Study On Seepage Field And Stress Field Of Near - Well Wall In Completion Of Open Hole And Perforation Completion Of Yuanba

YuanBa area gas reservoir, average depth of6673meters, is a large Marine gas field with high temperature, high pressure and high sulfur etc, belongs to the typical "high-risk" gas field, which are difficult to develop with uncontrollable safety problems.So this article mainly do research from the perspective of seepage field and stress field to the vertical Wells and horizontal Wells with open hole completion method, vertical Wells and horizontal well with perforation completion method, at the same time the two phase seepage analysis was carried out on the edge or bottom water gas reservoir.Through the experiment, the study of seepage field and stress field near the wellbore is not easy to achieve, so this article do study with the aid of large multi-physics field software COMSOL based on the finite element.Based on YuanBaOu block site investigation, data collection, reading, the block mainly adopts the method of completion are the liner completion, open hole completion and perforation completion, so this article has established the open hole completion and perforation completion fluid-structure coupling finite element model of seepage field, conducted the finite element simulation analysis.Through the study on seepage field and stress field of different well completion methods, the production is obtained under different well completion ways, at the same time discusses the relations of borehole stability with different output. In this paper, the main research contents and achievements are as follows:(1)Based on the seepage field fluid-structure coupling finite element model of Vertical Wells with open hole completion, formation stress field and seepage field, Von Mises stress field, rock volume strain distribution, density and viscosity of fluid distribution near the wellbore is analyzed and discussed in this paper, as to provide theoretical basis for different well completion method optimization.(2)Based on the seepage field fluid-structure coupling finite element model of horizontal Wells with open hole completio, the effect of the Angle of horizontal hole hole with the maximum horizontal in-situ stress to yield and stability of the wellbore is analyzed and researched in detail.through comprehensive consideration of safety and economic behavior of borehole and analysis, this paper suggested that the Angle of horizontal hole with maximum horizontal in-situ stress be controlled under20degrees.(3)According to the seepage field fluid-solid coupling finite element model analysis of vertical Wells with perforation completion, draw the conclusion:yield increases with the increase of the aperture, the maximum Von Mises stress near the hole decreases with the increase of the bottom hole flowing pressure, this paper gives a quantitative value. This paper established a mathematical model of the rule of plastic failure criterion of rock, through the analysis of a lot of research shows that the dangers of plastic deformation in the rock near the hole is reduced with the decrease of the production pressure difference, and the rock on the hole wall with plastic deformation danger is very thin, which has little influence to the stability of the hole. Considering from safety and economic behavior of gas Wells, suggest selecting20holes per meter,60degrees phase Angle for vertical Wells.(4)Based on the seepage field fluid-solid coupling finite element model of horizontal Wells with perforation completion, through the analysis of the seepage field and stress field of the different parameters, and the considering the stability of the wellbore,this paper suggested that45degrees angle of hole with maximum horizontal in-situ stress,20holes per meter,90degrees phase Angle.(5)Through the seepage field finite element simulation analysis to the edge or bottom water reservoir development,this paper can predict the bottom water breakthrough time, as well as the water saturation the different location near wellbore formation,which provides theory basis for shut-in coning control time of gas well; for Homogeneous formation of interconnected and non homogeneous formation balanceing gas water interface is an effective method for efficient development of gas reservoir, recommended the ICD completion control technology.