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Chapter D7 ver. 1

Oil and Gas Surveys in the Territories And Offshore

Table of Contents

Effective Date

This Chapter is effective July, 1981. The general instructions in this Chapter are under review. The general instructions in Part E of the Second Edition of the Manual of Instructions for the Survey of Canada Lands (published here and in Chapter D7 of the Third Edition of the Manual of Instructions for the Survey of Canada Lands for convenience) still apply in so far as they are consistent with new legislation, regulations or other policies. Please note chapter and section references are to the Second Edition of the Manual of Instructions for the Survey of Canada Lands.

Chapter Sections

Chapter E1
General Provisions

  1. These specifications apply to all legal surveys under the Canada Oil and Gas Land Regulations (COGLR) which govern the disposition of oil and gas under all offshore Canada Lands and the Yukon and Northwest Territories.
  2. Legal surveys may be approved by the Surveyor General for the purpose of establishing:
    1. the position of a well within a unit of a grid area pursuant to section 12, 13, 20, or 21 (2)( a) of the regulations,
    2. the position of monuments on a fixed platform pursuant to section 21 (3)( a) of the regulations, or
    3. the position of a boundary or boundaries or a grid area or any subdivision thereof pursuant to section 12 or 13 of the regulations.
  3. Approval by the Surveyor General of a plan of legal survey showing a well or other works, confirms only the positional information, and does not authorize the placement of the well or other works in the surveyed position.
  4. After approval of a legal survey within a grid area, that legal survey shall govern all other such surveys within the same grid area.
  5. Prior specific instructions for legal surveys are not essential but may be issued on request. It is the surveyor's responsibility to ensure that he has all pertinent, up-to-date control or other survey data necessary for any project. This data is available through the office of the Surveyor General, Department of Resources, 615 Booth Street, Ottawa, Ontario, KIA 0E9 - telephone number 613-995-4341.
  6. The General Instructions in Part B of this Manual apply to oil and gas surveys insofar as they are not inconsistent with the provisions of this Part.

Chapter E2
UTM Coordinate System

  1. (1) The Universal Transverse Mercator (UTM) system is a plane rectangular coordinate system derived by using a Gauss-Kruger transverse Mercator projection within narrow zones of the spheroid bounded by meridians. The projection is conformal and has a constant scale factor along the central meridian of the zone of 0.9996. The spheroid is divided into 6° zones with central meridian at west longitudes, λ = 3° ... 51°, 57°, 63° ... 135°, 141° ... Zones are numbered eastward from longitude 180°; the number 'n' of a zone is given by the formula: n = (183 - λ)/6.
    (2) The Clarke spheroid of 1866 is used to represent the shape of the earth for the UTM projection in North America. It has a and b axes of 6 378 206.4 metres and 6 356 583.8 metres respectively.
    (3) UTM coordinates are expressed in metres. The coordinate axes of a zone are the central meridian and the Equator, but the central meridian is given a false easting of 500 000 metres to avoid negative eastings.
    (4) Basic formulae for conversions between UTM and geographical coordinates can be found in the following references:
    Lee, L.P. "Conformal Projections Based on Elliptic Functions". Cartographica, Monograph 16, Dept. of Geography, York University, Toronto, 1976;
    Lee, L.P. "The Transverse Mercator Projection of the Spheroid". Empire Survey Review, Vol. VIII, No. 45, Oct. 1945;
    Redfearn, J.C.B. "Transverse Mercator Formulae". Empire Survey Review, Vol. IX, No. 69, July 1948;
    Schmid, Erwin. "The General Term in the Expansion for Meridian Length". The Canadian Surveyor, Vol. 25, No. 2, June 1971;
    Thomas, Paul D. "Conformal Projections in Geodesy and Cartography" Special Publication 251, United States Department of Commerce, National Geodetic Survey, Washington, 1952;
    United States Department of the Army. "Universal Transverse Mercator Grid". Technical Manual TM 5-241-8, U. S. Government Printing Office, Washington, April 1973.
    (5) Tables of official UTM coordinates for COGLR grid area corners between Latitudes 40° and 85° are available, on request, from the Surveyor General.
  2. Before plane coordinate computations can be made the measured quantities must be reduced to equivalent measure-ments on the projection plane. Distances may be reduced from the mean elevation of measurement to the projection plane by using the combined factor obtained from the preceding graph.

    Factor for Reducing Horizontal Distances to UTM Grid Distances - Figure E1 (755 KB)

  3. Measured angles, bearings or directions do not normally require any reduction to equivalent plane surface measurements before using them for plane coordinate computations because the curved spheroidal surface of the earth is only slightly tilted with respect to the UTM plane. However, whenever long sight lines are involved there may be a significant difference between an observed direction or bearing T (the azimuth, corrected for convergence between the central meridian and the observation point) and the grid bearing t. The difference is always less than 6" for sight lines less than 10 km but may be as much as a minute on a 100 km sight line. For a sight line between instrument station 1 and target station 2, with coordinates (N1, E1) and (N2, E2) respectively, the following formula gives the value of (t-T) to a small fraction of a second:

    The grid bearing t minus observed bearing T (in seconds) is equal to 0.85 seconds multiplied by 10 to the power of negative 9 times (N1 minus N2) times (2 multiplied by E1 plus E2 minus 1 500 000) where t is defined by the equation tan t equals (E2 minus E1) divided by (N2 minus N1)

  4. If a survey has many long lines or crosses zone boundaries it is advisable to use a computer program such as GALS, MANOR, or COSMOS which computes in geographic coordinates directly and provides UTM coordinates as a final output.
  5. The east and west boundaries of a grid area are defined in COGLR as meridians. The north and south boundaries are defined not as parallels of latitude but as straight lines being chords to parallels of latitude. Coordinates of points on any of the boundaries may be found directly by interpolation between the official UTM coordinates of the corners and areas are computed on the UTM plane from the coordinates. If the geographic coordinates of a point are given it may be easily and precisely located within a COGLR subdivision by first converting its geographic coordinates to UTM coordinates.

Chapter E3
Control

  1. If a legal survey within the grid area concerned has been approved by the Surveyor General pursuant to COGLR, then any other position subsequently determined within that grid area shall be derived from that legal survey, or if all monuments are missing, from the control monuments upon which it was based.
  2. If no previous legal survey has been approved under COGLR for the grid area concerned, positions shall be derived from nearby 1927 NAD control monuments specified by the Dominion Geodesist to be of third order or higher accuracy, or monuments shown on an approved plan of legal survey under COGLR. In general, the surveyor should use the best control available to maintain accuracy for later surveys which may be derived from his survey.
  3. Bearings shall be derived preferably from control monuments but may also be derived from astronomic observations provided that the required positional accuracy is maintained for the new stations.

Chapter E4
Methods and Accuracy

  1. As a general principle, legal surveys under COGLR shall be integrated with the authorized control for the particular grid area (See Chapter E3). This includes checking the stability and reliability of the control monuments used, adhering to specified accuracy requirements and systematically adjusting the discrepancies of the survey.
  2. Positions may be determined by any method, instrument or system that is demonstrated in the particular case to produce third order accuracy as defined in "Specifications and Recommendations for Control Surveys and Survey Markers, 1978". This document, issued by the Surveys and Mapping Branch, besides prescribing standards of positional accuracy gives measurement guidelines for obtaining the various orders of positional accuracy using conventional survey methods, and nominal standard deviations for various instruments and methods.
  3. Where the system used does not provide redundant measurements, checks must be obtained by using an indepen-dent system that will isolate the type of errors to which the main system is subject. The difference between the positions derived by the two systems should be within acceptable tolerances.
  4. In general, connections from stations to a control network shall be to the control monuments lying nearest and most nearly surrounding the station. Ideally the tie should start at one control monument, pass through the station in question and end at another control monument.
  5. When a Doppler satellite system is used to determine a required legal position, it is preferable to take simultaneous observations at both the new station and an authorized control station. Single point positioning expressed in relation to 1927 NAD may be authorized if the datum shift for the area is accurately known and the required accuracy can be achieved.

Chapter E5
Monumentation

  1. Monumentation is governed by Chapter B6 of this Manual and by the following provisions.
  2. Where the purpose of the survey is to establish the position of a well on land, at least two monuments shall be made near the well but in locations safe from damage by development or other operations.
  3. Where the purpose of the survey is to establish the position of monuments on a fixed bottom-mounted offshore development platform, at least two C. L. S. Rock Posts shall be fixed to the structure in locations that are safe from damage by operations on the platform.
  4. Where the purpose of the survey is to establish the position of a boundary or boundaries of a grid area, section or unit, each corner defining the boundary shall be monumented. Each section corner shall be marked with the four appropriate section numbers, and each unit corner that is not a section corner shall be marked with the four appropriate unit letters and the relevant section number or numbers.
  5. Connecting traverses on land from authorized control monuments to ground positions being established shall be monumented at each station but not more frequently than at about 1 km intervals.
  6. For posts placed in positions other than at section or unit corners, each post placed shall be marked with the letter "C", followed by a distinguishing serial number, e. g. C23, C34 or C34A.
  7. Structures of a permanent nature, such as well casing, wellhead equipment or concrete foundations that may serve as permanent references to a well whose position is being established shall be carefully tied in and described in the returns of survey.

Chapter E6
Documentation

  1. For surveys done by conventional land-based methods requirements for field records and returns are given in Chapters B10 and B12 of this Manual.
  2. For surveys using Doppler satellite systems, inertial survey systems or other position determining systems, submit a detailed report on the system used and on the method of operation, giving sufficient information to demonstrate the accuracy of the derived positions.
  3. The plan of survey shall include the relevant items of Chapter B11 and the following:
    1. in the descriptive heading, any name assigned to a well or offshore structure and reference to COGLR.
    2. features required by subsection 11( 2) COGLR.
    3. tabulated UTM coordinates of corners of the grid area and each unit involved, of all monuments and of each well.
    4. tabulated geographic coordinates on 1927 North American Datum and elevation above sea level of each well and all control monuments.
    5. identification of the source of coordinates used to control the survey, with name and date of adjustment, etc. and the basis and method used to obtain elevations.
    6. the perpendicular distances from the well or proposed well to the nearest unit boundaries.
    7. water depth at location (if applicable).

Specimen Plans

Note

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