As it's said before, look for API grades:
S for spark engine = Petrol.
C for compression engine = Diesel.
If your oil has got both, it's good to be used for both kind of engines. Just make sure you're using right API grade and viscosity rating.
Many companies blend their premium Diesel oils as 'Fleet oils'. These kind of oils are meant to be used by all kind of cars/trucks in a company's fleet. Oils like Delo Gold, Mobil Delvac, ZIC 5000, etc in Pakistan fall under this category. You're good to use these oil in your car as long as they're safe with your emission system (SL grade or newer).
Diesel oils offer many benefits over their Petrol counterparts. That includes better cleaning, better protection, longer drain intervals compared to conventional oil, and the price.
Heavy Duty Engine Oil (HDEO)s have higher Ash contents, that may not be desirable for oil burning engine, but lots of ash means lots of cleaning. It'd keep your engine very clean and it's very effective against sludge and deposits.
They also have very high reserve alkalinity (TBN) even more than synthetic oils. That is an oil's acid control property. Higher TBN (along with other factors) means you can go stretch drain intervals to semi-synthetic marks, about twice as much as conventional SG/SJ grade oil.
HDEO also have lots of ZDDP generally. The role of ZDDP as friction modifier in an oil is undeniable and unmatchable. While newer engines are built to run with lower ZDDP quantities, older flat tappet head designs need lots of ZDDP for cam protection. Having higher parts per million (PPM) of ZDDP means that your precious motor can stay protected not only better but also longer.
Combine this with higher TBN and you're already into semi-synthetic ODI (oil drain interval) range, for half the price!