HOUSTON, Aug. 4 (Xinhua) -- The number of active drilling rigs in the United States decreased by four to 1048, or 90 more than this time last year, showed weekly data collected by Baker Hughes released on Friday.

Meanwhile, the price of the West Texas Intermediate (WTI) for September delivery and Brent for October delivery decreased by 0.75 percent and 2.10 percent, respectively, in the week ending Aug. 3.

The Houston-based oilfield services company Baker Hughes reported that the number of active oil rigs decreased by two to 859 this week with more than half of oil rigs, or 480, were located in Permian Basin region of western Texas and southeastern New Mexico. The number of gas rigs dipped by three, hitting 183, and miscellaneous rig count increased by one this week.

Analysts attributed the decline in oil rigs to the big price differential between Midland and WTI due to pipeline bottlenecks, which are considered as a big threat against production growth of the Permian Basin.

Most of U.S. oil production growth comes from the Permian Basin and that supply needs to be transported to the Gulf refineries or to the ports in order to be exported.

Canada's total rig count remained the same this week. Canada's oil rig counts declined by two while gas rig increased by two. Canada's oil and gas rig count is now just up by six year on year. Oil rigs were up by 28 year on year in Canada, while the number of gas rigs was down by 22.

Analysts attributed the major decline in the Canadian gas rigs to the very low gas prices on the Canadian natural gas spot market. The natural gas producers prefer curtailing their production rather than increasing in the current depressed market.

Oil prices were pressured on Wednesday as the U.S. Energy Information Administration (EIA) reported build in the U.S. crude oil inventories. Moreover, the Organization of the Petroleum Exporting Countries (OPEC) reported that it increased its output by 300,000 barrels per day in July.

In addition to OPEC's output increase, Russia's crude oil supply went up by 150,000 barrels per day in July.

Pressured by those factors, WTI and Brent declined by 1.13 percent and 2.45 percent, respectively, on Wednesday.

Anas Alhajji, an energy economist based in Dallas, U.S. state of Texas, told Xinhua that "the July production numbers show a large increase in OPEC production close to 300,000 barrels per day, but exports increased only slightly, preventing prices from declining further."

Another factor that pressures the oil prices is the stronger U.S. dollar. U.S. dollar index, which reached its highest levels within the last 52 weeks on Friday.

"The main threat for growth in global demand this summer is the rising U.S. dollar," Alhajji said.

The U.S. dollar index is a measure of the value of the U.S. dollar relative to a basket of foreign currencies. Oil is mostly traded in U.S. dollars all over the world and a stronger U.S. dollar pressures the oil demand.

For the week ending Aug. 3, WTI for September delivery declined by 0.52 dollar to settle at 68.49 dollars a barrel on the New York Mercantile Exchange, reporting a loss of 0.75 percent. Brent crude October delivery declined by 1.57 U.S. dollar to settle at 73.21 dollars a barrel on the London ICE Futures Exchange, reporting a loss of 2.10 percent.

According to the Weekly Petroleum Status Report by EIA on Wednesday, U.S. commercial crude oil inventories, excluding those in the Strategic Petroleum Reserve (SPR) increased by 3.8 million barrels during the week ending July 27. In the previous week ending July 13, EIA reported a draw of 6.1 million barrels.

U.S. crude oil refinery inputs averaged 17.48 million barrels per day during the week ending July 27 which was 195,000 per day higher than the previous week's average.

U.S. crude oil imports averaged 7.75 million barrels per day last week, maintained the levels of the previous week. Over the past four weeks, crude oil imports averaged 8.00 million barrels per day, 0.4 percent higher than the same four-week period last year.

Total motor gasoline inventories decreased by 2.5 million barrels last week and are about 1.4 percent above the levels of the same week last year.

Distillate fuel inventories increased by 2.98 million barrels last week and are 16.9 percent below the levels of the same week last year. Total commercial petroleum inventories declined by 0.9 million barrels last week.

Total products supplied over the last four-week period averaged 20.87 million barrels per day, down by 0.6 percent from the same period last year. Over the past four weeks, motor gasoline supplied averaged 9.68 million barrels per day, down by 0.9 percent from the same period last year.

Distillate fuel supplied over the last four-week period averaged 3.93 million barrels per day, down by 5.9 percent from the same period last year. Over the past four weeks, jet fuel supplied averaged 1.79 million barrels per day, down by 1.7 percent from the same period last year.