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Informational Letter IL 93-4

30 June 1993

TO: All Oil and Gas Operators

POLICY FOR THE LOGGING OF HORIZONTAL WELLS

INTRODUCTION

In July of 1992, the Energy Resources Conservation Board (the Board) circulated a questionnaire regarding a proposed policy for the logging of horizontal wells. The questionnaire was intended to solicit industry's input on the need for logging of the horizontal section of wells drilled for infill purposes within designated pools. This Informational Letter IL 93-4 outlines the policy the Board will adopt for logging requirements in horizontal wells.

QUESTIONNAIRE SURVEY RESULTS

The Board suggested two proposals for handling/enforcing of logging requirements for horizontal development wells and asked for operators' input on these by way of a questionnaire. A total of 56 responses were received. Included in this total were operators who, combined, have drilled over 70 per cent of the horizontal wells in the province. The responses to the questionnaire provided valuable information which was considered in reaching the following conclusions:

Logging requirements for horizontal development wells tend to be site specific, are best known by the operator, and very rarely coincide with the current legislated minimum requirements.

Operators overwhelmingly prefer to select an appropriate logging program without requiring approval to waive normal open-hole logging requirements.

Information obtained is of importance primarily to the operator because it typically is production related, rather than used for determining reservoir parameters or the extent of reserves within a pool.

A gamma-ray porosity log would be the preferred minimum requirement if one was to be legislated. A drill-cutting snip log, although considered useful by many operators, was not considered an appropriate minimum requirement because consistent quality could not be assured.

LOGGING REQUIREMENTS OF HORIZONTAL WELLS

The Board will therefore adopt the following policy respecting the logging requirements for horizontal development wells:

Horizontal wells drilled outside a designated pool must be logged in accordance with section 11.140 (1)(a) of the Oil and Gas Conservation Regulations. Horizontal wells drilled as development wells (which are non-confidential at the time of licensing) within a designated pool are exempt from the normal logging requirements as per section 11.140 (1)(a), over the horizontal section of the hole, without prior approval from the Board. The vertical and build section of the well must be logged according to the normal requirements. As per section 11.140 (1)(b), operators are required to submit to the Board copies of all logs run.

Operators are encouraged to continue to run logs which will aid in a better understanding of the reservoirs being exploited.

This policy will come into effect on 1 July 1993. The Board will continue to monitor the practices associated with logging of horizontal wells and, if conditions warrant, modify the policy.

Any questions regarding logging requirements should be directed to the Board's Geology Department at 297-8214.

[Original signed by]

C.A. Langlo
Manager
ERCB, Geology Department