Page 59 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

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Computer usage in pipeline risk assessment and manage- Hard data versus engineering judgment (how to incor-
ment is further discussed in Chapter 8. porate widely held beliefs that do not have supporting
statistical data)
Build the program as you would build a new pipeline Uncertainty versus statistics (how much reliance to
place on predictive power of limited data)
A useful way to view the establishment of a risk management Flexibility versus situation-specific model (ability to
program, and in particular the risk assessment process, is to use same model for a variety of products, geographical
consider a direct analogy with new pipeline construction. In locations, facility types, etc.)
either case, a certain discipline is required. As with new con- It is important that all risk variables be considered even if only
struction, failures in risk modeling occur through inappropriate to conclude that certain variables will not be included in the
expectations and poor planning, while success happens through final model. In fact, many variables will not be included when
thoughtful planning and management. such variables do not add significant value but reduce the
Below. the project phases of a pipeline construction are usability of the model. These “use or don’t use” decisions
compared to a risk assessment effort. should be done carefully and with full understanding ofthe role
of the variables in the risk picture.
I. Conceptualization and scope creation phase: Note that many simplifying assumptions are often made,
Pipeline: Determine the objective, the needed capacity, especially in complex phenomena like dispersion modeling,
the delivery parameters and schedule. fire and explosion potentials, etc.. in order to make the risk
Risk assessment: Several questions to the pipeline opera- model easy to use and still relatively robust.
tor may better focus the effort and direct the choice of a Both probability variables and consequence variables are
formal risk assessment technique: examined in most formal risk models. This is consistent with
What data do you have? the most widely accepted definition of risk:
What is your confidence in the predictive value of the
data? Event risk = (event probability) x (event consequence)
What are the resource demands (and availability) in
terms of costs, man-hours, and time to set up and main- (See also “VI. Commissioning” for more aspects of a success-
tain a risk model? ful risk model design.)
What benefits do you expect to accrue, in terms of cost IV. Material procurement:
savings, reduced regulatory burdens, improved public Pipeline: Identify long-delivery-time items, prepare spec-
support, and operational efficiency? ifications, determine delivery and quality control
Subsequent defining questions might include: What por- processes.
tions of your system are to be evaluated-pipeline only? Risk assessment: Identify data needs that will take the
Tanks? Stations? Valve sites? Mainlines? Branch lines? longest to obtain and begin those efforts immediately.
Distribution systems? Gathering systems? Onshore/off- Identify data formats and level of detail. Take steps to
shore? To what level of detail? minimize subjectivity in data collection. Prepare data
collection forms or formats and train data collectors to
Estimate the uses for the model, then add a margin of safety ensure consistency.
because there will be unanticipated uses. Develop a schedule V Construction:
and set milestones to measure progress. Pipeline: Determine number of construction spreads,
material staging, critical path schedule, inspection pro-
11. Route selectiodROW acquisition: tocols.
Pipeline: Determine the optimum routing, begin the Risk assessment: Form the data collection team(s), clearly
process of acquiring needed ROW. define roles and responsibilities, create critical path
Risk assessment: Determine the optimum location for the schedule to ensure timely data acquisition, schedule
model and expertise. Centrally done from corporate milestones, and take steps to ensure quality assurance/
headquarters? Field offices maintain and use informa- quality control.
tion? Unlike the pipeline construction analogy, this aspect VI. Commissioning:
is readily changed at any point in the process and does not Pipeline: Testing of all components, start-up programs
have to finally decided at this early stage of the project. completed.
111. Design: Risk assessment: Use statistical analysis techniques
Pipeline: Perform detailed design hydraulic calculations; to partially validate model results from a numerical
specify equipment, control systems, and materials. basis. Perform a sensitivity analysis and some trial
Risk assessment: The heart of the risk assessment will be “what-ifs” to ensure that model results are believable
the model or algorithm-that component which takes and consistent. Perform validation exercises with expe-
raw information such as wall thickness, population den- rienced and knowledgeable operating and maintenance
sity, soil type, etc., and turns it into risk information. personnel.
Successful risk modeling involves a balancing between
various issues including: It is hoped that the risk assessment characteristics were
Identifying an exhaustive list ofcontributing factors ver- earlier specified in the design and concept phase of the
sus choosing the critical few to incorporate in a model project. but here is a final place to check to ensure the
(complex versus simple) following: