EXHIBIT 3.1


                                    RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                           PATTERSON-UTI ENERGY, INC.

           (Originally incorporated on October 14, 1993 under the name
                            Patterson Energy, Inc.)

         FIRST: The name of the Corporation is Patterson-UTI Energy, Inc.

         SECOND: The address of the Corporation's registered office in the State
of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of
Wilmington, County of New Castle. The name of its registered agent at such
address is The Corporation Trust Company.

         THIRD: The nature of the business or purposes to be conducted or
promoted are to engage in any lawful act or activity for which corporations may
be organized under the General Corporation Law of the State of Delaware.

         FOURTH: The total number of shares of stock that the Corporation shall
have authority to issue is two hundred one million (201,000,000) shares, of
which two hundred million (200,000,000) shares shall be Common Stock, having a
par value of $0.01 per share, and one million (1,000,000) shares shall be
Preferred Stock, having a par value of $0.01 per share. The shares of such
classes of stock shall have the following express terms:


Section 1.  PREFERRED STOCK

         1.1 Authority of the Board of Directors to Create Series. The Board of
Directors is hereby expressly granted authority, to the full extent now or
hereafter permitted herein and by the General Corporation Law of the State of
Delaware, at any time or from time to time, by resolution or resolutions, to
create one or more series of Preferred Stock, to fix the authorized number of
shares of any series (which number of shares may vary as between series and be
changed from time to time by like action), and to fix the terms of such series,
including, but not limited to, the following:

                  (a) the designation of such series, which may be by
                  distinguishing number, letter, or title;

                  (b) the rate or rates at which shares of such series shall be
                  entitled to receive dividends; the periods in respect of which
                  dividends are payable; the conditions upon, and times of
                  payment of, such dividends; the relationship and preference,
                  if any, of such dividends to dividends payable on any other
                  class or classes or any other series of stock; whether such
                  dividends shall be cumulative and, if cumulative, the date or
                  dates from which such dividends




                  shall accumulate; and the other terms and conditions
                  applicable to dividends upon shares of such series;

                  (c) the rights of the holders of the shares of such series in
                  case the Corporation be liquidated, dissolved or wound up
                  (which may vary depending upon the time, manner, or voluntary
                  or involuntary nature or other circumstances of such
                  liquidation, dissolution, or winding up) and the relationship
                  and preference, if any, of such rights to rights of holders of
                  shares of stock of any other class or classes or any other
                  series of stock;

                  (d) the right, if any, of the Corporation to redeem shares of
                  such series at its option, including any limitation of such
                  right, and the amount or amounts to be payable in respect of
                  the shares of such series in case of such redemption (which
                  may vary depending on the time, manner, or other circumstances
                  of such redemption), and the manner, effect, and other terms
                  and conditions of any such redemption;

                  (e) the obligation, if any, of the Corporation to purchase,
                  redeem, or retire shares of such series and/or to maintain a
                  fund for such purpose, and the amount or amounts to be payable
                  from time to time for such purpose or into such fund, or the
                  number of shares to be purchased, redeemed, or retired, the
                  per share purchase price or prices, and the other terms and
                  conditions of any such obligation or obligations;

                  (f) the voting rights, if any, which, if granted, may be full,
                  special, or limited, to be given the shares of such series,
                  including, without limiting the generality of the foregoing,
                  the right, if any, as a series or in conjunction with other
                  series or classes, to elect one or more members of the Board
                  of Directors either generally or at certain times or under
                  certain circumstances, and restrictions, if any, on particular
                  corporate acts without a specified vote or consent of holders
                  of such shares (such as, among others, restrictions on
                  modifying the terms of such series or of the Preferred Stock,
                  restricting the permissible terms of other series or the
                  permissible variations between series of the Preferred Stock,
                  authorizing or issuing additional shares of the Preferred
                  Stock, creating debt, or creating any class of stock ranking
                  prior to or on a parity with the Preferred Stock or any series
                  thereof as to dividends, or assets remaining for distribution
                  to the stockholders in the event of the liquidation,
                  dissolution, or winding up of the Corporation);

                  (g) the right, if any, to exchange or convert the shares into
                  shares of any other series of the Preferred Stock or into
                  shares of


                                                                               2



                  any other class of stock of the Corporation or the securities
                  of any other corporation, and the rate or basis, time, manner,
                  terms, and conditions of exchange or conversion or the method
                  by which the same shall be determined; and

                  (h) the other special powers, preferences, or rights, if any,
                  and the qualifications, limitations, or restrictions thereof,
                  of the shares of such series.

         The Board of Directors shall fix the terms of each such series by
resolution or resolutions adopted at any time prior to the issuance of the
shares thereof, and the terms of each such series may, subject only to
restrictions, if any, imposed by this Certificate of Incorporation or by
applicable law, vary from the terms of other series to the extent determined by
the Board of Directors from time to time and provided in the resolution or
resolutions fixing the terms of the respective series of the Preferred Stock.

         1.2 Status of Certain Shares. Shares of any series of the Preferred
Stock, whether provided for herein or by resolution or resolutions of the Board
of Directors, which have been redeemed (whether through the operation of a
sinking fund or otherwise) or which, if convertible or exchangeable, have been
converted into or exchanged for shares of stock of any other class or classes,
or which have been purchased or otherwise acquired by the Corporation, shall
have the status of authorized and unissued shares of the Preferred Stock of the
same series and may be reissued as a part of the series of which they were
originally a part or may be reclassified and reissued as part of a new series of
the Preferred Stock to be created by resolution or resolutions of the Board of
Directors or as a part of any other series of the Preferred Stock, all subject
to the conditions or restrictions on issuance set forth herein or in the
resolution or resolutions adopted by the Board of Directors providing for the
issue of any series of the Preferred Stock.

Section 2. COMMON STOCK

         2.1 Issuance, Consideration, and Terms. Any unissued shares of the
Common Stock may be issued from time to time for such consideration, having a
value of not less than the par value thereof, as may be fixed from time to time
by the Board of Directors. Any treasury shares may be disposed of for such
consideration as may be determined from time to time by the Board of Directors.
The Common Stock shall be subject to the express terms of the Preferred Stock
and any series thereof. Each share of Common Stock shall be of equal rank and
shall be identical to every other share of Common Stock. Holders of Common Stock
shall have such rights as are provided herein and by law.

         2.2 Voting Rights. Except as expressly required by law or as provided
in or fixed and determined pursuant to Section 1 of this Article FOURTH, the
entire voting power and all voting rights shall be vested exclusively in the
Common Stock. Each holder of shares of Common Stock shall be entitled to one (1)
vote for each share standing in such holder's name on the books of the
Corporation.


                                                                               3



         2.3 Dividends. Subject to Section 1 of this Article FOURTH, the holders
of Common Stock shall be entitled to receive, and shall share equally share for
share, when and as declared by the Board of Directors, out of the assets of the
Corporation which are by law available therefor, dividends or distributions
payable in cash, in property, or in securities of the Corporation.

         FIFTH: The Board of Directors is authorized to make, alter, or repeal
the Bylaws of the Corporation.

         SIXTH: Meetings of stockholders shall be held at such place, within or
without the State of Delaware, as may be designated by or in the manner provided
in the Bylaws, or, if not so designated, at the registered office of the
Corporation in the State of Delaware. Elections of directors need not be by
written ballot unless and to the extent that the Bylaws so provide.

         SEVENTH: Special meetings of the stockholders of the Corporation for
any purpose or purposes may be called at any time by the Board of Directors (or
a majority of the members thereof) of the Corporation by action at a meeting, a
majority of the members of the Board of Directors of the Corporation acting
without a meeting, the Chief Executive Officer of the Corporation, the President
of the Corporation or the holders of a majority of the issued and outstanding
stock of the Corporation entitled to be voted at such special meeting. Such
special meetings may not be called by any other person or persons or in any
other manner.

         EIGHTH: The Corporation reserves the right to amend, alter, or repeal
any provision contained in this Certificate of Incorporation in the manner now
or hereafter prescribed by statute, and all rights of stockholders herein are
subject to this reservation.

         NINTH: To the fullest extent permitted by the General Corporation Law
of the State of Delaware, as the same exists or may hereafter be amended, a
director of the Corporation shall not be liable to the Corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director.

         TENTH: Any action required or permitted to be taken by the holders of
the stock of the Corporation entitled to vote in the election of directors must
be effected at a duly called annual meeting or special meeting of such holders
and may not be effected by any consent in writing by such holders.

         ELEVENTH: Whenever a compromise or arrangement is proposed between the
Corporation and its creditors or any class of them and/or between the
Corporation and its stockholders or any class of them, any court of equitable
jurisdiction within the State of Delaware may, on the application in a summary
way of the Corporation or of any creditor or stockholder thereof or on the
application of any receiver or receivers appointed for the Corporation under the
provisions of Section 291 of Title 8 of the Delaware Code or on the application
of trustees in dissolution or of any receiver or receivers appointed for the
Corporation under the provisions of Section 279 of Title 8 of the Delaware Code
order a meeting of the creditors or class of creditors, and/or of the
stockholders or class of

                                                                               4



stockholders of the Corporation, as the case may be, to be summoned in such
manner as the said court directs. If a majority in number representing
three-fourths in value of the creditors or class of creditors, and/or of the
stockholders or class of stockholders of the Corporation, as the case may be,
agree to any compromise or arrangement and to any reorganization of the
Corporation as a consequence of such compromise or arrangement, the said
compromise or arrangement and the said reorganization shall, if sanctioned by
the court to which the said application has been made, be binding on all the
creditors or class of creditors, and/or on all the stockholders or class of
stockholders, of the Corporation, as the case may be, and also on the
Corporation.

         This Restated Certificate of Incorporation of Patterson-UTI Energy,
Inc. (i) was duly adopted by the Board of Directors of Patterson-UTI Energy,
Inc., without a vote of the stockholders, in accordance with Section 245 of the
Delaware General Corporation Law, (ii) only restates and integrates and does not
further amend the provisions of the Certificate of Incorporation of
Patterson-UTI Energy, Inc., as heretofore amended; and there is no discrepancy
between those provisions and the provisions of this Restated Certificate of
Incorporation.

         Dated this 8th day of May, 2001.


                                                  /s/ A. Glenn Patterson
                                                  -----------------------------
                                                  A. Glenn Patterson, President

                                                                               5

                            CERTIFICATE OF CORRECTION

                                       OF

                      RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                           PATTERSON-UTI ENERGY, INC.



         Pursuant to the provisions of Section 103(f) of the Delaware General
Corporation Law, Patterson-UTI Energy, Inc., a Delaware corporation (the
"Company"), adopts the following Certificate of Correction:

         FIRST: On May 8, 2001, the Company filed with the Secretary of State of
the State of Delaware a Restated Certificate of Incorporation dated May 8, 2001
(the "Restated Certificate of Incorporation"). The Restated Certificate of
Incorporation is an inaccurate record of the corporate action therein
referenced, as Section 1 of Article FOURTH thereof captioned "Preferred Stock"
failed to include a reference to the Series A Participating Preferred Stock
created by the Board of Directors of the Company through the filing of a
Certificate of Designation of the Company with the Secretary of State of the
State of Delaware on January 13, 1997.

         SECOND: Subsection 1.1 of Section 1 of Article FOURTH is corrected by
adding the following paragraph to the end of Subsection 1.1 thereof:

                  Pursuant to authority conferred by this Article FOURTH upon
         the board of directors of the Corporation, the board of directors
         created a series of 100,000 shares of preferred stock designated Series
         A Participating Preferred Stock by filing a Certificate of Designation
         of the Corporation with the Secretary of State of the State of Delaware
         (the "Secretary of State") on January 13, 1997, and the voting powers,
         designations, preferences and relative, participating, optional or
         other special rights, and the qualifications, limitations or
         restrictions thereof, of the Corporation's Series A Participating
         Preferred Stock are set forth on Annex A hereto and are incorporated
         herein by reference.




         IN WITNESS WHEREOF, the Company has caused this Certificate of
Correction to be signed by its duly authorized officer as of the 19th day of
November, 2001.

                                PATTERSON-UTI ENERGY, INC.



                                By:  /s/ Jonathan D. Nelson
                                    ------------------------------------------
                                     Jonathan D. Nelson
                                     Vice President - Finance, Chief Financial
                                     Officer, Secretary and Treasurer


                                       2

                                                                         ANNEX A

                           Certificate of Designation

                                       of

                      Restated Certificate of Incorporation

                                       of

                             Patterson Energy, Inc.


It is hereby certified that:

         1. The name of the corporation is Patterson Energy, Inc. (hereinafter
called the "Corporation");

         2. The Restated Certificate of Incorporation of the Corporation (the
"Restated Certificate of Incorporation"), is hereby amended so that the
designation and number of shares of the class and series acted upon in the
following resolution and the relative rights, preferences and limitations of
such class and series, are as stated in such resolution; and

         3. The following resolution was duly adopted by the Board of Directors
of the Corporation as required by Section 151 of the Delaware General
Corporation Law at a meeting duly called and held on January 2, 1997;

         RESOLVED, that pursuant to the authority granted to and vested in the
Board of Directors of this Corporation in accordance with the provisions of the
Restated Certificate of Incorporation, the Board of Directors hereby creates a
series of Series A Preferred Stock, $.01 par value, of the Corporation and
hereby states the designation and number of shares, and fixes the relative
rights, preferences and limitations thereof (in addition to the provisions set
forth in the Restated Certificate of Incorporation which are applicable to the
Preferred Stock of all classes and series) as follows:

         Section 1. Designation, Par Value and Amount. The shares of such series
shall be designated as "Series A Participating Preferred Stock" (hereinafter
referred to as "Series A Participating Preferred Stock"), the shares of such
series shall be without par value, and the number of shares constituting such
series shall be 100,000; provided, however, that, if more than a total of
100,000 shares of Series A Participating Preferred Stock shall be issuable upon
the exercise of Rights (the "Rights") issued pursuant to the Rights Agreement,
dated as of January 2, 1997, between the Corporation and Continental Stock
Transfer & Trust Company, a New York corporation, as Rights Agent (as amended
from time to time) (the "Rights Agreement"), the Board of Directors of the
Corporation, pursuant to Section 151 of the Delaware General Corporation Law,
shall direct by resolution or resolutions that a certificate be properly
executed, acknowledged and filed providing for the total number of shares of
Series A Participating Preferred Stock authorized to be issued to be increased
(to the extent that the Restated Certificate




of Incorporation then permits) to the largest number of whole shares (rounded up
to the nearest whole number) issuable upon exercise of the Rights.

         Section 2. Dividends and Distributions.

         (A) Subject to the prior and superior rights of the holders of any
shares of any series of Preferred Stock ranking prior and superior to the shares
of Series A Participating Preferred Stock with respect to dividends, the holders
of shares of Series A Participating Preferred Stock shall be entitled to
receive, when, as and if declared by the Board of Directors out of assets
legally available for the purpose, quarterly dividends payable in cash on the
last business day of March, June, September and December in each year (each such
date being referred to herein as a "Quarterly Dividend Payment Date"),
commencing on the first Quarterly Dividend Payment Date after the first issuance
of a share or fraction of a share of Series A Participating Preferred Stock, in
an amount per share (rounded to the nearest cent) equal to the greater of (a)
$.01 or (b) subject to the provision for adjustment hereinafter set forth, 100
times the aggregate per share amount of all cash dividends, and 100 times the
aggregate per share amount (payable in kind) of all non-cash dividends or other
distributions (other than a dividend payable in shares of Common Stock, par
value $.01 per share, of the Corporation (the "Common Stock") or a subdivision
of the outstanding shares of Common Stock by reclassification or otherwise)
declared on the Common Stock since the immediately preceding Quarterly Dividend
Payment Date, or, with respect to the first Quarterly Dividend Payment Date,
since the first issuance of any share or fraction of a share of Series A
Participating Preferred Stock.

         (B) The Corporation shall declare a dividend or distribution on the
Series A Participating Preferred Stock as provided in paragraph (A) above
immediately after it declares a dividend or distribution on the Common Stock
(other than a dividend payable in shares of Common Stock); provided that, in the
event no dividend or distribution shall have been declared on the Common Stock
during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $.01 per share on the
Series A Participating Preferred Stock shall nevertheless be payable on such
subsequent Quarterly Dividend Payment Date.

         (C) Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Participating Preferred Stock from the Quarterly Dividend
Payment Date next preceding the date of issue of such shares of Series A
Participating Preferred Stock, unless the date of issue of such shares is prior
to the record date for the first Quarterly Dividend Payment Date, in which case
dividends on such shares shall begin to accrue from the date of issue of such
shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a
date after the record date for the determination of holders of shares of Series
A Participating Preferred Stock entitled to receive a quarterly dividend and
before such Quarterly Dividend Payment Date, in either of which events such
dividends shall begin to accrue and be cumulative from such Quarterly Dividend
Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends
paid on the shares of Series A Participating Preferred Stock in an amount less
than the total amount of such dividends at the time accrued and payable on such
shares shall be allocated pro rata on a share-by-share basis among all such
shares at the time outstanding. The Board of Directors may fix a record date for
the determination of holders of shares of Series A Participating Preferred Stock
entitled to receive payment of a dividend or distribution declared

                                       2

thereon, which record date shall be not more than 15 days prior to the date
fixed for the payment thereof.

         Section 3. Voting Rights. The holders of shares of Series A
Participating Preferred Stock shall have the following voting rights:

         (A) Except as provided in paragraph C of this Section 3 and subject to
the provision for adjustment hereinafter set forth, each share of Series A
Participating Preferred Stock shall entitle the holder thereof to 100 votes on
all matters submitted to a vote of the stockholders of the Corporation.

         (B) Except as otherwise provided herein or by law, the holders of
shares of Series A Participating Preferred Stock and the holders of shares of
Common Stock shall vote together as one class on all matters submitted to a vote
of stockholders of the Corporation.

         (C) (i) If, on the date used to determine stockholders of record for
any meeting of stockholders for the election of directors, a default in
preference dividends (as defined in subparagraph (v) below) on the Series A
Participating Preferred Stock shall exist, the holders of the Series A
Participating Preferred Stock shall have the right, voting as a class as
described in subparagraph (ii) below, to elect two directors (in addition to the
directors elected by holders of Common Stock of the Corporation). Such right may
be exercised (a) at any meeting of stockholders for the election of directors or
(b) at a meeting of the holders of shares of Voting Preferred Stock (as
hereinafter defined), called for the purpose in accordance with the By-laws of
the Corporation, until all such cumulative dividends (referred to above) shall
have been paid in full or until noncumulative dividends have been paid regularly
for at least one year.

                  (ii) The right of the holders of Series A Participating
         Preferred Stock to elect two directors, as described above, shall be
         exercised as a class concurrently with the rights of holders of any
         other series of Preferred Stock upon which voting rights to elect such
         directors have been conferred and are then exercisable. The Series A
         Participating Preferred Stock and any additional series of Preferred
         Stock which the Corporation may issue and which may provide for the
         right to vote with the foregoing series of Preferred Stock are
         collectively referred to herein as "Voting Preferred Stock."

                  (iii) Each director elected by the holders of shares of Voting
         Preferred Stock shall be referred to herein as a "Preferred Director."
         A Preferred Director so elected shall continue to serve as such
         director for a term of one year, except that upon any termination of
         the right of all of such holders to vote as a class for Preferred
         Directors, the term of office of such directors shall terminate. Any
         Preferred Director may be removed by, and shall not be removed except
         by the vote of the holders of record of a majority of the outstanding
         shares of Voting Preferred Stock then entitled to vote for the election
         of directors. present (in person or by proxy) and voting together as a
         single class (a) at a meeting of the stockholders, or (b) at a meeting
         of the holders of shares of such Voting Preferred Stock, called for the
         purpose in accordance with the By-laws of the Corporation, or (c) by
         written consent signed by the holders of a majority of the then

                                       3

         outstanding shares of Voting Preferred Stock then entitled to vote for
         the election of directors, taken together as a single class.

                  (iv) So long as a default in any preference dividends on the
         Series A Participating Preferred Stock shall exist or the holders of
         any other series of Voting Preferred Stock shall be entitled to elect
         Preferred Directors, (a) any vacancy in the office of a Preferred
         Director may be filled (except as provided in the following clause (b))
         by an instrument in writing signed by the remaining Preferred Director
         and filed with the Corporation and (b) in the case of the removal of
         any Preferred Director, the vacancy may be filled by the vote or
         written consent of the holders of a majority of the outstanding shares
         of Voting Preferred Stock then entitled to vote for the election of
         directors, present (in person or by proxy) and voting together as a
         single class, at such time as the removal shall be effected. Each
         director appointed as aforesaid by the remaining Preferred Director
         shall be deemed, for all purposes hereof, to be a Preferred Director.
         Whenever (x) no default in preference dividends on the Series A
         Participating Preferred Stock shall exist and (y) the holders of other
         series of Voting Preferred Stock shall go longer be entitled to elect
         such Preferred Directors, then the number of directors constituting the
         Board of Directors of the Corporation shall be reduced by two.

                  (v) For purposes hereof, a "default in preference dividends"
         on the Series A Participating Preferred Stock shall be deemed to have
         occurred whenever the amount of cumulative and unpaid dividends on the
         Series A Participating Preferred Stock shall be equivalent to six full
         quarterly dividends or more (whether or not consecutive), and, having
         so occurred, such default shall be deemed to exist thereafter until,
         but only until, all cumulative dividends on all shares of the Series A
         Participating Preferred Stock then outstanding shall have been paid
         through the last Quarterly Dividend Payment Date or until, but only
         until, non-cumulative dividends have been paid regularly for at least
         one year.

         (E) Except as set forth herein (or as otherwise required by applicable
law), holders of Series A Participating Preferred Stock shall have no general or
special voting rights and their consent shall not be required for taking any
corporate action.

         Section 4. Certain Restrictions.

         (A) Whenever quarterly dividends or other dividends or distributions
payable on the Series A Participating Preferred Stock as provided in Section 2
are in arrears, thereafter and until all accrued and unpaid dividends and
distributions, whether or not declared, on shares of Series A Participating
Preferred Stock outstanding shall have been paid in full, the Corporation shall
not

                  (i) declare or pay dividends, or make any other distributions,
         on any shares of stock ranking junior (either as to dividends or upon
         liquidation, dissolution or winding up) to the Series A Participating
         Preferred Stock;

                  (ii) declare or pay dividends, or make any other
         distributions, on any shares of stock ranking on a parity (either as to
         dividends or upon liquidation, dissolution

                                       4

         or winding up) with the Series A Participating Preferred Stock, except
         dividends paid ratably on the Series A Participating Preferred Stock
         and all such parity stock on which dividends are payable or in arrears
         in proportion to the total amounts to which the holders of all such
         shares are then entitled;

                  (iii) redeem or purchase or otherwise acquire for
         consideration (except as provided in (iv) below) shares of any stock
         ranking junior (either as to dividends or upon liquidation, dissolution
         or winding up) to the Series A Participating Preferred Stock, provided
         that the Corporation may at any time redeem, purchase or otherwise
         acquire shares of any such junior stock in exchange for shares of any
         stock of the Corporation ranking junior (either as to dividends or upon
         dissolution, liquidation or winding up) to the Series A Participating
         Preferred Stock;

                  (iv) redeem or purchase or otherwise acquire for consideration
         any shares of Series A Participating Preferred Stock, or any shares of
         stock ranking on a parity (either as to dividends or upon liquidation,
         dissolution or winding up) with the Series A Participating Preferred
         Stock, except in accordance with a purchase offer made in writing or by
         publication (as determined by the Board of Directors) to all holders of
         such shares upon such terms as the Board of Directors, after
         consideration of the respective annual dividend rates and other
         relative rights and preferences of the respective series and classes,
         shall determine in good faith will result in fair and equitable
         treatment among the respective series or classes.

         (B) The Corporation shall not permit any subsidiary of the Corporation
to purchase or otherwise acquire for consideration any shares of stock of the
Corporation unless the Corporation could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

         Section 5. Reacquired Shares. Any shares of Series A Participating
Preferred Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall he retired and cancelled promptly after the acquisition
thereof. All such shares shall upon their cancellation become authorized but
unissued shares of Preferred Stock and may be reissued as part of a new series
of Preferred Stock subject to the conditions and restrictions on issuance set
forth herein, in the Restated Certificate of Incorporation. in any other
Certificate of Designation creating a series of Preferred Stock or as otherwise
required by law.

         Section 6. Liquidation, Dissolution or Winding Up.

         (A) Subject to the prior and superior rights of holders of any shares
of any series of Preferred Stock ranking prior and superior to the shares of
Series A Participating Preferred Stock with respect to rights upon liquidation,
dissolution or winding up (voluntary or otherwise), no distribution shall be
made to the holders of shares of stock ranking junior (either as to dividends or
upon liquidation, dissolution or winding up) to the Series A Participating
Preferred Stock unless, prior thereto, the holders of shares of Series A
Participating Preferred Stock shall have received $1.00 per share, plus an
amount equal to accrued and unpaid dividends and distributions thereon, whether
or not declared, to the date of such payment (the "Series A Liquidation
Preference"). Following the payment of the full amount of the Series A
Liquidation

                                       5

Preference, no additional distributions shall be made to the holders of shares
of Series A Participating Preferred Stock unless, prior thereto, the holders of
shares of Common Stock shall have received an amount per share (the "Capital
Adjustment") equal to the quotient obtained by dividing (i) the Series A
Liquidation Preference by (ii) 100 (the "Adjustment Number"). Following the
payment of the full amount of the Series A Liquidation Preference and the
Capital Adjustment in respect of all outstanding shares of Series A
Participating Preferred Stock and Common Stock, respectively, holders of Series
A Participating Preferred Stock and holders of Common Stock shall receive their
ratable and proportionate share of the remaining assets to be distributed in the
ratio of the Adjustment Number to 1 with respect to such Preferred Stock and
Common Stock, on a per share basis, respectively.

         (B) In the event, however, that there are not sufficient assets
available to permit payment in full of the Series A Liquidation Preference and
the liquidation preferences of all other series of preferred stock, if any,
which rank on a parity with the Series A Participating Preferred Stock, then
such remaining assets shall be distributed ratably to the holders of Series A
Participating Preferred Stock and the holders of such parity shares in
proportion to their respective liquidation preferences. In the event, however,
that there are not sufficient assets available to permit payment in full of the
Capital Adjustment, then such remaining assets shall be distributed ratably to
the holders of Common Stock.

         Section 7. Consolidation, Merger, etc. In case the Corporation shall
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case the shares of
Series A Participating Preferred Stock shall at the same time be similarly
exchanged or changed in an amount per share (subject to the provision for
adjustment hereinafter set forth) equal to 100 times the aggregate amount of
stock, securities, cash and/or any other property (payable in kind), as the case
may be, into which or for which each share of Common Stock is changed or
exchanged.

         Section 8. No Redemption. The shares of Series A Participating
Preferred Stock shall not be redeemable.

         Section 9. Ranking. The Series A Participating Preferred Stock shall
rank junior to all other series of the Corporation's Preferred Stock as to the
payment of dividends and the distribution of assets, unless the terms of any
such series shall provide otherwise.

         Section 10. Amendment. The Restated Certificate of Incorporation of the
Corporation shall not be further amended in any manner which would materially
alter or change the powers, preferences or special rights of the Series A
Participating Preferred Stock so as to affect them adversely without the
affirmative vote of the holders of a majority or more of the outstanding shares
of Series A Participating Preferred Stock, voting separately as a class.



                                       6

         IN WITNESS WHEREOF, this Certificate of Designation is executed on
behalf of the Corporation by its Chairman of the Board and attested by its
Secretary as of January 10, 1997.



                                       /s/  Cloyce A. Talbott
                                       --------------------------------
                                       Cloyce A. Talbott, Chairman and
                                       Chief Executive Officer




Attest:


/s/  James C. Brown
- -----------------------------
James C. Brown
Vice President - Finance



                                       7

                     AMENDMENT TO CERTIFICATE OF DESIGNATION

                                       OF

                      RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                           PATTERSON-UTI ENERGY, INC.



                  It is hereby certified that pursuant to authority granted to
and vested in the Board of Directors of the Corporation by the provisions of the
Restated Certificate of Incorporation of the Corporation, the Board of Directors
of the Corporation has duly adopted the following resolutions relating to an
amendment to the Certificate of Designation filed with the Delaware Secretary of
State on January 13, 1997 and subsequently filed as Annex A to the Certificate
of Correction of the Restated Certificate of Incorporation of the Corporation
filed on November 20, 2001:

                  1. RESOLVED, that the Certificate of Designation of the
Corporation filed by the Corporation with the Secretary of State of the State of
Delaware on January 13, 1997 and attached as Annex A to the Certificate of
Correction of the Restated Certificate of Incorporation filed on November 20,
2001, relating to the Series A Participating Preferred Stock of the Corporation
is hereby amended as follows:

                  (A) The number "100" appearing in the tenth and eleventh lines
of Section 2(A) is hereby changed in each instance to the number "1,000;"

                  (B) The number "100" appearing in the third line of Section
3(A) is hereby changed to the number "1,000;"

                  (C) The dollar number "$1.00" appearing in the seventh line of
Section 6(A) is hereby changed to the dollar number "$100" and the number "100"
appearing in the thirteenth line of Section 6(A) is hereby changed to the number
"1,000."

                  (D) The number "100" appearing in the sixth line of Section 7
is hereby changed to the number "1,000."

                  2. No shares of Series A Participating Preferred Stock of the
Corporation have been issued or are outstanding.

                  FURTHER RESOLVED, that the Certificate of Designation filed on
January 13, 1997, as amended pursuant to the foregoing resolution, is hereby
ratified and approved;

                  AND BE IT FURTHER RESOLVED, that the proper officers of the
Corporation be and each of them hereby is authorized to execute an amendment to
the Certificate of Designation of Restated Certificate of Incorporation pursuant
to the applicable section of the General Corporation Law of the State of
Delaware and to take all appropriate action to cause that amendment to the
certificate to be filed, recorded and become effective in accordance with
Section 103 of the General Corporation Law of the State of Delaware.


                  IN WITNESS WHEREOF, this Amendment to Certificate of
Designation has been executed effective as of this 20th day of November, 2001.




                                     /s/ Jonathan D. Nelson
                                    ------------------------------------------
                                    Jonathan D. Nelson
                                    Vice President - Finance, Chief Financial
                                    Officer, Secretary and Treasurer







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