BC WELL TESTING

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BC WELL TESTING REPORTING REQUIREMENTS
Last updated June 2005
Presented by Chris Grieve Reservoir Engineering
Technician Resource Conservation Branch BC Oil
and Gas Commission
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Presentation Outline

• 1) Drilling Production Regulations
• Pressure Testing Requirements
• Gas Well Flow Testing Requirements
• Compliance
• 2) Well Testing Reporting
• Pressure Tests
• Test Types
• PST Survey Report Form
• Common Questions
• Wellbore Formation Gradients
• Data Quality
• Flow Tests
• Test Types
• Deliverability Test Report
• Common Questions
• Clean Up Flows Underbalanced Drilling
• 3) Annual Pressure Surveys

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Drilling Production Regulations
Drilling Production Regulations
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Pressure Test Regulations
Section 95 Static Bottom Hole Pressure
Measurements 95(1) The static bottom hole
pressure of each completed zone of each oil or
gas well must be measured before initial oil or
gas production. 95(2) The static bottom hole
pressure of each producing pool must be measured
annually after initial measurement, unless
otherwise approved 95(3) All static bottom hole
pressures and the duration of the shut-in thereof
must be reported to the commission within 60 days
after the date on which the pressures were
measured. 95(4) When static bottom hole pressures
are measured, the surveyed wells must remain
shut-in until the reservoir pressure has been
attained in the well bore or until sufficient
data are available to permit the calculation of
the reservoir pressure and, in the latter case,
details of the reservoir pressure calculations
must be included in the report
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AOF Regulations

• Section 84 Gas Well Tests
• 84(1) The absolute open flow potential of a gas
  well must be determined by a method approved by
  an authorized commission employee.
• 84(2) each gas well must be tested and the
  absolute open flow potential determined by the
  operator
• Before 6 months have elapsed after the well has
  been placed on initial production,
• Immediately after each (major) work over
  performed on the well.
• When requested by an authorized commission
  employee.
• 84(3) A detailed report of any test made under
  this regulation must be submitted to the
  commission within 60 days of the date on which
  the test was completed.

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Failure to provide detailed absolute open flow
potential test reports or adequate static bottom
hole pressure data satisfactory to an authorized
commission employee may result in the well or
wells in question being shut in by the
Commissioner until adequate data is obtained.
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Well Testing Reporting Pressure Tests
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PST Test Types

• Drill Stem Test (DST)
• ok for initial pressure if valid

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Reservoir Pressure Survey Test (PST) Report Form

• Each pressure test submitted requires a completed
  PST Report
• download form off OGC website
• A complete PST package should include
• raw pressure data
• PTA analysis (where reqd)
• details of all reservoir pressure calculations
  including extrapolations, assumptions, etc.
• instructions available on website

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Common PST questions/errors

• Shut-in time must be reported! If SI time not
  listed on wireline report, please determine.
  N/A or EXT are not valid SI times!
• Only require one (complete) hardcopy of each PST
  package to be submitted to the Victoria office.
• If a SG immediately follows a build-up test, it
  is not necessary to submit two PST summary forms.
  All data can be included on one PST form.
• Its not necessary to extrapolate pressure data
  from recorder RD to MPP, but its ok if you do.
• For directional or horizontal wells, please
  report run depths in true vertical depth (TVD).
  Watch the depth units... TVD or MD depths are
  often misquoted on wireline reports.
• Please use the Comments box on the PST Summary
  Form to convey additional information which is
  useful in understanding the data.

• The BC Way
• OGC does not use a defined maximum rate of
  pressure increase (kPa/hr) in its determination
  of a stabilized pressure test.
• OGC does not define the required length of
  shut-in time for pressure tests.

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Wellbore Formation Gradients
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Non-Representative Wellbore Gradients
Example 1- Gas reservoir with non-representative
wellbore gradient
When a change in gradient data is seen on a SG
test, it is often indicative of a liquid level
encountered in the wellbore. However this
gradient information may not be not be
representative of the liquid, as in this
example. In this case, use best judgement to
determine the type of liquid (utilizing
production data, test notes, history of well,
etc) and report the appropriate gradient as the
wellbore gradient on the PST summary form. For
example, water would be 9.8 kPa/m and oil
estimated with 7.5 kPa/m. However, be careful of
Bottom-Up static gradient tests as these can
report odd gradient data on the bottom
stop. Remember to re-calculate LL based on the
appropriate gradients.
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Uncertain Formation Gradients
Example 2 - Gas reservoir but no gas gradient
seen on SG test
Formation gradients represent the primary
produced fluid (gas, oil) from a zone. Although
not directly measured, SG data collected within
the wellbore can often be used to determine the
formation gradient. To estimate a formation
gradient where wellbore gradient data is not
representative of the formation fluid (as in this
example) 1) Use previous well test data if
available 2) Use offsetting well
data from the same pool, or 3) For gas
formations, use data from the Gas Gradients by
Pressure Range table (available on our website).
For oil wells, assume 7.5kPa/m.
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Data Quality
Pressures used for pool mapping, well
classification, and reserves. Accurate testing
and reporting is important. Collecting quality
data is our goal.
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Well Testing Reporting Flow Tests
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AOF Test Types

• Single Point (SP)
• Multi Point (MP)
• Flow after Flow (FAF)
• 4 Point Modified Isochronal (FMPI)
• Clean Up (CU)
• Under Balanced Drilling

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Well Deliverability Test Report

• Each stand-alone flow test submitted requires a
  completed Deliverability Report
• download updated form off OGC website
• A complete package should include
• complete set of field notes (or daily production
  notes for in-line tests)
• AOF calculations
• Sandface Wellhead
• Extended Stabilized Rates
• gas analysis
• raw pressure data
• PTA analysis (where reqd)
• completed PST report form

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Common AOF questions/errors

• For gas wells only
• An AOF test is required within six months of a
  well being placed on initial production. That
  does not (necessarily) mean within six producing
  months. Once a well reports initial production,
  the clock is running.
• In-line flow testing acceptable, avoids flaring.
• If submitting an in-line flow test, please
  report only recent cumulative production for
  zone.
• Please indicate if gas produced during test was
  flared or conserved by checking the appropriate
  box on the Deliverability form!
• Single point tests acceptable, prefer
  multi-point
• For low productivity zones, typically lt 20
  e3m3/d, then wellhead AOF only is sufficient.
• Remember to include a copy of the field notes
  (or corresponding production data for in-line
  flows)
• Must report all well deliverability tests.

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Clean Up Flows

• For stand-alone clean-up flows where gas flaring
  occurs, report volumes and rates on
  Deliverability form, noting it as a CU TEST
  TYPE
• If clean-up is immediately prior to and part of
  AOF test, do not submit separate Deliverability
  form. Simply include clean up volumes and report
  rates as a CU RATE

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Underbalanced Drilling

• For underbalanced drilling with significant gas
  flaring, please submit a copy of the drilling
  field notes and a Deliverability Report Form
  indicating test type as UBD.
• On the form note only the NET gas rates and
  volumes produced during drilling.

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Annual Pool Pressure Survey
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Minimum Annual Pressure Test Requirements

• Minimum number of annual pressure tests for an
• Gas Pool 25 of total wells in pool or,
• 50 of producing wells (whichever is less)
• Oil Pool 25 of producing wells in pool

The OGC rounds up to the next whole number
when calculating the minimum number of pressure
tests required. This means that single well
pools need to be tested annually unless otherwise
approved.
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Annual Pressure Survey Tips

• Select wells that offer good pool coverage.
• Plant shutdowns are an excellent time to collect
  annual pressure survey data, often facilitating
  adequate SI time and no lost production.
• Suspended wells are also good test candidates.
• Annual testing applies within the calendar year.
• Initial pressure tests for development wells can
  be applied to the minimum annual pool testing
  requirements.
• OGC has right to order additional tests other
  than the outlined minimum.

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Modification of Annual Pool Pressure Test
Requirements
Where adequate pressure history exists, wells
have low productivity, and/or there are few
remaining reserves in a pool, the primary pool
operator may apply to have the annual pressure
testing requirement modified for that pool.

• A modified testing interval of two or more
  years, or a total exemption, may be granted.
• The operator must provide sufficient
  information to substantiate their request for
  modification.
• An application checklist is available from our
  website as a reference.

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What pools require testing this year?
Is the pool producing?
yes
no
Is the pool listed in Pools with Non-Annual
Pressure Testing Approval (Table 1)? (
available from the OGC website)
Pressure survey NOT required.
yes
no
Annual pressure survey required.
Table will specify either a) the frequency of
testing which calendar year the next tests
are due or, b) that the pool is exempt from
annual pressure testing.
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Pools with Non-Annual Pressure Survey Approval
(Table 1)
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Coordinating Operators
Coordinating Operators have been assigned to
certain large multi-operator pools for the
purpose of assisting in the collection of annual
pressure survey data. These operators draft the
testing schedule for the pools but individual
operators are still responsible for ensuring
testing requirements are met.
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Website Orientation
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http//www.ogc.gov.bc.ca/
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?? Questions ??
Chris Grieve Reservoir Engineering Technician
? [phone] ? chris.grieve_at_gov.bc.ca
or visit www.ogc.gov.bc.ca