Abstract: As the energy in ZH1-2L oil group of Wenchang HDB oilfield is insufficient and the production speed and recovery degree are both low,the analysis on reservoir heterogeneity needs to be carried out.As for ZH1-2L oil group,it is mainly of siltstone,fine sandstone and argillaceous siltstone and fine sandstone,interbedded with sandstone and mudstone.It belongs to medium-high porosity and low permeability reservoir,the reservoir heterogeneity is serious,and the argillaceous interlayer in internal reservoir is developed.From three aspects,the reservoir heterogeneity analysis has been carried out.The results indicate the sand body thickness has a stable distribution and the plane is relatively homogeneous.As for intra-formational heterogeneity,it belongs to heterogeous-homogeneous model.By using the casting thin sections method in core experimental analysis and the capillary pressure curve method,the reservoir in ZH1-2L group is proved to have strong the microscopicheterogeneity and poor micro pore throat structure development.