Document:

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                                                                     EXHIBIT 4.3

                                 PROMISSORY NOTE

$    Principal Amount                             Dated as of: July 21, 1992
                                                  Houston, Texas

     FOR VALUE RECEIVED, ____________________________________ (the "Borrower"),
promises to pay to the order of Seitel, Inc., a Delaware corporation
(hereinafter the "Company") the principal amount of
                                                                   AND 00/100
DOLLARS ($      ) together with interest thereon as hereinafter provided. This
promissory note is made and issued as partial consideration for the purchase by
the Borrower of certain shares of common stock of the Company (the "Shares").

     1. Calculation of Interest. Interest on the unpaid principal amount shall
accrue from the date hereof until the principal amount hereof and accrued
interest hereon shall be paid in full, at a rate of four percent (4%) per annum.
Interest shall be computed on the basis of a 360 day year of twelve 30-day
months.

     2. Payment of Principal. The principal amount hereof shall be due and
payable in nine (9) equal annual installments of
                                AND   /100 DOLLARS ($       ) commencing on the
first day of August, 1993 and ending on August 1, 2001. The balance of the
unpaid principal amount hereof shall be due and payable in full on August 1,
2002.

     3. Payment of Interest. Unpaid and accrued interest on the then unpaid
principal balance hereof shall be due and payable annually on each principal
payment date and thereafter until paid in full.

     4. Method of Payment. Payment of principal and accrued interest shall be
made in such coin or currency of the United States of America as, at the time of
payment, shall be legal tender for the payment of public and private debts.

     5. Prepayment Fees. Prepayment of this Note in whole or in part may be made
at any time without any fees, penalty, premium or discount.

     6. Place and Manner of Payment. All payments of principal and interest
shall be made by the Borrower to the Company at the offices of the Company at 50
Briar Hollow Lane West, Houston, Texas 77027.

     7. Attorneys' Fees. The Borrower agrees to pay the reasonable fees of any
attorney-at-law who may be employed by the Company to recover the amount hereof,
or any part hereof, in principal or interest, or to protect the interest of the
holder hereof, or to compromise or to take any other action with regard hereto.

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     8. Waiver. The Borrower hereby waives presentment, demand, protest and
notice of protest, and all other demands and notices in connection with the
payment and enforcement of this Note.

     9. Events of Default. Any one or more of the following shall constitute an
"Event of Default" hereunder:

     (A) Failure by the Borrower to pay any amount that has become due and
payable pursuant to any provision of this Note and such amount has remained
unpaid for a period of thirty (30) days from the date of receipt of written
demand by the Company;

     (B) The Borrower shall have applied for or consented to the appointment of
a custodian, receiver, trustee, liquidator, or other court appointed fiduciary
of all or a substantial part of its properties; or a custodian, receiver,
trustee, liquidator or other court appointed fiduciary shall have been appointed
with or without the consent of the Borrower, or the Borrower is generally not
paying its debts as they become due by means of available assets and the fair
use of credit, or has made a general assignment for the benefit of creditors; or
the Borrower has committed an act of bankruptcy, or has filed a voluntary
petition in bankruptcy, or a petition or an answer seeking reorganization or an
arrangement with creditors or seeking to take advantage of any insolvency law,
or an answer admitting the material allegations or a petition in any bankruptcy,
reorganization or insolvency proceeding to has taken action for the purpose of
effecting any of the foregoing; or if, within 45 days after the commencement of
any proceeding against the Borrower seeking any reorganization, rehabilitation,
arrangement, composition, readjustment, liquidation, dissolution or similar
relief under the Federal Bankruptcy Code or any present or future applicable
Federal, state or other statute or law, such proceeding shall not have been
dismissed; or if, within 45 days after the entry of an Order of Relief under the
Federal Bankruptcy Code or similar order under future similar legislation, the
appointment of any trustee, receiver, custodian, liquidator, or other court
appointed fiduciary of the Borrower of all or any substantial part of its
properties, such order or appointment shall not have been vacated or stayed on
appeal or otherwise or if, within 45 days after the expiration of any such stay,
such order or appointment shall not have been vacated;

     (C) Transfer for value by the Borrower of all or some of the shares of
common stock of the Company for which this promissory note was made by the
Borrower as partial consideration for the payment for said shares, without a
proportionate prepayment of the principal amount of this Note; and

     (D) Termination of Borrower's employment with the Company for any reason
whatsoever, whether voluntary or involuntary, and whether with or without cause.

     10. Remedies on Default. Whenever any Event of Default shall have occurred
and be continuing, the Company may:

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     (A) By notice to the Borrower, declare all amounts payable hereunder to be
immediately due and payable, whereupon the same shall become immediately due and
payable, both as to principal and interest, without presentment, demand,
protest, or other notice of any kind, all of which are expressly waived hereby,
anything in this Note to the contrary notwithstanding; and

     (B) Take any action at law or in equity to collect the payments then due
and thereafter to become due hereunder or to enforce performance and observance
of any obligation, agreement or covenant of the Borrower under this Note.

     11. Remedies Cumulative.

     (A) The occurrence of any Event of Default and the exercise of any remedy
by the Company shall not terminate any obligation of the Borrower incurred
hereunder.

     (B) No remedy herein conferred upon or reserved to the Company is intended
to be exclusive of any other available remedy or remedies, and such remedy or
remedies are in addition to each and every remedy now or hereafter existing at
law or in equity or by statute. Delay or omission in the exercise of any right,
remedy or power accruing upon any default or failure by the Company to insist
upon the strict performance of any of the covenants and agreements set forth in
this Note shall not impair any such right, remedy or power or be considered or
taken as a waiver or relinquishment of the right to insist upon and to enforce
in the future, by injunction or other appropriate legal or equitable remedy,
strict compliance by the Borrower with all of the covenantal and conditions
hereof, or of the rights to exercise any such rights or remedies, if such
default by the Borrower be continued or repeated.

     12. Security Interest. This promissory note is secured by a security
interest in the Shares, which have been pledged and delivered to the Company
pursuant to a certain Pledge Letter of even date herewith to perfect this
security interest.

     13. Successors and Assigns. The provisions hereof shall inure to the
benefit of, and be binding upon, the successors and assigns of the parties
hereto; provided, however, the Borrower may not assign or transfer their rights
and obligations hereunder.

     14. Governing Law. This Agreement and the rights and remedies of the
parties hereto shall in all respects be interpreted, construed, governed and
enforced in accordance with the laws and the public policies of the State of
Texas, without giving effect to conflict of laws principles.

     IN WITNESS WHEREOF, the undersigned has duly executed this Note on the day
and year first above written.

                                                  ______________________________
                                                    Borrower<PAGE>

                                                                     EXHIBIT 4.4

                                  SEITEL, INC.

                             SUBSCRIPTION AGREEMENT

To:  Seitel, Inc.
     50 Briar Hollow Road West
     Houston, Texas 77027

     1.   The undersigned hereby subscribes for      shares of common stock, par
value $.01 per share (the "Common Stock") issued by Seitel, Inc. (the "Company")
at a price of $5.375 per share. The undersigned agrees to tender payment of the
subscription price of the Common Stock subscribed for as set forth on the
signature page of this Subscription Agreement, upon return of this executed
Subscription Agreement.

          The undersigned agrees that this subscription is and shall be
irrevocable, but that it may be rejected, in whole or in part, by the Company,
and that the obligations of the undersigned hereunder will terminate if this
subscription is not accepted by the Company. The undersigned understands that
the Company will notify him if this subscription has been rejected for any
reason. If this subscription is rejected by the Company, the payment tendered by
him will be returned to him forthwith, without interest or deduction. If this
subscription is accepted by the Company, the amount of the payment tendered will
be applied by the Company for working capital purposes.

     2.   The undersigned understands and agrees that an investment in the
Company at the outset is an illiquid investment.

          (a)(i)    Texas Residents. The undersigned hereby acknowledges
that the Common Stock cannot be sold unless it is subsequently registered under
the Securities Act of 1933, as amended (the "Act") and applicable state
securities laws ("State Acts") including in particular the Texas Securities Act,
or an exemption from registration is available. The undersigned further
acknowledges that because the shares of Common Stock are not readily
transferable, he must bear the economic risk of his investment for an indefinite
period of time.

             (ii)   Other Residents. The undersigned must bear the economic risk
of investment in the Common Stock for an indefinite period of time, since Common
Stock has not been registered under the Securities Act of 1933, as amended (the
"Act") or applicable state securities laws ("State Acts"), and, therefore,
cannot be transferred or sold unless either subsequently registered under the
Act and applicable State Acts, or an exemption from registration is available
and a favorable opinion of counsel to that effect is obtained.

          (b) The Company plans to use its best efforts to file a registration
statement under the Act within one year from the date hereof for the Common
Stock, but there is no assurance that the registration statement in connection
therewith will be declared effective.

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     3.   The undersigned represents to and agrees with the Company, that:

          (a) The undersigned and his investment advisor(s), if any, have
carefully reviewed and understand the risks of and other considerations relating
to, a purchase of the Common Stock.

          (b) The undersigned and his investment advisor(s), if any, have been
afforded the opportunity to obtain any information necessary to verify the
accuracy of any representations or information set forth in the Memorandum and
have had all of their inquiries to the Company answered in full, and have been
furnished all requested materials relating to the Company and the offering and
sale of the Common Stock and any other matter described in the letter dated as
of July 21, 1992 accompanying this Subscription Agreement (the "Letter").

          (c) Neither the undersigned nor his investment advisor(s), if any,
have been furnished any offering literature by the Company or any of its
affiliates, associates or agents, other than the Letter and the exhibits and
attachments thereto.

          (d) The undersigned is acquiring the Common Stock for which he hereby
subscribes as principal for his own investment account, and not (1) with a view
to the resale or distribution of all or any part of such Common Stock, (2) on
behalf of another person who has not made the foregoing representation, or (3)
in order for any person to acquire less than the minimum subscription required
hereunder, unless a lesser subscription specifically has been accepted by the
Company.

          (e) The undersigned is an accredited investor, as defined in Rule
501(a) of Regulation D promulgated pursuant to the Act, by virtue of the fact
that (initial applicable choice):

          ____    (i)  The undersigned had individual income (exclusive of any
income attributable to spouse) of more than $200,000 in each of the most recent
two years or joint income with the undersigned's spouse in excess of $300,000
and reasonably expects to have income of at least the same level for the current
year.

          ____   (ii)  The undersigned has an individual net worth, or a
combined net worth with the undersigned's spouse, in excess of $1,000,000. For
purposes of this Subscription Agreement, "individual net worth" means the excess
of total assets at fair market value, including home and personal property, over
total liabilities.

          ____  (iii)  The undersigned is a director or executive officer of the
Company.

           Accredited partnership, corporation, trust or other entity:
       investors must initial one or both of the following two statements.

          ____   (iv)  The undersigned is a bank as defined in section 3(a)(2)
of the Act, or a savings and loan association or other institution as defined in
section 3(a)(5)(A) of the Act whether acting in its

                                       -2-

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individual or fiduciary capacity; a broker or dealer registered pursuant to
section 15 of the Securities Exchange Act of 1934; an insurance company as
defined in section 2(13) of the Act; an investment company registered under the
Investment Company Act of 1940 or a business development company as defined in
section 2(a)(48) of the Act; a Small Business Investment Company licensed by
the U.S. Small Business Administration under section 301(c) or (d) of the Small
Business Investment Act of 1958; a plan established and maintained by a state,
its political subdivisions, or any agency or instrumentality of a state or its
political subdivisions, for the benefit of its employees if such plan has total
assets in excess of $5,000,000; an employee benefit plan within the meaning of
the Employee Retirement Income Security Act of 1974 if the investment decision
is made by a plan fiduciary, as defined in section 3(21) of such Act, which is
either a bank, savings and loan association, insurance company, or registered
investment adviser, or if the employee benefit plan has total assets in excess
of $5,000,000 or, if a self-directed plan, with investment decisions made solely
by persons that are accredited investors.

          ____   (v)  The undersigned is a private business development company
as defined in section 202(a)(22) of the Investment Advisers Act of 1940.

          ____  (vi)  The undersigned is an organization described in section
501(c)(3) of the Internal Revenue Code, corporation, Massachusetts or similar
business trust, or partnership, not formed for the specific purpose of acquiring
the securities offered, with total assets in excess of $5,000,000.

          ____ (vii)  The undersigned is a trust, with total assets in excess of
$5,000,000, not formed for the specific purpose of acquiring the securities
offered, whose purchase is directed by a sophisticated person as described in
section 230.506(b)(2)(ii).

          ____ (viii) All of the equity owners of the undersigned qualify as
accredited investors under one of the statements set forth above.

          ____  (ix)  The undersigned otherwise meets the definition of
accredited investor set forth in Rule 501(a) of Regulation D, as follows
(explain briefly):

          ____   (x)  Check here if the undersigned does not meet any of the
above criteria for accredited investors.

          (f) The undersigned has evaluated the risks of investing in the
Company and has substantial experience in making investment decisions of this
type or is relying on his professional advisors or purchaser representative(s)
(check here if this is the case _____), in making this investment decision.

          (g) The undersigned understands the fundamental aspects of and risks
involved in an investment in the Company, including (1) the volatility in the
demand for seismic data and the highly competitive

                                       -3-

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nature of the Company's business, (2) the lack of liquidity and the
restrictions on transferability of the Common Stock, and (3) the potential
dilution due to the outstanding common stock equivalents.

          (h) The address set forth on the Subscription Agreement Signature Page
hereof is the undersigned's true and correct principal address, and the
undersigned has no present intention of becoming a resident of any other state
or jurisdiction.

          (i) The undersigned, if a corporation, partnership, trust or other
form of business entity, (1) is authorized and otherwise duly qualified to
purchase and hold the Common Stock, (2) has its principal place of business at
its residence address set forth on the Subscription Agreement Signature Page
hereof, (3) has not been formed for the specific purpose of acquiring the Common
Stock, and (4) has submitted and executed all documents required pursuant to the
Certificate for Corporate, Partnership, Trust and Joint Purchasers and Special
Subscription Instructions. The person executing this Subscription Agreement and
all other documents related to the offering hereby represents that he is duly
authorized to execute all such documents on behalf of the entity. IF THE
UNDERSIGNED IS ONE OF THE AFOREMENTIONED ENTITIES, IT HEREBY AGREES TO SUPPLY
ANY ADDITIONAL WRITTEN INFORMATION THAT MAY BE REQUIRED BY THE COMPANY.

          (j) All of the information that the undersigned has heretofore
furnished to the Company, or that is set forth herein with respect to himself,
his financial position, and his business and investment experience, is correct
and complete as of the date hereof, and, if there should be any material change
in such information prior to the closing of the sale of the Common Stock, the
undersigned will immediately furnish the revised or corrected information to the
Company.

          (k) The undersigned agrees to be bound by all of the terms and
conditions of the offering made by the Letter and the exhibits thereto.

          (1) No person other than the undersigned will have a direct or
indirect interest in the Common Stock subscribed for hereby.

     4.   The foregoing representations are true and accurate as of the date
hereof, shall be true and accurate as of the date of the closing of this
offering, and shall survive such closing. If, in any respect, such
representations shall not be true and accurate prior to or upon the closing of
this offering, the undersigned shall give written notice of such fact to the
Company, specifying which representations are not true and accurate and the
reasons therefor, with a copy to his purchaser representative(s), if any.

     5.   The undersigned agrees to indemnify and hold harmless the Company, and
each of the officers, directors, partners and shareholders of the Company, and
any selected dealer, from and against any loss, damage or liability due to or
arising out of a breach of any of the foregoing representations.

     6.   If the undersigned is more than one person or entity, the obligations
of the undersigned shall be joint and several and the

                                       -4-

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representations and the indemnification obligation herein contained shall be
deemed to be made by and be binding upon each such person and his heirs,
executors, administrators, successor and assigns.

     7.   (a) The Company agrees to use its best efforts to include the
shares of Common Stock in a registration' statement filed with the Securities
and Exchange Commission within one year from the date of the issuance of the
Common Stock and will to use its best efforts to cause such registration
statement to be declared effective and to maintain its effectiveness for a
period of two (2) years. The Company shall bear all of the Cost and Expense (as
hereinafter defined) of such registration.

          (b) The undersigned agrees that in connection with the Company's
registration of shares of Common Stock he shall:

               (i)  Deliver in writing all information to the Company concerning
          himself and his holdings of securities of the Company as shall be
          required in connection with the preparation and filing of any
          registration statement covering any shares of the Company's common
          stock owned by him; and

               (ii) Indemnify the Company, and each person who controls the
          Company within the meaning of Section 15 of the Act, from and against
          any and all losses, claims, damages, expenses and liabilities caused
          by any untrue statement of a material fact contained in any
          registration statement or prospectus furnished under the Act or caused
          by any omission to state a material fact therein necessary to make the
          statements therein not misleading, insofar as such losses, claims,
          damages, expenses and liabilities are caused by such untrue statement
          or omission based upon information furnished in writing to the Company
          by him expressly for use in any registration statement or prospectus.

          (c)  As used in this Subscription Agreement, "Cost and Expense" shall
include all of the costs and expenses relating to any registration statement to
which it relates, including, without limitation, registration, filing and
qualification fees, blue-sky expenses, printing expenses, fees and disbursements
of counsel to the Company, and accounting fees, except that underwriting
discounts and commissions and reimbursable underwriters' expenses (if any) shall
be borne by each Subscriber.

     8.   This subscription is not transferable or assignable by the
undersigned.

     9.   This subscription, upon acceptance by the Company, shall be binding
upon the heirs, executors, administrators, successors and assigns of the
undersigned.

     10.  This Subscription Agreement shall be construed in accordance with and
governed by the laws of the State of Texas, without giving effect to conflict of
law principles.

     11.  When the context in which words are used in this Agreement indicates
that such is the intent, singular words shall include the plural and vice versa
and masculine words shall include the feminine and the neuter genders and vice
versa.

                                       -5-

<PAGE>

                                  SEITEL, INC.
                      SUBSCRIPTION AGREEMENT SIGNATURE PAGE

     The undersigned hereby subscribes for shares of common stock, par value
$.01 per share, issued by Seitel, Inc., a corporation organized under the laws
of the State of Delaware, at $5.375 per share. This Subscription Agreement as
executed and the appropriate payment should be forwarded to Clare J. Attura, c/o
Helm Resources, Inc., 93 Mason Street, Greenwich, CT 06830.

     1. Dated: as of July 21, 1992

     2. Number of shares subscribed for:

     3. Aggregate Subscription Price :          (1)

     4. Subscription Payable: Cash:
                              Promissory Note:

----------------------------                      ----------------------------
Signature of Subscriber (and                      Taxpayer Identification or
title, if applicable)                             Social Security Number

----------------------------                      ----------------------------
Signature of Joint Purchaser                      Taxpayer Identification or
(if any)                                          Social Security Number

Name and Residence Address                        Mailing Address, if Different
(No Post Office Address)                          from Residence Address:

----------------------------                      ----------------------------
Name (please print)                               Name (please print)

----------------------------                      ----------------------------
Number and Street                                 Number and Street

----------------------------                      ----------------------------
City     State     Zip Code                       City      State   Zip Code

Subscription for      shares of common stock, par value $.01 per share,
of Seitel, Inc. accepted.

SEITEL, INC.

By:
   -------------------------
Title: Vice President

Date: as of July 21, 1992

                                       -6-

<PAGE>

                SPECIAL SUBSCRIPTION INSTRUCTIONS FOR CORPORATE,

                    PARTNERSHIP, TRUST, AND JOINT PURCHASERS

     If the investor is a corporation, partnership, trust, or other entity or
joint purchaser, the following additional instructions must be followed.
INFORMATION ADDITIONAL TO THAT REQUESTED BELOW MAY ALSO BE REQUIRED BY THE
COMPANY IN SOME CASES.

     I.   Authorization. The investor must provide a copy of (a) the
corporation's articles of incorporation, by-laws and authorizing resolution, (b)
the partnership agreement, or (c) the trust agreement, as applicable.

     II.  Subscription Agreement

          A. Corporations. An authorized officer of the corporation must date,
sign, and complete the Subscription Agreement with information concerning the
corporation. The officer should print the name of the corporation above his
signature, and print his name and office below his signature.

          B. Partnerships. An authorized partner must date, sign, and complete
the Subscription Agreement with information concerning the partnership. The
partner should print the name of the partnership above his signature, and print
his name and the words "general partner" below his signature.

          C. Trusts. In the case of a trust, the authorized trustee should date,
sign, and complete the Subscription Agreement with information concerning the
trust. The trustee should print the name of the trust above his signature, and
print his name and the word "trustee" below his signature. In addition, an
authorized trustee should also provide information requested in the Subscription
Agreement as it pertains to him as an individual.

          D. Joint Ownership. Except with regard to married couples, joint
investors must individually meet the investor suitability requirements; in all
cases, each must date, sign, and complete the Subscription Agreement. Joint
investors must state if they are purchasing the Common Stock as joint tenants
with the right of survivorship, tenants in common, or community property, and
each must execute the Subscription Agreement Signature Page.

     III. In certain circumstances, the investor may also be required to provide
an opinion of counsel to the same effect as the Certificate set forth on the
following page.

<PAGE>

                                  SEITEL, INC.

                CERTIFICATE FOR CORPORATE, PARTNERSHIP, AND TRUST

     If the investor is a corporation, partnership, trust, or other entity, an
authorized officer, partner, or trustee must complete, date, and sign this
Certificate.

                                   CERTIFICATE

I hereby certify that:

     a.   The investor has been duly formed and is validly existing and has full
          power and authority to invest in Helm Resources, Inc. (the "Company").
          The investor has not been formed for the purpose of investing in the
          Common Stock.

     b.   The investor's Subscription Agreement has been duly and validly
          authorized, executed, and delivered by the investor and, upon
          acceptance by the Company, will constitute the valid, binding, and
          enforceable obligation of the investor.

Dated:   ____________, 1992                    -------------------------------
                                               Name of investor (please print)

                                               ---------------------------------
                                               Signature and title of authorized
                                               officer, partner, or trustee

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