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UNITED STATES DEPARTMENT OF THE INTERIOR
MINERALS MANAGEMENT SERVICE
GULF OF MEXICO OCS REGION
| NTL No.
98-20 |
Effective Date: September 15,
1998 |
NOTICE TO LESSEES AND OPERATORS
OF FEDERAL OIL, GAS, AND SULPHUR
LEASES IN THE OUTER CONTINENTAL SHELF, GULF OF MEXICO OCS REGION
Shallow Hazards Requirements
This Notice to Lessees and Operators and Pipeline Right-of-way Holders (NTL)
supersedes NTL 83-3, dated September 22, 1983, and makes minor technical
amendments, updates cited regulatory authorities, deletes the Appendix, and
includes a statement regarding the Paperwork Reduction Act of 1995. The Gulf of
Mexico OCS Region (GOMR) is in the process of substantially changing the
requirements of this NTL as hereby issued and plans to issue a replacement NTL
to reflect those changes in the near future. If you have any questions regarding
this NTL, please contact the Geological and Geophysical Analysis Unit at (504)
736-2995.
I. Introduction
Pursuant to 30 CFR 250.104(b) and according to 30 CFR 250.105(a), the GOMR
has established a shallow hazards program to ensure that you conduct
exploratory, development, production, and transportation operations with a
minimum risk to human life and the environment. This NTL specifies the shallow
hazards requirements necessary to meet this objective.
This NTL is effective immediately and applies to all existing and future
leases and pipeline rights-of-way.
II. Shallow Hazards Analysis
A. Exploration Plans (EP’s) and Development Operations Coordination
Documents (DOCD’s)
According to 30 CFR 250.203(b)(1)(ix) and 250.204(b)(1)(vii), you must
include a shallow hazards analysis for each proposed drilling or platform site
in all EP’s and DOCD’s that propose seafloor-disturbing activities. You must
include detailed shallow hazards analyses of all pipeline routes in separate
pipeline applications, not in DOCD’s.
A shallow hazards analysis for activities proposed in an EP or a DOCD must
include the following:
1. A discussion and review of
all available geological and geophysical data within 150 meters (490 feet) of
each proposed operation.
2. An assessment of any
seafloor and subsurface geologic and man made features and conditions that may
have an adverse effect on the proposed operations. Seafloor geologic hazards
include fault scarps, gas vents, unstable slopes, and reefs. Subsurface geologic
hazards include faults, gas-charged sediments, abnormal pressure zones, and
buried channels. Man made hazards include pipelines, wellheads, shipwrecks,
ordnance, communication cables, and debris from previous oil and gas activities.
3. A specific discussion of
mass movement of sediments, unstable slopes, active faulting, or gaseous
sediments when the special operational constraints stipulation on some leases
require it.
4. A discussion of any special
safety measures that would minimize the adverse effects of shallow hazards on
the proposed operations including a discussion of how you will comply with the
requirements of Section IV, paragraph B, of this NTL.
5. For leases issued after
April 1983, you must include a copy of your high-resolution survey data from the
two lines closest to the proposed well or platform location with one copy of
each EP or DOCD.
In order to provide sufficient information on which to base a shallow hazards
analysis, you must conduct a shallow hazards survey, as described in Section
III, paragraphs C.2.a. or C.2.b., of this NTL. However, if you can make a
thorough analysis using available geological and geophysical information,
including CDP and seismic bright spot data and seismic velocity data, you are
not required to conduct a shallow hazards survey. If you are uncertain about the
adequacy of available data to prepare an acceptable analysis, you may contact
the appropriate GOMR geophysicist for guidance before you submit the EP or DOCD.
B. Applications for Permit to Drill
According to 30 CFR 250.401(d), the appropriate District Supervisor may
require additional shallow hazards surveying and/or analysis to support
applications to drill individual wells. The District Supervisor may also request
to review original survey data.
C. Platform Applications
The necessary shallow hazards information that must be included in platform
applications is specified in 30 CFR 250.901(b)(3)(v).
D. Pipeline Applications
According to 30 CFR 250.1007(a)(5), all pipeline applications must include a
shallow hazards analysis that addresses the entire length of the pipeline.
1. A shallow hazards analysis
for a pipeline for which you conducted a specific pipeline pre-installation
survey must include the following:
a. A shallow hazards report
prepared according to the requirements of Section III, paragraph D.2., of this
NTL.
b. A discussion of any special
safety measures that would minimize the effects of shallow hazards on the
proposed pipeline including a discussion of how you will comply with Section IV,
paragraph B, of this NTL.
2. A shallow hazards analysis
for a pipeline for which you did not conduct a specific pipeline
pre-installation survey must include the following:
a. A discussion of the specific
data and reports you used to make the analysis.
b. An assessment of any
seafloor and subsurface geologic and man made features and conditions that may
have an adverse effect on the proposed pipeline.
c. A discussion of any special
safety measures that would minimize the adverse effects of shallow hazards on
the proposed pipeline including a discussion of how you will comply with Section
IV, paragraph B, of this NTL.
To prepare an acceptable shallow hazards analysis for right-of-way pipelines,
you must conduct a pipeline pre-installation survey as prescribed in Section
III, paragraph C.2.d., of this NTL. However, for lease term pipelines, we do not
require you to conduct a pipeline pre-installation survey if you can make a
thorough analysis using available geological and geophysical data. If you are
uncertain about the adequacy of available data to prepare an acceptable analysis
for a lease term pipeline, you may contact the appropriate GOMR geophysicist for
guidance before you submit the pipeline application.
III. Shallow Hazards Surveys and Reports
A. Introduction
Since the following shallow hazards survey requirements are similar to those
for other surveys (e.g., archaeological resource and live-bottom), we encourage
you to conduct the surveys concurrently. When you cannot meet any of the survey
requirements for technical, logistical, or other justifiable reasons, you must
provide an explanation of the problem in the shallow hazards report.
B. Data Acquisition Instrumentation
Geophysical instrumentation for shallow hazards surveys must represent
state-of-the-art technological development, and you must deploy it in a manner
that minimizes interference between the instrumentation systems. You must key
all data recorders to the navigation system to ensure proper integration of
information. The equipment operator must ensure that all instruments are
adequately tuned and that all recorded data are readable, accurate, and properly
annotated.
You must use the following instrumentation when you conduct shallow hazards
surveys unless you justify to the appropriate GOMR geophysicist before you
conduct the survey that certain instrumentation is unnecessary.
1. Magnetometer
You must use a total field intensity instrument to determine the presence of
pipelines and other ferromagnetic objects. Tow the sensor of the magnetometer as
near as possible to the seafloor; a distance of six meters (20 feet) or less is
required. Magnetometer sensitivity must be one gamma or better, and the
background noise level must not exceed three gammas peak to peak. Whenever
possible, tow the magnetometer a minimum distance of three vessel lengths behind
the vessel to eliminate its magnetic influence.
2. Side-Scan Sonar
You must use a dual channel side-scan sonar system to record continuous
planimetric images of the seafloor. You must operate the system in a manner that
provides 100 percent coverage of the seafloor in the survey area. Data obtained
must be of such quality as to permit detection and evaluation of seafloor
objects and features within the survey area.
The vertical sound beam width must be appropriate to the water depth, and the
horizontal sound beam width must provide optimum resolution. You must tune the
instrument to enhance echo returns from small nearby objects and features
without sacrificing the quality of echo returns from more distant objects and
features.
3. Shallow Penetration Subbottom Profiler
You must use a subbottom profiler system to determine the character of
near-surface geological features. The system used must be capable of providing a
resolution of at least one meter (three feet) within the upper 15 meters (50
feet) of sediment.
4. Medium Penetration Seismic Profiler
You must use a profiler system to determine the character of deeper
geological features. The system used must be capable of penetrating at least 300
meters (980 feet).
For seafloor obstruction surveys and pipeline pre-installation surveys, as
discussed in paragraphs C.2.c. and C.2.d. of this section, we do not require a
medium penetration profiler system.
5. Depth Sounder
You must use a high-frequency narrow-beam depth sounder to make continuous
water depth measurements. Record bathymetric data with a recording sweep
appropriate to topography and water depth.
6. Additional Investigations
Under certain conditions, we may require additional instrumentation and
methods such as underwater television, still or movie cameras, divers, coring,
remote or manned submersibles, and additional geophysical survey lines.
C. Survey Parameters
You must adhere to the following navigation and survey pattern requirements
when conducting shallow hazards surveys:
1. Navigation
You must accomplish navigation for the survey by using a state-of-the-art
continuous positioning system correlated with annotated geophysical records. The
accuracy of the system must be on the order of ±30 meters at 322 kilometers. The
nominal fix spacing must be no more than 150 meters (490 feet).
2. Survey Pattern
You must design the pattern for each type of survey to cover the area of
anticipated physical disturbances. This area includes but is not limited to the
area within which drilling vessel or pipeline-lay barge anchors may be placed,
but does not include the area within which work boat anchors will be placed or
the area within which similar minimal disturbances may occur.
You must use the following survey patterns when you conduct a shallow hazards
survey unless you justify to the appropriate GOMR geophysicist before you
conduct the survey that a different survey pattern is adequate.
a. Lease Surveys - When
you plan multiple operations on the lease or are likely to do so, it may be
advantageous for you to conduct a lease survey. This survey must cover the
entire area of the lease, as well as that portion external to the lease within
which operational activities may cause physical disturbances. You must run the
survey along parallel lines spaced at a maximum of 300 meters (980 feet) with
cross lines spaced at a maximum of 900 meters (2,950 feet).
b. Site-Specific Surveys
- This survey must cover an area at least 1800 meters (5,900 feet) square. You
must run the survey along parallel lines spaced at a maximum of 300 meters (980
feet) with cross lines spaced at a maximum of 900 meters (2,950 feet). We do not
require site-specific surveys in areas where lease surveys adequately cover the
area.
c. Seafloor Obstruction
Surveys - Before you begin operations involving mobile drilling rigs,
pipeline-lay barges, and anchor-handling vessels, you may need to conduct a
seafloor obstruction survey to locate existing pipelines and other potential
hazards. We do not require a seafloor obstruction survey if the data from other
surveys are adequate to accomplish this purpose. You must run seafloor
obstruction surveys for wells and platforms in an area at least 300 meters (980
feet) square with three equidistant primary lines and at least one cross line.
You must run seafloor obstruction surveys for pipelines using the same pattern
as that required for pipeline pre-installation surveys discussed in paragraph
C.2.d. of this section.
d. Pipeline Pre-installation
Surveys - The pattern for pipeline pre-installation surveys must include a
line along the proposed pipeline route with an offset parallel line on either
side spaced to coincide with the area that the pipeline-lay barge anchors will
disturb. We do not require individual pipeline pre-installation surveys for
lease term pipelines in areas where other surveys adequately cover the area.
D. Shallow Hazards Reports
1. Introduction
You must include an evaluation of data gathered during the shallow hazards
survey and a synthesis with other available geological and geophysical
information in a report prepared and signed by a geophysicist or geologist
specializing in high-resolution geophysical interpretation.
You must submit three copies of each shallow hazards report to the Regional
Supervisor, Field Operations. You must submit the report with or in advance of
the EP, DOCD, or pipeline application for which it was prepared. We encourage
you to combine shallow hazards reports with archaeological resource reports
(when required), since many of the requirements for these reports are similar.
We do not require shallow hazards reports for seafloor obstruction surveys, as
discussed in Section III, paragraph C.2.c., of this NTL.
2. Report Contents
Your shallow hazards reports must include the following information:
a. A description of the area
surveyed including lease number(s), block number(s), OCS lease area(s), and
water depth.
b. A listing of the individuals
involved in survey implementation and report preparation, and a brief
description of the duties of each.
c. A discussion of the shallow
hazards survey including (1) a brief description of the navigation system with a
statement of its estimited accuracy for the area surveyed; (2) a brief
description of all survey instrumentation including scale and sensitivity
settings and tow depths for the magnetometer and side-scan sonar sensors; (3) a
description or diagram of the survey vessel including vessel size, sensor
configuration, navigation antenna location, cable lengths, and distances from
sensors to navigation antenna; (4) vessel speed; (5) sea state and weather
conditions; (6) a copy of the daily survey operations log; and (7) a description
of survey procedures including a statement of survey and record quality, a
comparison of data from survey line crossings, and a discussion of any problems
that may have affected the ability of the geophysicist or geologist to identify
and analyze shallow hazards in the survey area.
d. A map or separate maps at a
scale of 1:12,000 and oriented to true north that includes (1) a navigation
postplot of the survey area showing lease block lines, latitude-longitude
reference coordinates, survey lines and directions, and navigational shotpoints;
(2) bathymetry; (3) shallow geologic structure; (4) deep geologic structure
(from medium penetration profiler data); and (5) all anomalies such as side-scan
sonar contacts, magnetic anomalies, and areas of shallow gas. For proposed
pipeline routes, include the x and y coordinates of the origin and terminus of
the route and the points where the route crosses safety fairway and anchorage
area boundaries, existing pipelines, block lines, and the Federal/State boundary
line.
e. An assessment of the
potential for shallow hazards within the survey area including but not limited
to discussions of (1) general geological background; (2) previous oil and gas
activity including wells, platforms, and pipelines; (3) bathymetry; (4) seafloor
features including side-scan sonar contacts; (5) geological structure including
faults, river channels, and karst areas; (6) shallow gas and possible abnormal
pressure zones; (7) magnetic anomalies; and (8) unstable seafloor areas.
f. A list of all magnetic
anomalies including the (1) corrected location by line, shotpoint, and x and y
coordinates; (2) intensity; (3) duration; and (4) source (if known) of each.
g. A summary of conclusions and
recommendations supported by the survey data and analyses including a discussion
of known or potential shallow hazards and areas to be avoided or that may
require further investigations.
E. Original Survey Data
You should retain all original survey data for a lease and make it available
upon request to us at any time prior to lease termination. You should retain the
original survey data for a pipeline right-of-way until we notify you that the
as-built location report is acceptable.
IV. Requirements for Mitigation of Potential Shallow Hazards
A. EP’s, DOCD’s, and Pipeline Applications
When our review of a shallow hazards survey and report and/or shallow hazards
analysis indicates a potential hazard within the immediate area of your proposed
operations, you will select one of the following three alternatives:
1. Amend your EP, DOCD, or
pipeline application to locate the site of operations to avoid the potential
shallow hazard.
2. Demonstrate to us that the
use of special protective measures will minimize the risk to safe operations.
3. Establish, on the basis of
further investigation using such equipment and techniques the Regional
Supervisor, Field Operations, deems necessary, that such operations will not be
adversely affected by the shallow hazard.
B. On-site Requirements
1. Prior to performing
operations, you must buoy all existing pipelines and other potential hazards
located within 150 meters (490 feet) of the operation (including anchor
patterns). You may outline with buoys a safe working area large enough to
accommodate your proposed operations in lieu of marking each hazard in areas
highly congested with pipelines or debris.
2. In addition, you must
prepare a plat with a minimum scale of 1:12,000 depicting the location of the
proposed activity, all associated anchor patterns, and existing pipelines or
other potential hazards in the area. You must provide copies of this plat to key
personnel on all drilling rigs, derrick barges, pipeline-lay barges, and
anchor-handling vessels associated with the operations.
V. Paperwork Reduction Act of 1995 Statement
The Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) requires us to
inform you that we require the information collection discussed in this NTL to
carry out the Federal Government’s responsibilities to ensure that you conduct
OCS exploratory, development, production, and transportation operations with a
minimum risk to human life and the environment. Responses are mandatory.
Proprietary data are covered under 30 CFR 250, Subpart A.
An agency may not conduct or sponsor, and a person is not required to respond
to, a collection of information unless it displays a currently valid Office of
Management and Budget (OMB) Control Number. The OMB approved the information
collection reporting aspects of this NTL as part of the requirements in 30 CFR
250, Subpart B (EP’s, DOCD’s, and surveys and reports), Subpart D (APD’s and
surveys), Subpart I (platform applications and surveys), and Subpart J (pipeline
applications and surveys and reports) and assigned OMB control numbers
1010-0049, 1010-0053 (and 1010-0044 for Form MMS-123), 1010-0058, and 1010-0050,
respectively.
The Paperwork Reduction Act of 1995 also requires us to inform you about the
record keeping aspects of this NTL. The NTL requests that you to voluntarily
retain all original survey data and make them available to us when needed. We
must have access to these data to make determinations on plans, APD’s, platform
applications, and pipeline applications. We believe that the cost of retaining
these data is much less than the cost of reproducing them if they were lost or
discarded. We estimate the annual recordkeeping burden to be two hours in
addition to that involved with your usual and customary business practice. The
OMB has approved the record keeping burden of this collection under OMB control
number 1010-0049.
Direct comments regarding the burden estimate or any other aspect of the
information collection in this NTL to the Information Collection Clearance
Officer, Mail Stop 4230, Minerals Management Service, Department of the
Interior, 1849 C Street, N.W., Washington, DC 20240; and to the Office of
Management and Budget, Office of Information and Regulatory Affairs, Attention:
Desk Officer for the Department of the Interior (1010-0049), Washington, DC
20503.
Gary L. Lore
for Chris C. Oynes
Regional Director
Gulf of Mexico OCS Region
