Optimization of horizontal well completion

A comprehensive model has been successfully built for slotted-liner and perforated completions. The Green's functions or source function method was used for the development of the reservoir pressure response due to the 3D convergence of flow toward perforations/slots. The long-time asymptotic solutions were first derived under pseudo-radial flow. Then, the approach of additional drawdown due to completion pseudo-skin was developed to express the pressure response under boundary-dominated flow.; The model strictly considers the influence of well completions on both reservoir pressure response and wellbore hydraulics. The non-liner coupling matrix equations are discretized and solved numerically. The semi-analytical model is capable of incorporating the effects of selective completion, non-uniform mechanical skin, and high velocity flow effect. Formulae were derived to predict additional pressure drops due to mechanical skin and non Darcy effect in the perforation radial flow, slot semi-radial flow, and wellbore radial flow.; Based on large quantity of numerical experiments, regression correlations for productivity ratio (PR) have been obtained and can be used for fast and accurate prediction and optimization.; Pseudo-pressure function was used to extend the solutions of oil wells to gas wells. The gas wells have more concentrated flux and pressure drop on the heed end side due to gas expansion and acceleration. Non-Darcy flow has severe effect on the gas productivity of slotted-liner completion.; A user-friendly software for horizontal well completion optimization (HORCOM) was developed to provide a fast design and analysis tool. The software has a graphical user interface for pre- and post-processing and with windows programming features.; The model was verified by comparing the limiting cases. Sensitivity analysis was performed for perforation/slot parameters. Unique completion guidelines have been developed. For example, horizontal wells may need far lower perforation density than the vertical wells. For anisotropic formations, 180°-phasing along vertical plane is better than 90°-phasing. Using higher perforation/slot density and deeper penetration near the heel end of the well helps to obtain the highest gain in productivity.