Disposal wells may be specially drilled, though more often old wells are 

 used. Though brine is produced at all stages of production, it is more preva- 

 lent during the latter stages when the reserves are playing out. 



At the production site, treatment facilities for brine may be present. 

 Beyond the collector tank or pit these may include: skimmer, aerator, chemical 

 treater, sedimentation pit, filter, and pumps. A flowline runs from the brine 

 facility to the injector well or opens directly to marine waters. The flow- 

 lines often are made of noncorroding synthetic materials, and in upland areas 

 they are buried in the ground. The injector well or pipe opening may be a 

 long distance from the production facilities. Thus, it is not unusual to have 

 booster pumps along the way. These are surface-mounted on small concrete 

 bases or pilings. Power for booster pumps is most often electricity, and it 

 is usual practice to bury the lines in conduits unless a surface electric 

 source is found nearby. Burying the saltwater lines and conduits follows the 

 procedure previously described for flowlines. 



If the brine is discharged directly into marine waters, the pipe is 

 placed in an area where there is significant current to aid in dispersing the 

 fluids. Often the brine is warm; Evers (1972) gave a typical temperature of 

 43°C for water derived from freewater knockout and heater-treaters. The heat 

 is a result of geothermal temperatures, production treatment, and the low 

 specific heat of the brine. Heat dispersal is aided by current flow. 



If a new well is drilled for saltwater disposal, many of the steps pre- 

 viously described for new well drilling will be required. These will include 

 roadway preparation, all drilling operations, etc. If an old or dry well is 

 used, the preparations are much less extensive. It may be possible to inject 

 the brine into the same formation(s) from which petroleum was pumped. There- 

 fore, the installation of an injector pump at the wellhead may be all that is 

 necessary. In some cases, plugs may have to be drilled out and new or addi- 

 tional perforations may be required. This can often be accomplished by a 

 portable workover rig, a self-contained drilling rig mounted on a large truck. 

 Since this vehicle is not excessively large, no modifications of the road or 

 pad area are required. Drilling fluids for the workover rig are usually 

 wholly contained in steel tanks. If the well used was a dry hole originally, 

 casing may be required to protect water-bearing strata. A larger portable rig 

 may be required in this case because of the weight of the casing. Cementing 

 and perforation or screen emplacement may be additional steps required to 

 prepare a dry hole for saltwater disposal. 



At some production facilities, low production levels of brine or the 

 absence of old wells makes the disposal of brine by injection well prohibitively 

 expensive. Consequently tank trucks are used to haul brine to other disposal 

 facilities. If frequent hauling is necessary, roads leading to the production 

 site, particularly at soft spots or culverts, may need reinforcement. 



105 



