SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment) PATTERSON-UTI ENERGY INC (Name of Issuer) COMM (Title of Class of Securities) 703481101 (CUSIP Number) December 31, 2005 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(c) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS BANK PLC ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.000% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS CAPITAL SECURITIES LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England. ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS CAPITAL INC ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization U.S.A. ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ---------------------------------------------------------------------------- CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS PRIVATE BANK & TRUST (ISLE OF MAN) LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England. ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS PRIVATE BANK AND TRUST (JERSEY) LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS BANK TRUST COMPANY LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS BANK (Suisse) SA ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization Switzerland ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BARCLAYS PRIVATE BANK LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization England ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). BRONCO (BARCLAYS CAYMAN) LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization Cayman Islands ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). PALOMINO LIMITED ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization Cayman Islands ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ CUSIP No. 703481101 --------- ------------------------------------------------------------------------------ (1) Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). HYMF INC ------------------------------------------------------------------------------ (2) Check the appropriate box if a member of a Group* (a) / / (b) /X/ ------------------------------------------------------------------------------ (3) SEC Use Only ------------------------------------------------------------------------------ (4) Citizenship or Place of Organization U.S.A. ------------------------------------------------------------------------------ Number of Shares (5) Sole Voting Power Beneficially Owned - by Each Reporting ------------------------------ Person With (6) Shared Voting Power - ------------------------------ (7) Sole Dispositive Power - ------------------------------ (8) Shared Dispositive Power - ------------------------------------------------------------------------------ (9) Aggregate - ------------------------------------------------------------------------------ (10) Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares* ------------------------------------------------------------------------------ (11) Percent of Class Represented by Amount in Row (9) 0.00% ------------------------------------------------------------------------------ (12) Type of Reporting Person* ------------------------------------------------------------------------------ ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS BANK PLC ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 54 Lombard Street London, England EC3P 3AH ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS CAPITAL SECURITIES LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 5 The North Colonmade Canary Wharf, London, England E14 4BB ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS CAPITAL INC ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 200 Park Ave NY, NY 10166 ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP U.S.A. ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS PRIVATE BANK & TRUST (ISLE OF MAN) LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 4th Floor, Queen Victoria House Isle of Man, IM99 IDF ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS PRIVATE BANK AND TRUST (JERSEY) LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 39/41 Broad Street, St. Helier Jersey, Channel Islands JE4 8PU ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS BANK TRUST COMPANY LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 54 Lombard Street London, EC3P 3AH, England ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS BANK (Suisse) SA ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 10 rue d'Italie CH-1204 Geneva Switzerland ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP Switzerland ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BARCLAYS PRIVATE BANK LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 59/60 Grosvenor Street London, WIX 9DA England ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP England ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING BRONCO (BARCLAYS CAYMAN) LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE Walker House Mary Street PO Box 908 GT George Town, Grand Cayman (Cayman Islands) ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP Cayman Islands ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING PALOMINO LIMITED ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE Walker House Mary Street PO Box 908 GT George Town, Grand Cayman (Cayman Islands) ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP Cayman Islands ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 1(A). NAME OF ISSUER PATTERSON-UTI ENERGY INC ------------------------------------------------------------------------------ ITEM 1(B). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES P O DRAWER 1416 SNYDER TX 79550 ------------------------------------------------------------------------------ ITEM 2(A). NAME OF PERSON(S) FILING HYMF INC ------------------------------------------------------------------------------ ITEM 2(B). ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE 200 Park Avenue New York, NY 10166 ------------------------------------------------------------------------------ ITEM 2(C). CITIZENSHIP U.S.A. ------------------------------------------------------------------------------ ITEM 2(D). TITLE OF CLASS OF SECURITIES COMM ------------------------------------------------------------------------------ ITEM 2(E). CUSIP NUMBER 703481101 ------------------------------------------------------------------------------ ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13D-1(B), OR 13D-2(B), CHECK WHETHER THE PERSON FILING IS A (a) // Broker or Dealer registered under Section 15 of the Act (15 U.S.C. 78o). (b) // Bank as defined in section 3(a) (6) of the Act (15 U.S.C. 78c). (c) // Insurance Company as defined in section 3(a) (19) of the Act (15 U.S.C. 78c). (d) // Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) // Investment Adviser in accordance with section 240.13d(b)(1)(ii)(E). (f) // Employee Benefit Plan or endowment fund in accordance with section 240.13d-1(b)(1)(ii)(F). (g) // Parent Holding Company or control person in accordance with section 240.13d-1(b)(1)(ii)(G). (h) // A savings association as defined in section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) // A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15U.S.C. 80a-3). (j) // Group, in accordance with section 240.13d-1(b)(1)(ii)(J) ITEM 4. OWNERSHIP Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1. (a) Amount Beneficially Owned: - ------------------------------------------------------------------------------ (b) Percent of Class: 0.00% ------------------------------------------------------------------------------ (c) Number of shares as to which such person has: (i) sole power to vote or to direct the vote - ---------------------------------------------------------------- (ii) shared power to vote or to direct the vote - ---------------------------------------------------------------- (iii) sole power to dispose or to direct the disposition of - ---------------------------------------------------------------- (iv) shared power to dispose or to direct the disposition of - ---------------------------------------------------------------- As a result of disaggregation of certain subsidiaries of Barclays Bank PLC as of December 31, 2005, the aggregate number and percentage reported may vary significantly from prior reported holdings. ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following. /X/ ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON The shares reported are held by the company in trust accounts for the economic benefit of the beneficiaries of those accounts. See also Items 2(a) above. ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY Not applicable ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP Not applicable ITEM 9. NOTICE OF DISSOLUTION OF GROUP Not applicable ITEM 10. CERTIFICATION (a) The following certification shall be included if the statement is filed pursuant to section 240.13d-1(b): By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. (b) The following certification shall be included if the statement is filed pursuant to section 240.13d-1(c): By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. January 10, 2006 --------------------------------------- Date --------------------------------------- Signature Patrick Gonsalves Deputy Secretary, Barclays plc --------------------------------------- Name/Title