Project Abstract

<p> ABSTRACT<br><br>As the petroleum industry continues to experience advances and progress in drilling techniques, the use of horizontal well in field development has been increasing very rapidly throughout the oil industry. It becomes therefore important to adequately determine the performance of horizontal wells.<br><br>The existing methods available to determine horizontal well productivity at steady state requires complex mathematical analysis and are difficult to develop. In the course of this work, a new method was developed using simple analytical methods. Results obtained by this new method were compared to that gotten from already established methods of Borisov (1964), Giger (1984) and Joshi (1988). The major objective of this work is to present a simple and effective means to estimate the performance of horizontal wells. An excel sheet was also created in the course of this project to calculate and compare productivity index gotten from the various method. The spread sheet also enable me carry out sensitivity analysis of the results gotten by varying key parameters. <br></p>

Project Overview

<p> 1.1 INTRODUCTION<br><br>The major purpose of a horizontal well is to enhance reservoir contact and thereby enhance well productivity. A horizontal well is drilled parallel to the reservoir bedding plane. In other words, a vertical well is drilled perpendicular to the bedding plane (see fig1.1).<br><br><br><br>Figure 1-1<br><br><br><br>If the reservoir bedding plane is vertical, then a conventional vertical well will be drilled parallel to the bedding plane and in the theoretical sense it would be horizontal well. The objective here is to intersect multiple pay zones Horizontal wells have become popular for producing oil and gas reservoirs in many regions around the world. The objectives of horizontal wells include increasing oil and gas production, turning a non-commercial oil or gas reservoir into a commercial reservoir and controlling severe coning problems. Due to the fact that horizontal wells can enhance reservoir recovery, they should be taken into consideration when planning a field development. While horizontal wells are generally more expensive to drill than vertical wells, they often reduce the total number of wells required in a reservoir development. As an increasing number of horizontal gas wells are drilled, the need for a quick and reliable method to estimate the pressure-rate behavior of these wells is important to optimize well performance and make operational decisions. A reliable and simple analytical and empirical relationship will provide engineers a technique to assess the performance of horizontal wells prior to undertaking extensive and often time-consuming simulation studies to model the well behavior. <br><br>Inflow performance relationship (IPR) is a pressure-rate relationships used to predict performance of oil and gas wells. There is a linear relationship when the reservoir is producing at pressure above bubble point pressure i.e. when Pwf is greater or equal to bubble point pressure. A curve is obtained at Pwf less than bubble point pressure. The linear form of an IPR represents the Productivity Index (PI) which is the inverse of the slope of the IPR. Horizontal oil well IPR also depends on the flow condition that is whether it is transient, steady or pseudo-steady state flow, which is determined by reservoir boundary condition. As the use of horizontal and multilateral wells is increasing in modern exploitation strategies, inflow performance relationships for horizontal wells are needed. The objective of this work is to develop analytical equation and IPRs for horizontal oil wells in steady state conditions that are easy to apply.<br> <br></p>