Results for these business segments are presented below. We use the same accounting policies to prepare our business segment results  as are used to prepare our Consolidated Financial Statements. All interest and other non-operating income (expense) is attributable to  Corporate & Other area and is not allocated to specific business segments. Summarized financial information concerning our segments  is shown in the following table (in thousands): Reservoir  Description Production  Enhancement Reservoir  Management Corporate & Other (1) Consolidated December 31, 2013 Revenues from unaffiliated clients $ 522,251 $ 452,415 $ 98,842 $   — $ 1,073,508 Inter-segment revenues 3,432 3,140 1,742 (8,314) — Segment operating income (loss) 146,338 154,715 31,555 811 333,419 Total assets (at end of period) 321,106 255,764 37,660 46,480 661,010 Capital expenditures 22,601 7,124 1,366 4,325 35,416 Depreciation and amortization 14,898 7,745 945 1,883 25,471 December 31, 2012 Revenues from unaffiliated clients $ 495,529 $ 403,792 $ 81,759 $ — $ 981,080 Inter-segment revenue 2,484 2,757 1,492 (6,733) — Segment operating income (loss) 144,502 128,602 26,428 (2,252) 297,280 Total assets (at end of period) 293,974 242,254 34,532 65,756 636,516 Capital expenditures 16,987 7,423 920 5,821 31,151 Depreciation and amortization 14,094 6,139 731 1,953 22,917 December 31, 2011 Revenue from unaffiliated clients $ 469,775 $   371,449 $ 66,424 $ — $   907,648 Inter-segment revenue 1,515 1,947 1,686 (5,148) —  Segment operating income (loss) 116,244 112,576 21,887 47 250,754  Total assets (at end of period) 270,270 221,599 26,070 92,934 610,873  Capital expenditures 15,320 8,700 1,318 4,589 29,927 Depreciation and amortization 14,073 6,449 666 2,115 23,303 (1)  “Corporate and other” represents those items that are not directly relating to a particular segment and eliminations. 60