The Challenge Facing Multiphase Metering in Oil-Sands Thermal Developments

Abstract

Multiphase metering flow meters (MPFM) are being accepted more and more in oil and gas developments, replacing test separators, particularly on fields with large well networks. This is the case with Steam Assisted Gravity Drainage (SAGD) oil sands developments requiring large capital investment that need accurate production and reservoir data and have difficult processing techniques. This data includes:Real time measurement: good reservoir and steam chamber monitoring and steam injection versus oil production surveys.Cost reduction: steam oil ratio (SOR) optimisation, due to the economic and environmental cost of steam.Asset integrity: mitigation of the risk of steam breakthrough in oil producer wells. The flow meters have to be sized for either viscous liquids (water in oil emulsions) or less viscous, but very hot liquids (oil in water emulsions) and to differentiate between gas and steam, or be able to meter the gas and assess the steam loading. In SAGD developments the water content determination is essential and the meters have to include qualified systems for both high temperature and high water cut measurements. This paper outlines the business needs for MPFMs in SAGD and discusses the current difficulties with qualification, test loops, field trials and eventually, the perceived operational issues. The challenges facing multiphase metering in SAGD developments are as difficult as the industry faced when applying classical multiphase metering techniques several years ago. In order that these challenges are overcome it will be necessary for vendors and operators to develop and test the new technologies jointly. This will require that vendors dedicate sufficient effort in MPFM R&D and that operators participate in these developments, in JIP's and host field trials. Introduction Reservoir monitoring and modelling improves reservoir knowledge, simulation, reservoir optimisation, prediction of breakthrough times & well performance for different operating scenarios. Reservoir models and predictions are based in part on surface metering data. The reliability and uncertainty of this data defines the sensitivity of any reservoir model. Reservoir monitoring enables competent operating strategies to be set and is used to compile the year end reserves. Monitoring of well performance and production can provide continuous information on well behaviour throughout the well life. SAGD production will require:Initial steam injection rate (circulating - i.e. steam chamber creation and oil heating)Ramp up (with gas lift injection),Steam liftGas lift\Blow down,Break through Good reservoir monitoring can optimise the well spacing, and well length and contribute to the system learning curve for future developments. In addition to reservoir management, metering must be compliant with the required regulatory reporting needs.