Use of Inline Spinner for Determination of Zonal Flow Rates in Vertical and Moderately Deviated Wells

Accurate zonal flow rate determination is necessary for better reservoir behavior understanding and for making important decisions that can improve well productivity. Knowledge of the capabilities of different reservoir zones in the same well also has significant importance in reservoir performance monitoring and selection of perforation intervals in development wells. Conventional production log analysis techniques can usually yield good results only if the fullbore spinner readings are reliable. However, the fullbore spinner measurement may not be available in some wells. Examples include cases in which the fullbore spinner cannot access the well due to mechanical obstruction, or when the casing is not clean enough, causing potential plugging of fullbore spinner blades. In these situations, the fullbore flow-rate readings may not be available or at least unclear or confusing, which may lead to incorrect decisions. In many of these situations, inline spinner (ILS) data may be readily available. The ILS is often used for qualitative interpretation (i.e., determining which zones are producing), but there is not a specific method to use the ILS for a quantitative solution in the absence of surface measurements of rates. In this paper, we introduce a new method to calculate the volumetric zonal flow rate using ILS data with high accuracy. Approximately 40 oil wells are used to develop an empirical correlation to compute zonal flow rates from ILS data in casing strings. The new method was used to quantitatively interpret eight oil wells for validation. In these wells, fullbore and ILS data were significantly different. The new method for interpretation of ILS data provided results consistent with surface production tests and led to decisions that contributed to increasing production rates.