Exhibit 21.1

PRECISION DRILLING CORPORATION

SUBSIDIARIES

Name of Subsidiary	State or Jurisdiction of Organization
1443518 ALBERTA LTD.	ALBERTA
31795 YUKON INC.	YUKON
ARROWSTAR DRILLING PARTNERSHIP	ALBERTA
AXIS DIRECTIONAL DRILLING CORP.	TEXAS
BK LOG CO. LTD.	RUSSIAN FEDERATION
CANADIAN WASTE MANAGEMENT INC.	ALBERTA
CK LOG OVERSEAS LIMITED	CYPRUS
COMPUTALOG (CYPRUS) LIMITED	CYPRUS
COMPUTALOG CONSULTING CYPRUS LIMITED	CYPRUS
COMPUTALOG MEXICANA, S.A. de C.V.	MEXICO
COMPUTALOG OCEANWAVES SDN. BHD.	MALAYSIA
DI ENERGY, INC.	TEXAS
DI/PERFENSA INC.	TEXAS
DRILLERS INC., D.I. DE VENEZUELA, C.A.	VENEZUELA
GREY WOLF DRILLING DE VENEZUELA, C.A.	VENEZUELA
GREY WOLF DRILLING INTERNATIONAL LTD.	CAYMAN ISLANDS
GREY WOLF DRILLING LIMITED	CYPRUS
GREY WOLF DRILLING (BARBADOS) LTD.	BARBADOS
GREY WOLF DRILLING B.V.	NETHERLANDS
GREY WOLF DRILLING SERVICES COOPERATIEF U.A.	NETHERLANDS
GREY WOLF GLOBAL EMPLOYMENT CORPORATION	ALBERTA
GREY WOLF INTERNATIONAL DE MEXICO, S. DE R.L. DE C.V.	MEXICO
GREY WOLF INTERNATIONAL DRILLING CORPORATION	CANADA
GREY WOLF INTERNATIONAL, INC.	TEXAS
GREY WOLF MEXICO HOLDINGS LLC	NEVADA
GREY WOLF OILFIELD SERVICES (KSA) LIMITED	CYPRUS
GREY WOLF OILFIELD SERVICES LIMITED	CYPRUS
GREY WOLF SERVICES (IRAQ SOUTH) LIMITED	CYPRUS
GW DRILLING LIMITED	CAYMAN ISLANDS
GW IMPORTACIONES, S. DE R.L. DE C.V.	MEXICO
GW INERNATIONAL OILFIELD SERVICIOS LTD.	ALBERTA
INTER LEASING, INC.	BRITISH VIRGIN ISLANDS
INTER-TECH DRILLING SOLUTIONS (BARBADOS) LTD.	BARBADOS
KENTING INC.	DELAWARE
MURCO DRILLING CORPORATION	DELAWARE

2

NORJET GEOTECHNOLOGIES (OVERSEAS) LIMITED	CYPRUS
NORTHLAND ENERGY SERVICES (CYPRUS) LIMITED	CYPRUS
NORWEST WIRELINE SERVICES (OVERSEAS) LIMITED	CYPRUS
PD SUPPLY INC.	TEXAS
PERFORACIONES ANDINAS, S.A.	PANAMA
PRECISION BOLTING, INC.	CALIFORNIA
PRECISION COMPLETION & PRODUCTION SERVICES LTD.	DELAWARE
PRECISION DIRECTIONAL SERVICES LTD.	ALBERTA
PRECISION DIRECTIONAL SERVICES, INC.	TEXAS
PRECISION DIVERSIFIED OILFIELD SERVICES CORP.	ALBERTA
PRECISION DRILLING (US) CORPORATION	TEXAS
PRECISION DRILLING CANADA LIMITED PARTNERSHIP	ALBERTA
PRECISION DRILLING COMPANY, LP	TEXAS
PRECISION DRILLING HOLDINGS COMPANY	NEVADA
PRECISION DRILLING LLC	LOUISIANA
PRECISION DRILLING, INC.	DELAWARE
PRECISION EMPLOYMENT SERVICES CORP.	ALBERTA
PRECISION LIMITED PARTNERSHIP	ALBERTA
SERVICIOS GREY WOLF S. DE R.L. DE C.V.	MEXICO
SIERRA DRILL MANUFACTURING LTD.	ALBERTA