Exhibit 10.3

                                 PROMISSORY NOTE

     Flotek  Industries,   Inc.,  a  Delaware  corporation  (hereinafter  called
"Maker"),  for value  received,  promises  and  agrees  to pay on or before  the
Maturity Date (as hereafter  defined),  to Oklahoma  Facilities LLC, an Oklahoma
limited liability company, or its assigns (hereinafter called "Payee") in lawful
money of the United States of America the principal sum of FIVE HUNDRED THOUSAND
DOLLARS ($500,000),  together with interest on the unpaid principal balance at a
rate equal to the 'National Prime' Rate Floating (as reported in the Wall Street
Journal) +4.25% per annum,  adjustable as of date of change,  (calculated on the
basis of a 365-day year,  or a 366-day year in the case of a leap year),  but in
no event to exceed the maximum rate of nonusurious interest allowed from time to
time by law (hereinafter  called the "Contract  Interest Rate").  After maturity
(by  acceleration  or  otherwise),  interest shall accrue at a rate equal to the
'National  Prime' Rate Floating (as reported in the Wall Street  Journal) +7.25%
per annum,  adjustable  as of date of change  (hereinafter  called the  "Default
Rate"), which indebtedness shall be payable as follows:


          o MAKER  shall pay the  holder  hereof  on the  first  day of  August,
          September,  October and November,  2002,  the amount of interest which
          has accrued pursuant to this Note but has not been paid.

          o MAKER  shall pay the  holder  hereof  on the first day of  December,
          2002,  and  continuing  on the first day of each  succeeding  calendar
          month  thereafter  through and  including the earlier of the following
          occurrences,  namely (i) July 1, 2003,  or (ii) until all  amounts due
          hereunder are paid in full,  monthly payments of $8,045 each,  applied
          first to accrued and unpaid interest, then to reduction of principal.

          o MAKER  shall  further  pay the  holder  hereof  periodic  principal
          payments in amounts equal to each and every payment  received by Maker
          as payment on the amount owing to Maker or its  affiliate by Servicios
          Tecnicos Petrovalve under Invoice No. IN000995 dated April 11, 2002 in
          the amount of $437,075, such payments by Maker to the holder hereof to
          be paid within a reasonable period of time (not to exceed fifteen (15)
          days)  following  receipt  by  Maker  of  each  such  payment  on such
          receivable.

          o All principal and accrued interest remaining unpaid shall be due and
          payable in one lump sum  payment  upon the  earlier  of the  following
          occurrences:  (i)  within a  reasonable  period of time (not to exceed
          fifteen  (15) days)  following  receipt in full by Maker of the amount
          owing to Maker or its affiliate by Servicios Tecnicos Petrovalve under
          Invoice No.  IN000995  dated April 11, 2002 in the amount of $437,075;
          or (ii) August 1, 2003.

     If any amount owing under this Note is due and payable on a day that is not
a business  day,  such  payment  shall  instead  be due and  payable on the next
succeeding  business day. Maker has the right to prepay this Note in whole or in
part at any time and from time to time  without  penalty,  on not less than five
business  days' prior  notice.  Any such  prepayment  shall be applied  first to
accrued but unpaid interest, then to principal.

     FOR PURPOSES of this Note, an "Event of Default" shall occur whenever:  (a)
A default is made in the payment  when due of any payment due  hereunder  or any
amount  required  to be paid by the Maker  under the terms of this Note and such
default  continues  for five (5) days  after  such due  date,  (b)  Maker  shall
commence   a   voluntary   case  or  other   proceeding   seeking   liquidation,
reorganization  or other  relief  with  respect  to itself or its debts or other
liabilities  under  any  bankruptcy,  insolvency  or  other  similar  law now or
hereafter in effect,  and (c) an involuntary  case or other  proceeding shall be
commenced against Maker which seeks liquidation,  reorganization or other relief
with respect to Maker or its debts or other  liabilities  under any  bankruptcy,
insolvency or other similar law now or hereafter in effect and such  involuntary
case or other proceeding shall remain undismissed for a period of 90 days.

     IF AN Event of Default shall occur, the holder hereof may, at the option of
the holder,  without demand,  notice, or presentment,  declare the entire unpaid
principal  balance of this  Note,  together  with all  accrued  unpaid  interest
thereon,  to be due and  payable  immediately.  Upon any such  declaration,  the
principal of this Note and all accrued  interest shall become and be immediately
due and  payable,  and the holder  hereof may  thereupon  proceed to protect and
enforce the obligations of the Maker  hereunder by suit in equity,  by action of
law, or by other appropriate  proceedings,  whether for specific performance (to
the extent permitted by law) of any covenant or agreement contained herein or in
aid of the  exercise  of any power  granted  herein,  or proceed to enforce  the
payment of this Note or to enforce  any other  legal or  equitable  right of the
holder hereof.

     MAKER agrees to pay all reasonable costs and expenses (including attorneys'
fees  and  expenses)  expended  or  incurred  by Payee  in  connection  with the
enforcement of this Note and collection of any sums due hereunder.

     IT IS the  intention of Maker and Payee to conform  strictly to  applicable
usury  laws.  Accordingly,  if the  transactions  contemplated  hereby  would be
usurious  under  applicable law (including the laws of the State of Oklahoma and
the laws of the United States of America), then, in that event,  notwithstanding
anything to the contrary  herein or in any agreement  entered into in connection
with or as  security  for this  Note,  it is agreed  that the  aggregate  of all
consideration  which  constitutes  interest under  applicable law that is taken,
reserved,  contracted  for,  charged or received under this Note or under any of
the other  aforesaid  agreements or otherwise in connection with this Note shall
under no  circumstances  exceed  the  maximum  amount  of  interest  allowed  by
applicable  law,  and  any  excess  shall  be  canceled  automatically  and,  if
theretofore paid, shall be credited on the Note by the holder hereof (or, to the
extent that this Note shall have been or would thereby be paid in full, refunded
to the Maker).

     THE  PAYMENT  of this Note is secured  pursuant  to the terms of a Security
Agreement  dated  the  date  hereof  between  Maker  and  Payee  (the  'Security
Agreement').

     MAKER agrees that  $284,040 of the  proceeds of the loan  evidenced by this
Note  shall  be  advanced  by  Payee   directly  to  Jan-L   Construction   Co.,
Inc.('Jan-L'),  for the immediate  payment and  satisfaction in full to Jan-L of
the  amount  owing by a  subsidiary  of Maker to  Jan-L  under  Application  and
Certificate  for Payment dated March 5, 2002.  Maker  further  agrees that Payee
shall  directly  advance to Jan-L,  out of the proceeds of the loan evidenced by
this Note, Jan-L's attorney fees actually incurred in connection with the filing
of its Mechanics and Materialmen's Lien (but in no event to exceed $1,650).

     THIS NOTE has been  executed and  delivered in the State of Texas but shall
be  construed  in  accordance  with and  governed  by the  laws of the  State of
Oklahoma  and of the United  States of  America.  Maker and Payee agree that the
venue for any action brought to enforce,  construe,  invalidate, or in any other
respect  dealing with this Note shall  exclusively  be in the District  Court of
Stephens County, State of Oklahoma.

                                        FLOTEK INDUSTRIES, INC.


                                        By:/s/ Jerry D. Dumas, Sr.
                                        --------------------------
                                        Name:Jerry D. Dumas, Sr.
                                        Title:CEO of Flotek Industries, Inc.







                       COLLATERAL ASSIGNMENT OF RECEIVABLE


     THAT FLOTEK INDUSTRIES,  INC., and PETROVALVE,  INC., whose address is 7030
Empire Central Drive, Houston, Texas 77040 ("Obligors"), for a good and valuable
consideration paid, the receipt and sufficiency of which is hereby acknowledged,
hereby TRANSFER,  ASSIGN and CONVEY unto OKLAHOMA FACILITIES,  LIMITED LIABILITY
COMPANY,  an Oklahoma limited liability company ("Secured  Party"),  and further
grant to Secured Party a security interest in the accounts receivable  described
in Exhibit A (referred to as the "Collateral" or the "Pledged Receivable").

     TO HAVE AND TO HOLD  the  above  described  Collateral,  together  with all
rights and  privileges  which the Obligors may have by virtue of being the legal
and equitable owners and holder of said Collateral.

     This transfer and assignment is made to secure the  performance and payment
of that  certain  Promissory  Note dated  July 19,  2002 by and  between  Flotek
Industries, Inc. and Secured Party (herein called the "Note"), payable by Flotek
Industries,  Inc. to the order of Secured  Party,  all renewals  and  extensions
thereof,  and upon full payment thereof this transfer shall be null and void and
the Collateral  shall,  at the expense of Obligors,  be  retransferred,  without
warranty or recourse, to Obligors by Secured Party.

     Obligors  warrant  and  covenant  that (i) they  own the  Collateral  above
described  and have good right and title to the same and full  right,  authority
and  power to  convey  the same to  Secured  Party as  herein  set forth and are
granting  a  valid  first  security  interest  to  Secured  Party  in and to the
Collateral,  (ii) the  outstanding  principal  balance on the  Collateral  owing
Obligors is as described in Exhibit "A" hereto,  and (iii) the principal  places
of business and states of corporate registration (issuance of corporate charter)
of the Obligors and their  predecessor  and affiliate  companies are only in the
States of Delaware, Texas and/or Oklahoma.

     In the event of  default  in the  payment of any sums due under the Note in
accordance  with the terms  thereof,  as may be  applicable,  Secured  Party may
elect,  Obligors hereby expressly  waiving notice,  demand and  presentment,  to
declare the entire indebtedness hereby secured immediately due and payable.

     In the event of  default  in the  payment  of said  obligation  when due or
declared  due,  Secured  Party  shall have the right to sell the  Collateral  at
public sale or private sale, as permitted  under the Uniform  Commercial Code of
the State of Oklahoma, and Secured Party shall transfer to the purchaser at such
sale said  Collateral,  and the recitals in such  transfer  shall be prima facie
evidence of the truth of the matters  therein  stated and all  prerequisites  to
such sale required  hereunder and under the laws of this State shall be presumed
to have been  performed.  The  proceeds  of the sale shall be  applied  first to
reasonable  expenses  of the  sale  and  then  toward  the  payment  of the Note
rendering  the balance,  if any,  and surplus,  if any, to the person or persons
legally  entitled  thereto  under the  Uniform  Commercial  Code of the State of
Oklahoma.  Secured  Party shall have the right to purchase at any such sale,  as
permitted under the Uniform Commercial Code of the State of Oklahoma.

     Secured  Party,  in  addition  to the rights and  remedies  provided in the
preceding paragraph, shall have the rights and remedies of a Secured Party under
the Uniform Commercial Code of the State of Oklahoma, and Secured Party shall be
entitled  to avail  itself of all such other  rights and  remedies as may now or
hereafter exist at law or in equity for the collection of said  indebtedness and
the  foreclosure of the security  interest  created hereby and the resort to any
remedy provided hereunder or provided by the Uniform Commercial Code of Oklahoma
or by any other law of the State of Oklahoma,  shall not prevent the  concurrent
employment of any other appropriate remedy or remedies.

     The  requirement of reasonable  notice to Obligors of the time and place of
any public sale of the  Collateral,  or of the time after which any private sale
or any other intended  disposition  thereof is to be made,  shall be met if such
notice is mailed,  postage  prepaid,  to  Obligors  at the  address of  Obligors
designated  at the beginning of this  instrument,  at least ten (10) days before
the date of any  public  sale or at least ten (10) days  before  the time  after
which any private sale or other disposition is to be made.

     Secured  Party may remedy any default,  without  waiving same, or may waive
any default without waiving any prior or subsequent default.

     The security interest herein created shall not be affected by or affect any
other security taken for the obligation hereby secured, or any part thereof, and
any extensions may be made of the obligation  without  affecting the priority of
this security  interest or the validity  thereof without  reference to any third
party,  and the obligee of said obligation  shall not be limited by any election
of remedies if it chooses to foreclose this security interest by suit. The right
to sell under the terms  hereof shall also exist  cumulative  with said suit and
one method  shall not bar the  other,  but both may be  extended  at the same or
different times, nor shall one be a defense to the other.

     The pronouns used in this  agreement are in the masculine  gender but shall
be construed as feminine or neuter as occa-sion may require. "Secured Party" and
"Obligors"  as used in this  agreement  include,  shall  bind  and  inure to the
benefit  of the  respective  heirs,  executors  or  administrators,  successors,
representatives, receivers, trustee and assigns of such parties.


     The law governing this secured  transaction shall be the Uniform Commercial
Code as adopted in the State of Oklahoma and other  applicable laws of the State
of Oklahoma.  All terms used herein which are defined in the Uniform  Commercial
Code of the State of  Oklahoma  shall  have the same  meaning  herein as in said
Code.

     Obligors  authorize Secured Party, at Secured Party's option and subsequent
to default on the Note, to collect and receipt for any and all sums becoming due
upon  the  Promissory  Notes,  such  sums to be held by  Secured  Party  without
liability  for  interest  thereon,  and apply the same toward the payment of the
Promissory  Notes as and when the same becomes  payable and Secured  Party shall
have the full control of the  Collateral  until the  Promissory  Notes are fully
paid and shall have the further right to release the lien or liens  securing the
Promissory  Notes upon the full and final payment thereof to Secured Party,  but
Secured Party is under no  obligation  to make or enforce the  collection of the
Promissory  Notes  and the  failure  of  Secured  Party for any cause to make or
enforce  the  collection  thereof  shall not in any way  prejudice  the right of
Secured Party to  thereafter  make or enforce  collection  thereof or in any way
affect the indebtedness to Secured Party hereby secured.

         EXECUTED this 25th day of July, 2002.

                                 "OBLIGORS":

                                 FLOTEK INDUSTRIES, INC.


                                 By:/s/ Jerry D. Dumas, Sr.
                                 --------------------------
                                 Name: Jerry D. Dumas, Sr.
                                 Title:CEO of Flotek Industries, Inc.

                                 PETROVALVE, INC.


                                 By:/s/ Jerry D. Dumas, Sr.
                                 --------------------------
                                 Name: Jerry D. Dumas, Sr.
                                 Title:CEO of Petrovalve, Inc.










                                   EXHIBIT "A"


 The Collateral is:


   The amounts owed by Servicios Tecnicos Petrovalve to the Obligor pursuant to
the following invoice:

  Document No.     Doc. Date        Due Date          Amount
  IN000995          4/11/02          5/11/02       $437,075.00