<SEC-DOCUMENT>0001258897-19-001375-index.html : 20190208
<SEC-HEADER>0001258897-19-001375.hdr.sgml : 20190208
<ACCEPTANCE-DATETIME>20190208085243
ACCESSION NUMBER:		0001258897-19-001375
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20190208
DATE AS OF CHANGE:		20190208

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PIONEER ENERGY SERVICES CORP
		CENTRAL INDEX KEY:			0000320575
		STANDARD INDUSTRIAL CLASSIFICATION:	DRILLING OIL & GAS WELLS [1381]
		IRS NUMBER:				742088619
		STATE OF INCORPORATION:			TX
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-33018
		FILM NUMBER:		19577903

	BUSINESS ADDRESS:	
		STREET 1:		1250 N.E. LOOP 410
		STREET 2:		SUITE 1000
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78209
		BUSINESS PHONE:		2108287689

	MAIL ADDRESS:	
		STREET 1:		1250 N.E. LOOP 410
		STREET 2:		SUITE 1000
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78209

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PIONEER DRILLING CO
		DATE OF NAME CHANGE:	20011102

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SOUTH TEXAS DRILLING & EXPLORATION INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SOUTH TEXAS DRILLING CO
		DATE OF NAME CHANGE:	19810715

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DIMENSIONAL FUND ADVISORS LP
		CENTRAL INDEX KEY:			0000354204
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				222370029
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746
		BUSINESS PHONE:		(512) 306-7400

	MAIL ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DIMENSIONAL FUND ADVISORS INC
		DATE OF NAME CHANGE:	19920929
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>dfs546.htm
<DESCRIPTION>SCHEDULE 13G/A
<TEXT>
Document 1 - file: dfs546.htm

</DOCUMENT>
</SEC-DOCUMENT>