Warren Buffett's company, Berkshire Hathaway (BRK.A 0.12%) (BRK.B -0.01%), owns lots of stocks. Two of the biggest are oil giants Chevron (CVX -2.57%) and Occidental Petroleum (OXY -1.94%). They currently clock in as Berkshire's fifth and sixth largest holdings.

Buffett's company has added to those oil stocks over the past few months. Given the current oil price point and other catalysts they have on the horizon, those purchases could really pay off. That upside makes them stocks that investors will want to make sure they grab this month.

Upside catalysts abound

Berkshire Hathaway currently owns over 126 million shares of Chevron, or about 6.8% of its outstanding shares, worth more than $19.6 billion, or 5.4% of its investment portfolio. Buffett's company recently boosted its position in the oil giant. His company took advantage of a sell-off in the oil stock following its decision to buy rival Hess in a roughly $60 billion deal.

Acquiring Hess would enhance and extend Chevron's production and free cash flow growth outlook into the 2030s. It would enable the oil giant to more than double its free cash flow by 2027, assuming crude averages around $70 per barrel. Oil is currently in the $80s, meaning it would produce an even bigger gusher of cash in the future, assuming it closes the deal and oil remains at the higher level. Neither is a sure thing, especially since rival ExxonMobil, Hess' partner in a lucrative offshore oil development in Guyana, might seek to acquire Hess' position in that project.

However, Chevron can still thrive even if it doesn't acquire Hess. The company's current high-return capital program positions it to grow its free cash flow by more than 10% annually through 2027, assuming oil averages $60 per barrel. That would enable it to produce enough cash to fund its capital program; grow its attractive dividend, which is currently yielding 4.2%; and repurchase shares at the low end of its $10 billion to $20 billion annual target range, which is enough to retire about 3% of its outstanding shares at the current price. Meanwhile, at $70 oil, it could repurchase stock at the high end of that range, which is enough to retire 6% of its outstanding shares each year.

Add in Chevron's attractive income yield to its upside potential, and the oil giant could deliver strong total returns in the coming years even if oil prices cool off and the Hess deal falls apart.

A forever oil stock

Buffett's company has been buying shares of Occidental Petroleum hand over fist. It currently owns over 248 million shares, which account for an eye-popping 28.2% of its outstanding shares and are worth $15.5 billion, or 4.2% of its investment portfolio. Warren Buffett recently highlighted Occidental as having the characteristics of a "forever" holding.

One of the things Buffett loves about Occidental is its leadership in helping make America the world's top oil producer. The company has helped unlock a treasure trove of oil and gas in the Permian Basin, where it's one of the leading producers.

Occidental is working to bolster its position in that key oil basin by agreeing to acquire CrownRock for $12 billion. The acquisition will boost its free cash flow by $1 billion over the next year at $70 oil. On top of that, it will enhance its low-cost resource base. The growing cash flow from this deal will give Occidental the money to repay debt; repurchase shares, including the preferred stock owned by Berkshire Hathaway; and grow its dividend. It recently boosted its payout by another 22%.

On top of its oil business, Occidental is emerging as a leader in the potentially lucrative carbon capture and storage market. It's building the world's largest direct air capture project in the Permian Basin, which should come online next year. Several companies have purchased carbon credits from the company to support the commercialization of that project, which is the first of many it has in development. Occidental believes it could eventually make as much money off carbon capture as it currently does producing oil and gas.

Great entry points

Chevron and Occidental have gained less than 5% this year, even though crude prices have surged 13%. They trade at very compelling values, given the cash they can produce at the current oil price point. Add in their other catalysts, and they look like very compelling buys right now.