Summary
Simulation history matching is a daunting, time-consuming task with numerous
unknowns and several plausible answers. Scale differences in the data
frequently obscure results, limiting its application in completion strategies.
Good history matching does not guarantee accurate production forecasts,
however. Reliable predictions, required for well planning, depend on the
ability of the user to reduce the uncertainties to find consistent and timely
solutions. Logs can provide appropriate conditioning data for history matching
to enable its use for reservoir management. Electrofacies, capillary pressure,
and absolute and relative permeability, imprinted on logs, can be
mathematically linked with irreducible water saturation
(Swi). Unlike reservoir simulators, well logs are at the
right scale for completion designs. Logs facilitate upscaling, honoring rock
and fluid properties and the physics of flow (Haro 2006). Logs are snapshot
measurements that are amenable for conversion into dynamic forecasting tools by
use of flow and pressure equations. This concept permits creation of synthetic
production logs (SPLTs) over time, from which production decline can be
calculated. This method consists of integrating material balance, flow/pressure
algorithms, fluid data, cores, and log data. Thus, the corresponding analytical
expressions are required. In this approach, every well represents a finite,
gridded tank, capable of producing a measurable volume of fluids, limited by
its petrophysical constraints. Superposition, in terms of pressure and flow,
combines the various components within and among wells. The quality of the
results is ensured because material balance must be honored at every depth at
all times under different production scenarios and the prevailing drive
mechanism. This log-handling technique helps when making strategic economic
decisions to maximize reserves and optimize the reservoir-development plan.
This strategy is used to obtain oil in place (OIP), drainage radii, lateral
connectivity, fluid-bank arrival times, productivity indices (PIs), inflow
performance relationship (IPR), production allocation, and recovery per zone
per well. Current log analyses or simulators generally do not provide these
parameters at this detail. This refined use of logs streamlines completion
designs and improves conformance, enabling us to comply with an important part
of daily reservoir management.
© 2012. Society of Petroleum Engineers
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History
- Original manuscript received:
26 April 2011
- Meeting paper published:
31 October 2011
- Revised manuscript received:
10 April 2012
- Manuscript approved:
15 August 2012
- Published online:
11 October 2012
- Version of record:
30 October 2012
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