Bangalore: After seeing surge in the crude prices, the stocks of oil and gas sector saw considerable decline last week. Compared to the last month, the value of oil and gas stocks dropped by almost five percent from 9,814.23 to 9,315.68. When the value is compared to last week, it descended by almost two percent. Some of the major oil and gas companies ended the week flat. Reliance Petroleum lost almost nine percent in last one week, while Reliance Industries lost three percent and Essar oil went down by almost four percent. Whereas Hindustan Petroleum gained by 0.5 percent last week. Oil stocks fell on reports oil and gas producers could be forced to pay royalties to the government on the basis of sale prices in the future rather than the present system of 'wellhead value', threatening profits of oil companies such as ONGC, Reliance Industries and Cairn India. The new method, which is now being examined by the oil ministry, could represent a fundamental overhaul of the system of calculating royalties, and boost revenues for the cash-strapped exchequer, weighed down by mounting deficits, reports suggest. After the thumping win in recently concluded Loksabha election, government had also hinted of increasing the domestic prices of petrol, diesel and cooking gas. Union Petroleum Minister, Murli Deora said, "Government is still considering deregulation of fuel prices despite crude oil prices near $70 a barrel, but an increase in controlled fuel prices can signal once again that the government is reluctant to allow prices to be set by the market at a time when crude prices are rising." However, when markets closed today, the total market capitalization of the oil and gas sector was 4,739,334.29 crores. Markets seem to be on positive node as out of 10 companies listed on the sensex, seven have ended the day positively. The oil and gas stocks ended the day by going up by mere two points from 9,312.93 to 9,315.68. During the day, the stock reached a high of 9,387.03 and a low of 9,198.12 points with a total of 2.31crore shares traded through the day.