Percolation Mechanism And The Development Design Of Horizontal Wells And Multi-lateral Wells

The technology of horizontal well and multi-lateral horizontal well is an important method for oil and gas development and improving recovery both at home and abroad. The study on percolation mechanism and development and design of horizontal well and multilateral can give full play to potentiality of horizontal well and multilateral horizontal well, make a great significance for improving the development effect of the oil field.In this paper, in view of a range of issues occurred in the infiltrating fluid of horizontal well, from the basic theory of fluid mechanics in porous medium, base on the mathematical model, the horizontal well single well stable flow theories of reservoirs with enclosed boundaries, reservoirs with a constant pressure outer boundary, bottom water drive reservoir, gas cap drive reservoir, reservoirs with edge water and enclosed top and bottom, reservoirs with enclosed top and bottom but without edge water as well as bubble point reservoir are studied, and based on this, the corresponding productivity equation can be obtained. By using the pseudo-three-dimensional thinking, the seepage problem in the three-dimensional is transformed into two-dimensional, the stable percolation theory of four branches horizontal wells is studied and on this basis, the productivity equations of n-lateral horizontal wells are analogized.The transient flow theory of the horizontal well is studied, and the mathematical model of transient flow of horizontal well is established through integral transform and asymptotic analysis and other methods, the production formula of late pseudo steady state flow is obtained, and does the sensitivity analysis on parameters.The transient flow theory of lateral horizontal well is studied, the pressure distribution expression of n-lateral horizontal well in the conditions of two boundary is obtained, and we can calculate the pressure dynamic characteristics curves of the different branches, and analyze the affecting factors that affect the pressure behavior. And study oil-water two-phase percolation theory for horizontal well, obtain the characteristics of oil-water two-phase flow, and calculate the development indexes, according to the example, we analyze affecting factors that affect the deliverability of oil-water 2-phase percolation of horizontal well from the injection efficiency, crude oil viscosity. And from the two major aspects, formation and wellbore, the comprehensive and in-depth qualitative analysis and quantitative analysis can be done for the factors which impact the productivity of horizontal well, while the brief analysis of production influence factors of lateral horizontal well also be done.Finally, the determination of reasonable length of horizontal section in the development design of horizontal well and the reasonable level position and vertical location in the edge and bottom water reservoir are studied, and the reasonable length of horizontal wells and the optimum position that horizontal wells in the reservoir when the well bore friction is taken into consideration are obtained.