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All of these components need to be considered when analyzing
<br />a company's produced water disposal costs. Once capital costs
<br />are amortized, and gathering considered, total disposal costs
<br />can vary widely - from about $0.12 / bbl in SE New Mexico to
<br />more than $5.00 / bbl in the Green River or Wind River Basins
<br />in Wyoming.
<br />Water volumes can vary widely between regions and can have
<br />an impact on economics of disposal options. The New Mexico
<br />Oil Conservation Division (NMOCD) reports that produced wa-
<br />ter is estimated to be 653 million barrels in 2005. This includes
<br />water from East Indian Basin where one well can produce 3,000
<br />bbls / day of water, but only costs about $0.17 / bbl for disposal.
<br />This low disposal cost is a result of the tremendous investment
<br />in disposal infrastructure made by operators to accommodate
<br />the larger volumes of water produced per well in this region.
<br />MYCO Industries, Inc. operates five wells east of Carlsbad,
<br />NM that produce a total of about 120bb1 /day of water. With no
<br />disposal gathering infrastructure available, disposal costs for
<br />these wells run $2.70 /bbl. This price is a combination of hourly
<br />trucking rates to haul produced water to a commercial site and
<br />a disposal fee of $0.50/barrel to actually dispose of the water.
<br />Also worth considering is the fact that the cost of converting a
<br />dry hole is not going to change just because there is less water
<br />available for disposal.
<br />Technological and Logistical Hurdles
<br />Wyoming and New Mexico produce similar quantities of water,
<br />but volumes vary widely between regions. For example, pro-
<br />duced water volume from coal bed methane(CBM) production
<br />in the Powder River Basin(PRB) is about 1.5 million barrels
<br />per day from about 15,000 wells, or an average of 100 bbls /day/
<br />well. The gas production from the area is about 900 mmcfd.
<br />These figures indicate that, for each mcf of gas produced, there
<br />is also 12/3 bbl of water produced. Conversely, in the Green
<br />River Basin (GRB) in Southwest Wyoming, there is an average
<br />of only about one -tenth of a bbl of water produced per mcf of
<br />gas. The high volume of water produced in the PRB - more
<br />than 16 times the volume produced in the GRB - has raised
<br />many controversial questions about producing gas from the
<br />PRB.
<br />Produced water quality will present technological hurdles.
<br />Produced water quality varies as widely as quantity from
<br />area to area and has a tremendous impact on treatment op-
<br />tions available. Table 1 presents a brief summary of typical
<br />produced waters encountered in the oil field, illustrating the
<br />challenge related to treatment.
<br />Treatment Technologies
<br />Five years ago, Yates Petroleum knew nothing about water
<br />treatment technologies. After considerable time and money,
<br />we've moved along that learning curve. There is still a lot
<br />to learn and a way to go before we are treating meaningful
<br />volumes of water, but we believe that we are at the forefront
<br />of New Mexico producers who see the value to the state, our
<br />industry, and our company in pursuing produced water treat-
<br />ment options.
<br />Four different types of technical solutions have evolved in
<br />the oil and gas produced water treatment arena: membranes,
<br />evaporative technologies, ion exchange, and thermal com-
<br />pression.
<br />-Thermal compression requires expensive pressure vessels,
<br />and the operator must still dispose of a concentrate stream. It
<br />does not appear to be as economic as other technologies.
<br />•It appears the key to any membrane technology will be pre-
<br />treatment. Conventional reverse osmosis (RO) membranes
<br />are easily fouled by bacteria, hydrocarbons, heavy metals,
<br />and other suspended solids such as calcium sulfates.
<br />•Ion exchange treatment techniques have become the applica-
<br />tion of choice in the Powder River Basin where water quali-
<br />ties are fairly good with the exception of elevated sodium
<br />levels.
<br />Evaporative technologies have evolved from using simple
<br />misters dependent on ambient conditions to more sophisti-
<br />cated systems that recover much of the latent heat of vapor-
<br />ization.
<br />All units
<br />mg/L
<br />Pecos River
<br />Disposal Well
<br />Well 1
<br />Well 2
<br />Well 3
<br />Well 4
<br />Well 5
<br />States
<br />NM
<br />NM
<br />NM
<br />WY
<br />WY
<br />NM
<br />NM
<br />Bicarbonates
<br />127
<br />705
<br />488
<br />3,318
<br />1,680
<br />39
<br />464
<br />Hardness (CaCO3)
<br />n/a
<br />n/a
<br />11,000
<br />n/a
<br />n/a
<br />88,000
<br />15,000
<br />Arsenic
<br />0.082
<br />0.078
<br />n/a
<br />n/a
<br />0.036
<br />n/a
<br />n/a
<br />Calcium
<br />620
<br />582
<br />3,600
<br />404
<br />70
<br />30,000
<br />5,200
<br />Chlorides
<br />2,020
<br />3,100
<br />48,000
<br />n/a
<br />9,360
<br />182,000
<br />80,000
<br />Sodium
<br />1,064
<br />12,010
<br />27,261
<br />444
<br />6,250
<br />78,398
<br />45,591
<br />Sulfates
<br />2,040
<br />11,160
<br />1 1,800
<br />1212
<br />14
<br />600
<br />400
<br />TDS
<br />6,350
<br />18,070
<br />181,629
<br />15,977
<br />115,700
<br />1294,167
<br />132,135
<br />
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