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In my most recent article I stressed the value of historical production to model unconventional wells. It is not a perfect method as it does not account for all variables. Drilling and completion techniques are the most difficult to gauge. This is why it is important to compare a series of wells from one operator in the same general area. It provides a baseline. This allows focus to remain on other variables and how it affects production.

My article Bakken Update: EOG's Parshall Field EURs of 2 Million Barrels of Oil focused on consistent data points. I used EOG Resources (EOG) for several reasons. It is a top producer with a good well design. In 2007, EOG completed a large number of wells in Parshall Field. This allowed for a comparison of wells in the same area, with the consistency of one operator. Results were consistent as IP rates improved when larger amounts of water and proppant were used. EOG continued to use short laterals throughout its development of Parshall Field. Only one well modeled below 500 MBo. Two of these wells were over 1000 MBo.

What EOG is to Parshall Field, Whiting (WLL) is to Sanish. Whiting has been developing this area since 2006. I was unable to obtain enough on wells completed in 2007, so I expanded the chosen wells to July of 2008. This data will show Whiting has produced well results much like EOG's in Parshall. Whiting has used a wider choke which should produce higher 24-hour IP rates. Wider chokes can cause a more rapid depletion as well. EOG used only short laterals, while most other operators used long laterals. This should provide higher EURs for Whiting. This is misleading as EOG garners more resource per foot. EOG has historically used more water and proppant per foot, which should reduce depletion. Table 1 offers production rates from 10 Whiting wells completed in 2007 and through the first six months of 2008.

2007-2008 Whiting Sanish Field Well Depletion
WellIP Rate360-Day IP720-Day IP1080-Day IP1440-Day IP1800-Day IP
167311323404365309269252
164631081372301246214191
169022192411307248216202
170232669715533460389364
168521765385323285*266

249

168711567365274230207*194
167811923469367308265248
16734945218157142*133124
170923027965805685591553
167801519814571443363339
Avg.1801512400336314294
71.6%21.9%16%6.5%6.5%

In Table 1, the wells marked with an * had some production problems. This was during the flooding of western North Dakota. I didn't see any production decreases after production was resumed, so I still used the data. The numbers in bold were estimated using the average depletion of the other wells. When depletion falls below 8% the majority of production from fractures has ceased. The 6.5% is a terminal decline and should remain constant throughout the life of the well. This is matrix production, which models differently from the first few years of well life.

EOG Well Depletion In Parshall Field In Bo/d

Table 2

WellIP Rate360- Day IP720-Day IP1080-Day IP1440-Day IP1800-Day IP
16637970449313251215234
164611487469410321264231
165431015440321261226197
165321285489365291253223
16467783333240198171150
164971675502364292246
16635581286203162135116
164841670535379302254219
16457922481339275232202
165501329421307253217
166711198466340282242212
16483870494396321272239
163701553421332269226195
164691267533396322276249
16578817489358291253
16371918552421342288250
16713781740494389322
167681441793535424350
167951519814561438360
Avg.1162511372299253209

Rate

56%

27.3%

19.6%15.4%17.4%

I added Table 2 from my EOG article as a comparison. Whiting's 360-day depletion of 71.6% was higher than the EOG well average of 56%. EOG's depletion is higher than Whiting's for years two, three and four. It is possible Whiting's increased initial depletion is from a larger choke, but I believe it has more to do with proppant. The data comparison seems to prove production curve flattens at some point. The only question is when. Keep in mind the best cumulative oil producer of the two groups was drilled and completed by Whiting. Well number 17092 has produced 872636 barrels of oil since its IP test on 6/20/08.

Whiting Sanish Field Well Design

Table 3

WellLateralChokeProppant
16731762516/641900000
16463835013/48
16902951618/641840000
17023944328/641625500
16852943228/641244000
16871942628/641629000
16781976224/643104180
16734848220/641963740
17092953926/641705000
16780771917/641959000
Avg.8929 1885602

The Whiting wells in Table 3 used 211 pounds of proppant/foot. EOG's Parshall wells used 420 pounds/foot. EOG is able to prop the fractures open wider and longer by using more. This seems to lengthen the time the EOG wells produced from the fractures before converting to exponential decline (matrix production). The lower production and decreased depletion in Whiting's wells at the 1440-day IP seem to indicate these wells are already in exponential decline.

2007-2008 Whiting EURs In Sanish Field

Table 4

Well1800-Day IPOil ProducedEUR
16731252453600907200
16463191343800687600
16902202363600727200
170233646552001310400
16852249448200896400
16871194349200698400
16781248446400892800
16734124223200446400
170925539954001990800
167803396048001209600
Avg.272488340976680

At first glance the Whiting wells look better than EOG's. This is not the case when taking lateral length into consideration. The average lateral length of the Whiting wells are twice that of EOG's. In reality, the Whiting wells produced half the resource per foot. Well number 17092 is a great well, modelling to almost 2 million barrels of oil. These wells do not include natural gas or natural gas liquids in EURs, which accounts for an estimated 8% of production in Mountrail County.

2008 Alger Field Cumulative Oil Production

Table 5

WellOperatorOil Produced
17572(HES)161906
17378HES85546
17389HES109702
17477(OAS)57829
17165(STO)147781
16893STO78980
17359STO130287
17481STO159345
16898STO55476
17018STO69007
Avg. 105586

In Table 5, I listed all of the Alger Field wells completed in 2008. I chose this field due to Brigham's success in the area and its close proximity. It is thought of by some to be as good if not better than the Sanish and Parshall Fields. The best result in table 5 was lower than all of EOG and Whiting's results. The reason is not geology, but well design. As these operators are now producing excellent results in these areas.

In summary, the Sanish and Parshall Fields are considered to be some of the best areas in the Bakken. Using wider chokes produces high 24-hour IP rates, but increases the depletion curve. Using more proppant increases production over the first few years of production significantly. It also flattens the depletion curve and leads to exponential decline at a later time. EOG was the top operator in 2007, but Whiting also produced very good results. When compared to other operators in the area, both EOG and Whiting outperformed. Looking at the second half of 2012, we are seeing a change in well design. More water depots are being constructed as agricultural water is converted to commercial uses. Proppant from Russia and China has increased pushing costs down about 40% year over year. As these costs decrease, more will be used. This should continue to improve well results.

Source: Bakken Update: Whiting's Sanish Well Models To 2 Million Barrels Of Oil

Additional disclosure: The models used in this article are estimates. These wells could end up producing significantly less or more oil over the next few decades. This is not a buy recommendation.All of the wells in this article are measured in barrels of oil. Natural gas and natural gas liquids were not included in estimates. If you would like to see more of my articles, go to shaleinsight.net