HOT WATER CIRCULATION METHOD
The most commonly used method of bottom hole heating is the
circulation of hot water through a heat exchange system. This
involves heating water by the use of circulating coils or
conventional low pressure steam boiler equipment with its
relatively inefficient use of fuel and the need for a power and
pumping unit for circulation.
This method, although having some merit at shallow depths is
expensive on operation and limited in application because of the
inability to provide adequate temperatures at lower depths.
ELECTRICAL HEATING
The application of heat by the use of electricity also has been
tried extensively and found useful to a limited extent in some
situations, but because of the cost of operation and secondary
problems of cable maintenance it has not proven to be a
satisfactory answer under the conditions of pressure, chemical
action, depth, and other conditions found in these problem
wells.
THE LAWLER SYSTEM OF BOTTOM HOLE HEATING
The Lawler system of bottom hole heating uses high pressure,
high temperature steam as a source of heat and utilizes simple
principles of physics to obtain the transfer and application of
required temperatures at depth.
The system not only solves the problems of heating of wells
effectively but does so with a high degree of operating economy as
well.
This fact of operating economy takes on added significance when
it is noted that the cost of recovery has in many cases of well
stimulation by electrical heating or circulation of hot water been
greater than the value of the added production obtained.
PRODUCTION INCREASE DATA
From an economic point of view the figures relating to
production increase are the most important of the above data.
A sub-marginal producing well was chosen intentionally for the
testing because of the greater problem involved in returning this
type of well to profitable production.
Other experience with bottom hole heating indicates it is easier
to increase substantially the production of a 20-bbl. well, for
instance, than to bring a sub-marginal producer into profitable
production.
The average daily increase of production obtained in this test
was 6.5 bbls. per day. This was an increase from the daily average
of 2.5 bbls. before heating to an average production of 9 bbls. per
day after heating. This is a 360% increase, and when projected to a
yearly basis would be an increase of 2,340 bbls.
GAS CONSUMPTION DATA
The second most important factor established by these tests is
the outstanding economy of the operation as shown by the low gas
consumption of 100 cubic feet per hour in bottom hole heating test.
Field sources of gas are often available for these purposes.
WELL DEPTH
The depth of this test was 2200 feet which was a typical depth
for the wells in this field.
The maximum depth at which the equipment will operate is not
known as further testing is required to establish this fact.
However, in consideration of the large reserve of working
pressure available during the test at 2200 feet it can be assumed
that the generator will produce sufficient steam pressure and
temperature to introduce the heat required to reach formations much
deeper than this test.
SPECIFICATIONS
LAWLER MODEL NO. 100- A DRY STEAM GENERATOR
TYPE…..WATER TUBE DESIGN
TUBE SURFACE -100 sq.ft. Heating
Surface
MATERIAL . . Molybdenum Seamless Steel Tubing
MAXIMUM PRESSURE . . .500 P.S.I.
Working
3000 P.S.I. Hydrostatic Test SUSTAINED EVAPORATION 300 lbs.
per hour
B. T. U. INPUT – 105,000 to 210,000
B.T.U. per Hour
OVERALL DIMENSIONS Height 30′
Length 52′, Width 21′
WATER CAPACITY … 10 gal. Full
Capacity
5 Gallons at Operating Level
WEIGHT……….500 pounds
STARTING TIME – 200 P.S.I. within
Fifteen Minutes
FEED WATER PUMPS Walking Beam
or Lifting Unit Operated
WATER CONTROLS . . . Pressure
Regulator, Electro Magnetic and
Sight Water Level
FUEL …. Natural Gas, or Butane
FUEL CONSUMPTION . . 100,000 –
200,000 Cu.Ft. per Hour Natural Gas
BURNER . . . Bryant Industrial Type
ELECTRIC CONTROL 6 or 12 Volt
D.C.; 110 Volt A.C.
FEED WATER MAKE-UP ….
… by Condensation Return
