Inter-well and inter-field allocation: besides the benefit of zonal allocation improvements, the ROCM process can be performed under well/field allocation uncertainty. This can be particularly insightful when multiple platforms/fields have been combined into one metering scheme and uncertainty is propagated to wells and/or platforms/fields.
POSEIDON™ ALLOCATION will allow quantification of contributions of phases by layer. This module is designed in order to tackle problems in 3 different work processes:
1. Commingled Analysis
A comprehensive analysis of production and perforation data to quantify the amound of oil/water/gas produced within commingled period of wells operations. Impact of flow-units grouping can be established and the results are provided per field/block/well.
Commingling assessment is done by merging the well events (open/close perforation sequences) with the well production rates, a precise calculation of commingled production is performed. This process allows the quantitative understanding of the zonal allocation uncertainty.
The commingling assessment analysis also allows the determination of the zonal allocation uncertainty for each flow unit. Understanding the zonal uncertainty is an important aspect of the LTRO process, as it qualifies the aggregation strategy of targets issued from the remaining oil assessment, and also provides a Value of Information quantified basis towards reservoir surveillance decisions.
2. Perform Multiphase Allocation
Multi-pahase production allocation (well-to-layers) uses classical deterministic (reservoir properties and pressure driven) or innovative stochastic (including prediction of watercut and GOR evolution) approaches.
Advanced phase-based Allocation (AA) is performed at the flow unit level. AA allows for the recognition of different WCT and GOR contributions from commingled layers, rather than applying a constant allocation factor to all phases as classically done in KH type allocations.
In this work process, a high-resolution vertical (layer-wise) allocation, at the flow-unit level, is performed. Alternative allocation methodologies may be performed in order to select a reference case and up to two alternative realisations. This process honours all available data in terms of PLT data and flushed zones identified in infill wells.
POSEIDON™ ALLOCATION carries out a multi-phase allocation by fully integrating a pseudo-steady state rate formulation with fractional flow modelling. Permeability profiles at the well and production logs are included in the allocation process. By preciesly evaluating the phase allocation uncertainty for each well and layer, the optimum reservoir surveillance program can be determined.
Deterministic methods such as KH, KHP and KHPM are generated and comparisons made to key reservoir diagnostics such the RF vs PV plots.
3. Workflow Validation
Multi-phase production allocation (well-to-layers) workflow has been validated against synthetic simulation case. In the synthetic case, a well is perforated and produced from multiple layers. Well’s simulated production is allocated back to individual zone using multi=phase production allocation workflow. The allocated zonal production then is compared with simulation and KH-based allocation results.