Exhibit 10.2

SECOND AMENDMENT TO THE
PATTERSON-UTI ENERGY, INC. 2005 LONG-TERM INCENTIVE PLAN

THIS AGREEMENT is by Patterson-UTI Energy, Inc. (the “Sponsor”),

W I T N E S S E T H:

WHEREAS, the Sponsor maintains the Plan known as the “Patterson-UTI Energy, Inc.
2005 Long-Term Incentive Plan” (the “Plan”); and

WHEREAS, the Sponsor retained the right in Section 12.1 of the Plan to amend the
Plan from time to time; and

WHEREAS, the Board of Directors of the Sponsor approved resolutions on April 10,
2008 to amend the Plan;

NOW, THEREFORE, the Sponsor agrees that, effective as of, and contingent upon,
the approval of the Company’s stockholders of the First Amendment to the
Patterson-UTI Energy, Inc. 2005 Long-Term Incentive Plan, the Plan is hereby
amended as follows:

1. Section 3.1(a) of the Plan is hereby amended and restated in its entirety as
follows:

3.1 Number of Shares. (a)  Subject to adjustment as provided in Section 12.2 and
this Section 3.1, the total number of Shares authorized for grant under the Plan
shall be 10,250,000, reduced by the total number of Shares subject to any
options or awards granted under the Prior Plans during the period commencing on
January 1, 2005 and ending on the effective date of this Plan (the
“Pre-Effective Period”). Any Shares that are subject to Awards of Options or
Stock Appreciation Rights, whether granted under this Plan or a Prior Plan
during the Pre-Effective Period, shall be counted against this limit as one
(1) Share for every one (1) Share granted. Any Shares that are subject to Awards
other than Options or Stock Appreciation Rights, whether awarded under this Plan
prior to June 5, 2008 or a Prior Plan during the Pre-Effective Period, shall be
counted against this limit as one and six tenths (1.6) Shares for every one
(1) Share awarded. Any Shares that are subject to Awards other than Options or
Stock Appreciation Rights awarded under this Plan on or after June 5, 2008 shall
be counted against this limit as two (2) Shares for every one (1) Share awarded.
In connection with the granting of a Performance Unit denominated in dollars,
the number of Shares that shall be counted against this limit shall be an amount
equal to the quotient of (i) the dollar amount in which the Performance Unit is
denominated, divided by (ii) the Fair Market Value of a Share on the date the
Performance Unit is granted.

2. Section 3.1(d) of the Plan is hereby amended and restated in its entirety as
follows:

(d) Any Shares that again become available for grant pursuant to this Article
shall be added back as (x) one (1) Share if such Shares were subject to Options
or Stock Appreciation Rights granted under the Plan or options or stock
appreciation rights granted under the Prior Plans, (y) as one and six tenths
(1.6) Shares if such Shares were subject to Awards other than Options or Stock
Appreciation Rights granted under the Plan that are forfeited, expire or
otherwise terminate prior to June 5, 2008 or (z) as two (2) Shares if such
Shares were subject to Awards other than Options or Stock Appreciation Rights
granted under the Plan that are forfeited, expire or otherwise terminate on or
after June 5, 2008.

Approved and Adopted by the Board of Directors April 10, 2008

Effective June 5, 2008