PRESSURES AND PRESSURE DERIVATIVES OF VERTICAL AND HORIZONTAL WELLS

ABSTRACT

The optimization of the performance of oil and gas wells (whether vertical or directional) as well as well location from external reservoir boundaries or faults has been a major concern of the reservoir engineer over the years. This work presents an accurate method for evaluating the performance of both the vertical and horizontal wells each located within an intersecting sealing/no-flow boundary and a constant-pressure boundary. The main aim of this study was to investigate the transient pressure behaviour of a vertical well as well as a horizontal well located within an intersecting sealing fault and a constant pressure boundary. The methods employed in computing the dimensionless pressures and dimensionless pressure derivatives for both well types include the method of images and principle of superposition. The computations were also made using Microsoft Excel, Python and MATLAB software. The results obtained show that for the selected parameters; 1) the models give accurate estimation of distances between active and image wells, PD and PD’, 2) at 30 hours of production, both wells completely overcome the effects of the boundaries at 2000 ft. equidistant to faults, 3) for the infinite-acting reservoir, a characteristic values of PD’ for the vertical and horizontal wells are 0.5 and 0.2 respectively, 4) for both well types, the effect of the upper boundary is greatly felt between distances of 5.00ft. and 10.00 ft., and beyond this region, the effect of the lower boundary becomes gradually felt and then, greatly felt beyond 15.00 ft.