EXHIBIT 99.12

Supplemental Information About Oil and Gas Producing Activities (unaudited)

The following disclosures, including proved reserves, future net cash flows, and costs incurred attributable to Enerplus' crude oil and natural gas operations have been prepared in accordance with the provisions of the Financial Accounting Standards Board's Accounting Standards Update (ASU) No. 2010-03 "Extractive Activities – Oil and Gas (Topic 932) (the "ASU"). The standard requires the use of a 12 month average price to estimate proved reserves calculated as the unweighted arithmetic average of first-day-of-the-month prices within the 12 month period prior to the end of the reporting period. Proved reserves and production volumes are presented net of royalties in accordance with U.S. protocol.

A. PROVED OIL AND NATURAL GAS RESERVE QUANTITIES

Users of this information should be aware that the process of estimating quantities of "proved developed" and "proved undeveloped" crude oil, natural gas and natural gas liquids is very complex, requiring significant subjective decisions in the evaluation of all available geological, engineering and economic data for each reservoir. The data for a given reservoir may change substantially over time as a result of numerous factors including, but not limited to, additional development activity, evolving production history, and continual reassessment of the viability of production under varying economic conditions. Consequently, material revisions to existing reserve estimates occur from time to time. Although every reasonable effort is made to ensure that reserve estimates reported represent the most accurate assessments possible, the significance of the subjective decisions required and variances in available data for reservoirs make these estimates generally less precise than other estimates presented in connection with financial statement disclosures. Future fluctuations in prices and costs, production rates, or changes in political or regulatory environments could cause the Corporation's reserves to be materially different from that presented.

Proved reserves, proved developed reserves and proved undeveloped reserves are defined under the ASU. Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a given date forward, from known reservoirs and under existing economic conditions, operating methods and government regulation. Proved developed reserves are reserves that can be expected to be recovered through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively minor compared to the cost of a new well. Proved undeveloped reserves are reserves that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion. The proved reserves disclosed herein are determined according to the definition of "proved reserves" under NI 51-101 which may differ from the definition provided in SEC rules, however the difference should not be material. The reserves data presented in this Exhibit are a summary of evaluations, and as a result the tables may contain slightly different numbers than the evaluations themselves due to rounding. Additionally, the columns and rows in the tables may not add due to rounding. See "Presentation of Enerplus' Oil and Gas Reserves, Contingent Resources, and Production Information" in Enerplus' Annual Information Form. All cost information in this section is stated in Canadian dollars and is calculated in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP").

Subsequent to December 31, 2016, no major discovery or other favourable or adverse event is believed to have caused a material change in the estimates of proved reserves as of that date.

Enerplus’ December 31, 2016 proved crude oil, natural gas and natural gas liquids reserves are located in western Canada, primarily in Alberta, British Columbia and Saskatchewan, as well as in the United States, primarily in the states of Montana, North Dakota and Pennsylvania. Enerplus’ net proved reserves summarized in the following chart

represent the Corporation’s lessor royalty, overriding royalty, and working interest share of reserves, after deduction of any Crown, freehold and overriding royalties:

 

Purchases of reserves in place

In 2016, the Company acquired working interests in the Ante Creek North oil property located in Alberta. This purchase represented all of the purchase of reserves in place for Enerplus in 2016.

Sales of reserves in place

        In 2014, the Company sold working interests in developed and undeveloped land in eighteen predominantly natural gas properties in Alberta and one property in British Columbia.

        Additionally, the Company sold all interests in the Jonah natural gas property in Wyoming which accounts for all of the United States sales of reserves in place volumes for 2014.

In 2015, the Company sold working interests in developed and undeveloped land in two oil properties located in Alberta and Saskatchewan and 11 predominantly shallow natural gas properties also located in Alberta and Saskatchewan.

 

In 2016, the Company sold working interests in developed and undeveloped land in six oil properties located in Alberta and 12 natural gas properties located in Alberta and Saskatchewan.

 

Additionally, the Company sold almost all non-operated working interests in the Bakken/Three Forks crude oil property in North Dakota, which accounts for all of the United States sales of reserves in place for 2016.

 

Discoveries and extensions

       United States discoveries and extensions for the periods ending December 31, 2014, 2015 and 2016 were primarily due to successful well development of the Company's Bakken/Three Forks crude oil property in North Dakota, and the Marcellus natural gas property in Pennsylvania. In these periods, the Company added 16,498 MBbl, 4,397 Mbbl and 12,515 MBbl of net proved oil and NGLs reserves with respect to Bakken/Three Forks properties in 2014, 2015 and 2016, respectively. The Company added 130,400 MMcf, 1,810 MMcf and 22,017 MMcf of net proved natural gas reserves in 2014, 2015 and 2016, respectively, in the Marcellus natural gas property.

 

        Canadian natural gas discoveries and extensions for the period ending December 31, 2014, accounted for an increase of 27,175 MMcf net proved reserves primarily due to the Company's Alberta drilling program. Roughly half of these reserves were producing as of December 31, 2014. The largest undeveloped portion of the addition was an addition of 10,549 MMcf in the Wilrich.

 

In 2015, Canadian discoveries and extensions accounted for an increase of 1,276 MBbl of net proved oil and NGLs reserves and 2,769 MMcf of net proved natural gas reserves, primarily due to the expansion of the Med Hat Glauconitic C polymer floods.

 

In 2016, Canadian discoveries and extensions accounted for an increase of 83 MBbl of net proved oil and NGLs reserves due to assigning reserves to a location in the Saskatchewan Ratcliffe oil property.

 

Revisions of previous estimates

Revisions to United States oil reserves in 2014 were due to the improved production performance of the Bakken/Three Forks oil property. The revisions to United States natural gas reserves in 2014 were due to improved production performance of the Marcellus natural gas property.

 

In 2015, negative revisions to United States natural gas reserves were primarily due to a decrease in the constant price gas price forecast versus 2014, causing undeveloped reserves to become uneconomic and therefore removed.

 

In 2016, negative revisions to United States oil reserves were primarily due to the removal of undeveloped locations that would not be drilled within five years of initial booking. Positive revisions to United States natural gas reserves were primarily due to improved production performance of the Marcellus natural gas property.

 

In 2014, the positive revisions to Canadian natural gas reserves were primarily due to an increase in the constant gas price forecast versus 2013. 

 

In 2015, the negative revisions to Canadian natural gas reserves were primarily due to a decrease in the constant gas price forecast versus 2014.

 

In 2016, the positive revisions to Canadian natural gas reserves were due to a slightly higher gas price forecast and slightly lower operating costs.

 

B. CAPITALIZED COSTS RELATED TO OIL AND GAS PRODUCING ACTIVITIES

The capitalized costs and related accumulated depreciation and depletion, including impairments, relating to Enerplus’ oil and gas exploration, development and producing activities are as follows:

 

Note:

(1)Includes capitalized costs of proved and unproved properties.

C. COSTS INCURRED IN OIL AND GAS PROPERTY ACQUISITION, EXPLORATION AND DEVELOPMENT ACTIVITIES

Costs incurred in connection with oil and gas producing activities are presented in the table below. Property acquisition costs include costs incurred to purchase, lease, or otherwise acquire oil and gas properties, including an allocation of purchase price on business combinations that result in property acquisitions. Development costs include asset retirement costs capitalized and the costs of drilling and equipping development wells and facilities to extract, gather and store oil and gas, along with an allocation of overhead. Exploration costs include costs related to the discovery and the drilling and completion of exploratory wells in new crude oil and natural gas reservoirs.

 

 

 

 

D. RESULTS OF OPERATIONS FOR OIL AND GAS PRODUCING ACTIVITIES

The following table sets forth revenue and direct cost information relating to Enerplus' oil and gas producing activities for the years ended December 31, 2016, 2015 and 2014:

 

 

 

 

Notes:

E. STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS RELATING TO PROVED OIL AND NATURAL GAS RESERVE QUANTITIES

The following tables set forth the standardized measure of discounted future net cash flows from projected production of the Enerplus’ crude oil and natural gas reserves:

 

 

 

 

 

F. CHANGES IN STANDARDIZED MEASURE OF DISCOUNTED FUTURE CASH FLOW RELATING TO PROVED OIL AND NATURAL GAS RESERVES