Exhibit

Pursuant to your request, we have prepared estimates of the extent and value of the net proved oil and gas reserves, as of December 31, 2017, of certain properties in which Callon Petroleum Company (Callon) has represented that it owns an interest. This evaluation was completed on January 26, 2018. The properties evaluated consist of working interests located in Texas and offshore Gulf of Mexico. Callon has represented that these properties account for 100 percent on a net equivalent barrel basis of Callon’s net proved reserves as of December 31, 2017. The net proved reserves estimates 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 Callon.

Reserves estimates 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, 2017. Net reserves are defined as that portion of the gross reserves attributable to the interests owned by Callon after deducting all interests owned by others.

Estimates of oil and gas reserves and future net revenue 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.

Data used in this evaluation were obtained from reviews with Callon personnel, from Callon 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 Callon 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.

Estimates of reserves were prepared by the use of appropriate geologic, petroleum engineering, and evaluation principles and techniques that are in accordance with practices generally recognized by the petroleum industry, which are presented in the publication of the Society of Petroleum Engineers PRMS and publications of the Society of Petroleum Evaluation Engineers Monograph III and IV.

A performance-based methodology integrating the appropriate geology and petroleum engineering data was utilized for the evaluation of all reserves categories. Performance-based methodology primarily includes (1) production diagnostics, (2) decline-curve analysis, and (3) model-based analysis (if necessary, based on availability of data). Production diagnostics include data quality control, identification of flow regimes, and characteristic well performance behavior. Analysis was performed for all well groupings (or type-curve areas).

Characteristic rate-decline profiles from diagnostic interpretation were translated to modified hyperbolic rate profiles, including one or multiple b-exponent values followed by an exponential decline. Based on the availability of data, model-based analysis may be integrated to evaluate long-term decline behavior, the impact of dynamic reservoir and fracture parameters on well performance, and complex situations sourced by the nature of unconventional reservoirs. The methodology used for the analysis was tempered by experience with similar reservoirs, stage of development, quality and completeness of basic data, production history, and the appropriate reserves definitions.

Based on the current stage of field development, production performance, the development plans provided by Callon, and the analyses of areas offsetting existing wells with test or production data, reserves were classified as proved.

Callon has represented that its senior management is committed to the development plan provided by Callon and that Callon has the financial capability to drill the locations as scheduled in its development plan.

Future oil and gas producing rates estimated for this report were based on production rates considering the most recent data available. The forecast production rates were estimated to be within the capacity of the wells or reservoirs to produce.

Gas quantities estimated herein are expressed as sales gas. Sales gas is defined as that portion of the total gas to be delivered into a gas pipeline for sale after field separation, processing, fuel use, and flare. Gas reserves are expressed at a temperature base of 60 degrees Fahrenheit and at the pressure base of the state or area in which the interest is located. Gas reserves estimates included herein are expressed in thousands of cubic feet (Mcf). Oil reserves estimated herein are those to be recovered by conventional lease separation. Oil reserves included herein are expressed in barrels (bbl) representing 42 United States gallons per barrel.

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.

(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.

(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.

(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.

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.

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.

(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 development status shown herein represents the status applicable on December 31, 2017. In the preparation of this study, data available from wells drilled on the evaluated properties through December 31, 2017, were used in estimating gross ultimate recovery. When applicable, gross production estimated through December 31, 2017, was deducted from gross ultimate recovery to arrive at the estimates of gross reserves. In some fields this required that the production rates be estimated for up to 4 months, since production data from certain properties were available only through August 2017.

Our estimates of Callon’s net proved reserves attributable to the reviewed properties were based on the definition of proved reserves of the SEC and are summarized as follows, expressed in thousands of barrels (Mbbl), millions of cubic feet (MMcf), and thousands of barrels of oil equivalent (Mboe):



	Estimated by DeGolyer and MacNaughton Net Proved Reserves as of December 31, 2017
	Oil (Mbbl)	Sales Gas (MMcf)	Oil Equivalent (Mboe)
Proved
Developed Producing	49,794	100,443	66,534
Developed Non-Producing	2,126	3,946	2,784
Total Proved Developed	51,920	104,389	69,318

Undeveloped	55,151	75,021	67,655
Total Proved	107,071	179,410	136,973

Note: Gas is converted to oil equivalent using an energy equivalent factor of 6,000 cubic feet of gas per 1 barrel of oil equivalent.

Values shown herein are expressed in terms of future gross revenue, future net revenue, and present worth. Future gross revenue is that revenue which will accrue to the evaluated interests from the production and sale of the estimated net reserves. Future net revenue is calculated by deducting estimated production taxes, ad valorem taxes, operating expenses, and capital and abandonment costs from the future gross revenue. Operating expenses include field operating expenses, transportation expenses, compression charges, and an allocation of overhead that directly relates to production activities. Future income tax expenses were not taken into account in the preparation of these estimates. Present worth is defined as future net revenue discounted at the arbitrary discount rate of 10 percent per year compounded monthly over the expected period of realization. Present worth should not be construed as fair market value because no consideration was given to additional factors that influence the prices at which properties are bought and sold.

Revenue values in this report were estimated using the initial prices and costs specified by Callon. Future prices were estimated using guidelines established by the SEC and the Financial Accounting Standards Board (FASB). The prices used in this report were based on SEC guidelines. The assumptions used for estimating future prices and expenses are as follows:

Callon 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. Callon supplied differentials by field to a West Texas Intermediate reference price of $51.34 per barrel and the prices were held constant thereafter. The volume-

Callon has represented that the gas 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. Callon supplied differentials to the Henry Hub gas reference price of $2.98 per million British thermal units ($/MMBtu). The gas price differential includes revenue from the sale of natural gas liquids attributed to Callon. The prices were held constant thereafter. British thermal unit factors were provided by Callon and used to convert prices from $/MMBtu to dollars per thousand cubic feet. The volume-weighted average gas price attributable to the estimated proved reserves was $3.467 per thousand cubic feet.

Current operating expenses and future capital and abandonment costs were based on estimates provided by Callon. These expenses and costs were used in estimating future expenses and costs required to operate the properties. These expenses and costs were held constant for the producing lives of the properties. Future capital expenditures were estimated using 2017 values and were not adjusted for inflation. Abandonment costs, based on information provided by Callon, were not adjusted for inflation.

The estimated future revenue and expenditures attributable to the production and sale of Callon’s net proved reserves, as of December 31, 2017, of the properties evaluated, expressed in thousands of dollars (M$), are summarized as follows:



	Proved Developed Producing (M$)	Proved Developed Non-Producing (M$)	Total Proved Developed (M$)	Proved Undeveloped (M$)	Total Proved (M$)
Future Gross Revenue	2,808,542	120,871	2,929,413	2,990,915	5,920,328
Production and Ad Valorem Taxes	193,110	8,343	201,453	202,520	403,973
Operating Expenses	802,850	21,917	824,767	418,317	1,243,084
Capital and Abandonment Costs	40,072	301	40,373	686,389	726,762
Future Net Revenue	1,772,510	90,310	1,862,820	1,683,689	3,546,509
Present Worth at 10 Percent	975,208	55,121	1,030,329	546,426	1,576,755

Note: Future income taxes were not taken into account in the preparation of these estimates.

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 reserves, we are not aware of any such governmental actions which would restrict the recovery of the December 31, 2017, estimated reserves.

In our opinion, the information relating to estimated proved reserves, estimated future net revenue from proved reserves, and present worth of estimated future net revenue from proved reserves of oil 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, 932-235-50-9, 932-235-50-30, and 932-235-50-31(a), (b), and (e) 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), (8), and 1203(a) of Regulation S-K of the Securities and Exchange Commission; provided, however, that (i) future income tax expenses have not been taken into account in estimating the future net revenue and present worth values set forth herein and (ii) estimates of the proved developed and proved undeveloped reserves are not presented at the beginning of the year.

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 Callon. Our fees were not contingent on the results of our evaluation. This letter report has been prepared at the request of Callon. DeGolyer and MacNaughton has used all assumptions, procedures, data, and methods that it considers necessary to prepare this report



	Submitted,

	/s/ DeGolyer and MacNaughton
	DeGOLYER and MacNAUGHTON
	Texas Registered Engineering Firm F-716



	/s/ Gregory K. Graves, P.E.
	Gregory K. Graves, P.E.
[Seal]	Senior Vice President
	DeGolyer and MacNaughton



	/s/ Gregory K. Graves, P.E.
	Gregory K. Graves, P.E.
[Seal]	Senior Vice President
	DeGolyer and MacNaughton


1.	That I am a Senior Vice President with DeGolyer and MacNaughton, which company did prepare the letter report addressed to Callon dated January 26, 2018, and that I, as Senior Vice President, was responsible for the preparation of this letter report.