You must log in to edit PetroWiki. Help with editing
Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. More information
Material balance models in production forecasting
Whenever we make a production forecast, we use a model of the reservoir and production system, whether it be in the form of a simple mathematical equation (e.g. decline curves) or a full-field 3-D simulation model with surface networking. But no matter how complex the model, it is always a simplification of reality. The aim of the forecaster, in making reliable predictions, is to use a model that is sufficiently representative of the physical processes and constraints, and that adequately allows, on a resource-benefit basis, for treatment of uncertainty in the input and output of the model.
Somewhere in the spectrum of modelling techniques, material balance plays an important role; either in supporting a more complex model (e.g. ground-truthing results) or as the principal methodology for producing forecasts. Material balance treats the reservoir as a tank (or limited number of tanks) with uniform properties. Other than what is required to calculate volumes, there is limited geological input. This lends simplicity and practicality but at the same time limits the applicability in more complex reservoirs. This chapter describes the potential uses of material balance, when to use the technique and offers practical guidelines on its use.
What is material balance
General description of the technique; inputs and outputs, what can and can’t be modelled. Vertical Lift / Surface networks.
Uses of material balance
Reservoir performance, performance-based verification of reservoir / aquifer / gas cap volumes,
When to use material balance
With the increased capability of and accessibility to high-powered CPUs, the default option of the reservoir forecaster today is to build a 3-D simulation model. Whilst this often gives the impression of rigour and can look impressive to the less scientifically-inclined, the use of a simulation model may be overkill. It requires additional input that may not add to the representativeness of the model and, furthermore, may not be supported by reliable / available data. At the same time, this modelling route invokes a significantly increased resource and time cost that may detract from producing a reliable forecast. Material balance should always be considered early as a modelling option on the route to generating production forecasts.
Based on complexity of reservoir (permeability variation), complexity of reservoir fluid system ( oil vs gas, single vs multiphase) and complexity of development plan. Data availability (geological and performance data) and uncertainty. Time/resources availability. Is surface network modelling (e.g. in a gas-field complex) the most important determinant in production performance?
INSERT Reservoir Heterogeneity (Pending permission approval)
Forecasting guidelines using material balance modelling
Summary guidelines on how and when to use. List of 10 to 15 bullet points
References
Noteworthy papers in OnePetro
Noteworthy books
Society of Petroleum Engineers (U.S.). 2011. Production forecasting. Richardson, Tex: Society of Petroleum Engineers. WorldCat or SPE Bookstore
External links
See also
Production forecasting glossary
Challenging the current barriers to forecast improvement
Commercial and economic assumptions in production forecasting
Controllable verses non controllable forecast factors
Discounting and risking in production forecasting
Documentation and reporting in production forecasting
Empirical methods in production forecasting
Establishing input for production forecasting
Integrated asset modelling in production forecasting
Long term verses short term production forecast
Look backs and forecast verification
Material balance models in production forecasting
Probabilistic verses deterministic in production forecasting
Production forecasting activity scheduling
Production forecasting analog methods
Production forecasting building blocks
Production forecasting decline curve analysis
Production forecasting expectations
Production forecasting flowchart
Production forecasting frequently asked questions and examples
Production forecasting in the financial markets
Production forecasting principles and definition
Production forecasting purpose
Production forecasting system constraints
Reservoir simulation models in production forecasting
Types of decline analysis in production forecasting
Uncertainty analysis in creating production forecast
Uncertainty range in production forecasting
Using multiple methodologies in production forecasting