Downhole Steam Quality and Flow Rate Estimation in Selective Steam Well Injection Completions

Abstract

Objectives/Scope: To determine quality, mass and volumetric flows in each sands where steam has been injected using well completions with selectivity elements under critical regime. From pressuretemperature logs and ILT run in wells, were used to estimate density, volumetric and mass flow of steam, and heat injected at each distributor element which wells are completed. Methods, Procedures, Process: When steam is injected into a well, the quality and mass flow at the well head is usually known. With the logs of pressure and temperature, together with the ILT and flow control devices in critical regime, it is possible to know the conditions of the steam (saturated, sub-saturated and over-saturated), and speed of flow, it is possible to determine in function of the completion of the well, diameter of tubing for injection and diameter of the throat, the following variables or properties, like volumetric flow, mass flow, quality and density of the steam, in each point or element for distribution of the well. Results, Observations, Conclusions: The methodology developed has allowed to determine the steam mass flow and injected energy that flows in each distributing element and how much is injected in each selected sand, obtaining that the highest mass flows are obtained where the lower qualities of the steam exist and vice versa, as well as the total energy injected in each sand looks almost independent of the steam quality in a range of 15% to 90%. This is due to the behavior of the mass flow and the latent heat of vaporization and their relation to the quality of the steam in throat under critical regime. As the steam quality increases, the mass flow through the throat decreases, and by the contrary the latent heat of vaporization increases. So the combination of both generates a total heat injection is almost independent of the quality of the steam, and the total amount of heat injected being a direct function of the diameter of the throat and the number of devices used for steam distribution. Novel/Additive Information: The novel combination of flow equations in pipes, critical flow in throat and flow through the spinner used in the ILT, allowed to estimate the mass flow and the energy injected into the reservoir with wells using selective completions in critical flow conditions. It was determined the existing differences in the conditions used during the design of the well completion and those existing during the steam injection. With this new methodology, the steam injector well completion is optimally designed, as well as obtaining the efficiency of the steam injection by sand, through a better estimation of the SOR and the oil incremental recovery during the continuous steam injection process.