EXHIBIT 10(iv)

NOTICE: THIS NOTE HAS NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, NOR UNDER ANY STATE SECURITIES
LAW AND MAY NOT BE PLEDGED, SOLD, ASSIGNED OR TRANSFERRED UNLESS (I) A REGISTRATION
STATEMENT WITH RESPECT THERETO IS EFFECTIVE UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
AND ANY APPLICABLE STATE SECURITIES LAW REQUIREMENTS HAVE BEEN MET OR (II) EXEMPTIONS FROM
THE REGISTRATION REQUIREMENTS UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND THE
REGISTRATION OR QUALIFICATION REQUIREMENTS OF APPLICABLE STATE SECURITIES LAWS ARE
AVAILABLE.

Secured Revolving
Replacement Promissory Note

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FOR VALUE RECEIVED, the undersigned,
Providence Exploration, LLC, a Texas limited liability company, with offices at 100
Crescent Court, Dallas, Texas 75201 (the Maker), unconditionally promises to
pay to the order of Healthbridge, Inc., a Texas corporation, with offices at 1066 West
Hastings Street, Suite 2610, Vancouver, British Columbia, V6E 3X2 (the Payee),
the principal sum of five million U.S. Dollars (U.S. $5,000,000), or so much thereof as
may be advanced and outstanding from time to time pursuant to Section 4 of this Secured
Revolving Replacement Promissory Note (this Note), together with interest on
such principal amount as provided below.

1.    
          Interest. The unpaid principal balance of this Note shall bear interest from the
          date of this Note until this Note shall have been paid in full at the lower of
          (i) Seven Percent (7%) per annum, or (ii) the maximum non-usurious rate of
          interest permissible under applicable law; provided, however, that any amount
          not paid when due in accordance with the terms of this Note shall bear interest
          from the date such payment was due until paid at the lower of (i) Fifteen
          Percent (15%) per annum or (ii) the maximum non-usurious rate of interest
          permissible under applicable law.

2.    
          Payment of Principal and Interest. Principal and accrued interest under this
          Note shall be paid in full by December 1, 2006. Interest on this Note shall be
          computed on the basis of a year of 365 days for the actual number of days
          elapsed.

3.    
          Currency; Place of Payment. Principal and all accrued interest are payable in
          lawful money of the United States of America and in immediately available funds,
          at 1066 West Hastings Street, Suite 2610, Vancouver, British Columbia, V6E 3X2,
          or at such other address as the Payee may from time to time designate in
          writing.

4.    
          Additional Borrowings; Prepayment. Maker may borrow, repay, and reborrow
          hereunder, and may request in writing for draws against the principal amount of
          this Note at any time. Payee may, at its sole discretion, provide to Maker the
          funds so requested by Maker. The Maker reserves the right to prepay without
          notice all or any part of the unpaid principal balance or outstanding interest
          of this note without premium or penalty.

5.    
          No Set-Off. Payment of principal and interest on this Note shall be made without
          any deductions whatsoever, including but not limited to any deduction for any
          set-off, recoupment or counterclaim. Unless the Payee otherwise agrees, all
          payments on this Note shall be applied first to accrued and unpaid interest and
          then to unpaid principal.

6.    
          Severability. Any provision of this Note that is prohibited or unenforceable in
          any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of
          such prohibition or unenforceability without invalidating the remaining portions
          of this Note in such jurisdiction, and any such prohibition or unenforceability
          in any such jurisdiction shall not invalidate or render unenforceable such
          provision in any other jurisdiction.

7.    
          No Waiver; Cumulative Remedies.

|(a) | The Payee shall not, by any act (except by a written instrument executed and
          delivered in accordance with subparagraph (b) below), delay, indulgence,
          omission or otherwise be deemed to have waived any right, remedy or other power
          under this Note or to have acquiesced in any default under this Note. The
          rights, remedies and powers provided to the Payee under this Note are
          cumulative, may be exercised singly or concurrently, and are not exclusive of
          and shall be in addition to all other rights, remedies, or powers provided by
          applicable law. The Payee may exercise any or all rights, remedies and powers at
          any time(s) in any order which the Payee chooses in its discretion.
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|(b) | No waiver, amendment, supplement or other modification of any of the terms or
          provisions of this Note shall be effective unless set forth in a writing
          executed and delivered by the party sought to be charged.
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8.    
          Events of Default; Acceleration. An Event of Default shall exist
          under this Note if any one of the following occurs:

|(a) | The Maker shall fail to make any payment when due under this Note (including
          any payment due by reason of acceleration) and such failure shall continue for a
          period of five days after the Payee shall have given the Maker written notice of
          such failure.
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|(b) | Dissolution, liquidation, business failure of the Maker or any guarantor of
          this Note, appointment of a liquidator or receiver for any of the property of
          the Maker or any guarantor of this Note, assignment for the benefit of creditors
          by the Maker or any guarantor of this Note, or the commencement of any case or
          proceeding under any bankruptcy or insolvency laws by or against the Maker or
          any guarantor of this Note, or failure of the Maker or any guarantor generally
          to pay its debts when they become due.
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Upon the occurrence and at any time
during the continuance of any Event of Default, the Payee, by written notice to the Maker,
may declare the entire unpaid principal balance of this Note and all accrued and unpaid
interest on this Note to be due and payable immediately, and upon any such declaration the
entire unpaid principal balance of this Note and all accrued and unpaid interest on this
Note shall become immediately due and payable, without the need for presentment, demand
for payment, protest, notice of dishonor or protest or any other notice of any kind, all
of which are expressly waived by the Maker.

9.    
          Collection Expenses. If this Note is placed in the hands of an attorney for
          collection, or is collected in whole or in part by suit or through bankruptcy
          proceedings or other legal proceedings of any kind, the Maker agrees to pay, in
          addition to all other sums payable under this Note, all costs and expenses of
          collection and enforcement, including, but not limited to, reasonable
          attorneys fees.

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10.    
          Usury. It is the intent of the Payee in accepting this Note and the Maker in the
          execution of this Note to contract in strict compliance with applicable usury
          law. In furtherance of that intent, the Payee, by accepting this Note, and the
          Maker stipulate and agree that none of the terms and provisions contained in
          this Note, or in any other agreement by the Maker in favor of the Payee, shall
          ever be construed to create a contract to pay for the use, forbearance or
          detention of money, or interest, at a rate in excess of the maximum non-usurious
          interest rate permitted to be charged by applicable law.

Neither the Maker nor any guarantors,
endorsers or other parties now or in the future becoming liable for payment of this Note
shall be required to pay interest on the Note, or on any other agreement by the Maker in
favor of the Payee, at a rate in excess of the maximum non-usurious interest that may
lawfully be charged under applicable law, and the provisions of this Item 10 shall control
over all other provisions of this Note or any other agreement which may be in apparent
conflict with this Item 10.

The Payee, by its acceptance of this
Note, expressly disavows any intention to charge or collect excessive unearned interest or
finance charges in the event the maturity of this Note is accelerated. If the Payee shall
collect monies and/or any other thing of value deemed to constitute interest that would
increase the effective interest rate on this Note to a rate in excess of the maximum
non-usurious rate of interest permitted to be charged by applicable law (whether as a
result of acceleration of this Note, pre-payment, or otherwise), an amount equal to
interest in excess of the lawful rate shall, upon such determination, at the option of the
Payee, be either immediately returned to the Maker or credited against the principal
balance of this Note then outstanding, in which event any and all penalties of any kind
under applicable law as a result of such excess interest shall be inapplicable.

By execution of this Note, the Maker
acknowledges that it believes the indebtedness evidenced by this Note (and interest on
such indebtedness) to be non-usurious and agrees that if, at any time, the Maker should
have reason to believe the same is in fact usurious, it will give the Payee notice of such
condition and the Maker agrees that the Payee shall have 90 days after receipt of such
notice in which to make appropriate refund or other adjustment in order to correct such
condition if in fact such condition exists.

The term applicable law
as used in this Item 10 shall mean the internal laws of the State of Texas or the laws of
the United States, whichever laws provide for the lowest maximum non-usurious rate of
interest applicable to indebtedness similar to that represented by this Note, as such laws
now exist or may be changed or amended or come into effect in the future.

11.    
          Certain Waivers. The Maker and any guarantor, endorser or other surety with
          respect to this Note (collectively, the Obligors) and each of them
          (i) waive(s) presentment, diligence, protest, demand, notice of demand, notice
          of acceptance or reliance, notice of non-payment, notice of dishonor, notice of
          protest and all other notices to parties in connection with the delivery,
          acceptance, performance, default or enforcement of this Note, any endorsement or
          guaranty of this Note, or any collateral (if any); (ii) consent(s) to any and
          all delays, extensions, renewals or other modifications of this Note or the debt
          evidenced by this Note, any waivers of any term of this Note, any subordination
          of the debt evidenced by this Note, or any collateral, any impairment of any
          collateral, and any failure to act by the Payee or any other forbearance or
          indulgence shown by the Payee, from time to time and in one or more instances
          (without notice to or assent from any of the Obligors) and agree(s) that none of
          the foregoing shall release, discharge or otherwise impair any of their
          liabilities; (iii) agree(s) that the full or partial release or discharge of any
          Obligor shall not release, discharge or otherwise impair the liabilities of any
          other Obligor(s); and (iv) waive(s) any defenses based on surety-ship or
          impairment of collateral.

12.    
          Security. This Note shall be secured by a first security interest in certain
          assets of Maker and a subordinated security interest in the assets of PDX
          Drilling I, LLC (Providence), as evidenced by a Deed of Trust by and
          among Payee, Maker and a designated trustee, by a Amended and Restated Security
          Agreement by and between Payee and Maker and a Security Agreement by and between
          Payee and Providence. In addition, this Note shall be guaranteed by Providence,
          as evidenced by a Guaranty Agreement which secures certain assets of said
          guarantor to ensure payment in full of the Note and accrued interest.

13.    
          Governing Law. THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN
          ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS, U.S.A., WITHOUT REGARD TO ITS
          RULES PERTAINING TO CONFLICTS OF LAWS.

14.    
          Replacement Note. This Note amends, restates and replaces (but does not
          constitute payment or satisfaction of) the Promissory Note Dated December 1,
          2005 previously executed by the Maker to the order of Payee.

IN WITNESS WHEREOF, the Maker has
executed and delivered this Note as of the date set forth above.

Maker:

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