Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B47/00—Survey of boreholes or wells
  • E21B47/10—Locating fluid leaks, intrusions or movements
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/12—Packers; Plugs
  • E21B33/124—Units with longitudinally-spaced plugs for isolating the intermediate space

Definitions

• the present invention relates to a flowmeter designed to find areas containing currents in a hole bored in rock.
• a serious problem is the slowness of the measurements. Measuring only the vertical current at a given depth in a hole provides practically no informa ⁇ tion about chinks at different depths in the rock or the magnitude and direction of currents flowing in them.
• making accurate measurements e.g. by sections of a few hundred metres over the who ⁇ le length of the hole to obtain the flow rates and di ⁇ rections for the section is a very slow business in long holes going to depths as large as thousands of metres.
• the object of the invention is to produce a new type of flowmeter which makes it possible to search even deep holes and locate the areas containing currents for mo ⁇ re elaborate further investigation.
• the flowmeter of the invention comprises sui ⁇ table flexible and elastic parting elements by means of which the section to be measured is separated from the hole substantially pressure-tightly.
• the parting elements are made of an elastic ma- terial that is pressed against the surfaces of the ho ⁇ le under measurement, such that they are tightly pressed against the hole without any inflatable or ex ⁇ pandable structures activated by means of a pressure medium.
• the flowmeter is provided with an open flow duct forming a free flow connection past the section under measurement delimited by the parting elements, so that currents occurring in other parts of the hole will not produce any pressure differences against the parting elements and these will, with a relatively low pressure, sufficiently seal off the ho- le section to be searched.
• the flowmeter comprises a measuring duct leading from the section under measurement to a point outside it and provided with measuring instruments by means of which the total flow of currents flowing into or out of the section can be measured.
• the flexible and elastic parting elements us ⁇ ed are preferably plate-shaped or ring-shaped rubber or plastic discs with a free external diameter somew ⁇ hat larger than the diameter of the hole to be sear- ched.
• the rubber or plastic discs preferably have a shape turned or curved somewhat upwards, per ⁇ mitting easy descent of the flowmeter down the hole by the agency of its own weight. At the measuring depth, the flowmeter is pulled back up through a small dis ⁇ tance, causing the discs to buckle into a different position. In this condition, the internal tension of the parting element itself presses it against the hole surface, increasing its tightness.
• the rubber discs of the invention acting as parting elements cannot withstand a very large pressu ⁇ re.
• the pressure level in the section under measurement is the same as in the rest of the hole, so there is no need for a high pressure-tightness.
• both parting elements are made up of seve ⁇ ral, e.g. three successive rubber discs.
• the prototype of the flowmeter of the invention was implemented using three rubber discs, which can withstand the pressure of a l£-meter water column and therefore pro ⁇ vide a sufficient tightness in all relevant measure ⁇ ment circumstances.
• the flowmeter's own weight may press the rubber discs to one side, causing the sealing to leak on the other side.
• the measuring equipment preferably includes a suitable impulse source and sensors for measuring the direction and velocity of the impulse transmitted by the impulse source.
• the length of the bore hole section measured by the flowmeter of the invention is preferably freely adjustable. This can be achieved e.g. by using sui ⁇ table extension pieces, of which a desired number can be mounted between the parting elements. In this way, the length of the hole section measured at a time may vary e.g. from one metre to over ten metres. Therefo ⁇ re, the hole can be first searched in very long sec ⁇ tions, whereupon the sections containing currents can be checked in shorter sections. Hole portions that re ⁇ quire slower and more precise flow measurements using more accurate equipment can thus be located with an accuracy of e.g. one metre.
• the flowmeter of the invention has signifi ⁇ cant advantages over prior-art technology.
• the flowme ⁇ ter allows very fast measurement of holes several ki ⁇ lometres in length, making it possible to locate hole portions containing currents, which are then examined more closely using other equipment.
• the time required for measuring and exa- mining a single hole is reduced from months to a few days.
• the flowmeter of the invention as presented in the drawing comprises an open pipe 7 with three ring-shaped, elastic parting elements 1 at each end, forming between them a measurement section 3 in the hole 2.
• the pipe 7 forms an open flow duct 4 past the measurement section 3 delimited by the parting ele ⁇ ments 1 in the hole
• the parting elements 1 are elastic and flexi- ble rubber flanges which, slightly deviating from the direction of the radius of the hole, extend obliquely upwards. Their size is so chosen that their elasticity will cause them to press against the round surface of the hole, in other words, their free external diameter is somewhat larger than that of the hole.
• the pipe 7 between the parting elements 1 is provided with two apertures 8 which, however, do not communicate with the open flow channel 4, but form the starting point of a measuring duct 5 which runs inside the pipe 7 to measuring equipment 6 and, through this equipment, opens into the hole portion above the flow ⁇ meter.
• the measuring equipment 6 comprises an impul ⁇ se source 10 placed in the measuring channel, and, placed on either side of it, sensors 11 allowing the impulse sent by the impulse source, i.e. the velocity and direction of motion of the impulse, to be measu ⁇ red.
• the flowmeter is provided with a hoisting and control cable 9 by means of which the flowmeter can be raised and lowered in the hole under measurement e.g. using a suitable winch and through which the measurement information obtained from the measuring equipment 6 is transferred to suitable pro ⁇ cessing apparatus provided above ground.
• the flowmeter is used as follows.
• the flow e- ter, suspended by the hoisting and control cable 9, is lowered into the hole to be measured to a desired mea ⁇ suring depth.
• the flowmeter is pulled up through a short distance (a few centimetres), cau ⁇ sing the plate-shaped parting elements to be pressed tightly against the hole surface. In this way, a sec ⁇ tion 3 to be measured has been separated from the hole with sufficient sealing.
• pipe 7 provides a free flow path (arrows A) for external cur ⁇ rents past the measurement section 3.
• the rock 12 within the area covered by the measurement section 3 contains any fissures 13 with currents (arrow B) in them, these currents can cause a flow through the apertures 8 into the measuring duct 5 and through it (arrow C) further outside the flowme ⁇ ter.
• the flow rates in the measuring duct 5 may show large variations, which is why flow measurement is performed by two methods.
• flow measurement is started by an impulse method, in which the water is heated momentarily by means of a heating thermistor 10 and the movement of the heat impulse produced by it in the water is monitored by means of sensors 11 placed on either side of the heating thermistor at a distance from it.
• an impulse method in which the water is heated momentarily by means of a heating thermistor 10 and the movement of the heat impulse produced by it in the water is monitored by means of sensors 11 placed on either side of the heating thermistor at a distance from it.
• sensors 11 placed on either side of the heating thermistor at a distance from it.
• This method can be used to measure currents with flow rates varying from a few millilitres to three thousand millilitres per hour.
• the di- vergence of the measurement results increases, and the flow is determined by using a cooling method.
• the cooling method the heating thermistor 10 is heated, whereupon its cooling down is monitored, because the cooling takes place the faster the higher is the flow rate.
• the cooling method it has been possi ⁇ ble to extend the measuring range to 60000 ml/h and beyond.
• the flowmeter can be easily moved, raised or lowered to the next place, and measurements can thus be continued one section at a time over the whole length of the bore hole.
• the apparatus preferably compri- ses a pump for keeping the water level in the hole un ⁇ der measurement at a constant height.
• This can be implemented using a long surge pipe whose lower end is blocked while the upper end is open. With this soluti ⁇ on, the pumping of the water is effected from inside the surge pipe as the water in the hole flows into the surge pipe placed on a constant height.
• the water le ⁇ vel inside the pipe varies but remains at constant height in the hole, i.e. at the level of the upper end of the pipe.
• the apparatus may further comprise a pump for pumping water into the hole while the hoisting and control cable is being pulled up. This prevents the water level from falling as a result of the cable being raised. In this way, the pumps can be used to keep the pressure conditions as constant as possible throughout the measuring operation.
• the measuring programs proper are contained in a measuring computer which sends control commands to a processor in the flowmeter and receives measurement results from the processor.
• the measure ⁇ ment results are subjected to conversions as required and they are presented on a display screen and saved in files.
• the measuring computer reads the pressure data (air pressure and ground water level), controls the hose pump, reads the pulses of a cable counter and stops the winch on the basis of the cable counter pulses.
• the measuring programs of the proces- sor are stored in the flowmeter's program storage.

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• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geophysics (AREA)
• Measuring Volume Flow (AREA)
• Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)
• Geophysics And Detection Of Objects (AREA)

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Citations (4)

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• 1996
  • 1996-01-12 US US08/913,011 patent/US5804714A/en not_active Expired - Lifetime
  • 1996-01-12 CA CA002214786A patent/CA2214786C/en not_active Expired - Lifetime
  • 1996-01-12 WO PCT/FI1996/000028 patent/WO1997025517A1/en active IP Right Grant
  • 1996-01-12 EP EP96900620A patent/EP0815346B1/en not_active Expired - Lifetime
  • 1996-01-12 AU AU44501/96A patent/AU4450196A/en not_active Abandoned
  • 1996-01-12 KR KR1019970706264A patent/KR100270143B1/ko not_active IP Right Cessation
  • 1996-01-12 DE DE69626633T patent/DE69626633T2/de not_active Expired - Lifetime
  • 1996-01-12 JP JP09524881A patent/JP3045317B2/ja not_active Expired - Lifetime
• 1997
  • 1997-08-21 FI FI973441A patent/FI110336B/fi not_active IP Right Cessation

Patent Citations (4)

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