Research and Application of Tracing Well Test in the Gas Field of Multi-strata

Abstract

H gas field is a low permeability and porosity gas reservoir with mainly carbonate rock and edge and bottom water. The gas field is exploited by multiple strata and the seepage system of each of the strata is different. Through combination with geologic characteristics of different reservoir types, tracing well test technology is applied to research on characteristics of all pressure build up well test curves in H gas field. The interpretation precision and reliability has been effectively improved. Raising and deepening the cognition about each of the strata meets the actual status of the reservoir. The result indicated that the horizontal well characteristics of horizontal wells are obvious, porous reservoirs for the performance are the apparent homogeneous models, fractured porous reservoirs for the performance are the dual medium models. The fractures are the main seepage channels, pores are the main reservoir spaces. Bioclastic limestone reservoir is the performance of the double porosity reservoir. Late pressure derivative curves go up with edge response characteristics and reservoir permeability change is weaker and stress sensitivity decrease in Bioclastic limestone reservoir. Donghe sandstone reservoir is homogeneous model characteristic, the change of reservoir permeability is smaller and reservoir stress sensitivity is weaker. Ordovician carbonate rocks reservoir is the dual medium reservoir characteristic. The higher reservoir permeability indicate that fractures of the reservoir are more developed, permeability change is weaker in water-unbreak through wells and formation coefficient decrease in water-breakthrough wells in ordovician carbonate rocks reservoir. On the basis of tracking well test research, combined with reservoir characteristics and development characteristics of each well, development adjustment countermeasures of H gas field are formulated according to different well test models. Research and application of tracing well test on well test curve characteristics provides the helpful basis for high-efficiency development in H gas field and will be taken as a reference for the development of other similar gas fields.