The Effect Evaluation Of Multi Thermal Fluid Huff-puff And Driving In The Typical Offshore Heavy Oil Reservoir

The N oilfield is a typical offshore heavy oil reservoir in China,horizontal well multi thermal fluid huff and puff is used to develop the actual block.However,with the increasing of huff-puff cycles,problems such as decreasing of reservoir pressure,breakthrough of edge-bottom water,and gas channeling gradually appeared.The decreasing of periodic production is obvious,and there is insufficient understanding of the problems existing in the development and replacement technology of huff-puff.Therefore,it is necessary to evaluate the current multi thermal fluid thermal recovery effect,to clarify its development mechanism,and to develop related researches on the transfer of flooding.Firstly,based on the knowledge of reservoir characteristics and fluid characteristics of the actual block in N oilfield,this paper systematically summarizes and analyzes the injection and production characteristics of multi thermal fluid huff-puff thermal recovery wells in typical offshore heavy oil reservoirs.Combining with the production dynamic curve and reservoir structural characteristics,the production pattern of thermal recovery of multi thermal fluid is divided,and the problems in development are analysed.Secondly,the numerical model of discrete wellbore is optimized to research the multi thermal fluid mechanism of horizontal wells.Then the study concluds the main mechanism of multi thermal fluid huff and puff: reducing viscosity by heat and gas,expanding sweep efficiency,gas assisted gravity drainage and improving the thermal efficiency.Meanwhile,it researches the driving mechanism combining with the feature of plane and vertical displacement.Finally,reservoir numerical simulation methods are used to evaluate the development effect of multiple thermal fluid in horizontal wells of typical heavy offshore oil reservoirs from the aspects of injection-production parameters and well patterns,etc.The results of this study are of guiding significance for improving the development effect of multi thermal fluid in offshore heavy oil reservoirs.