Summary
The unified test protocol for laboratory formation-damage assessments
consists of functional procedures that attempt to standardize formation-damage
service projects. Setting functional requirements was preferred above
comprehensive equipment specifications and detailed instructions on laboratory
work processes.
To assess the formation-damage potential of a fluid for drilling or well
operations, three sections of the protocol need to be accomplished:
Information, Simulation, and Analysis.
This paper presents the three sections and discusses the effect of the
functional approach. Special emphasis is put on a distinction between well
fluids that experience dynamic and static filtration regimes because these
require different ways of simulating fluid applications to the rock sample. To
provide engineering parameters relevant to field scale and to identify the full
range of potential formation-damage mechanisms that may affect the reservoir,
analyses on cm, mm, and µm scales are suggested.
Minimum requirements to scaleup formation-damage measurements to field scale
are presented. Also, an option for full-scope diagnostic formation-damage
assessments is demonstrated.
Applications of numerical models that have been suggested in earlier
research yield return permeability, filtrate-invasion depth, laboratory skin,
efficiency of flow, and loss of revenue as parameters to benchmark the
formation damage of well fluids.
Introduction
Prevention of formation damage through fluids used for drilling and well
operations provides one of the key elements for the economic success of oil-
and gasfield developments. It affects not only commercial interests, but also
the total quality of the production process. Hence, it comes along with
increased up time and process reliability, and a reduction in total health-,
safety-, and environment-related risks. The latter is related to reduced
exposure of staff and environment because the need for stimulation/workover
operations on damaged wells, or even the drilling of additional wells to
exploit the full reservoir potential, is reduced.
The work reported in this paper was part of a research initiative supported
by the European Union (E.U.) Commission within the fifth framework research and
technical development program. This research initiative, Well Productivity
2002 (WP2002), aimed to deliver development strategies and new products to
drill, complete, and maintain wellbores in such a manner that the optimum
delivery potential of a hydrocarbon reservoir is protected.
As one task to approach the project objectives, a work package was defined
to develop cost-effective laboratory and field diagnostic methods to
characterize and quantify formation damage. The particular objectives of this
work package were, among others, to do the following:
• Establish minimum equipment requirements for sim¬ple screening-type
formation-damage assess-ments.
• Demonstrate a viable and unified set of labora-tory test protocols for
screening- and diagnostic-type tests.
The test protocol presented below attempts to satisfy these objectives. This
protocol is based on a functional approach. Suggestions are given to satisfy
functional requirements in practice. The primary thought when developing the
protocol was to structure the communication between user and supplier of the
service project and to link field and laboratory closer together.
© 2006. Society of Petroleum Engineers
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History
- Original manuscript received:
18 June 2004
- Revised manuscript received:
8 May 2005
- Manuscript approved:
2 June 2005
- Version of record:
20 February 2006
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