6.5: Summary and Final Tasks

Summary

In this lesson, we discussed a very important task performed by production engineers working on crude oil and natural gas production wells. This task is to calculate the pressure drop in well tubing. As we will see, this is a very powerful tool for helping production engineers design and optimize production and injection wells. In addition to aiding in the initial well design, these analyses help in decisions on improving well performance, such as, adding artificial lift (gas lift or pump) to the well, stimulating the well (hydraulic fracture or acidation), and other workovers and well interventions.

In this lesson, we discussed the basics of tubing hydraulics related to oil and gas production. The well hydraulics are governed by an energy balance that relates the pressure, velocity, and elevation of a flowing fluid to its potential energy and frictional losses. The resulting equation, the Darcy-Weisbach Equation, related the rate flowing through the pipe/tubing to the pressure drop in the tubing.

For single-phase flow, the flow problem can be solved with theoretical considerations, while for multi-phase flow empirical correlations are used. These multi-phase flow correlations are based on flow pattern maps which enable different mathematical descriptions of dynamic two-phase data (such as, hold-up, slip velocity, and frictional losses) in different flow regimes. For selection of the appropriate correlation, production engineers reply on flow tests to assess the accuracy of the different flow correlations and to calibrate these correlations to their wells.

Final Tasks