Annual report pursuant to Section 13 and 15(d)

Estimated Quantities of Net Proved, Proved Developed and Proved Undeveloped Oil, Ngls and Natural Gas Reserves (Detail)

v2.4.0.8
Estimated Quantities of Net Proved, Proved Developed and Proved Undeveloped Oil, Ngls and Natural Gas Reserves (Detail)
 12 Months Ended
Dec. 31, 2013
MMBbls
Dec. 31, 2012
MMBbls
Dec. 31, 2011
MMBbls
Oil
      
Reserve Quantities [Line Items]      
Proved reserves, beginning balance 54.8 51.4 34.0
Revisions of previous estimates (4.3) [1] (1.1) [2] 0.8 [3]
Extensions and discoveries 13.9 [4] 8.2 [5] 2.0 [6]
Purchase of minerals in place 1.5 [7] 2.5 [8] 20.7 [9]
Production (7.0) (6.0) (6.1)
Proved reserves, ending balance 58.5 54.8 51.4
Sales of reserves (0.4) [10] (0.2) [11]  
Oil | Proved Developed Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 36.2 35.3 23.4
Oil | Proved Undeveloped Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 22.3 19.5 28.0
NGLs
      
Reserve Quantities [Line Items]      
Proved reserves, beginning balance 15.2 17.1 4.2
Revisions of previous estimates 0.2 [1] (2.6) [2] 5.5 [3]
Extensions and discoveries 2.6 [4] 2.6 [5] 0.4 [6]
Purchase of minerals in place   0.2 [8] 8.9 [9]
Production (2.1) (2.1) (1.9)
Proved reserves, ending balance 15.9 15.2 17.1
Sales of reserves    [10]    [11]  
NGLs | Proved Developed Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 11.1 11.0 11.0
NGLs | Proved Undeveloped Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 4.8 4.2 6.1
Natural Gas
      
Reserve Quantities [Line Items]      
Proved reserves, beginning balance 285,100 289,700 256,300
Revisions of previous estimates 2,100 [1] (4,800) [2] 13,500 [3]
Extensions and discoveries 22,000 [4] 29,600 [5] 17,700 [6]
Purchase of minerals in place 4,400 [7] 25,500 [8] 55,900 [9]
Production (53,300) (53,800) (53,700)
Proved reserves, ending balance 259,900 285,100 289,700
Sales of reserves (400) [10] (1,100) [11]  
Natural Gas | Proved Developed Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 232,700 243,500 251,400
Natural Gas | Proved Undeveloped Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 27,200 41,600 38,300
Barrel Equivalent
      
Reserve Quantities [Line Items]      
Proved reserves, beginning balance 117.5 [12] 116.9 [12] 80.9 [12]
Revisions of previous estimates (3.8) [1],[12] (4.6) [12],[2] 8.6 [12],[3]
Extensions and discoveries 20.2 [12],[4] 15.7 [12],[5] 5.3 [12],[6]
Purchase of minerals in place 2.3 [12],[7] 7.0 [12],[8] 39.0 [12],[9]
Production (18.0) [12] (17.1) [12] (16.9) [12]
Proved reserves, ending balance 117.7 [12] 117.5 [12] 116.9 [12]
Sales of reserves (0.5) [10],[12] (0.4) [11],[12]  
Barrel Equivalent | Proved Developed Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 86.1 [12] 86.9 [12] 76.4 [12]
Barrel Equivalent | Proved Undeveloped Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 31.6 [12] 30.6 [12] 40.5 [12]
Natural Gas Equivalent
      
Reserve Quantities [Line Items]      
Proved reserves, beginning balance 705,100,000 [12] 701,100,000 [12] 485,400,000 [12]
Revisions of previous estimates (22,800,000) [1],[12] (27,500,000) [12],[2] 51,100,000 [12],[3]
Extensions and discoveries 121,000,000 [12],[4] 94,500,000 [12],[5] 32,000,000 [12],[6]
Purchase of minerals in place 13,700,000 [12],[7] 42,000,000 [12],[8] 234,100,000 [12],[9]
Production (107,900,000) [12] (102,800,000) [12] (101,500,000) [12]
Proved reserves, ending balance 705,900,000 [12] 705,100,000 [12] 701,100,000 [12]
Sales of reserves (3,200,000) [10],[12] (2,200,000) [11],[12]  
Natural Gas Equivalent | Proved Developed Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 516,100,000 [12] 521,200,000 [12] 458,200,000 [12]
Natural Gas Equivalent | Proved Undeveloped Reserves
      
Reserve Quantities [Line Items]      
Proved reserves, ending balance 189,800,000 [12] 183,900,000 [12] 242,900,000 [12]
[1] Includes upward revision due to price of 11.3 Bcfe; negative revisions of 29.6 Bcfe at our Spraberry field for performance and technical changes, 13.9 Bcfe at our High Island 21/22 field for performance, 7.9 Bcfe at our Ship Shoal 349/359 field for performance; and positive performance revisions of 4.3 Bcfe at our Main Pass 98 field, 4.0 Bcfe at our South Timbalier 314, 3.5 Bcfe at our Main Pass 108 field and 3.2 at our South Timbalier 176 field.
[2] Includes downward revisions due to price of 8.0 Bcfe and negative performance revisions of 17.9 Bcfe at our Spraberry field.
[3] Includes revision of 6.3 Bcfe due to an increase in average prices; 16.5 Bcfe for a change in NGLs marketing arrangements; 11.3 Bcfe increase due to additional compression at our Tahoe field that increases production and ultimate recoveries; and 10.6 Bcfe at our Fairway field for revisions to reserve estimates from the acquisition date to year end.
[4] Includes extensions and discoveries of 75.4 Bcfe at our Spraberry field, 25.3 Bcfe at our Ship Shoal 349/359 field and 11.5 Bcfe at our Mississippi Canyon 698 field.
[5] Includes extensions and discoveries of 69.5 Bcfe at our Spraberry field and extensions and discoveries of 16.2 Bcfe at our High Island 21/22 field
[6] Includes discoveries of 13.9 Bcfe at our Main Pass 98 field and 8.0 Bcfe at our Ship Shoal 349/359 field and extensions of 3.7 Bcfe at our Main Pass 108 field.
[7] Primarily due to the acquisition of the Callon Properties.
[8] Due to the acquisition of the Newfield Properties
[9] Primarily due to the acquisition of the Opal Properties and the Fairway Properties.
[10] Primarily due to the sales of our non-working interests in the Green Canyon 60 field, the Green Canyon 19 field and the West Delta area block 29.
[11] Due to the sale of our interest in the South Timbalier 41 field.
[12] The conversion to barrels of oil equivalent and cubic feet equivalent were determined using the energy-equivalent ratio of six Mcf of natural gas to one Bbl of crude oil, condensate or NGLs (totals may not compute due to rounding). The energy-equivalent ratio does not assume price equivalency, and the energy-equivalent prices for oil, NGLs and natural gas may differ significantly.