Rex Energy Provides Additional Information On 61% Net Increase In Proved Reserves And Reports 2010 Drill Bit F&D Costs Of $.68/MCFE

• Year-end 2010 proved reserves increased to 201.7 BCFE
• Total reserve replacement at 1,560% with reserve to production ratio of 27.6 years
• Drill Bit Finding and Development Costs of $.68/ MCFE

STATE COLLEGE, Pa., Feb. 14, 2011 (GLOBE NEWSWIRE) -- Rex Energy Corporation (Nasdaq:REXX) reported year end 2010 proved oil and gas reserves of 201.7 Bcfe, an increase of 61% over year end 2009. Of the 201.7 Bcfe proved reserves, 63% was attributable to natural gas and  37% to oil, condensate and natural gas liquids. The proved developed portion of year-end 2010 reserves was 43% of total proved reserves. 

Rex Energy successfully replaced 1,560% of its estimated 2010 production of 7,310 MMcfe, which equates to a reserves to production ratio of approximately 27.6 years.

	2009	2010
Proved Reserves (MMcfe)	125,223	201,679
Production (MMcfe)	5,877	7,310
Drill Bit Capital Employed (millions 1)	$ 34.4	$ 78.0
Drill-bit Finding and Development Cost ($/Mcfe)	$ 0.53	$ 0.68
All-in Capital Employed (millions)	$ 52.7	$ 151.4
All-in Finding and Development cost ($/Mcfe)	$ 0.80	$ 1.97
1 Exploration and development capital employed

Unaudited estimates of exploration and development costs for 2010 were $78.0 million. When including lease acquisitions, total 2010 capital expenditures were $150.4 million. Drill bit finding and development (F&D) costs were $0.68 per Mcfe while total F&D costs for 2010 were $1.97 per Mcfe.

Year-End 2010 Proved Reserves

The following table is a reconciliation of the changes in the company's proved reserves between December 31, 2009 and December 31, 2010:

	Natural Gas (Mmcf)	Oil and NGLs (Mbbl)	Total (Mmcfe)
Balance – December 31, 2009	56,163	11,510	125,223
Extensions and discoveries 1	93,230	3,462	114,002
Sale of minerals in place 2	(12,252)	(370)	(14,472)
Estimated production 3	(3,008)	(717)	(7,310)
Revisions to previous estimates 4	(6,512)	(1,542)	(15,764)
Balance – December 31, 2010 5	127,621	12,343	201,679
Proved developed reserves as of December 31, 2010	32,477	8,799	85,272
1Butler County, Pennsylvania Marcellus Shale Reserves up 248% over 2009 2 Sales to Sumitomo as part of joint venture transaction 3 Unaudited 2010 production figures 4 Includes reclassification of 3.7 Bcfe and 13.5 Bcfe from Appalachian Basin (non-Marcellus) and Illinois Basin, respectively, to the probable category 5 Total proved reserves increased 95%, adjusting for production, asset sales and revisions

 

	Proved Reserves by Asset Area
	PDP (MMcfe)	PDNP (MMcfe)	PUD (MMcfe)	Total (MMcfe)	PV10 (M$)
Appalachia Conventional	6,015	0	0	6,015	$8,916
Marcellus – Butler Operated	10,086	9,188	104,070	123,344	74,795
Marcellus – Non-Operated	11,126	0	12,337	23,463	23,822
Illinois	48,857	0	0	48,857	161,870
Total	76,084	9,188	116,407	201,679	$269,403

The majority of Rex Energy's proved reserve growth was attributed to the expanded horizontal drilling in its operated Butler County, Pennsylvania development. Total proved reserves attributed to the company in Butler County increased by 248%. Excluding the sale of minerals in place to Rex Energy's joint venture partner, Sumitomo Corporation, Butler County reserves increased by 278% over year-end 2009 reserves. 

	Total Company Net Marcellus Wells
	2009	2010
PDP	9.5	12.8
PDNP	0.5	2.8
PUD	13.5	35.8
Total	23.5	51.4

Of the 51.4 net PUD wells booked in 2010, 8.3 net wells were booked based on the use of reliable technologies for reporting proved reserves. The company had a total net proved developed to proved undeveloped ratio of Marcellus Shale wells of 2.29 to 1.0 at year-end 2010. Rex Energy expects to convert 40% of its Butler County proved undeveloped reserves to proved developed reserves by the end of 2011.