Question

project the depletion time in years for Petroleum, Natural gas assuming the world reserve estimates stay constant and under the following 3 scenarios-

1) The world consumption rate stays constant

2)The world consumption rate increases at 2% per year

3)The world consumption rate increases at 5% per year.

Assuming the constant value for petrol is 97,104 billion barrels per day

entire year consumption is 97104*365.

left reserve is 1650 billion barrels.

Assuming Natural gas consumption constant value is 127,884 billion cubic feet per year.

Reserves left is 6879 trillion cu. ft.

Answer 1

Seems like there is some error in values of petroleum reserves and consumption. As given reserve is less than one day consumption.

Left reserve = 1,650 billion

Per day consumption = 97,104 billion

So there is some error.

However Natural Gas is correct and I was able to solve that.

Reserve of Natural Gas = 6,879,000 billion cuft

Consumption = 127,884 billion cuft

Reserve will be completed in

If Constant = 53.79 years

If 2% increase every year = 35.88 Years

If 5% increase every year = 25.75 Years

Find the steps in below table

	If Constant		If 2% Increases		If 5% Increases
YRs	Researve Balance	Consumption	Researve Balance	Consumption	Researve Balance	Consumption
	68,79,000	1,27,884	68,79,000	1,27,884	68,79,000	1,27,884
YR 1	67,51,116	1,27,884	67,51,116	1,30,442	67,51,116	1,34,278
YR 2	66,23,232	1,27,884	66,20,674	1,33,051	66,16,838	1,40,992
YR 3	64,95,348	1,27,884	64,87,624	1,35,712	64,75,846	1,48,042
YR 4	63,67,464	1,27,884	63,51,912	1,38,426	63,27,804	1,55,444
YR 5	62,39,580	1,27,884	62,13,487	1,41,194	61,72,360	1,63,216
YR 6	61,11,696	1,27,884	60,72,292	1,44,018	60,09,144	1,71,377
YR 7	59,83,812	1,27,884	59,28,274	1,46,899	58,37,767	1,79,946
YR 8	58,55,928	1,27,884	57,81,376	1,49,836	56,57,822	1,88,943
YR 9	57,28,044	1,27,884	56,31,539	1,52,833	54,68,879	1,98,390
YR 10	56,00,160	1,27,884	54,78,706	1,55,890	52,70,489	2,08,310
YR 11	54,72,276	1,27,884	53,22,816	1,59,008	50,62,179	2,18,725
YR 12	53,44,392	1,27,884	51,63,808	1,62,188	48,43,454	2,29,661
YR 13	52,16,508	1,27,884	50,01,620	1,65,432	46,13,793	2,41,144
YR 14	50,88,624	1,27,884	48,36,189	1,68,740	43,72,649	2,53,202
YR 15	49,60,740	1,27,884	46,67,449	1,72,115	41,19,447	2,65,862
YR 16	48,32,856	1,27,884	44,95,334	1,75,557	38,53,585	2,79,155
YR 17	47,04,972	1,27,884	43,19,776	1,79,068	35,74,431	2,93,112
YR 18	45,77,088	1,27,884	41,40,708	1,82,650	32,81,318	3,07,768
YR 19	44,49,204	1,27,884	39,58,058	1,86,303	29,73,550	3,23,156
YR 20	43,21,320	1,27,884	37,71,755	1,90,029	26,50,394	3,39,314
YR 21	41,93,436	1,27,884	35,81,726	1,93,829	23,11,079	3,56,280
YR 22	40,65,552	1,27,884	33,87,897	1,97,706	19,54,799	3,74,094
YR 23	39,37,668	1,27,884	31,90,191	2,01,660	15,80,705	3,92,799
YR 24	38,09,784	1,27,884	29,88,531	2,05,693	11,87,906	4,12,439
YR 25	36,81,900	1,27,884	27,82,837	2,09,807	7,75,468	4,33,061
YR 26	35,54,016	1,27,884	25,73,030	2,14,003	3,42,407	4,54,714
YR 27	34,26,132	1,27,884	23,59,026	2,18,283
YR 28	32,98,248	1,27,884	21,40,743	2,22,649	25 Years +	342407/454714
YR 29	31,70,364	1,27,884	19,18,094	2,27,102	25 Years +	0.75
YR 30	30,42,480	1,27,884	16,90,992	2,31,644		25.75 Years
YR 31	29,14,596	1,27,884	14,59,348	2,36,277
YR 32	27,86,712	1,27,884	12,23,071	2,41,003
YR 33	26,58,828	1,27,884	9,82,068	2,45,823
YR 34	25,30,944	1,27,884	7,36,245	2,50,739
YR 35	24,03,060	1,27,884	4,85,506	2,55,754
YR 36	22,75,176	1,27,884	2,29,752	2,60,869
YR 37	21,47,292	1,27,884
YR 38	20,19,408	1,27,884	35 Years +	229752/260869
YR 39	18,91,524	1,27,884	35 Years +	0.88
YR 40	17,63,640	1,27,884		35.88 Years
YR 41	16,35,756	1,27,884
YR 42	15,07,872	1,27,884
YR 43	13,79,988	1,27,884
YR 44	12,52,104	1,27,884
YR 45	11,24,220	1,27,884
YR 46	9,96,336	1,27,884
YR 47	8,68,452	1,27,884
YR 48	7,40,568	1,27,884
YR 49	6,12,684	1,27,884
YR 50	4,84,800	1,27,884
YR 51	3,56,916	1,27,884
YR 52	2,29,032	1,27,884
YR 53	1,01,148	1,27,884
YR 54	-26,736	1,27,884