Shares of Occidental Petroleum Corporation OXY have outperformed the Zacks Domestic Integrated Oil and Gas industry in the last six months. While the company’s shares rallied 10.8%, the industry gained 5.9%.Occidental Petroleum continues to benefit from increasing oil production in the Permian Resources and from its focus on high margin production region. Improving operating efficiency is also lowering barrels of oil equivalent (boe) operating expenses of the company in Permian Resources region. Year to date, operating expenses per boe is $8.14, down from $12.93 per boe in 2016, reflecting an improvement of 37%.Capital expenditures in the first nine months of 2017 were $2.4 billion compared with $1.8 billion in the last-year period. Year to date, the company has invested nearly $2 billion in its Oil & Gas segment, which boosted its performance. Occidental Petroleum expects to increase its capital expenditure to $1.1 billion for the fourth quarter, taking its 2017 spending to nearly $3.6 billion.Occidental Petroleum is also gaining from improving contribution from Chemical segment, primarily due to improving pricing and operations. The company will generate additional cash flow from the Chemical segment in 2018, thanks to the startup of the 4CPe plant in the fourth quarter of this year and from improving product prices.The company’s operation is subject to natural calamities and disasters. Occidental Petroleum had to temporarily shut its chlorovinyl production, primarily due to impact of Hurricane Harvey, which lowered its pre-tax income by nearly $60 million in the third quarter. Harvey also lowered the company’s Permian Resources production by 1,000 boe/d in the third quarter.The company’s Zacks Consensus Estimate for 2017 and 2018 earnings per share moved up 18.5% and 10.2%, respectively in last 90 days. The company delivered positive surprises in last three quarters with an average surprise of 31.9%.Zacks Rank & Stocks to ConsiderThe stock carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the same industry are Conoco Phillips COP, Mammoth Energy Services, Inc. TUSK and EQT GP Holdings, LP EQGP.Conoco Phillips sports a Zacks Rank #1(Strong Buy). You can see the complete list of today’s Zacks #1 Rank stocks here. The company delivered a positive earnings surprise of 77.78% in last quarter. Its 2017 Zacks Consensus Estimate moved up 79.3% to 52 cents in last 90 days.Mammoth Energy Services, a Zacks Rank #2 (Buy) stock, pulled off a positive earnings surprise in two of last four quarters. Its 2017 Zacks Consensus Estimate moved up 2600.0% to 27 cents in last 30 daysEQT GP Holdings, a Zacks #2 stock, reported positive earnings surprise in two of last four quarters. Its 2017 Zacks Consensus Estimate moved up 2.0% to $1.01 in last 90 days.Today's Stocks from Zacks' Hottest StrategiesIt's hard to believe, even for us at Zacks. But while the market gained +18.8% from 2016 - Q1 2017, our top stock-picking screens have returned +157.0%, +128.0%, +97.8%, +94.7%, and +90.2% respectively.And this outperformance has not just been a recent phenomenon. Over the years it has been remarkably consistent. From 2000 - Q1 2017, the composite yearly average gain for these strategies has beaten the market more than 11X over. Maybe even more remarkable is the fact that we're willing to share their latest stocks with you without cost or obligation.See Them Free>>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report ConocoPhillips (COP): Free Stock Analysis Report Occidental Petroleum Corporation (OXY): Free Stock Analysis Report EQT GP Holdings, LP (EQGP): Free Stock Analysis Report MAMMOOTH ENERGY (TUSK): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research