ConocoPhillips remains an excellent value in the oil patch.There are many ways to invest in oil and gas, from upstream exploration and production (E&P) companies to midstream pipeline and infrastructure players, to downstream marketing and refining companies, to integrated majors that operate across the value chain.The upstream side of the industry tends to be the most sensitive to changes in oil and gas prices. With oil prices near the lowest level in a year, even top E&Ps like ConocoPhillips (COP 0.32%) a ...