Model Experiments of Steam Stimulation in Nigerian Tar Sands

Abstract

The possibility of producing heavy oil from the Nigerian tar sand deposit by steam stimulation was investigated in the laboratory using a scaled andfive unscaledphysical models (tar sands packs). The effect of oil saturation and different matrix grain size on oil recovery were also studied.A fabricated 91.44 cm (diameter), 33 cm (high) high pressure cast iron vessel (prototype scaled down by a factor of 104), a 15 c m (diameter), 22.1 c m (high) high pressure stainless steel vessel, and two pressure reducing valves were used for the study. Steam was obtained from a locally fabricated boiler. Heavy oil was obtained from oil seeping from the deposit.The result of the study showed that heavy oil could be produced from the section of the deposit containing mobile heavy oil by steam stimulation. When the same amount of steam was injected into similar sand packs containing different oil saturation, the highest oil recovery was obtained from the sandpack with the lowest oil saturation. This implies that more steam will be required to produce from highly saturated heavy oil deposits. A greater amount of oil was produced from a sand pack with larger matrix grain size than from another sand pack with smaller matrix grain size for the same oil saturation steam quantity, and quality.

How Economic is Steam-Assisted Gravity Drainage for the In-situ Development of the Nigerian Bitumen Deposit?

“…Through numerical studies 9,10 , the technical feasibility of SAGD for the exploitation of this deposit has been demonstrated. As a sequel to the foregoing and other grounding works [11][12][13][14][15][16] , we believe that the next logical step in the maturation of the SAGD technology for the Nigerian system is to assess its economics. This is exactly the objective of the current paper.…”