There are seven "common graphs" that can be accessed from all the tab views (Play Types, Producing Zones, Operators and Trends). These are specialized graphs that do not pertain to any specific section. The seven graphs are:
Pie Charts
The Overall Class Pie Chart and the Overall Status Pie Chart provide a synopsis of well distribution. The graphs below show the well distribution for a development driven company with a relatively even mix of oil and gas assets.
Distribution Graphs
Distribution graphs are provided for initial production (boe), reserves (boe) and drilling costs ($). The example below shows the reserves distribution for the Cantuar-Success - Sands. The best wells will yield ultimate recoverables of more than 2,000 mboe, while the worst wells will fail completely. 75% of the wells will recover ~15 mboe and 25% of the wells will recover ~150 mboe. The median recovery is 52 mboe.
Yearly Change in Production Rate Graphs or
Normalized Yearly Average Production Change (Decline) Graphs
These graphs, provided for both oil and gas, show the average yearly change (decline) in production rates on a percentage basis. The steeper the rate of change, the greater the rate of production decline. The flatter the rate of change in production, the more sustained the production rate for any given area, play, operator or zone.
For example, the graph below shows the Normalized Yearly Average Production Rate Change for a large operator. The steep decline in the first few years is a function of the normal initial decline ('flush' production / pressure drawdown) in combination with the type of play involved, regulatory issues or any number of other factors. Over time, the rate of change flattens out as reservoir pressures and production regimes begin to stabilize.
In some years, such as Year 5 & Year 6, the rate of change is positive. This could be a result of well 'workovers', changes in production practices or other changes made by the operator. In latter years, the influence of statistical error and the effect on the calculated averages when the older, 'marginal' wells have declined to the point where they are taken off stream leaving the stronger, more stable and anomalous, producers, should not be overlooked.
How is the Change in Production Rate Calculated for each Year?
For each well, the first year day rate is compared to the second year day rate and a percent change in day rate is calculated for Year 1. The Year 1 Change in Production Rate for all wells is then calculated using a weighted average (based on production hours). First year production is defined as the first year in which a well produces for a minimum of three months and second year production is defined as the second year in which a well produces for a minimum of three months. If a well does not meet the cut-off in its second year, then its third year will become its second production year.
To calculate the Year 2 Change in Production Rate, a change in production rate from year 2 to 3 is used. For Year 3, years 3 and 4 are compared, and so on. In latter years, the number of wells that meet the minimum three month production cut-off decreases.
Only gas wells are considered for Yearly Change in Gas Production Rate graphs and only oil wells are considered for Yearly Change in Oil Production Rate graphs.
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