Exhibit 99.1







Explanatory Note:



The future net cash flows discounted
at 10% of our proved reserves included in the attached report of DeGolyer and MacNaughton filed is approximately $1.0 million lower
than the future net cash flows discounted at 10% included within the Supplemental Oil and Gas Disclosures (Unaudited) in this Annual
Report on Form 10-K due to the different bases used for the calculation of each value. The future net cash flows discounted at
10% of our proved reserves of $2.2 million included in the report of DeGolyer and MacNaughton was calculated on a project  basis,
which means that it deducts income tax expenses although the Company has enough tax basis and net operating loss carryforwards
to more than offset the income tax expenses. The future net cash flows discounted at 10% of our proved reserves of $3.2 million
included within the Supplemental Oil and Gas Disclosures (Unaudited) was calculated on a company basis, which means that it does
not deduct any income tax expenses because the Company has enough tax basis and net operating loss carryforwards to more than offset
the income tax expenses.



This Explanatory Note is not part of
the attached Report.















DeGolyer and MacNaughton



5001 Spring Valley Road

Suite 800 East

Dallas, Texas 75244











February 28, 2012



La Cortez Energy

Calle 67 No. 7-35

Oficina 409

Bogota D.C., Colombia

Gentlemen:



Pursuant to your request,
we have conducted a reserves evaluation of the net proved, probable, and possible crude oil reserves, as of December 31, 2011,
of certain selected properties owned by La Cortez Energy (La Cortez). This evaluation was completed on February 28, 2012. La Cortez
has represented that these properties account for 100 percent on a net equivalent barrel basis of La Cortez’s net proved
reserves as of December 31, 2011. The net proved reserves estimates prepared by us have been prepared in accordance with the reserves
definitions of Rules 4–10(a) (1)–(32) of Regulation S–X of the Securities and Exchange Commission (SEC) of the
United States. This report was prepared in accordance with guidelines specified in Item 1202 (a)(8) of Regulation S-K and is to
be used for inclusion in certain SEC filings by Sample.



Reserves included herein
are expressed as net reserves. Gross reserves are defined as the total estimated petroleum to be produced from these properties
after December 31, 2011. Net reserves are defined as that portion of the gross reserves attributable to the interests owned by
La Cortez after deducting all interests owned by others.



Estimates of oil, condensate,
and natural gas should be regarded only as estimates that may change as further production history and additional information become
available. Not only are such reserves estimates based on that information which is currently available, but such estimates are
also subject to the uncertainties inherent in the application of judgmental factors in interpreting such information.















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Data used in this evaluation
were obtained from reviews with La Cortez personnel, La Cortez’s files, from records on file with the appropriate regulatory
agencies, and from public sources. In the preparation of this report we have relied, without independent verification, upon such
information furnished by La Cortez with respect to property interests, production from such properties, current costs of operation
and development, current prices for production, agreements relating to current and future operations and sale of production, and
various other information and data that were accepted as represented. A field examination of the properties was not considered
necessary for the purposes of this report.





Methodology and Procedures



Estimates of reserves
were prepared by the use of appropriate geologic, petroleum engineering, and evaluation principals and techniques that are in accordance
with practices generally recognized by the petroleum industry as presented in the publication of the Society of Petroleum Engineers
entitled “Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information (Revision as of February
19, 2007).” The method or combination of methods used in the analysis of each reservoir was tempered by experience with similar
reservoirs, stage of development, quality and completeness of basic data, and production history.



When applicable, the
volumetric method was used to estimate the original oil in place (OOIP). Structure and isopach maps were constructed to estimate
reservoir volume. Electrical logs, radioactivity logs, core analyses, and other available data were used to prepare these maps
as well as to estimate representative values for porosity and water saturation. When adequate data were available and when circumstances
justified, material balance and other engineering methods were used to estimate OOIP.



Estimates of ultimate
recovery were obtained after applying recovery factors to OOIP. These recovery factors were based on consideration of the type
of energy inherent in the reservoirs, analyses of the petroleum, the structural positions of the properties, and the production
histories. When applicable, material balance and other engineering methods were used to estimate recovery factors. An analysis
of reservoir performance, including production rate, reservoir pressure, and gas-oil ratio behavior, was used in the estimation
of reserves.





For depletion-type
reservoirs or those whose performance disclosed a reliable decline in producing-rate trends or other diagnostic characteristics,
reserves were estimated by the application of appropriate decline curves or other performance relationships. In the analyses of
production-decline curves, reserves were estimated only to the limits of economic production or to the limit of the production
licenses as appropriate.













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Definition of Reserves



Petroleum reserves
included in this report are classified by degree of proof as proved, probable, or possible. Reserves classifications used in this
report are in accordance with the reserves definitions of Rules 4–10(a) (1)–(32) of Regulation S–X of the SEC.
Reserves are judged to be economically producible in future years from known reservoirs under existing economic and operating conditions
and assuming continuation of current regulatory practices using conventional production methods and equipment. In the analyses
of production-decline curves, reserves were estimated only to the limit of economic rates of production under existing economic
and operating conditions using prices and costs consistent with the effective date of this report, including consideration of changes
in existing prices provided only by contractual arrangements but not including escalations based upon future conditions. The petroleum
reserves are classified as follows:



Proved oil and gas reserves
– 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 regulations—prior to the time at which contracts
providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic
or probabilistic methods are used for the estimation. The project to extract the hydrocarbons must have commenced or the operator
must be reasonably certain that it will commence the project within a reasonable time.





(i) The area of the reservoir considered
as proved includes:

(A) The area identified by drilling
and limited by fluid contacts, if any, and (B) Adjacent undrilled portions of the reservoir that can, with reasonable certainty,
be judged to be continuous with it and to contain economically producible oil or gas on the basis of available geoscience and engineering
data.



(ii) In the absence of data on fluid
contacts, proved quantities in a reservoir are limited by the lowest known hydrocarbons (LKH) as seen in a well penetration unless
geoscience, engineering, or performance data and reliable technology establishes a lower contact with reasonable certainty.











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(iii) Where direct observation from
well penetrations has defined a highest known oil (HKO) elevation and the potential exists for an associated gas cap, proved oil
reserves may be assigned in the structurally higher portions of the reservoir only if geoscience, engineering, or performance data
and reliable technology establish the higher contact with reasonable certainty.



(iv) Reserves which can be produced
economically through application of improved recovery techniques (including, but not limited to, fluid injection) are included
in the proved classification when:

(A) Successful testing by a pilot
project in an area of the reservoir with properties no more favorable than in the reservoir as a whole, the operation of an installed
program in the reservoir or an analogous reservoir, or other evidence using reliable technology establishes the reasonable certainty
of the engineering analysis on which the project or program was based; and (B) The project has been approved for development by
all necessary parties and entities, including governmental entities.



(v) Existing economic conditions include
prices and costs at which economic producibility from a reservoir is to be determined. The price shall be the average price during
the 12-month period prior to the ending date of the period covered by the report, determined as an unweighted arithmetic average
of the first-day-of-the-month price for each month within such period, unless prices are defined by contractual arrangements, excluding
escalations based upon future conditions.



Probable reserves – Probable
reserves are those additional reserves that are less certain to be recovered than proved reserves but which, together with proved
reserves, are as likely as not to be recovered.



(i) When deterministic methods are
used, it is as likely as not that actual remaining quantities recovered will exceed the sum of estimated proved plus probable reserves.
When probabilistic methods are used, there should be at least a 50% probability that the actual quantities recovered will equal
or exceed the proved plus probable reserves estimates.













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and MacNaughton





(ii) Probable reserves may be assigned
to areas of a reservoir adjacent to proved reserves where data control or interpretations of available data are less certain, even
if the interpreted reservoir continuity of structure or productivity does not meet the reasonable certainty criterion. Probable
reserves may be assigned to areas that are structurally higher than the proved area if these areas are in communication with the
proved reservoir.



(iii) Probable reserves estimates
also include potential incremental quantities associated with a greater percentage recovery of the hydrocarbons in place than assumed
for proved reserves.



(iv) See also guidelines in paragraphs
(iv) and (vi) of the definition of possible reserves.



Possible reserves – Possible
reserves are those additional reserves that are less certain to be recovered than probable reserves.





(i) When deterministic methods are
used, the total quantities ultimately recovered from a project have a low probability of exceeding proved plus probable plus possible
reserves. When probabilistic methods are used, there should be at least a 10% probability that the total quantities ultimately
recovered will equal or exceed the proved plus probable plus possible reserves estimates.



(ii) Possible reserves may be assigned
to areas of a reservoir adjacent to probable reserves where data control and interpretations of available data are progressively
less certain. Frequently, this will be in areas where geoscience and engineering data are unable to define clearly the area and
vertical limits of commercial production from the reservoir by a defined project.



(iii) Possible reserves also include
incremental quantities associated with a greater percentage recovery of the hydrocarbons in place than the recovery quantities
assumed for probable reserves.



(iv) The proved plus probable and
proved plus probable plus possible reserves estimates must be based on reasonable alternative technical and commercial interpretations
within the reservoir or subject project that are clearly documented, including comparisons to results in successful similar projects.











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and MacNaughton





(v) Possible reserves may be assigned
where geoscience and engineering data identify directly adjacent portions of a reservoir within the same accumulation that may
be separated from proved areas by faults with displacement less than formation thickness or other geological discontinuities and
that have not been penetrated by a wellbore, and the registrant believes that such adjacent portions are in communication with
the known (proved) reservoir. Possible reserves may be assigned to areas that are structurally higher or lower than the proved
area if these areas are in communication with the proved reservoir.



(vi) Pursuant to paragraph (iii) of
the proved oil and gas reserves definition, where direct observation has defined a highest known oil (HKO) elevation and the potential
exists for an associated gas cap, proved oil reserves should be assigned in the structurally higher portions of the reservoir above
the HKO only if the higher contact can be established with reasonable certainty through reliable technology. Portions of the reservoir
that do not meet this reasonable certainty criterion may be assigned as probable and possible oil or gas based on reservoir fluid
properties and pressure gradient interpretations.



Developed oil and gas reserves
– Developed oil and gas reserves are reserves of any category that can be expected to be recovered:



(i) 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; and



(ii) Through installed extraction
equipment and infrastructure operational at the time of the reserves estimate if the extraction is by means not involving a well.



Undeveloped oil and gas reserves
–Undeveloped oil and gas reserves are reserves of any category 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.











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DeGolyer and MacNaughton





(i) Reserves on undrilled acreage
shall be limited to those directly offsetting development spacing areas that are reasonably certain of production when drilled,
unless evidence using reliable technology exists that establishes reasonable certainty of economic producibility at greater distances.





(ii) Undrilled locations can be classified
as having undeveloped reserves only if a development plan has been adopted indicating that they are scheduled to be drilled within
five years, unless the specific circumstances justify a longer time.



(iii) Under no circumstances shall
estimates for undeveloped reserves be attributable to any acreage for which an application of fluid injection or other improved
recovery technique is contemplated, unless such techniques have been proved effective by actual projects in the same reservoir
or an analogous reservoir, as defined in [section 210.4–10 (a) Definitions], or by other evidence using reliable technology
establishing reasonable certainty.



The extent to which
probable and possible reserves ultimately may be reclassified as proved reserves is dependent upon future drilling, testing, and
well performance. The degree of risk to be applied in evaluating probable and possible reserves is influenced by economic and technological
factors as well as the time element. Probable and possible reserves in this report have not been adjusted in consideration of these
additional risks and therefore are not comparable with proved reserves.





Primary Economic Assumptions



The following economic
assumptions were used for estimating existing and future prices and costs:



Oil Prices



La Cortez has represented that the
oil prices were based on a reference price, calculated as the unweighted arithmetic average of the first-day-of-the-month price
for each month within the 12-month period prior to the end of the reporting period, unless prices are defined by contractual arrangements.
La Cortez supplied differentials by field to a West Texas Intermediate reference price of $95.96 per barrel and the prices were
held constant thereafter. The volume-weighted average price attributable to estimated proved reserves was $77.97 per barrel.













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DeGolyer and MacNaughton





Operating Expenses and Capital Costs



Operating expenses and capital costs,
based on information provided by La Cortez, were used in estimating future costs required to operate the properties. In certain
cases, future costs, either higher or lower than existing costs, may have been used because of anticipated changes in operating
conditions. These costs were not escalated for inflation.

While the oil and gas
industry may be subject to regulatory changes from time to time that could affect an industry participant’s ability to recover
its oil and gas reserves, we are not aware of any such governmental actions which would restrict the recovery of the December 31,
2011, estimated oil volumes. The reserves estimated in this report can be produced under current regulatory guidelines.



Our estimates of La
Cortez’s net proved, probable, and possible reserves attributable to the reviewed properties are based on the definitions
of proved, probable, and possible reserves of the SEC and are as follows, expressed in thousands of barrels (Mbbl):



|                      |  | Estimated by DeGolyer and MacNaughton Net Proved Reserves as of December 31, 2011 |      
|--------------------- |  | --------------------------------------------------------------------------------- | -----
|                      |  | Oil (Mbbl)                                                                        |      
|                      |  |                                                                                   |      
|Mirto Field, Colombia |  |                                                                                   |      
|Proved Developed      |  |                                                                                   | 86.1 
|Proved Undeveloped    |  |                                                                                   | 0    
|                      |  |                                                                                   |      
|Total Proved          |  |                                                                                   | 86.1 
|                      |  |                                                                                   |      
|Probable              |  |                                                                                   | 149.6
|Possible              |  |                                                                                   | 457.9
|                      |  |                                                                                   |      



Note: Probable and possible reserves have not been risk adjusted to make them comparable to proved reserves.



In our opinion, the
information relating to estimated proved, probable, and possible reserves of oil, condensate, natural gas liquids, and gas contained
in this report has been prepared in accordance with Paragraphs 932-235-50-4, 932-235-50-6, 932-235-50-7, and 932-235-50-9 of the
Accounting Standards Update 932-235-50, Extractive Industries – Oil and Gas (Topic 932): Oil and Gas Reserve Estimation
and Disclosures (January 2010) of the Financial Accounting Standards Board and Rules 4–10(a) (1)–(32) of Regulation
S–X and Rules 302(b), 1201, 1202(a) (1), (2), (3), (4), (5), (8), and 1203(a) of Regulation S–K of the Securities and
Exchange Commission; provided, however, that estimates of proved developed and proved undeveloped reserves are not presented at
the beginning of the year.

















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DeGolyer and MacNaughton





To the extent the above-enumerated
rules, regulations, and statements require determinations of an accounting or legal nature, we, as engineers, are necessarily unable
to express an opinion as to whether the above-described information is in accordance therewith or sufficient therefor.



DeGolyer and MacNaughton
is an independent petroleum engineering consulting firm that has been providing petroleum consulting services throughout the world
since 1936. DeGolyer and MacNaughton does not have any financial interest, including stock ownership, in La Cortez. Our fees were
not contingent on the results of our evaluation. This letter report has been prepared at the request of La Cortez. DeGolyer and
MacNaughton has used all assumptions, data, procedures, and methods that it considers necessary and appropriate to prepare this
report.





| |  | Submitted,                             
| |  | ---------------------------------------
| |  |                                        
| |  | /s/ DeGOLYER and MacNAUGHTON           
| |  |                                        
| |  | DeGOLYER and MacNAUGHTON               
| |  | Texas Registered Engineering Firm F-716









|       |  | {00131403.1 / 0903-001}/s/ R.M. Shuck, P.E.
|------ |  | -------------------------------------------
|       |  | R.M. Shuck P.E.                            
|[SEAL] |  | Senior Vice President                      
|       |  | DeGolyer and MacNaughton                   

















CERTIFICATE of QUALIFICATION





I, R.M. Shuck, Petroleum
Engineer with DeGolyer and MacNaughton, 5001 Spring Valley Road, Suite 800 East, Dallas, Texas, 75244 U.S.A., hereby certify:



| | 1. | That I am a Senior Vice President with DeGolyer and MacNaughton, which company did prepare the
letter report addressed to La Cortez dated February 28, 2012, and that I, as Senior Vice President, was responsible for the
preparation of this report.
| | -- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 2. | That I attended the University of Houston, and that I graduated with a Bachelor of Science degree
in Chemical Engineering in the year 1977; that I am a Registered Professional Engineer in the State of Texas; that I am a member
of the International Society of Petroleum Engineers; and that I have in excess of 34 years of experience in oil and gas reservoir
studies and reserves evaluations.
| | -- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------









|       |  | {00131403.1 / 0903-001}/s/ R.M. Shuck, P.E.
|------ |  | -------------------------------------------
|       |  | R.M. Shuck P.E.                            
|[SEAL] |  | Senior Vice President                      
|       |  | DeGolyer and MacNaughton