Novel methods for modelling, design and control of advanced well completion performance

Abstract

This thesis presents new approaches to modelling of reservoir and well flow performance when the wells are completed with Advanced Well Completions (AWC). The particular focus of this research is modelling fluid flow in the reservoir-AWC-well systems using simple, reduced-physics models that do not necessarily require detailed reservoir description yet are comprehensive enough to capture the major trends in the system to achieve the AWC performance evaluation and design objectives. This allows rapid screening and design of the AWC technology that is at the same time less subject to the reservoir uncertainty due to less input on the reservoir geology required. Such models can also complement, e.g. in order to steer or speed-up, the existing AWC modelling and design workflows that involve full reservoir simulation. The outcome aids reliable investigation of expected AWC and reservoir performance derived from the available data in order to perform quick scoping of reservoir management concepts and options prior, or in addition, to detailed modelling. This is particularly important in real field models where the numerical reservoir simulation is often uncertain and computationally expensive, especially when coupled with AWC wellbore models. The study first introduces three main classes of flow control technologies used in AWCs: passive (realised with Inflow Control Devices - ICDs), the recently introduced autonomous (Autonomous Flow Control Devices - AFCDs) and active (Inflow Control Valves - ICVs). The traditional workflows for AWC performance modelling and design using commercial numerical reservoir simulation for each AWC class are discussed and evaluated. Finally, the novel, rapid AWC modelling methods are developed that can reliably inform reservoir development and management decisions. The thesis develops the following approaches and modelling methods aimed at analysis and design of AWC flow performance: 1. The model describing the trade-off between the well productivity loss and the improved inflow equalisation in AWCs in well with heel-toe effect and heterogeneous reservoir 2. The technique to estimate the additional, long-term value derived by controlling zonal flow rate (AWC’s well) in pistonlike and non-pistonlike displacement. 3. The concept relating the various short-term, AWC design methods and their long term outcomes. 4. Characterisation of inter-well and inter-layer connectivity for waterflooded reservoirs developed with wells completed with zonal gauges and ICV completions. 5. Consequently, the framework for optimal ICV control when the inter-well connectivities are estimated. This work enables application of rapid AWC design and optimisation. Moreover, integration with the reservoir waterflood monitoring results in a better understanding of the reservoir performance. Practical utility of the proposed methods is illustrated in case studies