...it will fall further.
The decline curve really is a measure of reservoir quality and volume. A really sharp initial decline will always be followed by more declines over the ensuing several months - and of course to the economic limit. The production profiles ar hyperbolic - which simply means that when production is plotted on a semi log graph - it shows a decreasing rate of decline or gently tapering off curved plot. (An exponential decline is a straight line on semilog charts).
Usually something with a 50-60% first month decline (from the first 24-48 hour stable after recovery of frac fluid average flow) will show something like a 20-30% decline for the next month and maybe 15-20% third month and then the month over month decline rates steadily decrease to something more exponential in nature at a 10-15% annual decline. The sharper the first month drop - the greater the rates of decline in ensuing months until the rate of decline tapers off to something "more stable" appearing.
If you have a good thick reservoir that initial decline will be much much shallower. The thinner and tighter the sand lenses the steeper and more dramatic that entire first year decline - and the lower the eventual likely year end exit production and the steeper ensuing year over year declines...
For a lot of these Hz MSF wells the first few months on production can show quite erratic behaviour depending on how they do the frac and the fluids used and what kind of formation damage they cause while fraccing. Sometimes after a wobbly IP the ensuing month can even show a level or increasing oil production before the normal hyperbolic decline profile sets in. But in these cases the operator is usually reluctant to give initial numbers as they are so depressing they wait hoping they get a better after "clean up" number to publish. So a 700 bopd IP leading to a 180 bopd average first month production volume is not a great well.
If I compare it to a Petrobakken Taylorton well that showed a 770 bopd IP with 250 bopd first month average - there could be a cumulative oil production of some 60,000 to perhaps 80,000 barrels of oil produced to its economic limit? But that was in a locally excellent part of the reservoir with 2.5m of 15% porosity sand development. (Production after 8 months was around 95 bopd).
A second Connaught (Legacy) Bakken well at Taylorton with a two day IP of over 580 bopd and a first month average of 146 bopd ended up at 31.7 bopd after 8 months. This well will likely have a cumulative oil production between 30,000 to 40,000 barrels at economic limit.
These were the two highest IP Taylorton area MSF Hz wells (But they are not actually the best wells?). I simply show these numbers as the Cardium is often compared to the Bakken - and it is similar in that the producing porous sands layers are often thin and streaky. The biggest difference is that the Bakken typically produces more water than the Cardium.
So yes that drop from a 700 bopd Ip to a 180 bopd first month average would indicate an ultimate cumulative production somewhere between 30,000 barrels of oil on the low side to maybe 70,000 barrels on the high side perhaps? It is highly unlikely to be any better.