# US 4,395,338 A · Method and system for dewatering reserve pits

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- Number: US 4,395,338 A
- Document ID: US4395338A
- Status: Granted
- Kind: A
- Application number: 06/367,415
- Filed: 1982-04-12
- Granted: 1983-07-26
- Earliest claimed: 1982-04-12
- Inventors: Billy L. Rowton
- Web page: https://patentgrep.com/patent/US4395338A

## CPC

- C02F 1/048: {Purification of waste water by evaporation}
- E21B 21/063: {by separating components}
- E21B 41/005: {Waste disposal systems}
- Y10S 210/901: Specified land fill feature, e.g. prevention of ground water fouling
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method and system for dewatering a reserve pit at the drilling site of an oil or gas well. The pumpable waste sludge, including some bit cuttings, spent drilling mud, hydrocarbons and miscellaneous liquid wastes are first pumped from the pit into a holding tank. In the holding tank, sediments and solid particles are separated from the liquid content of the sludge. The liquid is then pumped into a high temperature boiler to separate the water, as steam, from salt and other water soluble solids and from heavy hydrocarbons. Separated solids are returned to the reserve pit. On completion of the process, the pit contains no unacceptable environmental contaminants and a minimal quantity of liquid. It is then earth filled to restore the topography to near its original condition. The apparatus employed in the invention includes a pump which is connected in a hose extending between the reserve pit and a holding tank. Another pump is connected between the holding tank and a boiler. Conveyor apparatus is provided for returning solids from the points of separation to the reserve pit.

## Claims

### Claim 1

A method of dewatering a reserve pit of the type used in drilling oil and gas wells comprising:
pumping water and entrained solids from the pit to a holding tank;
straining solid particles from the material pumped from the pit before the material reaches the holding tank;
settling out solids from the liquid and solids pumped into the holding tank;
pumping liquid from the holding tank to a boiler;
boiling away liquid pumped into the boiler from the holding tank;
returning to the reserve pit all solids separated from the material pumped from the reserve pit; and then
filling the reserve pit with earth.

### Claim 2 (depends on 1)

A method of dewatering a reserve pit as defined in claim 1 and further characterized as including the steps of:
firing the boiler with a liquefied petroleum gas;
driving pumps for pumping material from the reserve pit to the holding tank and from the holding tank to the boiler with water cooled engines; and
exchanging heat between the liquefied petroleum gas and the water coolant for the engines to pre-heat the liquefied petroleum gas and cool the water.

### Claim 3

A system for dewatering a reserve pit of the type used in drilling oil and gas wells comprising:
a holding tank for settling solids from liquid;
first conduit means connected to the holding tank and adapted to extend to and into the reserve pit;
a first pump interconnected in the first conduit means for pumping liquids from the reserve pit via said first conduit means to the holding tank;
filter means associated with said first conduit means for separating solids from liquids passing through said first conduit means from the reserve pit to the holding tank;
a first engine drivingly connected to said first pump;
a boiler;
second conduit means interconnected between the holding tank and the boiler for conveying liquid from said holding tank to said boiler;
a second pump interconnected in the second conduit means for pumping liquids from said holding tank via said second conduit means to said boiler;
a second engine drivingly connected to said second pump;
burner means for heating and firing said boiler;
a source of liquefied petroleum gas for fueling said burner means;
heat exchange means for exchanging heat between the liquefied petroleum gas used to fuel said burner means and a coolant used for cooling said engines employed for driving said pumps;
first means for conveying solids from said holding tank to said reserve pit; and second means for conveying solids from said boiler to said reserve pit.