Mr. Erik Milito - The House Committee on Natural Resources ...

Annex D 1
(normative)
Process Summary: Isolating Potential Flow Zones During Well Construction
Isolating a potential flow zone with cement is an interdependent process. Individual process elements such as slurry
design and testing, applied engineering and job execution all impact the ability to successfully install a cement barrier.
Superimposed upon these elements are the conditions found in the well at the time of cementing.
Certain cementing process elements contained in this annex may be individually critical to isolating a potential flow
zone or may be of minor consequence until made critical by a separate (sometimes unrelated) event or past well
engineering decisions. Conversely, certain elements may not be dominant factors in the success in one cementing
operation, yet vitally important in another.
Collectively, the elements described below produce the design, engineering and operational framework for
successfully isolating a potential flow zone.
Flow Potential Risk Assessment
<strong>The</strong> results from any pre-spud hazard assessment of the proposed drill site should be provided to the cementing service provider
to be used as a basis of design for the cementing program or used in the slurry design guidelines provided by the operator.
Typically the information provided will include location of possible hydrocarbon bearing, water bearing and lost circulation
intervals as well as over-pressured or under-pressured zones.
Site Evaluation
Assess Flow
Potential
Communication
Was a pre-spud hazard assessment conducted for the proposed well site
Are there any potential flow zones within the well section to be cemented
Has the information concerning the type, location, and likelihood of potential flow zones been
communicated to key parties (cementing service provider, rig contractor, or 3rd parties)
Critical Drilling Fluid Parameters
<strong>The</strong> drilling fluid design should be appropriate for parameters such as formation type, wellbore stability, formation damage
potential, cuttings removal and proper management of ECD, etc. <strong>The</strong> drilling fluid used to drill a hole section containing a
potential flow zone may not be ideal for cementing operations.
Within the limitations imposed by the drilling fluid used, computer modeling shall be conducted to assess the impact of the drilling
fluid circulation and cement placement on the pore and fracturing pressure limits and on drilling fluid removal across any hole
section with a potential flow zone. This analysis will allow the cementing service provider and operator to consider alternate
means of meeting the objective of isolating potential flow zones should drilling fluid circulation or cementing placement be ECD
constrained limits.
Rheology
Density
Fluid Loss
Are rheological properties and static gel strength value conducive to cuttings removal, solids suspension
and proper management of ECD
Are fluid densities sufficient to maintain well control without inducing lost circulation
Is filtration control appropriate for formation type and well conditions
1 Users of these forms should not rely exclusively on the information contained in this document. Sound business, scientific,
engineering, and safety judgment should be used in employing the information contained herein.
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