Borehole Producer Method

In the borehole producer method (Figure 21.28), parallel galleries (used for air inlet and product gas withdrawal) are constructed in the coal bed. The boreholes are drilled from one gallery to another about 5 ft (1.5 m) apart and are filled with valves at their inlets and with iron seatings at their outlets. Electric ignition of the coal in each borehole is achieved by ranole control. 

FIGURE 21.28 Borehole producer method of underground coal gasification. (From Braunstein, H.M. et al.. Environmental health and control aspects of coal conversion An information overview. Report ORNL-EIS-94, Oak Ridge National Laboratory, Oak Ridge, TN, 1977.)... 

Deep anodes consist of parallel-connected single anodes which are set in boreholes 50 to 100 m deep with a diameter of 0.3 m. The boreholes can be produced by a variety of boring methods, but the air lift method has proved particularly suitable (see Fig. 9-10). The borehole is filled with water to ground level according to the principle of a mammoth pump. Compressed air is fed via a pipe to... 

Reverse circulation U or C 2000+ M,R,I plugging of certain formations is critical good for recovery and injection well construction continuous coring available produced fluids require handling (hazardous if NAPL is encountered) Formation relatively undisturbed compared with other methods large-diameter boreholes can be drilled ... 

Inversion of the borehole temperature profile to learn the surface temperatures that produced it can be done in various ways. These include control methods (MacAyeal et al. 

So far we have performed detailed studies for flow over isolated bodies, for example, curved fractures, shale arrays, and fractured boreholes. Here we will focus on steady and transient-compressible reservoir-scale flows produced by multilateral well systems. Because their topologies are not simple, we turn to computational methods. We will highlight problems that arise in reservoir simulator development, and importantly, we will describe a recently developed, three-dimensional algorithm that is very robust, numerically stable, exceptionally fast, and extremely accurate, and now available to the user community. Engineering implementation is an objective of the work oil companies want practical solutions that optimize operations, profits, and time value of money. The model provides tools that evaluate what if production scenarios, infill drilling strategies, and waterflood sweep efficiencies. In addition to being accurate, the solutions require minimal hardware, software, and costly human resources. 

---