Study On Deep Exploitation Of Du84 Block In Liao He Field

Du 84 block Xinglongtai reservoir has entered the late CSS(cyclic steam stimulation)developing period, the cyclic steam stimulation method effects and the production of the horizontal wells have been decreasing year by year, the developing effects of the horizontal wells have been prominently increasing. The adoption in horizontal wells to extract interwell remaining oil during the late vertical-well-developing period has become a trend. In order to extract remaining oil and enhance recovery of Xing Ⅱ-Ⅳ layer group, elaborate geology description of the reservoir, building three-dimensional geological model, scientific arrangement of horizontal wells for thin layers and reasonable allocation of horizontal well parameter are the key points for the late developing period.This paper consists of the deep study on the geological characteristics of DU 84 Xing Ⅱ-Ⅳ layer group and the feasibility research of the development methods. With the combination of these two studies, the geology region of the potential reservoir can be determined.In this paper, five categories of original data have been used to describe the geological characteristics of DU 84 Xing Ⅱ-Ⅳ layer group.By using geological modeling software —PetrelTM, Xing Ⅱ-Ⅳ layer group random three-dimensional geological model has been built.Bases on the geological characteristics and developing status, the remaining oil distribution has been determined. By comparing the experiment results and referring to the advanced modes of production from all over the world, the developing method has also been chosen.Geology research shows that Xing Ⅱ-Ⅳ layer group can be divided into 3 sandstone layer groups including 8 layers. Wherein Xing Ⅱ can be divided into 2 sandstone layer groups including 5 layers and Xing ⅡI can be considered as 1 sandstone layer group including 3layers. By combining well logs data and seismic data, the locations of three boundary faults have been rectified. Their main functions are to control the sedimentation and the tectonic structure and development of the reservoir. The cancellation of 3 intra-block faults makes the tectonic structure in the block more reasonable. The tectonic structure of each layer has a west-east decreasing incline feature, forming a southeast tilted monocline structure.According to the analysis of the stratigraphic correlation and sand body distribution characteristics, the provenance of the target layers mainly came from north and northwest.The zonal sand bodies mainly developed in the south and east of the lower part of this structure. In the north and northwest of the higher structure region, sand body thickness decreased, especially along the lateral orientation of the sand body and the sand body did not spread out in this region. Studies on the development methods suggest that for the wells with single layer thickness more than 10 m and located in the poor reservoir connectivity area, layer adjustment and supplement method can be applied. In the region where interwell remaining oil accumulated and in line with the single sand body distribution characteristics, should the layer thickness is between 5m and 10 m, thin layer horizontal infill well method will be applied; should the layer thickness is more than 10 m, dual horizontal well SAGD method willbe applied.By using the dimensional geological model, 634 wells with layer thickness more than10 m are found in the poor reservoir connectivity geological region, including 60 regions line with the single sand body distribution characteristics and with layer thickness between 5m and 10m, 10 regions more than 10m.