Perforated completion is one of the most commonly used completion methods in oil and gas development. The single well productivity is largely determined by the completion method for a given oil-gas well. The well test analysis and single well productivity calculation are normally realized by using a 2-D open hole model, however, this approach may cause large errors. Based on properties of perforated completion and permeability anisotropy of reservoirs, a three-dimensional numerical well test model was proposed to analyze the transient flow in perforated vertical wells. With the model, well test type curves and pressure fields of perforated wells are obtained by using the 3-D finite elemnet method (FEM). Through analyses of well test type curves and the three-dimensional flow in the pressure field, six flow phases can be recognized on well test type curves of perforated wells, i. e. wellbore storage, the first transition, early-time partly radial flow around the perforation, the second transition, late-time system radial flow and boundary-dominated flow. Among them the early-time partly radial flow around the perforation is the most important characteristic of perforated wells. Effects of perforated completion parameters, such as perforation density, length, phase angle and permeability anisotropy, on the transient pressure and derivative responses were studied, which provides theoretical guidance to design perforating types and analyze well test data of perforated wells. The calculation result of the total skin factor of perforated wells showed that the productivity of a perforated well may be higher than that of an open hole if the perforation is long enough or the perforation density is high enough. Increasing the perforation length is an effective way to enhance the productivity of a perforated well.
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