Now that crude oil prices have risen above $70 per barrel, the energy sector is once again looking attractive to investors. However, some are already wondering if oil and natural gas sector stocks are still good buys after their significant gains this year.

While higher oil prices can support profits in this space and justify rising stock prices, basing your investment decisions on a metric as volatile as the price of crude can be a risky strategy.

For those who would like to invest based on a more stable thesis, these three stocks look well-positioned to flourish while oil prices are high, but should also prove resilient if prices fall.

Enbridge

Enbridge (NYSE:ENB) is a leading pipeline company with operations in the U.S. and Canada. It transports and stores oil, natural gas, and other hydrocarbon liquids, and provides related services. Its huge and diversified asset infrastructure provides it with relatively stable earnings. Enbridge's contracts are largely fee-based, so its revenues and earnings are not directly impacted by short-term fluctuations in commodity prices.

Man wearing hard hat at an oil refinery.

Image source: Getty Images.

Its key strength is the strategic location of its pipelines. Its liquids pipelines connect Canada's oil sands to refineries across the Gulf Coast. These refineries are designed to process heavy Canadian oil, and changing over to handle other grades of crude may not be always efficient for them. Moreover, the rates Enbridge charges are competitive, so its pipeline capacity is usually in high demand.

Management has raised Enbridge's dividend payout annually for 26 straight years, making it an attractive stock for income investors. At its current share price, it offers a yield of nearly 6.5%. Enbridge expects to grow its cash flow by 5% to 7% annually through 2023. The approximately 10 billion Canadian dollars worth of capital projects that it plans to put into service in 2021 should support its efforts to hit those cash flow targets, as well as providing fuel for further dividend growth.

Valero Energy

Top independent refiner Valero Energy (NYSE:VLO) is well-placed to benefit from a recovery in the demand for refined products. The widespread national rollout of COVID-19 vaccines, the resultant steep dropoff in new case counts in the U.S., and the arrival of summer driving season should all help produce a surge in gasoline demand. Even though there are some concerns as thus far, demand has not risen as much as expected, conditions could change in the coming weeks. Moreover, a more robust U.S. economic recovery should result in a broad-based recovery in the demand for gasoline.

Beyond how the company will fare due to macroeconomic conditions, Valero has its own individual strengths, one of which is its capital discipline. The refiner's debt-to-capital ratio has historically been conservative compared to its peers.

VLO Debt To Capital (Quarterly) Chart

VLO Debt To Capital (Quarterly) data by YCharts

Also, management is targeting a net debt-to-capital ratio of 20% to 30% in the long run, and aims to return 40% to 50% of its annual adjusted net cash from operating activities to shareholders through a combination of dividends and share buybacks.

In addition to its strong refining operations, Valero Energy's activities in the renewable diesel segment help diversify its earnings while positioning it to take advantage of global efforts to transition to cleaner energy sources. The company plans to expand its renewable diesel production capacity from 290 million gallons per year right now to 1.2 billion gallons per year by 2023. The refiner's capacity expansion decisions have been based on attractive returns on invested capital from this business.

With a dividend yield of 4.8% at current share prices, Valero Energy offers an attractive way to gain exposure to the refining segment of the energy sector.

Chevron

Volatile oil prices, lower oil and gas demand due to the pandemic, and the ongoing shift toward greater use of renewable energy sources have combined to keep a lid on the prices of oil sector stocks lately. Strengthening crude prices have put an updraft under those stocks this year, but broadly speaking, their prices remain lower, and their yields higher, than historical levels. Top oil company Chevron (NYSE:CVX) is offering an attractive yield now, despite the recent gains in its stock price.

CVX Dividend Yield Chart

CVX Dividend Yield data by YCharts

Chevron's diversified operations -- which run from oil and gas exploration and production through transport, refining, and distribution -- help it a bit compared to pure-play producers. In addition, the company's balance sheet strength and its capital discipline have helped it navigate these challenging times. The company's debt-to-capital ratio of 25% is the lowest among its main peers. This also makes Chevron's dividend more reliable than the payouts of its more leveraged rivals.

Chevron is a Dividend Aristocrat with 34 consecutive years of payout increases. Its attractive yield, financial strength, diversified business, and commitment to its dividend should make it an appealing stock for dividend investors looking for energy-sector exposure.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.