User:Brett Berlin/sandbox

Berlin Gas Field
The Berlin gas field is located near the Texas-Oklahoma border in Beckham County, Oklahoma. The field contains recoverable reserves between 242-362 bcf and covers 41 square miles, making it the largest accumulation of hydrocarbons in the Anadarko basin. The Anadarko basin, including the Berlin field and nearby Elk City oilfield, helped boom the agricultural town of Elk City, Oklahoma.

History
The Berlin field was discovered in 1977 by the Apexco 1 Fowler well that drilled to 18,000 ft prior to deploying a mud logging tool. Until actual samples were taken, the group thought the zone consisted of a low porosity sandstone from looking at the neutron-density log, but samples later proved the zone to be a sandy dolomite with promising porosity and oil staining. The discovery was unexpected due to the facie's only containing Desmoinesian and Atokan rock and not any dolomite lithology. After the initial discovery in 1977, it was not until 2 years later that the first exploration offset well was drilled and completed in an unsuccessful search of the nearby Morrow reservoir. The first offset well produced 4.1 MMCF at just over 116,000 m3/day. A second offset well was drilled and produced 5.2 MMCF at over 147,000 m3/day. Finally, the first successful and third offset well was drilled in August 1980, that produced 11.3 MMCF at nearly 320,000 m3/day. With the success of drilling multiple prolific wells in the Atokan reservoir and other nearby wells caused a boom in drilling activity, which resulted in 37 additional wells drilled and the field developing exponentially within the next 2 years.

Geology
The Berlin field lies in an over-pressured reservoir at a depth of 15,000 ft. The reservoir rock is composed of recycled detrital Arbuckle Dolomite dating back nearly 480 ma during the Cambrian-Ordovician period. During the Atokan age, Arbuckle Dolomite and a finite amount of granite rock from the Precambrian era were eroded from the Amarillo-Wichita mountains which were then deposited as a clastic wedge adjacent to the uplift.

The field is bound on the west by the Wichita-Amarillo uplift, and the dry gas that consists in the field is trapped by a stratigraphic pinch out. The field has low porosity and permeability so hydraulic fracking is necessary to effectively develop the field.

Development
After the field was initially discovered in 1977, it wasn't until a two years later in 1979 when an offset well was drilled. This was an exploration well drilled in search of the nearby Morrow Reservoir. This well produced 4.1 MMCF. There was a subsequent well drilled that produced 5.2 MMCF. Finally a third well was drilled in August 1980 that produced 11.3 MMCF. The Berlin Gas field was then rapidly produced with over 30 producing wells by 1982, and 41 wells by 1983 when the field reached peak production of 53 MMCFG/D. In 1985, hydraulic fracturing was introduced in the field increasing production substantially. It was determined the production rate of the field was declining 7% every year. As of 1988 the field had a cumulative production of 101 BCFG which is an estimated 22% of the initial gas in place.