Document:

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                                                                   Exhibit 10.10

THE WARRANTS AND UNDERLYING SHARES OF COMMON STOCK REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE
"ACT"), AND ARE "RESTRICTED SECURITIES" AS THAT TERM IS DEFINED IN RULE 144
UNDER THE ACT. THE SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD OR OTHERWISE
TRANSFERRED EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
ACT, OR PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE ACT, THE
AVAILABILITY OF WHICH IS TO BE ESTABLISHED TO THE SATISFACTION OF THE COMPANY.

                                                     Warrant Certificate No. P-1
                                                        Issue Date: May 24, 2001

                        WARRANT TO PURCHASE 61,570 SHARES
            VOID AFTER 5:00 P.M., MOUNTAIN TIME, ON DECEMBER 31, 2006

                        NATURAL GAS SERVICES GROUP, INC.
                        WARRANT AGREEMENT AND CERTIFICATE

      This certifies that, for value received, Berry-Shino Securities, Inc., an
Arizona corporation, located at 14500 N. Northsight Blvd., Suite 101,
Scottsdale, AZ 85260, the registered holder hereof (the "Warrant Holder"), is
entitled to purchase from Natural Gas Services Group, Inc., a Colorado
corporation (the "Company") with its principal office located in Midland, Texas,
at any time commencing one year from the Issue Date set forth above, and before
5:00 P.M., Mountain Time, on December 31, 2006 (the "Termination Date") at the
purchase price of $3.25 per share (the "Exercise Price"), the number of shares
of the Company's Common Stock (the "Shares") set forth above. The number of
Shares purchasable upon exercise of this Warrant and the Exercise Price per
Share shall be subject to adjustment from time to time as set forth in Section 5
below.

Section 1. Sale and Delivery of Warrant. The Warrants represented hereby were
issued as placement agent warrants in connection with the private offering
commenced in October 2000 of the Company's Series A 10% Subordinated Notes due
December 31, 2006 (the "Private Offering").

Section 2. Transfer or Exchange of Warrant.

2.1   The Company shall be entitled to treat the registered owner of any Warrant
(the "Warrant Holder") as the owner in fact thereof for all purposes and shall
not be bound to recognize any equitable or other claim to or interest in such
Warrant on the part of any other person, and shall not be liable for any
registration of transfer of Warrants which are registered or to be registered in
the name of a fiduciary or the nominee of a fiduciary unless made with the
actual knowledge that a fiduciary or nominee is committing a breach of trust in
requesting such registration of transfer, or with such knowledge of such facts
that its participation therein amounts to gross negligence or bad faith.

2.2   This Warrant may not be sold, transferred, assigned or hypothecated except
pursuant to all applicable federal and state securities laws.

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2.3   A Warrant shall be transferable only on the books of the Company upon
delivery of this Warrant Certificate duly endorsed by the Warrant Holder or by
his duly authorized attorney or representative, or accompanied by proper
evidence of succession, assignment or authority to transfer. Upon any
registration of transfer, the Company shall deliver a new Warrant Certificate to
the persons entitled thereto.

Section 3. Term of Warrants; Exercise of Warrants.

3.1   Subject to the terms of this Agreement and Certificate, the Warrant Holder
has the right, which may be exercised commencing immediately and ending at 5:00
p.m. Mountain Time on the Termination Date, to purchase from the Company the
number of Shares which the Warrant Holder may at that time be entitled to
purchase on exercise of this Warrant.

3.2   A Warrant shall be exercised by surrender to the Company, at its principal
office, of this Warrant Agreement and Certificate, together with the form of
election to purchase attached hereto as Exhibit A, duly completed and signed,
and payment to the Company of the Exercise Price (as defined in accordance with
the provisions of Section 4 hereof) for the number of Shares in respect of which
such Warrant is then exercised. Except as provided in Section 3.3, payment of
the aggregate Exercise Price shall be made in cash or certified funds.

3.3   In addition to and without limiting the rights of the Holder under the
terms of this Warrant, the Holder shall have the right (the "Conversion Right")
to convert this Warrant or any portion thereof into Shares as provided in this
Section 3.3 at any time prior to the Termination Date.

            a. Upon exercise of the Conversion Right with respect to a
particular number of Shares (the "Converted Shares"), the Company shall deliver
to the Holder, without payment by the Holder of any Exercise Price or any cash
or other consideration, that number of Shares equal to the quotient obtained by
dividing the Net Value (as hereinafter defined) of the Converted Shares by the
fair market value (as defined in paragraph 3.3(c) below) of a single Share,
determined in each case as of the close of business on the Conversion Date (as
hereinafter defined). The "Net Value" of the Converted Shares shall be
determined by subtracting the aggregate Exercise Price of the Converted Shares
from the aggregate fair market value of the Converted Shares. No fractional
securities shall be issuable upon exercise of the Conversion Right, and if the
number of securities to be issued in accordance with the foregoing formula is
other than a whole number, the Company shall pay to the Holder an amount in cash
equal to the fair market value of the resulting fractional Share.

            b. The Conversion Right may be exercised by the Holder by the
surrender of this Warrant at the principal office of the Company or at the
office of the Company's stock transfer agent, if any, together with a written
statement specifying that the Holder thereby intends to exercise the Conversion
Right and indicating the number of Shares subject to the Warrant which are being
surrendered (referred to in subparagraph 3.3(a) above as the Converted Shares),
in the form attached to and by this reference incorporated in this Warrant as
Exhibit B, in exercise of the Conversion Right. Such conversion shall be
effective upon receipt by the Company of this Warrant together with the
aforesaid written statement, or on such later date as is specified therein (the
"Conversion Date"),

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but not later than the expiration date of the Warrant. Certificates for the
Converted Shares issuable upon exercise of the Conversion Right, together with a
check in payment of any fractional Warrant Share and, in the case of a partial
exercise a new warrant evidencing the Warrant Shares remaining subject to the
Warrant, shall be issued as of the Conversion Date and shall be delivered to the
Holder within twenty-one days following the Conversion Date.

            c. For purposes of this Section 2.3, the "fair market value" of a
Share as of a particular date shall be its "market price," which, for purposes
of this Section 2.3 shall mean, if the Shares are traded on a securities
exchange or on Nasdaq, the closing price of the Shares on such exchange or the
last sale price on Nasdaq, or, if the Shares are otherwise traded in the
over-the-counter market, the average of the closing bid and ask price, in each
case averaged over a period of five consecutive trading days prior to the date
as of which "market price" is being determined. If at any time the Shares are
not traded on an exchange or Nasdaq, or otherwise traded in the over-the-counter
market, the "market price" shall be deemed to be the fair value thereof
determined in good faith by the Board of Directors of the Company as of a date
which is within 15 days of the date as of which the determination is to be made.

3.4   Subject to Section 5 hereof, upon surrender of a Warrant Agreement and
Certificate and payment of the Exercise Price as aforesaid, the Company shall
issue and cause to be delivered with all reasonable dispatch to or upon the
written order of the Warrant Holder exercising such Warrant and in such name or
names as such Warrant Holder may designate, certificates for the number of
Shares so purchased upon the exercise of such Warrant. Such certificate or
certificates shall be deemed to have been issued and any person so designated to
be named therein shall be deemed to have become a holder of record of such
Shares as of the date of receipt by the Company of such Warrant Agreement and
Certificate and payment of the Exercise Price. The rights of purchase
represented by the Warrants shall be exercisable, at the election of the Warrant
Holders thereof, either in full or from time to time in part and, in the event
that a Warrant Agreement and Certificate is exercised to purchase less than all
of the Shares purchasable on such exercise at any time prior to the Termination
Date, a new Warrant Agreement and Certificate evidencing the remaining Warrant
or Warrants will be issued.

3.5   The Warrant Holder will pay all documentary stamp taxes, if any,
attributable to the initial issuance of the Shares upon the exercise of
Warrants.

4.    Registration Rights.

4.1   The Warrant Holder shall have the following rights with respect to
registration by the Company of the shares of Common Stock issuable upon exercise
of this Warrant. Such shares are referred to hereafter as the "Warrant Shares."

            a. At any time within the period commencing one year from the date
hereof and expiring six years from the date hereof, whenever the Company files a
registration statement under the Securities Act of 1933 which relates to an
initial public offering of the Company's Common Stock, the Company shall offer
to the Warrant Holder the opportunity to register or qualify the Warrant Shares
for public sale, and the Company shall be required to include the Warrant Shares
in

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the registration statement if the holders of a majority of the Warrant Shares
(calculated as if all placement agent warrants had been exercised) request that
their Warrant Shares be included; provided, however, that if the offering to
which the proposed registration statement relates is an underwritten offering
and such underwriter objects to the inclusion of the Warrant Shares in such
registration statement, the Company shall be under no obligation to include any
Warrant Shares, except that the Warrant Holder shall be entitled to have its
Warrant Shares included pro rata with all other selling Warrant Holders. The
Company will pay all fees of such registration, other than underwriters'
discounts or commissions relating to Warrant Shares registered on behalf of the
Warrant Holder and fees of separate counsel, if any, engaged by the Warrant
Holder. The Company shall give 20 days' prior written notice to the Warrant
Holder of the Company's intention to file a registration statement under the
Act, which notice shall constitute an offer to the Warrant Holder to have its
Warrant Shares included in such registration statement as long as a majority of
the Warrant Holders so elect, and the Warrant Holder shall notify the Company in
writing within ten days after receipt of such notice if the Warrant Holder
desires to accept such offer. Neither the delivery of such notice nor the
acceptance by the Warrant Holder of such offer (such Warrant Holder a
"Participating Warrant Holder") shall obligate the Company to file such
registration statement and, notwithstanding the actual filing of the
registration statement, the Company may at any time prior to its effectiveness
elect not to pursue the registration without liability to the Warrant Holder.

            b. In the event the underwriter for the Company's initial public
offering of its Common Stock objects to the inclusion of all Warrant Shares held
by Warrant Holders who elected to be included in the registration statement
under the preceding paragraph, then not less than a majority of the Warrant
Holders of those Warrant Shares excluded due to the underwriter's objection may
demand that the Company effect a registration on Form S-3 to include the
previously excluded Warrant Shares. The Company will use commercially reasonable
efforts to effect as soon as practicable the registration under the Act of all
such previously excluded Warrant Shares. This right to demand registration on
Form S-3 is effective only if the Company is eligible to use Form S-3.

            c. The Company's contractual obligation to include the Warrant
Shares on behalf of the Warrant Holder in a registration statement filed on
behalf of the Company shall be subject to the reasonable cooperation of the
Warrant Holder with the Company. The Warrant Shares held by the Warrant Holder
may be excluded from a registration statement at the election of the Company in
the event all information essential for the Company and its counsel to prepare
the registration statement is not furnished by the Warrant Holder, after the
Warrant Holder, upon written request of the Company or its counsel, has been
given a reasonable amount of time (not less than ten business days from the date
such request has been sent to the Warrant Holder) to transmit the requested
information to the Company and/or its counsel.

4.2   A Participating Warrant Holder will provide the Company such information
relating to the Participating Warrant Holder and its plan of distribution as may
be necessary for the completion of the registration statement.

4.3   In the event of any registration under the Act of any of the Warrant
Shares pursuant to this Agreement, the Company will use its best efforts to
obtain blue sky qualification of the Warrant

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Shares in Colorado and Arizona and in such other states as the Company may agree
upon reasonable request of the Participating Warrant Holder.

4.4   In the event of any registration under the Act of any of the Warrant
Shares pursuant to this Agreement, the Participating Warrant Holder will be
responsible for ensuring that the Warrant Shares are sold in strict compliance
with the registration statement (including, without limitation, the plan of
distribution to be included therein) and all other applicable federal and state
securities laws and regulations.

4.5   In the event of any registration under the Act of any of the Warrant
Shares pursuant to this Agreement, the Company will agree to indemnify and hold
harmless each Participating Warrant Holder and each underwriter, and each other
affiliate of a Participating Warrant Holder or such underwriter within the
meaning of the Act against any losses, claims, damages or liabilities, joint or
several, to which any Participating Warrant Holder or such underwriter or such
controlling person may become subject under the Act or otherwise, insofar as
such losses, claims, damages or liabilities (or actions in respect thereof)
arise out of or are based upon any untrue statement or alleged untrue statement
of any material fact contained, on the effective date thereof, in any such
registration statement, any preliminary prospectus or final prospectus contained
therein or any amendment thereof or supplement thereto, or any document incident
to registration or qualification of the Warrant Shares covered thereby under
state securities or blue sky laws, or arise out of or are based upon the
omission or alleged omission to state therein a material fact required to be
stated therein, or any violation by the Company of the Act or state securities
or blue sky laws applicable to the Company and relating to any action or
inaction required by the Company in connection with such registration or
qualification under such state securities or blue sky laws; provided, however
that the Company will not be liable in any such case to any indemnified person
to the extent that any such loss, claim, damage or liability arises out of or is
based upon an untrue statement or alleged untrue statement or omission or
alleged omission made in such registration statement, said preliminary
prospectus or said prospectus or said amendment or supplement, or any document
incident to registration or qualification under state securities or blue sky
laws, in reliance upon and in conformity with any information furnished in
writing to the Company or its counsel by such indemnified person specifically
for use in the preparation thereof or if such loss, claim, damage, liability or
action arose out of the violation of any duty to which the Participating Warrant
Holder may be subject, including the obligation to deliver a copy of any
prospectus, supplement or amendment to a purchaser of the Warrant Shares and
such prospectus, supplement or amendment was made available to the Participating
Warrant Holder by the Company.

4.6   In the event of any registration of the Warrant Shares under the Act
pursuant to this Agreement, each Participating Warrant Holder will agree to
indemnify and hold harmless the Company and each affiliate and controlling
person, as defined by the Act, of the Company, each officer or employee of the
Company who signs the registration statement, each director of the Company, any
agent of the Company and each underwriter, and any and all affiliates and
controlling persons, as defined by the Act, of such persons against any and all
such losses, claims, damages or liabilities as the Participating Warrant Holders
and others are indemnified against by the Company and will reimburse the Company
and each of the foregoing persons for any losses, claims, damages or liabilities
(or actions in respect thereof) and for any legal or any other expenses incurred
by each

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such person, if the statement or omission in respect of which such loss, claim,
damage or liability is asserted was made in reliance upon and in conformity with
information furnished to the Company in writing by such Participating Warrant
Holder or on its behalf specifically for use in connection with the preparation
of such registration statement or prospectus.

Section 5. Adjustment of Exercise Price and Shares.

5.1   If the Company shall at any time subdivide its outstanding Common Stock by
recapitalization, reclassification or split-up thereof, the number of Shares of
Common Stock subject to this Warrant immediately prior to such subdivision shall
be proportionately increased, and if the Company shall at any time combine the
outstanding Common Stock by recapitalization, reclassification or combination
thereof, the number of Shares of Common Stock subject to this Warrant
immediately prior to such combination shall be proportionately decreased. Any
corresponding adjustment to the Exercise Price shall become effective at the
close of business on the record date for such subdivision or combination.

5.2   In the event of a dividend (other than in shares of Common Stock of the
Company), the proposed dissolution or liquidation of the Company, or any
corporate separation or division, including, but not limited to, a split-up,
split-off or spin-off, or a merger or consolidation of the Company with another
Company, or the sale of all or substantially all of the assets of the Company,
the Board may provide that each Warrantholder will have the right to exercise
this Warrant (at its then current Exercise Price) solely for the kind and amount
of shares of stock and other securities, property, cash or any combination
thereof receivable upon such dissolution, liquidation, corporate separation or
division, or merger or consolidation by a holder of the number of shares of
Common Stock for which this Warrant might have been exercised immediately prior
to such dissolution, liquidation, corporate separation or division, or merger or
consolidation; or, in the alternative, the Board may provide that this Warrant
will terminate as of a date fixed by the Board; provided, however that not less
than 30 days' written notice of the date so fixed must be given to the
Warrantholder, who will have the right, during the period of 30 days preceding
such termination, to exercise this Warrant as to all or any part of the shares
of Common Stock covered by this Warrant.

5.3   The preceding paragraph will not apply to a merger or consolidation in
which the Company is the surviving Company and shares of Common Stock are not
converted into or exchanged for stock, securities of any other Company, cash or
any other thing of value. Notwithstanding the preceding sentence, in case of any
consolidation or merger of another Company into the Company in which the Company
is the surviving Company and in which there is a reclassification or change
(including a change to the right to receive cash or other property) of the
shares of Common Stock (excluding a change in par value, or from no par value to
par value, or any change as a result of a subdivision or combination, but
including any change in such shares into two or more classes or series of
shares), the Board may provide that the holder of this Warrant will have the
right to exercise this Warrant solely for the kind and amount of shares of stock
and other securities (including those of any new direct or indirect parent of
the Company), property, cash or any combination thereof receivable upon such
reclassification, change, consolidation or merger by the holder of the number of
shares of Common Stock for which this Warrant might have been exercised.

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5.4   In the event of a change in the Common Stock of the Company as presently
constituted into the same number of shares with a different par value, the
shares resulting from any such change will be deemed to be the Common Stock of
the Company within the meaning of this agreement.

5.5   The Company agrees that without the Warrant Holder's consent or absent
consent, without a reasonable adjustment to the Exercise Price of this Warrant,
no shares of Common Stock, and no securities convertible into shares of Common
Stock, will be issued at a price per share (or a conversion price, if
applicable) less than the fair market value of the Company's Common Stock on the
date of issuance; provided, however that this paragraph will not apply to: (i)
options granted under the Company's 1998 Stock Option Plan; or (ii) securities
issued in connection with any merger or acquisition.

5.6   To the extent that the foregoing adjustments relate to stock or securities
of the Company, such adjustments will be made in good faith by the Board.

5.7   Except as expressly provided in this Warrant, the Warrantholder will have
no rights by reason of any subdivision or consolidation of shares of stock of
any class, or the payment of any stock dividend or any other increase or
decrease in the number of shares of stock of any class, or by reason of any
dissolution, liquidation, merger, or consolidation or spin-off of assets or
stock of another Company; and any issue by the Company of shares of stock of any
class, or securities convertible into shares of stock of any class, will not
affect, and no adjustment will be made with respect to, the number or price of
shares of Common Stock subject to this Warrant. The grant of this Warrant will
not affect in any way the right or power of the Company to make adjustments,
reclassifications, reorganizations or changes of its capital or business
structures, or to merge or consolidate, or to dissolve, liquidate, or sell or
transfer all or any part of its business or assets.

Section 6. Mutilated or Missing Warrant Certificates. In case any Warrant
Certificate shall be mutilated, lost, stolen or destroyed, the Company shall, at
the request of the holder of such Certificate, issue and deliver, in exchange
and substitution for and upon cancellation of the mutilated Certificate, or in
lieu of and substitution for the Certificate, lost, stolen or destroyed, a new
Warrant Certificate of like tenor and representing an equivalent right or
interest; but only upon receipt of evidence satisfactory to the Company of such
loss, theft or destruction of such Warrant Certificate and indemnity, if
requested, also satisfactory to the Company. An applicant for such a substitute
Warrant Certificate shall also comply with such other reasonable regulations and
pay such other reasonable charges as the Company may prescribe.

Section 7. Reservation of Shares of Common Stock. There has been reserved, and
the Company shall at all times keep reserved so long as any of the Warrants
remain outstanding, out of its authorized Common Stock a number of shares of
Common Stock sufficient to provide for the exercise of the rights of purchase
represented by the outstanding Warrants and the underlying securities.

Section 8. No Fractional Shares. The Company shall not be required to issue
fractional shares or scrip representing fractional shares upon the exercise of
the Warrants. As to any final fraction of a Share which the Warrant Holder would
otherwise be entitled to purchase upon such exercise, the

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Company shall pay a cash adjustment in respect of such final fraction in an
amount equal to the same fraction of the market price of a share of Common Stock
on the business day preceding the day of exercise.

Section 9. Transfer and Exercise to Comply With the Securities Act of 1933.

9.1   Neither the Warrants nor the Warrant Shares may be sold, transferred or
otherwise disposed of except to a person, who, in the opinion of counsel for the
Company, is a person to whom such securities may legally be transferred pursuant
to the provisions of this Agreement without registration, and without the
delivery of a current prospectus, under the Act with respect thereto.

9.2   Unless the Company has on file with the Securities and Exchange Commission
a current registration statement to permit the Company to issue registered
shares upon exercise of the Warrants, the Warrants may not be exercised except
in a transaction exempt from registration under the Act.

9.3   The Company shall cause the following legend to be set forth on each
Warrant Certificate and certificates representing the Warrant Shares, unless
counsel for the Company is of the opinion as to any such Certificates that such
legend is unnecessary:

            The securities represented by this certificate may not be offered
            for sale, sold or otherwise transferred except pursuant to an
            effective registration statement made under the Securities Act of
            1933 (the "Act"), or pursuant to an exemption from registration
            under the Act the availability of which is to be established to the
            satisfaction of the Company.

Section 10. Notices. Any notice pursuant to this Agreement by the Company or by
the Warrant Holders shall be in writing and shall be deemed to have been duly
given if delivered or mailed certified mail, return receipt requested, (a) if to
the Company, to Natural Gas Services Group, Inc., 2911 So. County Road 1260,
Midland, TX 79706, attn: President; and (b) if to the Warrant Holder, to the
address set forth above. Each party hereto may from time to time change the
address to which notices to it are to be delivered or mailed hereunder by notice
in accordance herewith to the other party.

Section 11. Successors. All the covenants and provisions of this Agreement by or
for the benefit of the Company or the Warrant Holders shall bind and inure to
the benefit of their respective successors and assigns hereunder.

Section 12. Applicable Law. This Warrant Agreement and Certificate and any
replacement Certificate issued hereunder shall be deemed to be a contract made
under the laws of the State of Colorado and for all purposes shall be construed
in accordance with the laws of said State.

Section 13. Benefits of This Agreement. Nothing in this Agreement shall be
construed to give to any person or Company other than the Company and the
Warrant Holders any legal or equitable right, remedy or claim under this
Agreement and this Agreement shall be for the sole and exclusive benefit of the
Company and the Warrant Holders.

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DATED: _________________, 2001                  NATURAL GAS SERVICES GROUP, INC.

                                                By:_____________________________
                                                   Wallace Sparkman, President

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                                                                       EXHIBIT A

                                  PURCHASE FORM

                                                     DATED _______________, ____

      THE UNDERSIGNED HEREBY IRREVOCABLY ELECTS TO EXERCISE THE WARRANT
REPRESENTED BY THIS WARRANT CERTIFICATE TO THE EXTENT OF PURCHASING __________
SHARES OF NATURAL GAS SERVICES GROUP, INC. AND HEREBY MAKES PAYMENT OF $3.25 PER
SHARE IN PAYMENT OF THE EXERCISE PRICE THEREOF.

                     INSTRUCTIONS FOR REGISTRATION OF STOCK

NAME:

________________________________________________________________________________
                     (PLEASE TYPE OR PRINT IN BLOCK LETTERS)

ADDRESS:

________________________________________________________________________________

SIGNATURE______________________________________________________

DATED: ___________________,______

--------------------------------------------------------------------------------

                                 ASSIGNMENT FORM

      FOR VALUE RECEIVED, __________________________, HEREBY SELLS, ASSIGNS AND
TRANSFERS UNTO

NAME:

________________________________________________________________________________
                     (PLEASE TYPE OR PRINT IN BLOCK LETTERS)

ADDRESS:

________________________________________________________________________________
THE RIGHT TO PURCHASE SHARES OF NATURAL GAS SERVICES GROUP, INC. REPRESENTED BY
THIS WARRANT CERTIFICATE TO THE EXTENT OF _________ SHARES AS TO WHICH SUCH
RIGHT IS EXERCISABLE AND DOES HEREBY IRREVOCABLY CONSTITUTE AND APPOINT NATURAL
GAS SERVICES GROUP, INC. TO TRANSFER THE SAME ON THE BOOKS OF THE COMPANY WITH
FULL POWER OF SUBSTITUTION IN THE PREMISES.

____________________________________________________
SIGNATURE

DATED:  ___________________,______

                                        NOTICE: THE SIGNATURE OF THIS ASSIGNMENT
                                        MUST CORRESPOND WITH THE NAME AS IT
                                        APPEARS UPON THE FACE OF THIS WARRANT
                                        CERTIFICATE IN EVERY PARTICULAR, WITHOUT
                                        ALTERATION OR ENLARGEMENT OR ANY CHANGE
                                        WHATEVER.

<PAGE>

                                                                       EXHIBIT B

                        WARRANT CONVERSION EXERCISE FORM

TO: NATURAL GAS SERVICES GROUP, INC.

      Pursuant to Section 2.3 of the Warrant Certificate from Natural Gas
Services Group, Inc. (the "Company") to the undersigned Holder, the Holder
hereby irrevocably elects to convert Warrants with respect to Shares of the
Company into ___________ Shares of the Company.

A conversion calculation is attached hereto as Exhibit B-1.

     The undersigned requests that certificates for such Shares be issued as
follows:

     Name:       __________________________________________

     Address:    __________________________________________

                 __________________________________________

     Deliver to: __________________________________________

and that a new Warrant Certificate for the balance remaining of the Warrants, if
any, subject to the Warrant be registered in the name of, and delivered to, the
undersigned at the address stated above.

     Dated: _______________________

                                          ______________________________________
                                          [NAME OF WARRANT HOLDER]

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                                                                     EXHIBIT B-1

                        CALCULATION OF WARRANT CONVERSION

Shares to be Delivered by Company       =  Net Value
                                           ---------
                                            fmv

                              fmv       =  $____________

                              Net Value =  aggregate fmv of Converted Shares -
                                           aggregate Exercise Price of Converted
                                           Shares

                                        =  $____________ - $____________

                                        =  $____________

   Shares to be Delivered by Company    =  _____________

                   Fractional Shares    =  ____________<PAGE>
                                                                   Exhibit 10.11

                             STOCK PURCHASE WARRANT

                          TO SUBSCRIBE FOR AND PURCHASE
                    10% CONVERTIBLE SERIES A PREFERRED STOCK

                                       OF

                        NATURAL GAS SERVICES GROUP, INC.

         THIS CERTIFIES THAT, for value received, Neidiger,Tucker,Bruner, Inc.
(herein called "Purchaser"), or its registered assigns, is entitled to subscribe
for and purchase from Natural Gas Services Group, Inc. (herein called the
"Company"), a corporation organized and existing under the laws of the State of
Colorado, at the price specified below (subject to adjustment as noted below) at
any time after the date hereof to and including July 31, 2006 (the "Expiration
Date") Thirty Eight Thousand One Hundred Sixty Five (38,165) fully paid and
nonassessable shares of the Company's 10% Convertible Series A Preferred Stock
(herein the "Preferred Stock") (subject to adjustments as noted below).

         The Warrant purchase price shall be $3.25 per share of Preferred Stock,
provided the number of shares of the Company's common stock which may be
obtained upon conversion of the Preferred Stock may be adjusted from time to
time as set forth in the Company's Articles of Amendment to Articles of
Incorporation filed with the Colorado Secretary of State on July 30, 2001
("Amendment").

         This Warrant is subject to the following provisions, terms and
conditions:

         1. The rights represented by this Warrant may be exercised by the
holder hereof, in whole or in part, by written notice of exercise delivered to
the Company 20 days prior to the intended date of exercise and by the surrender
of this Warrant (properly endorsed if required) at the principal office of the
Company and upon payment to it by official bank check of the purchase price for
such shares. The Company agrees that the shares so purchased shall be and are
deemed to be issued to the holder hereof as the record owner of such shares as
of the close of business on the date on which this Warrant shall have been
surrendered and payment made for such shares as aforesaid. Subject to the
provisions of the next succeeding paragraph, certificates for the shares of
stock so purchased shall be delivered to the holder hereof within a reasonable
time, not exceeding 10 days, after the rights represented by this Warrant shall
have been so exercised, and, unless this Warrant has expired, a new Warrant
representing the number of shares, if any, with respect to which this Warrant
shall not then have been exercised shall also be delivered to the holder hereof
within such time.

         2. Notwithstanding the foregoing, however, the Company shall not be
required to deliver any certificate for shares of stock upon exercise of this
Warrant except in accordance with the provisions, and subject to the
limitations, of paragraph 7 hereof.

         3. The Company represents and warrants that this Warrant has been duly
authorized by all necessary corporate action, has been duly executed and
delivered and is a legal and

                                       1
<PAGE>
binding obligation of the Company. The Company covenants and agrees that all
shares of Preferred Stock which may be issued upon the exercise of the rights
represented by this Warrant according to the terms hereof will, upon issuance,
be duly authorized and issued, fully paid and nonassessable. The Company further
covenants and agrees that during the period within which the rights represented
by this Warrant may be exercised, the Company will at all times have authorized,
and reserved for the purpose of issue or transfer upon exercise of the
subscription rights evidenced by this Warrant, a sufficient number of shares of
its Preferred Stock to provide for the exercise of the rights represented by
this Warrant.

         4. This Warrant is issued in connection with the private placement of
the Company's 10% Convertible Series A Preferred Stock, the Preferred Stock
issuable pursuant to the exercise of this Warrant shall be the Company's 10%
Convertible Series A Preferred Stock, and the Holder shall have the benefit of
the rights and adjustments set forth in the Amendment as if the Preferred Stock
underlying the Warrants were issued as of the date hereof.

         5. This Warrant shall not entitle the holder hereof to any voting
rights or other rights as a stockholder of the Company.

         6. The holder of this Warrant, by acceptance hereof, agrees to give
written notice to the Company before transferring this Warrant or transferring
any Preferred Stock issuable or issued upon the exercise hereof of such holder's
intention to do so, describing briefly the manner of any proposed transfer of
this Warrant or such holder's intention as to the disposition to be made of
shares of Preferred Stock issuable or issued upon the exercise hereof. Such
holder shall also provide the Company with a counsel's opinion satisfactory to
the Company to the effect that the proposed transfer of this Warrant or
disposition of shares of Preferred Stock may be effected without registration or
qualification (under any Federal or state law) of this Warrant or the shares of
Preferred Stock issuable or issued upon the exercise hereof. Upon receipt of
such written notice and opinion by the Company, such holder shall be entitled to
transfer this Warrant, or to exercise this Warrant in accordance with its terms
and dispose of the shares of Preferred Stock received upon such exercise or to
dispose of shares of Preferred Stock received upon the previous exercise of this
Warrant, all in accordance with the terms of the notice delivered by such holder
to the Company, provided that an appropriate legend respecting the aforesaid
restrictions on transfer and disposition may be endorsed on this Warrant or the
certificates for such shares of Preferred Stock.

         7. Subject to the provisions of paragraph 6 hereof, this Warrant and
all rights hereunder are transferable, in whole or in part, at the principal
office of the Company by the holder hereof in person or by duly authorized
attorney, upon surrender of this Warrant properly endorsed. Each taker and
holder of this Warrant, by taking or holding the same, consents and agrees that
the bearer of this Warrant, when endorsed, may be treated by the Company and all
other persons dealing with this Warrant as the absolute owner hereof for any
purpose and as the person entitled to exercise the rights represented by this
Warrant, or to the transfer hereof on the books of the Company, any notice to
the contrary notwithstanding; but until such transfer on such books, the Company
may treat the registered holder hereof as the owner for all purposes.

                                       2
<PAGE>
         8. This Warrant is exchangeable, upon the surrender hereof by the
holder hereof at the principal office of the Company, for new Warrants of like
tenor representing in the aggregate the right to subscribe for and purchase the
number of shares of Preferred Stock which may be subscribed for and purchased
hereunder, each of such new Warrants to represent the right to subscribe for and
purchase such number of shares of Preferred Stock as shall be designated by said
holder hereof at the time of such surrender.

         9.       The Company covenants and agrees as follows:

                  (a) For purposes of this Section 9:

                           (i) The term "register", "registered" and
                  "registration" refer to a registration effected by preparing
                  and filing a registration statement or similar document in
                  compliance with the Securities Act, and the declaration or
                  ordering of effectiveness of such registration statement or
                  document;

                           (ii) The term "Registrable Securities" means any
                  Common Stock of the Company issued or issuable upon the
                  conversion of the Preferred Stock.

                           (iii) "Securities Act" means the Securities Act of
                  1933, as amended.

                           (iv) The term "Securities Holder" means any person
                  owning or having the right to acquire the Preferred Stock or
                  Registrable Securities or any assignee thereof, including
                  without limitation and without need for an express assignment,
                  subsequent holders of the Preferred Stock or Registrable
                  Securities; and

                           (v) The term "Form S-3" means such form under the
                  Securities Act as in effect on the date hereof or any
                  registration form under the Securities Act subsequently
                  adopted by the Securities and Exchange Commission ("SEC")
                  which permits inclusion or incorporation of substantial
                  information by reference to other documents filed by the
                  Company with the SEC.

                  (b)      (i) If the Company shall receive at any time after
                  July 31, 2002 and before August 1, 2006, a written request
                  from the Securities Holders of a majority of the Preferred
                  Stock and of the Registrable Securities then outstanding that
                  the Company file a registration statement under the Securities
                  Act covering the registration of all or a portion of the
                  Registrable Securities then outstanding, then the Company
                  shall, within ten (10) days of the receipt thereof, give
                  written notice of such request to all Securities Holders and
                  shall, subject to the limitations of subsections 9(b)(ii) and
                  9(b)(iii), use its best efforts to effect as soon as
                  practicable, and in any event within 120 days of the receipt
                  of such request, the registration under the Securities Act of
                  all Registrable Securities which the Securities Holders
                  request to be registered within twenty (20) days of the
                  mailing of such notice by the Company.

                                       3
<PAGE>
                           (ii) If the Securities Holders initiating the
                  registration request hereunder ("Initiating Holders") intend
                  to distribute the Registrable Securities covered by their
                  request by means of an underwriting, they shall so advise the
                  Company as a part of their request made pursuant to this
                  Section 9 and the Company shall include such information in
                  the written notice referred to in subsection 9(b)(i). In such
                  event, the right of any Securities Holder to include the
                  Securities Holder's Registrable Securities in such
                  registration shall be conditioned upon such Securities
                  Holder's participation in such underwriting and the inclusion
                  of such Securities Holder's Registrable Securities in the
                  underwriting (unless otherwise mutually agreed by a majority
                  of the Initiating Securities Holders and such Securities
                  Holder to the extent provided herein). All Securities Holders
                  proposing to distribute their Registrable Securities through
                  such underwriting shall (together with the Company as provided
                  in subsection 9(d)(v)) enter into an underwriting agreement in
                  customary form with the underwriter or underwriters selected
                  for such underwriting. Notwithstanding any other provision of
                  this Section 9, if the underwriter advises the Initiating
                  Holders in writing that marketing factors require a limitation
                  of the number of shares to be underwritten, then the
                  Initiating Holders shall so advise all Securities Holders of
                  Registrable Securities which would otherwise be underwritten
                  pursuant hereto, and the number of shares of Registrable
                  Securities that may be included in the underwriting shall be
                  allocated among all Securities Holders thereof, including the
                  Initiating Holders, in proportion (as nearly as practicable)
                  to the amount of Registrable Securities of the Company owned
                  by each Securities Holder; provided, however, that the number
                  of shares of Registrable Securities to be included in such
                  underwriting shall not be reduced unless all other securities
                  are first entirely excluded from the underwriting.

                           (iii) The Company is obligated to effect only one (1)
                  such registration pursuant to this Section 9.

                  (c) If (but without any obligation to do so) after July 31,
         2002 and before August 1, 2008, the Company proposes to register
         (including for this purpose a registration effected by the Company for
         shareholders other than the Securities Holders) any of its stock or
         other securities under the Securities Act in connection with the public
         offering of such securities solely for cash (other than a registration
         relating solely to the sale of securities to participants in a Company
         stock plan, or a registration on any form which does not include
         substantially the same information as would be required to be included
         in a registration statement covering the sale of the Registrable
         Securities or an SEC Rule 145 transaction), the Company shall, at such
         time, promptly give each Securities Holder written notice of such
         registration. Upon the written request of each Securities Holder given
         within twenty (20) days after mailing of such notice by the Company,
         the Company shall, subject to the provisions of Section 9(h), cause to
         be registered under the Securities Act all of the Registrable
         Securities that each such Securities Holder has requested to be
         registered.

                                       4
<PAGE>
                  (d) Whenever required under this Section 9 to effect the
         registration of any Registrable Securities, the Company shall:

                           (i) Prepare and file with the SEC a registration
                  statement with respect to such Registrable Securities and use
                  its best efforts to cause such registration statement to
                  become effective, and, upon the request of the Securities
                  Holders of a majority of the Registrable Securities registered
                  thereunder, keep such registration statement effective for up
                  to 180 days.

                           (ii) Prepare and file with the SEC such amendments
                  and supplements to such registration statement and the
                  prospectus used in connection with such registration statement
                  as may be necessary to comply with the provisions of the
                  Securities Act with respect to the disposition of all
                  securities covered by such registration statement.

                           (iii) Furnish to the Securities Holders such numbers
                  of copies of a prospectus, including a preliminary prospectus,
                  in conformity with the requirements of the Securities Act, and
                  such other documents as they may reasonably request in order
                  to facilitate the disposition of Registrable Securities owned
                  by them.

                           (iv) Use its best efforts to register and qualify the
                  securities covered by such registration statement under such
                  other securities or Blue Sky laws of such jurisdictions as
                  shall be reasonably requested by the Securities Holders,
                  provided that the Company shall not be required in connection
                  therewith or as a condition thereto to qualify to do business
                  or to file a general consent to service of process in any such
                  states or jurisdictions.

                           (v) In the event of any underwritten public offering,
                  enter into and perform its obligations under an underwriting
                  agreement, in usual and customary form, with the managing
                  underwriter of such offering. Each Securities Holder
                  participating in such underwriting shall also enter into and
                  perform its obligations under such an agreement.

                           (vi) Notify each Securities Holder of Registrable
                  Securities covered by such registration statement at any time
                  when a prospectus relating thereto is required to be delivered
                  under the Securities Act of the happening of any event as a
                  result of which the prospectus included in such registration
                  statement, as then in effect, includes an untrue statement of
                  a material fact or omits to state a material fact required to
                  be stated therein or necessary to make the statements therein
                  not misleading in the light of the circumstances then
                  existing.

                  (e) It shall be a condition precedent to the obligations of
         the Company to take any action pursuant to this Section 9 with respect
         to the Registrable Securities of any selling Securities Holder that
         such Securities Holder shall furnish to the Company such information
         regarding itself, the Registrable Securities held by it, and the
         intended

                                       5
<PAGE>
         method of disposition of such securities as shall be required to effect
         the registration of such Securities Holder's Registrable Securities.

                  (f) All expenses other than underwriting discounts and
         commissions and non-accountable expenses, incurred in connection with
         registrations, filings or qualifications pursuant to Section 9(b),
         including (without limitation) all registration, filing and
         qualification fees, printers' and accounting fees, reasonable fees and
         disbursements of counsel for the Company, and the reasonable fees and
         disbursements of one counsel for the selling Securities Holders, shall
         be borne by the Company.

                  (g) The Company shall bear and pay all expenses incurred in
         connection with any registration, filing or qualification of
         Registrable Securities with respect to any registrations pursuant to
         Section 9(c) for each Securities Holder, including (without limitation)
         all registration, filing and qualification fees, printers and
         accounting fees relating or apportionable thereto and the fees and
         disbursements of one counsel for the selling Securities Holders
         selected by them, but excluding underwriting discounts and commissions
         and non-accountable expenses relating to Registrable Securities.

                  (h) In connection with any offering involving an underwriting
         of shares of the Company's capital stock, the Company shall not be
         required under Section 9(c) to include any of the Securities Holders'
         Registrable Securities in such underwriting unless they accept the
         terms of the underwriting as agreed upon between the Company and the
         underwriters selected by the persons entitled to select the
         underwriters, and then only in such quantity as the underwriters
         determine in their sole discretion will not jeopardize the success of
         the offering by the Company. If the total amount of Registrable
         Securities requested by Securities Holders to be included in such
         offering exceeds the amount of securities sold other than by the
         Company that the underwriters determine in their sole discretion is
         compatible with the success of the offering, then the Company shall be
         required to include in the offering only that number of such
         securities, including Registrable Securities, which the underwriters
         determine in their sole discretion will not jeopardize the success of
         the offering (the securities so included to be apportioned pro rata
         among all selling stockholders according to the total amount of
         securities owned by each selling stockholder or in such other
         proportions as shall mutually be agreed to by such selling
         stockholders). For purposes of the preceding parenthetical concerning
         apportionment, for any selling stockholder which is a holder of
         Registrable Securities and which is a partnership or corporation, the
         partners, retired partners and stockholders of such holder, or the
         estates and family members of any such partners and retired partners
         and any trusts for the benefit of any of the foregoing persons shall be
         deemed to be a single "selling stockholder", and any pro rata reduction
         with respect to such "selling stockholder" shall be based upon the
         aggregate amount of shares owned by all entities and individuals
         included in such "selling stockholder", as defined in this sentence.
         Those Registrable Securities which are thus excluded from the
         underwritten public offering shall be withheld from the market by the
         holders thereof for a period, not to exceed 90 days, which the
         underwriters reasonably determine is necessary in order to effect the
         underwritten public offering.

                                       6
<PAGE>
                  (i) No Securities Holder shall have any right to obtain or
         seek an injunction restraining or otherwise delaying any such
         registration as the result of any controversy that might arise with
         respect to the interpretation or implementation of this Section 9.

                  (j) In the event any Registrable Securities are included in a
         registration statement under this Section 9:

                           (i) The Company will indemnify and hold harmless each
                  Securities Holder, any underwriter (as defined in the
                  Securities Act) for such Securities Holder and each person, if
                  any, who controls such Securities Holder or underwriter within
                  the meaning of the Securities Act or the Securities Exchange
                  Act of 1934, as amended (the "1934 Act"), against any losses,
                  claims, damages or liabilities (joint or several) to which
                  they may become subject under the Securities Act, or the 1934
                  Act or other federal or state law, insofar as such losses,
                  claims, damages or liabilities (or actions in respect thereof)
                  arise out of or are based upon any of the following
                  statements, omissions or violations (collectively a
                  "Violation"): (1) any untrue statement or alleged untrue
                  statement of a material fact contained in such registration
                  statement, including any preliminary prospectus or final
                  prospectus contained therein or any amendments or supplements
                  thereto, (2) the omission or alleged omission to state therein
                  a material fact required to be stated therein, or necessary to
                  make the statements therein not misleading, or (3 ) any
                  violation or alleged violation by the Company of the
                  Securities Act, the 1934 Act, any state securities law or any
                  rule or regulation promulgated under the Securities Act, or
                  the 1934 Act or any state securities law; and, subject to
                  subparagraph (iii) below, the Company will pay to each such
                  Securities Holder, underwriter or controlling person, as
                  incurred, any legal or other expenses reasonably incurred by
                  one law firm retained by them (or such additional law firms
                  retained by a Securities Holder or Securities Holders if such
                  Securities Holder or Securities Holders reasonably believe
                  there exists a conflict of interest among them) in connection
                  with investigating or defending any such loss, claim, damage,
                  liability or action; provided, however, that the indemnity
                  agreement contained in this subsection 9(j)(i) shall not apply
                  to amounts paid in settlement of any such loss, claim, damage,
                  liability or action if such settlement is effected without the
                  consent of the Company (which consent shall not be
                  unreasonably withheld), nor shall the Company be liable in any
                  such case for any such loss, claim, liability or action to the
                  extent that it arises out of or is based upon a Violation
                  which occurs in reliance upon and in conformity with written
                  information furnished expressly for use in connection with
                  such registration by any such Securities Holder, underwriter
                  or controlling person.

                           (ii) Each selling Securities Holder will indemnify
                  and hold harmless the Company, each of its directors, each of
                  its officers who has signed the registration statement, each
                  person, if any, who controls the Company within the meaning of
                  the Securities Act, any underwriter, any other Securities
                  Holder selling securities in such registration statement and
                  any controlling person of any such underwriter or other
                  Securities Holder, against any losses, claims, damages

                                       7
<PAGE>
                  or liabilities (joint or several) to which any of the
                  foregoing persons may become subject, under the Securities
                  Act, or the 1934 Act or other federal or state law, insofar as
                  such losses, claims, damages, or liabilities (or actions in
                  respect thereto) arise out of or are based upon any Violation,
                  in each case to the extent (and only to the extent) that such
                  Violation occurs in reliance upon and in conformity with
                  written information furnished by such Securities Holder
                  expressly for use in connection with such registration; and
                  each such Securities Holder will pay, as incurred, any legal
                  or other expenses reasonably incurred by any person intended
                  to be indemnified pursuant to this subsection 9(j)(ii), in
                  connection with investigating or defending any such loss,
                  claim, damage, liability or action; provided, however, that
                  the indemnity agreement contained in this subsection 9(j)(ii)
                  shall not apply to amounts paid in settlement of any such
                  loss, claim, damage, liability or action if such settlement is
                  effected without the consent of the Securities Holder, which
                  consent shall not be unreasonably withheld; and provided,
                  further that, in no event shall any indemnity under this
                  subsection 9(j)(ii) exceed the net proceeds from the offering
                  received by such Securities Holder.

                           (iii) Promptly after receipt by an indemnified party
                  under this Section 9(j) of notice of the commencement of any
                  action (including any governmental action), such indemnified
                  party will, if a claim in respect thereto is to be made
                  against any indemnified party under this Section 9(j), deliver
                  to the indemnifying party a written notice of the commencement
                  thereof and the indemnifying party shall have the right to
                  participate in, and, to the extent the indemnifying party so
                  desires, jointly with any other indemnifying party similarly
                  noticed, to assume the defense thereof with counsel mutually
                  satisfactory to the parties; provided, however, that an
                  indemnified party (together with all other indemnified parties
                  which may be represented without conflict by one counsel)
                  shall have the right to retain one separate counsel, with the
                  fees and expenses to be paid by the indemnifying party, if
                  representation of such indemnified party by the counsel
                  retained by the indemnifying party would be inappropriate due
                  to actual or potential differing interests between such
                  indemnified party and any other party represented by such
                  counsel in such proceeding. The failure to deliver written
                  notice to the indemnifying party within a reasonable time of
                  the commencement of any such action, if prejudicial to its
                  ability to defend such action, shall relieve such indemnifying
                  party of any liability to the indemnified party under this
                  Section 9(j), but the omission so to deliver written notice to
                  the indemnifying party will not relieve it of any liability
                  that it may have to any indemnified party otherwise than under
                  this Section 9(j).

                           (iv) The obligations of the Company and Securities
                  Holders under this Section 9(j) shall survive the completion
                  of any offering of Registrable Securities in a registration
                  statement under this Section 9, and otherwise.

                  (k) Without any obligation hereunder, or otherwise, to become
         a publicly reporting company under the 1934 Act, but with a view to
         making available to the

                                       8
<PAGE>
         Securities Holder the benefits of Rule 144 promulgated under the
         Securities Act and any other rule or regulation of the SEC that may at
         any time permit a Securities Holder to sell Registrable Securities to
         the public without registration or pursuant to a registration on Form
         S-3, the Company agrees, if it becomes a publicly reporting company
         under such Act, to:

                           (i) make and keep public information available, as
                  those terms are understood and defined in SEC Rule 144, at all
                  times;

                           (ii) once qualified, maintain its qualification for
                  registration on Form S-3 for the sale of the Registrable
                  Securities;

                           (iii) file with the SEC in a timely manner all
                  reports and other documents required by the Company under the
                  Securities Act and the 1934 Act; and

                           (iv) furnish to any Securities Holder, so long as the
                  Securities Holder owns any Registrable Securities, forthwith
                  upon request (1) a written statement by the Company that it
                  has complied with the reporting requirements of SEC Rule 144,
                  the Securities Act and the 1934 Act, or that it qualifies as a
                  registrant whose securities may be resold pursuant to Form
                  S-3, (2) a copy of the most recent annual or quarterly report
                  of the Company and such other reports and documents so filed
                  by the Company, and (3) such other information as may be
                  reasonably requested in availing any Securities Holder of any
                  rule or regulation of the SEC which permits the selling of any
                  such securities without registration or pursuant to such form.

                  (l) From and after the date of this Agreement, the Company
         shall not, without the prior written consent of the Securities Holders
         of a majority of the outstanding Preferred Stock and Registrable
         Securities, enter into any agreement with any holder or prospective
         holder of any securities of the Company which would allow such holder
         or prospective holder to include such securities in any registration
         filed under Section 9(b) or 9(c) hereof, unless under the terms of such
         agreement, such holder or prospective holder may include such
         securities in any such registration to the extent that the inclusion of
         such securities is junior to that of the Registrable Securities of the
         Securities Holders.

                  (m) Any provision of this Section 9 may be amended and the
         observance thereof may be waived (either generally or in a particular
         instance and either retroactively or prospectively), only with the
         written consent of the Company and the Securities Holders owning a
         majority of the Preferred Stock and Registrable Securities then
         outstanding. Any amendment or waiver effected in accordance with this
         paragraph shall be binding, upon each Securities Holder of any
         Preferred Stock and Registrable Securities then outstanding, each
         future Securities Holder of all such Preferred Stock and Registrable
         Securities, and the Company.

                                       9
<PAGE>
         10.      (a) In addition to and without limiting the rights of the
         holder of this Warrant under the terms of this Warrant, the holder of
         this Warrant shall have the right (the "Conversion Right") to convert
         this Warrant or any portion thereof into shares of Preferred Stock as
         provided in this Section 10 at any time after 90 days from the date of
         issuance of this Warrant and then from time to time prior to its
         expiration. Upon exercise of the Conversion Right with respect to a
         particular number of shares of Preferred Stock subject to this Warrant
         (the "Converted Warrant Shares"), the Company shall deliver to the
         holder of this Warrant, without payment by the holder of any purchase
         or exercise price or any cash or other consideration, that number of
         shares of Preferred Stock equal to the quotient obtained by dividing
         the Net Value (as hereinafter defined) of the Converted Warrant Shares
         by the fair market value (as defined in paragraph (c) below) of a
         single share of Preferred Stock, determined in each case as of the
         close of business on the Conversion Date (as hereinafter defined). The
         "Net Value" of the Converted Warrant Shares shall be determined by
         subtracting the aggregate Warrant purchase price of the Converted
         Warrant Shares from the aggregate fair market value of the Converted
         Warrant Shares.

                  (b) The Conversion Right may be exercised by the holder of
         this Warrant by the surrender of this Warrant at the principal office
         of the Company together with a written statement specifying that the
         holder thereby intends to exercise the Conversion Right and indicating
         the number of shares of Preferred Stock subject to this Warrant which
         are being surrendered (referred to in paragraph (a) above as the
         Converted Warrant Shares) in exercise of the Conversion Right. Such
         conversion shall be effective upon receipt by the Company of this
         Warrant together with the aforesaid written statement, or on such later
         date as is specified therein (the "Conversion Date"), but not later
         than the expiration date of this Warrant. Certificates for the shares
         of Preferred Stock issuable upon exercise of the Conversion Right,
         together with a check in payment of any fractional share and, in the
         case of a partial exercise, a new warrant evidencing the shares
         remaining subject to this Warrant, shall be issued as of the Conversion
         Date and shall be delivered to the holder of this Warrant within 10
         days following the Conversion Date.

                  (c) For purposes of this Section 10, "fair market value" of a
         share of Preferred Stock shall be determined as follows:

                  First, the number of shares of the Company's Common Stock into
         which each share of the Company's Preferred Stock is convertible under
         Article II.6(d)(i) of the Amendment shall be determined ("common share
         equivalent"); then

                  Second, the common share equivalent shall be multiplied by the
         per share market price of the Company's Common Stock. "Market price of
         the Company's Common Stock ("Market Price") shall mean:

                  (a) if the Common Stock is listed and registered on any
         national securities exchange or traded on The Nasdaq Stock Market
         ("Nasdaq"), the closing bid price;

                                       10
<PAGE>
                           (b) if such Common Stock is not at the time listed on
                  any such exchange or traded on Nasdaq but is traded on the OTC
                  Bulletin Board, or if not, on the over-the-counter market as
                  reported by the National Quotation Bureau or other comparable
                  service, the closing bid price for such stock; or

                           (c) if clauses (a) and (b) above are not applicable,
                  the fair value per share of such Common Stock as determined in
                  good faith and on a reasonable basis by the Board of Directors
                  of the Company.

         11. The Company covenants that all shares of Preferred Stock that may
be issued and delivered to a Securities Holder upon the exercise of this Warrant
and payment of the Warrant purchase price will be, upon such delivery, validly
and duly issued, fully paid and nonassessable.

         12. The Company covenants that:

                  (a) Subject to the terms and conditions contained herein, this
         Warrant shall be binding on the Company and its successors and shall
         inure to the benefit of the original Securities Holder and the
         successors and assigns of the Securities Holder.

                  (b) If the Company fails to perform any of its obligations
         hereunder, it shall be liable to the Securities Holder for all damages,
         costs and expenses resulting from the failure, including, but not
         limited to, all reasonable attorney's fees and disbursements.

                  (c) This Warrant cannot be changed or terminated or any
         performance or condition waived in whole or in part except by an
         agreement in writing signed by the party against whom enforcement of
         the change, termination or waiver is sought.

                  (d) If any provision of this Warrant shall be held to be
         invalid, illegal or unenforceable, such provision shall be severed,
         enforced to the extent possible, or modified in such a way as to make
         it enforceable, and the invalidity, illegality or unenforceability
         shall not affect the remainder of this Warrant.

         13. All questions concerning this Warrant will be governed and
interpreted and enforced in accordance with the internal law, not the law of
conflicts, of the State of Colorado.

         IN WITNESS WHEREOF, Natural Gas Services Group, Inc. has caused this
Warrant to be signed by its duly authorized officer and this Warrant to be dated
as of January 23, 2002.

                                     NATURAL GAS SERVICES
                                     GROUP, INC.

                                     By: ______________________________________
                                     Its:  President

                                       11
<PAGE>
                             RESTRICTION ON TRANSFER

         "The securities evidenced hereby may not be transferred without (i) the
opinion of counsel satisfactory to this corporation that such transfer may be
lawfully made without registration under the Federal Securities Act of 1933 and
all applicable state securities laws or (ii) such registration."

                                       12
<PAGE>
                                SUBSCRIPTION FORM

              To be Executed by the Holder of this Warrant if such
          Holder Desires to Exercise this Warrant in Whole or in Part:

To:      Natural Gas Services Group, Inc. (the "Company")

                  The undersigned
                                  ---------------------------

                     Please insert Social Security or other
                        identifying number of Subscriber:

                    ----------------------------------------

hereby irrevocably elects to exercise the right of purchase represented by this
Warrant for, and to purchase thereunder, __________ shares of the Preferred
Stock (the "Preferred Stock") provided for therein and tenders payment herewith
to the order of the Company in the amount of $___________, such payment being
made as provided on the face of this Warrant.

         The undersigned requests that certificates for such shares of Preferred
Stock be issued as follows:

Name:
              ------------------------------------------------------------------
Address:
              ------------------------------------------------------------------
Deliver to:
              ------------------------------------------------------------------
Address:
              ------------------------------------------------------------------

and, if such number of shares of Preferred Stock shall not be all the shares of
Preferred Stock purchasable hereunder, that a new Warrant for the balance
remaining of the shares of Preferred Stock purchasable under this Warrant be
registered in the name of, and delivered to, the undersigned at the address
stated above.

Dated:

                         Signature
                                    --------------------------------------------
                                    Note: The signature on this Subscription
                                    Form must correspond with the name as
                                    written upon the face of this Warrant in
                                    every particular, without alteration or
                                    enlargement or any change whatever.

                                       13
<PAGE>
                               FORM OF ASSIGNMENT
                       (To Be Signed Only Upon Assignment)

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto:

                           ---------------------------
                                     [NAME]

 this Warrant, and appoints

                           ---------------------------
                                     [NAME]

to transfer this Warrant on the books of the Company with the full power of
substitution in the premises. Dated: In the presence of:

                                     -------------------------------------------
                                    (Signature must conform in all respects to
                                    the name of the holder as specified on the
                                    face of this Warrant without alteration,
                                    enlargement or any change whatsoever, and
                                    the signature must be guaranteed in the
                                    usual manner)

                                       14
<PAGE>
                        WARRANT CONVERSION EXERCISE FORM

TO:      Natural Gas Services Group, Inc.

         Pursuant to Section 10 of this Warrant, the Holder hereby irrevocably
elects to convert this Warrant into     shares of Preferred Stock of the
Company. A conversion calculation is attached hereto as Exhibit A.

         The undersigned requests that certificates for such Preferred Stock be
issued as follows:

Name:
              ------------------------------------------------------------------
Address:
              ------------------------------------------------------------------
Deliver to:
              ------------------------------------------------------------------

and that a new Warrant Certificate for the balance remaining of the Warrant
Shares, if any, be registered in the name of, and delivered to, the undersigned
at the address stated above.

                           Signature
                                     ------------------------------------
                           Dated
                                     ------------------------------------

                                       15

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