As of December 31, 2010, our Michigan operations comprised approximately 68% of our total estimated proved reserves. For the year ended December 31, 2010, our average production was 10.7 MBoe/d or 64.1 MMcfe/d. Estimated proved reserves attributable to our Michigan properties as of December 31, 2010 were 80.3 MMBoe. Our integrated midstream assets enhance the value of our Michigan properties as gas is sold at MichCon prices, and we have no significant reliance on third party transportation. We have interests in 3,545 productive wells in Michigan.
In 2010, we drilled 16 wells, completed 28 well optimization projects (fracture stimulations, recompletions and workovers) and completed eight line twinning and/or compression optimization projects. The line twinning and compression optimization projects targeted casing pressure reduction in the pressure sensitive Antrim Shale. Line twinning converts a single line gathering system, where natural gas and water are transported from the well to the central processing facility in one line, to a dual line system where the water and gas each have their own line to the central processing facility. As a result, the casing pressure at the well can be lowered thus increasing production. Our capital spending in Michigan for the year ended December 31, 2010 was approximately $24 million.
The Antrim Shale underlies a large percentage of our Michigan acreage; wells tend to produce relatively predictable amounts of natural gas in this reservoir. On average, Antrim Shale wells have a proved reserve life of more than 20 years. Since reserve quantities and production levels over a large number of wells are fairly predictable, maximizing per well recoveries and minimizing per unit production costs through a sizeable well-engineered drilling program are the keys to profitable Antrim development. Growth opportunities include infill drilling and recompletions, horizontal drilling and bolt-on acquisitions. In 2010, our average production from the Antrim Shale was 44.5 MMcf/d or 7.4 MBoe/d. Our estimated proved reserves attributable to our Antrim Shale interests as of December 31, 2010 were 66.8 MMBoe or 401 Bcfe, of which 94% was p roved developed. In 2010, we drilled 13 wells and eight recompletions, and completed eight line twinning and/or compression optimization projects. We have interests in 3,266 productive wells in the Antrim Shale.
Our non-Antrim interests are located in several reservoirs including the Prairie du Chien ("PdC"), Richfield ("RCFD"), Detroit River Zone III ("DRRV") and Niagaran ("NGRN") pinnacle reefs. In 2010, our average production from our non-Antrim interests was 19.6 MMcf/d or 3.3 MBoe/d. Our estimated proved reserves attributable to our non-Antrim interests as of December 31, 2010 were 13.5 MMBoe or 81 Bcfe.
The PdC produces dry gas, gas and condensate or oil with associated gas, depending upon the area and the particular zone. There are some proved non-producing zones in existing well bores that provide recompletion opportunities, allowing us to maintain or, in some cases, increase production from our PdC wells as currently producing reservoirs deplete.
The vast majority of our RCFD/DRRV wells are located in Kalkaska and Crawford counties in the Garfield and Beaver Creek fields. Potential exploitation of the Garfield RCFD/DRRV reservoirs either by secondary waterflood and/or improved oil recovery with CO 2 injection is under evaluation; however, because this concept has not been proved, there are no recorded reserves related to these techniques. Production from the Beaver Creek RCFD/DRRV reservoirs consists of oil with associated natural gas.
Our NGRN wells produce from numerous Silurian-age Niagaran pinnacle reefs located in the northern part of the lower peninsula of Michigan. Depending upon the location of the specific reef in the pinnacle reef belt of the northern shelf area, the NGRN pinnacle reefs produce dry natural gas, natural gas and condensate or oil with associated natural gas.
In 2010, we drilled three wells and completed 20 well optimization projects (fracture stimulations, recompletions and workovers).