A research into recyclable foam fluid for petroleum exploration and development

Since foam liquid has been applied widely in the oil and gas field exploration and development, as in drilling, downhole operation and enhanced oil recovery, for its low density, low filtration, low damage, high viscosity and high carrying capacity, an in-depth study is necessary to make it more economical, more efficient and more environmentally friendly. Through theoretical analysis and a large number of tests, this research selected AOS-CoAO from the anionic surfactant and zwitterionic surfactant compound system as foaming agent for recyclable foam, with Xanthan gum as foam stabilizer for it can greatly improve foam stability, and with acid-base system of calcium oxide and sulfuric acid as regulator for it almost does not affect the activity of foam. It has been shown that the recyclable foam under question has good salt resistance, desirable foamability and stability either in sea water or in oil field wastewater, and high temperature resistance - its performance keeps mostly unchanged under 302 F. Having been recycled for 10 times, it still has foam height of over 150 mm and foam half-life period of over 200 min. When the concentration of crude oil is lower than 20%, the foamability and stability are desirable; when the concentration is greater than 20%, the foamability and stability drop significantly.