7. Decline Curve Analysis

The oil and gas business is a high risk and challenging venture and despite this risk and uncertainties, several exploration and production operations are still going on in the Niger Delta region and other parts of the world. It is important to note that reserves is what drive the oil and gas business and every operator wants to produce his/her field in a safe and economic way without a rapid decline in the production rate. Thus, they wish to remain in their plateau stage for a long period. Decline curve analysis is key to determine the most probable life of a well or field and also estimate the future performance. This is important in determining the value of oil and gas economics. This chapter presents the various methods of decline curve analysis, the applications, the causes of production decline, factors affecting the decline rate and also the methods of identifying the decline model of any field from historical data. Several fields’ example questions and solutions to capture all the decline methods are also presented to determine the model parameter, forecast of future production, abandonment time and rate.