WELL TEST ANALYSIS OF A HORIZONTAL WELL NEAR A CONSTANT PRESSURE BOUNDARY

This project work presents a well test analysis of a horizontal well located near a constant pressure boundary using image well theory and the principle of superposition. The total dimensionless pressure of the object well was derived as a function of wellbore storage constant, skin factor, well length, wellbore radius, and distance from the constant-pressure boundary. The computation of dimensionless pressure, pressure derivative, and pressure gradient was performed using Python software, where the formulas were programmed and run with various dimensionless parameters. Microsoft Excel was then utilized to generate logarithmic plots of the results. The Results obtained from the computation revealed that increasing the wellbore storage constant (Cᴰ) elevated dimensionless pressure (pᴰ) and suppressed its derivative (pᴰ′), extending the storage-dominated regime and delaying reservoir-controlled flow. Larger wellbore radii reduced drawdown and enhanced flow efficiency, while longer wells lowered both pᴰ and pᴰ′, improving drainage and sustaining productivity. Higher skin factors increased pressure drop and delayed derivative stabilization, indicating reduced well efficiency. The influence of boundary distance (d) showed that smaller distances accelerated boundary-dominated flow, while larger distances prolonged transient periods and delayed boundary effects. At late times, dimensionless pressure gradients and derivatives stabilized at asymptotic values of 1.1513/2Lᴰ and α/2Lᴰ, respectively. The findings provide a basis for optimizing well placement, completion design, and production strategy in reservoirs with active aquifer support or constant-pressure boundaries.