Effects of Formation Damage and High-Velocity Flow on the Productivity ofSlotted-Liner Completed Horizontal Wells

摘要

Slotted-liner is a relatively simple and cost-effective wellrncompletion technique for horizontal wells. However, fluidrnflow into a slotted-liner completion is quite complicated due tornthree dimensional flow convergence around slots and limitedrnopen-to-flow areas. Furthermore, the compounded effects ofrnformation damage and non-Darcy flow on the fluid flowrntowards slotted-liners must be considered in well completionrndesign process.rnThis paper presents a comprehensive semi-analyticalrnmodel for estimating the productivity of horizontal wellsrncompleted with slotted liners. The semi-analytical model isrnobtained by coupling the reservoir flow and wellbore flowrnequations. The model includes the additional pressure dropsrndue to mechanical skin and non-Darcy effect. Additionally,rnthe model could handle non-uniform flux, non-uniform skinrndistribution, and selective completion with blank pipes. Bothrnoil well and gas wells are evaluated. For gas wells, thernstandard pseudo-functions are used. Detailed discussion of therneffects of formation damage and non-Darcy flow is provided.rnResults indicate that the productivity reduction because ofrnformation damage is more significant for slotted-linerrncompletion than the openhole completion due to increasedrnpressure drop with flow convergence in the region withrnreduced permeability. Control of drilling damage ratio is morernimportant than control of drilling damage radius. High slotrndensity with low phasing angle helps to reduce the non-Darcyrnflow effect.