Posted on Monday, April 09, 2018
The Montney Tight Gas Fairway (MTGF) exists in the same region as the tight gas deep basin for many other formations. Disposal formations (that may be prolific producers to the east) become too tight within the MTGF. Other candidates are limited to specific geologic anomalies – such as the Leduc reefs or Debolt faults. Wells drilled into these formations outside of these anomalies are not productive enough.
Existing injection wells within the Montney Tight gas fairway are generally for pressure maintenance with marginal disposal capacity. While useful for secondary recovery, there are not economically viable without the benefit of oil recovery. In many cases these secondary recovery schemes exist on geological sweet spots with higher porosity and permeability that are limited in aerial extent.
Within the Montney tight gas fairway there are simply none of the hugely prolific disposal wells found elsewhere. Whereas there are single wells in the Edmonton/Ft. Saskatchewan area capable of taking > 100,000 m3/month, a prolific MTGF well might take only 10,000 m3 per month. Immediately east of the MTGF, a prolific well might take approximately 30,000 m3/ per month. Compounding the problem of the low quality of many potential candidate formations is the fact that the Fairway exists along the edge of the deformation front. This means that the drilling depth to candidate formations can be significantly deeper. For example, a Leduc formation disposal well in the Kaybob area can be found at 2,600m depth and easily accept >25,000 m3 per month. In the Kakwa/Gold Creek area in the MTGF, a Leduc well would be completed at >3600m depth and accommodate <20,000 m3 per month.
Finally, the Montney is sour across some of the fairway, particularly in the deepest parts of the basin on the Alberta side. This complicates water disposal, as it either limits potential disposal formations or requires treatment to remove H2S.
These factors are driving up disposal costs to uneconomic levels. As such, our Water Hub designs are incorporating higher water reuse strategies, sour water sweetening/reuse and evaporator systems to reduce disposal volumes. With careful planning and technology selection, we are driving down the cost of water disposal and improving economics.K'nowbe Montney Disposal Cumulative.pdf (940.2KB)