Dynamic Effects Of Injectionproduction In Chang 6 Reservoir In Yanwumao Area

In this study,the Chang 6 low-permeability reservoir in Yanwumao area is used as the research object.By using the data of drilling,logging,well logging and production dynamics,and combining the static analysis with dynamic verification,this paper makes an in-depth study on the inter-well sand body connectivity and dynamic effects of injection-production.According to the regional criteria layer and the auxiliary marker layer,the target layer is divided and compared,and the structure of the top surface of the small layer and the distribution characteristics of the sedimentary microfacies are clarified.A single layer will be divided according to the stable development of mudstone in the area,the method of"single well determination of microfacies,connecting-well determination of boundary,multi-section delineation of sand body"was combined with the method of elevation comparison and thickness prediction to circle the single sand body.Based on the research results of stratigraphic division and comparison,sedimentary microfacies division,etc.,the sequential indication simulation and sequential Gaussian simulation methods are used to carry out three-dimensional geological modeling of the study area.The variational function suitable for the geological conditions of each layer in the study area is used to predict the unknown area between Wells.By combining the sedimentary microfacies and attribute models obtained by geological modeling software with the production dynamic data,the inter-well connectivity was comprehensively judged.The Chang 6 reservoir group is divided into four subgroups,Chang 6₄,Chang 6₃,Chang 6₂and Chang 6₁ from the bottom to top.Chang 6₂ is divided into three small layers,Chang 6₂³,Chang 6₂² and Chang 6₂¹,and Chang 6₁ is divided into three small layers,Chang 6₁³,Chang 6₁²and Chang 6₁¹.The structural evolution of each small layer shows obvious inheritance,which is a gentle west-dipping monocline.The study area mainly develops microfacies of underwater distributary channels,mouth bar,distal bar,and interdistributary bays.The Chang 6₁³ small layer was divided into Chang 6₁^3-1 and Chang 6₁³-2-2 two single layers.By drawing the distribution map of the single layer sand body,it was found that the distribution of the sand body in the underwater distributary channel was large,the distribution range of the sand body in the mouth bar was smaller than that in the underwater distributary channel,and the distribution of microfacies in the interdistributary bays was limited.The contact modes of sand body in the study area mainly include isolation type,up and down contact type,up and down superposition type and lateral superposition type.The stacking types of Chang 6₂¹ small layer sand bodies were divided into five types:thick and thick stacking area,thick and thin stacking area,thin and thin stacking area,isolated thick sand body and isolated thin sand body.The sand body connectivity of the main strata in the study area in Chang 6₁³ and Chang 6₂¹ is defined.The lateral stacking degree of the sand body in the study area is large,and the sand body continuity is good.The sand body connectivity is mainly affected by the stratigraphic framework,the thickness of the sand body and the internal structure of the sand body.Combined with the production dynamic data,it is found that the water injection within the same single sand body is effective and has good connectivity,and the connection between the injection well and the production well is parallel to the direction of the river,which has the advantage of relatively fast water drive velocity.The research results are of guiding significance to the development adjustment of the research area,the effective use of reserves and the improvement of oilfield production efficiency.