West Flank Coso FORGE: 3D Temperature Model

x,y,z data of the 3D temperature model for the West Flank Coso FORGE site. Model grid spacing is 250m.

The temperature model for the Coso geothermal field used over 100 geothermal production sized wells and intermediate-depth temperature holes. At the near surface of this model, two boundary temperatures were assumed: (1) areas with surface manifestations, including fumaroles along the northeast striking normal faults and northwest striking dextral faults with the hydrothermal field, a temperature of ~104 deg C was applied to datum at +1066 meters above sea level elevation, and (2) a near-surface temperature at about 10 meters depth, of 20 deg C was applied below the diurnal and annual conductive temperature perturbations. These assumptions were based on heat flow studies conducted at the CVF and for the Mojave Desert.
On the edges of the hydrothermal system, a 73 deg C/km temperature gradient contour was established using conductive gradient data from shallow and intermediate-depth temperature holes. This contour was continued to all elevation datums between the 20 deg C surface and -1520 meters below mean sea level. Because the West Flank is outside of the geothermal field footprint, during Phase 1, the three wells inside the FORGE site were incorporated into the preexisting temperature model.

To ensure a complete model was built based on all the available data sets, measured bottom-hole temperature gradients in certain wells were downward extrapolated to the next deepest elevation datum (or a maximum of about 25% of the well depth where conductive gradients are evident in the lower portions of the wells). After assuring that the margins of the geothermal field were going to be adequately modelled, the data was contoured using the Kriging method algorithm. Although the extrapolated temperatures and boundary conditions are not rigorous, the calculated temperatures are anticipated to be within ~6 deg C (20 deg F), or one contour interval, of the observed data within the Coso geothermal field. Based on a lack of temperature data west of 74-2TCH, the edges of this model still seem to have an effect on West Flank modeled temperatures.

西弗兰克科索FORGE场地三维温度模型的x、y、z数据。模型网格间距为250米。该科索地热田的温度模型使用了超过100口地热生产规模的水井和中间深度温度孔。在此模型的近地表，假设了两个边界温度：(1) 包括东北走向的正断断层和西北走向的右旋断层上的喷气孔在内的地表表现区域，在海拔高度+1066米处应用了约104摄氏度的温度作为基准，(2) 在日际和年际传导温度扰动之下，约10米深处的近地表温度为20摄氏度。这些假设基于在CVF和莫哈韦沙漠进行的地球热流研究。(3) 在地热系统边缘，利用浅层和中间深度温度孔的传导梯度数据建立了73摄氏度/千米的温度梯度等值线。此等值线延续至20摄氏度地表和平均海平面以下-1520米之间的所有海拔基准点。由于西弗兰克位于地热田边界之外，在第一阶段，FORGE场地内的三口井被纳入现有的温度模型中。为确保基于所有可用数据集构建完整的模型，某些井的测量底孔温度梯度向下外推至下一个最深海拔基准点（或井深下部的传导梯度明显时井深的最大约25%）。在确认地热田边缘将得到充分建模后，数据使用克里金方法算法进行等值线绘制。尽管外推的温度和边界条件并非严格精确，但预计计算出的温度将与科索地热田内观察到的数据在约6摄氏度（20华氏度）或一个等值线间隔内相符。鉴于在74-2TCH以西缺乏温度数据，此模型边缘似乎对西弗兰克模拟温度仍有影响。