1) COMMITMENT INCREASE AND JOINDER AGREEMENT

Parties: PATTERSON UTI ENERGY INC | AMBAR LONE STAR FLUIDS SERVICES, LLC | BANK OF AMERICA, N.A.
Document Date: 8/4/2009
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

Parties: DJO FINANCE LLC | PATTERSON MEDICAL SUPPLY, Inc
Law Firm: Briggs Morgan
Document Date: 7/31/2009
Governing Law:Minnesota

3) PATTERSON COMPANIES, INC. Fiscal 2010 Incentive Plan

Parties: PATTERSON COMPANIES, INC.
Document Date: 6/24/2009
Industry: Medical Equipment and Supplies
Sector: Healthcare

4) CREDIT AGREEMENT

Parties: PATTERSON UTI ENERGY INC | AMEGY BANK, NATIONAL ASSOCIATION | BANK OF AMERICA, N.A. | BANK OF TOKYO-MITSUBISHI UFJ, LTD. | COMERICA BANK | HSBC BANK USA, NA | WELLS FARGO BANK, NA
Law Firm: Fulbright Jaworski
Document Date: 3/25/2009
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

5) CONSULTING AGREEMENT

Parties: VALOR ENERGY CORP | Gary Patterson & Associates
Document Date: 3/2/2009
Industry: Forestry and Wood Products
Sector: Basic Materials

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

Parties: PATTERSON UTI ENERGY INC
Document Date: 6/6/2008
Industry: Oil Well Services and Equipment
Sector: Energy

7) AMENDED AND RESTATED CREDIT AGREEMENT

8) AMENDMENT #1 TO EXECUTIVE EMPLOYMENT AGREEMENT

Parties: Segmentz, Inc | Mark Patterson
Document Date: 11/13/2007
Industry: Misc. Transportation
Sector: Transportation
Governing Law:Michigan

9) PATTERSON-UTI ENERGY, INC. CHANGE IN CONTROL AGREEMENT

Parties: PATTERSON-UTI ENERGY, INC
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

10) FIRST AMENDMENT TO CHANGE IN CONTROL AGREEMENT BETWEEN PATTERSON-UTI ENERGY, INC. AND KENNETH N. BERNS

Parties: PATTERSON UTI ENERGY INC
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

11) FIRST AMENDMENT TO CHANGE IN CONTROL AGREEMENT BETWEEN PATTERSON-UTI ENERGY, INC. AND JOHN E. VOLLMER III

Parties: PATTERSON-UTI ENERGY, INC
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

12) FIRST AMENDMENT TO CHANGE IN CONTROL AGREEMENT

Parties: PATTERSON UTI ENERGY INC
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

13) FIRST AMENDMENT TO CHANGE IN CONTROL AGREEMENT BETWEEN PATTERSON-UTI ENERGY, INC. AND MARK S. SIEGEL

Parties: PATTERSON UTI ENERGY INC
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

14) FIRST AMENDMENT TO CHANGE IN CONTROL AGREEMENT

Parties: PATTERSON-UTI ENERGY, INC. | DOUGLAS J. WALL
Document Date: 11/5/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

15) EMPLOYMENT AGREEMENT

Parties: PATTERSON UTI ENERGY INC
Law Firm: Fulbright Jaworski
Document Date: 9/24/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

16) AIRCRAFT TIME SHARING AGREEMENT

Parties: CERNER CORP /MO/ | Neal L. Patterson
Document Date: 2/9/2007
Industry: Computer Networks
Sector: Technology
Governing Law:Missouri

17) EMPLOYMENT AGREEMENT

Parties: BASIC ENERGY SERVICES INC | Thomas Monroe Patterson
Document Date: 1/4/2007
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

18) ASSET PURCHASE AGREEMENT

Parties: KEY ENERGY SERVICES INC | Key Energy Drilling, Inc | Key Energy Drilling Beneficial, L.P | Key Rocky Mountain, Inc. | Key Four Corners, Inc. | Patterson-UTI Drilling Company LP, LLLP | Patterson-UTI Energy, Inc.
Law Firm: Porter & Hedges, L.L.P.;Fulbright & Jaworski L.L.P.
Document Date: 10/19/2006
Industry: Oil Well Services and Equipment
Governing Law:Texas

19) EMPLOYMENT AGREEMENT

Parties: PATTERSON UTI ENERGY INC | A. Glenn Patterson
Document Date: 5/5/2006
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

20) CONTRACT TO PURCHASE LIMITED PARTNERSHIP INTERESTS

Parties: BAYFIELD LOW INCOME HOUSING LIMITED PARTNERSHIP | MPF BAYFIELD ACQUISITION, LLC | MACKENZIE PATTERSON FULLER, INC
Document Date: 11/17/2005
Governing Law:New York

21) DISTRIBUTORSHIP AGREEMENT

Parties: SCHICK TECHNOLOGIES INC | PATTERSON DENTAL COMPANY
Document Date: 11/9/2005
Industry: Medical Equipment and Supplies
Governing Law:Minnesota

22) EXHIBIT 10.1 AMENDED AND RESTATED EMPLOYMENT AGREEMENT

Parties: PRIME GROUP REALTY TRUST | Jeffrey A. Patterson | Prime Office Company, LLC
Law Firm: Vedder Price Kaufman & Kammholz, P.C;
Document Date: 11/9/2005
Industry: Real Estate Operations
Sector: Services
Governing Law:Illinois

23) AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT

Parties: STAKTEK HOLDINGS INC | W. Kirk Patterson
Document Date: 10/26/2005

24) ASSET PURCHASE AGREEMENT BY AND BETWEENPATTERSON SERVICES, INC. AND ALLIS-CHALMERS TUBULAR SERVICES, INC.

Parties: Allis Chalmers Energy Inc | PATTERSON SERVICES, INC. | ALLIS-CHALMERS TUBULAR SERVICES, INC.
Law Firm: Locke Liddell & Sapp LLP
Document Date: 9/8/2005
Governing Law:Texas

25) EMPLOYMENT AGREEMENT

Parties: AbilityOne Corporation | AbilityOne II, LLC | Patterson Dental Company | Retep, Inc, AbilityOne Products Corp
Law Firm: Vedder Price
Document Date: 8/9/2005
Industry: Medical Equipment and Supplies
Sector: Healthcare
Governing Law:Illinois

26) PATTERSON-UTI ENERGY, INC. 2005 LONG-TERM INCENTIVE PLAN

Parties: PATTERSON UTI ENERGY INC
Document Date: 6/21/2005
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Delaware

27) AMENDED AND RESTATED CREDIT AGREEMENT

28) TERMINATION AGREEMENT

Parties: PATTERSON UTI ENERGY INC
Document Date: 2/25/2005
Industry: Oil Well Services and Equipment

29) ASSET PURCHASE AGREEMENT

Parties: PATTERSON UTI ENERGY INC | Key Energy Drilling, Inc. | Key Energy Drilling beneficial, L.P. | Key rocky mountain, inc. | Key four corners, inc. | Key Energy Services, Inc. | Patterson-UTI Drilling Company LP, LLLP | Patterson-UTI Energy, Inc.
Document Date: 2/25/2005
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

30) Exhibit 2.1 ASSET PURCHASE AGREEMENT among Key Energy Drilling, Inc. Key Energy Drilling beneficial, L.P. Key rocky mountain, inc. Key four corners, inc. and Key Energy Services, Inc. and Patterson-UTI Drilling Company LP, LLLP and Patterson-UTI Energy, Inc. Dated as of December 7, 2004

Parties: Key Energy Drilling, Inc | Key Energy Services, Inc | KEY FOUR CORNERS, INC | KEY ROCKY MOUNTAIN, INC | Patterson (GP) LLC | Patterson-UTI Drilling Company LP | Patterson-UTI Energy, Inc
Law Firm: Porter Hedges;Fulbright Jaworski
Document Date: 2/25/2005
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

31) Summary Description of 2003 Cash Bonus Plan

Parties: PATTERSON UTI ENERGY INC
Document Date: 2/25/2005
Industry: Oil Well Services and Equipment

32) Summary Description of Director Compensation

Parties: PATTERSON UTI ENERGY INC
Document Date: 2/25/2005
Industry: Oil Well Services and Equipment

33) REGISTRATION RIGHTS AGREEMENT

Parties: MACKENZIE PATTERSON FULLER, INC | SUTTER HOLDING COMPANY, INC | William Knuff, III, Co-Chairman, Co
Law Firm: Kirkland Ellis
Document Date: 2/1/2005
Governing Law:California

34) EXECUTION COPY GUARANTY

Parties: MacKenzie Patterson Fuller, Inc | Sutter Holding Company, Inc
Law Firm: Kirkland Ellis
Document Date: 2/1/2005
Industry: Investment Services
Sector: Financial
Governing Law:California

35) EXECUTION COPY GUARANTY

Parties: MacKenzie Patterson Fuller, Inc | Sutter Holding Company, Inc
Law Firm: Kirkland Ellis
Document Date: 2/1/2005
Industry: Investment Services
Sector: Financial
Governing Law:California

36) EXECUTION COPY GUARANTY

Parties: MacKenzie Patterson Fuller, Inc | Sutter Holding Company, Inc
Law Firm: Kirkland Ellis
Document Date: 2/1/2005
Industry: Investment Services
Sector: Financial
Governing Law:California

37) GUARANTY

Parties: SUTTER HOLDING CO INC | William Knuff, III | MacKenzie Patterson Fuller, Inc.,
Law Firm: Kirkland & Ellis LLP
Document Date: 2/1/2005
Industry: Investment Services
Sector: Financial
Governing Law:California

38) GUARANTY

Parties: SUTTER HOLDING CO INC | MacKenzie Patterson Fuller, Inc | Robert Dixon
Law Firm: Kirkland & Ellis LLP
Document Date: 2/1/2005
Industry: Investment Services
Sector: Financial
Governing Law:California

39) EXHIBIT 2.1 ARTICLES OF MERGER AND PLAN OF MERGER OF PATTERSON DENTAL COMPANY AND PATTERSON COMPANIES, INC.

Parties: PATTERSON COMPANIES, INC. | PATTERSON DENTAL COMPANY
Document Date: 9/9/2004
Industry: Medical Equipment and Supplies
Sector: Healthcare

40) AGREEMENT AND PLAN OF MERGER

Parties: PATTERSON UTI ENERGY INC | PATTERSON-UTI ACQUISITION, LLC | TMBR/SHARP DRILLING, INC.
Law Firm: Fulbright & Jaworski L.L.P.; Lynch, Chappell & Alsup, P.C.; Haynes and Boone, LLP
Document Date: 2/12/2004
Industry: Oil Well Services and Equipment
Sector: Energy
Governing Law:Texas

41) PATTERSON-UTI ENERGY, INC. CHANGE IN CONTROL AGREEMENT