INTRODUCTION. The California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR), and the US Bureau of Land Management (BLM) receive monthly production, injection, and related data from operators of oil, gas, and geothermal xxxxx in California. Most of these data are non- confidential and available through the DOGGR website (xxxx://xxx.xxxxxxxxxxxx.xx.xxx/). For data visualization, very powerful Microsoft Excel based tools have been developed that may either be used directly or easily modified to fit individual needs. They may be used to: 1) easily organize and retrieve data-groups, 2) reduce large data sets to meaningful sizes, and 3) graphically present the data. With the help of these tools the user can quickly and easily review data in many different ways. Data trends, as well as discrepancies, become more visible and easier to discern. In Figure 1, field-wide average production and average wellhead pressure, reduced at a rate of 6:1, are plotted. There are just too many points to interpret. However, when the same data are “appropriately reduced,” in this case 1050:1, (Figure 2) a clear trend and useful information emerges (details are discussed in section 6.1). Steam Pressure Steam Pressure The Geysers Geothermal field, which is located about 00 xxxxx xxxxx xx Xxx Xxxxxxxxx, California, USA, started production in 1960 with a 12 MW power plant. The field development picked up at a rapid pace from 1979 through 1989, although wellhead flowing pressure started showing a decline by 1984. Despite the drilling of new xxxxx and an increase in installed capacity, the steam production peaked at 112 billion kg in 1987 (Figure 3). From 1976 through 1980 the mass replacement rate (i.e., the fluid re-injection rate) was about 24%, which is approximately the cooling tower recovery at The Geysers. Injection % Injection Steam Production From 1980 through 1993, streams and creeks were tapped, thereby increasing the mass replacement rate to about 28%. From 1995 through 1997, the mass replacement increased to about 55%, due to major steam curtailments, and from 1997 onward due to additional Lake County pipeline injection (Figure 4). The Lake County 42-km pipeline transports about 1.05 million kg of secondary treated effluent per month to The Geysers for injection, which results in additional steam. An additional pipeline bringing 1.25 million kg month of tertiary treated effluent per month from Santa Xxxx and other municipalities in Sonoma County began o...
