GB842975A - Method of and apparatus for flooding sample cores taken from oil-bearing rock strata - Google Patents

Abstract

842,975. Testing oil-bearing rock samples. DEUTSCHE ERDOL A.G. June 6, 1956 [June 7, 1955], No. 17549/56. Class 106 (2). [Also in Group XXIX] A method of flooding sample cores taken from oil-bearing rock strata to ascertain the extent to which oil can be removed by forcing water into the strata, comprises enclosing a sample core 2, Fig. 1, in a soft metal casing' 2a, placing the filled casing in a medium 1a that is maintained at a higher pressure than the flooding pressure, reproducing the pressure and temperature of the rock strata in the sample core 2 and in the medium 1a, and then flooding the core to expel the oil from it. The expelled oil is collected in a measuring-apparatus 23, having means 22 for separating the liquid and gaseous constituents from one another, the gases being sucked into collecting means 25, 27, 29, through a pressure-regulator 24 (see Group XXIX) maintaining a constant pressure in the separator 22. The core 2 in its casing 2a is initially filled with salt water and the volume of its pores determined by the amount of liquid absorbed. The sample in its casing is then placed in the chamber 1 to which oil under pressure is supplied by a pump 3. The chamber 1 is surrounded by a jacket 1b through which a heated liquid flows. By opening suitable valves, compressed air from a bottle 16, or compressed mineral oil from a pump 17, is used to cause crude oil in a container 8 to flow through the core sample to expel the water therein. When oil begins to emerge from the sample via a pipe 6, the container 8 is shut off and a vessel 10 containing water from the strata is used to expel the oil in the sample to the receiver 23 via the separator 22. To collect the gases in the separator 22, a levelling vessel 26 is lowered to create a subatmospheric pressure in a measuring tube 25 coupled to the separator 22 through the pressure-regulator 24. As soon as gas is released by the oil an almost inappreciable superatmospheric pressure is produced which suffices to operate the regulator 24 so that gas flows from the separator 22 to the measuring tube 25. When the tube 25 is filled it is shut off and the levelling vessel 28 and measuring tube 27 is connected to the system. By raising the levelling vessel 26 the gas in the tube 25 is passed to a collecting-tube 29. As soon as water drops appear at the outlet side of a regulator valve 21 the receiver 23 is removed. A differential pressure-measuring device 31 is connected across the rock core. Core casing. The soft metal casing 2a, Fig. 2, may be an easily fusible alloy of bismuth and tin, the casing terminating in brass rings f and end caps 2b formed with conduits.