关键词: 水平井, 最优长度, 层流, 紊流, 摩擦损失, 设计, 方法

Abstract:

Because of friction loss in horizontal wellbore, pressure drop of horizontal wellbore may equal to that of reservoir pressure drop, which results that the reservoir pressure drop at the tip of horizontal wellbore is rather small or equals to zero, this phenomenon often appears in high permeability or coning reservoirs, pressure difference of these reservoirs is low or limited.Therefore, studying the design method of optimal horizontal wellbore length has a guide meaning to development program design of horizontal wells.By dividing three reservoir type cases (bottom water drive reservoir, gas cap and bottom water drive reservoir, gas cap drive reservoir), the paper derives flow model in reservoir, flow model in horizontal wellbore, the optimal length model of horizontal wellbore, in the process of derivation, the factors, such as flow regime (laminar flow, turbulent flow) and relative roughness of wellbore, which have influence on productivity of horizontal wells, are considered.Finally, the paper gets a few conclusions by example calculation.

Key words: horizontal wells, optimal length, laminar flow, turbulent flow, friction loss, design, method