POWER OF ATTORNEY
For Executing Forms 3, 4 and 5

Know all by these presents, that the undersigned hereby constitutes

and appoints each of Timothy Yang, Eric Hillerman and Stephanie John,

his true and lawful attorney-in-fact to:

(1) Execute for and on behalf of the undersigned Forms 3, 4 and 5 in

accordance with Section 16(a) of the Securities Exchange Act of 1934,

as amended and the rules thereunder;

(2) Do and perform any and all acts for and on behalf of the undersigned

which may be necessary or desirable to complete the execution of any

such Form 3, 4 or 5 and the timely filing of such form with the United

States Securities and Exchange Commission and any other authority; and

(3) Take any action of any type whatsoever in connection with the foregoing

which, in the opinion of such attorney-in-fact, may be of benefit to, in

the best interest of, or legally required by, the undersigned, it being

understood that the documents executed by such attorney-in-fact on behalf

of the undersigned pursuant to this Power of Attorney shall be in such

form and shall contain such terms and conditions as such attorney-in-fact

may approve in their discretion.

The undersigned hereby grants to each such attorney-in-fact full power and

authority to do and perform all and every act and thing whatsoever requisite,

necessary, or proper to be done in the exercise of any of the rights and powers

herein granted, as fully to all intents and purposes as such attorney-in-fact

might or could do if personally present, with full power of substitution or

revocation, hereby ratifying and confirming all that such attorney-in-fact, or

his substitute or substitutes, shall lawfully do or cause to be done by virtue

of this power of attorney and the rights and powers herein granted.  The

undersigned acknowledges that the foregoing attorney-in-fact, in serving in

such capacity at the request of the undersigned, is not assuming any of the

undersigneds responsibilities to comply with Section 16 of the Securities

Exchange Act of 1934, as amended.

This power of attorney shall continue in full force and effect until revoked

in writing by the undersigned or his attorney-in-fact.

In witness whereof, the undersigned has caused the Power of Attorney  to be

executed as of this 9th day of November, 2015.

/s/ Lawrence S. Massaro

in full force and effect until revoked

in writing by the undersigned or his attorney-in-fact.

In witness whereof, the undersigne