Miscellaneous Subsurface Methods 541 



of Oklahoma City. Directional wells are extracting the oil from beneath 

 the buildings without disturbing the buildings or impairing the beauty of 

 the grounds. 



Western business and residential areas of Long Beach, California, 

 are underlain at shallow depths with oil-bearing sands. Zoning prohibit- 

 ing the erection of derricks has prevented the development of these re- 

 sources by vertical wells. One group of operators has leased a strip of 

 land 27 feet wide and 6,200 feet long adjoining the area restricted by 

 zoning. Using this land as surface locations for directionally drilled wells, 

 the oil beneath the zoned area is being removed without disturbance to 

 the surface improvements. These wells, spaced in line eighteen feet apart, 

 are deflected at very shallow depths at rates of increase in drift as great 

 as eight degrees per hundred feet of drilled hole. Some wells are bottomed 

 as distant as eight or ten city blocks from their surface locations to pro- 

 duce from a shallow sand at about 3,000 feet. The drift angle of many 

 of these wells exceeds 60 degrees. All wells must be drilled within cylinders 

 to prevent collision between wells. This orderly development of subsurface 

 community leases is still being carried on. 



An example of producing from a small lease that is inaccessible be- 

 cause of zoning restrictions is shown in figure 267. The subsurface rights 

 to a small, irregularly shaped parcel of land were obtained by the opera- 

 tors. The lease was completely covered by buildings, and the area was 

 zoned against the use of drilling rigs. Plans called for two wells to be 

 drilled to a shallow oil zone of about a 3,000-foot depth. Surface rights 

 were obtained for rig locations about 1,100 feet from the subsurface lease 

 in a district where city zoning restrictions permitted oil operations. An 

 easement was obtained to permit the passage of the wells under property 

 between the surface and bottom locations. The known presence of lower 

 oil sands made it advisable to straighten the wells on bottom, as in future 

 redrilling operations the liners could be pulled and the wells deepened 

 vertically to keep them within the lease boundaries. Proposals were drawn 

 by the survey engineers and checked by the petroleum engineer and oper- 

 ator. 



The drawing shows plans and vertical sections of both wells as pro- 

 posed (light lines) and the single-shot survey of the wells as they were 

 directionally drilled (heavy lines) . The proposal specified that one well 

 was to be deflected at a 200-foot depth, increasing the drift at the rate of 

 4° 00' per 100 feet of hole drilled to a maximum drift of 32° 36'. After 

 about 1,250 feet of hole was drilled at this angle, the drift was to be re- 

 duced at 3° 00' per 100 feet of hole drilled to vertical at bottom. The 

 other well was drawn on a similar plan except that deflection started at a 

 400-foot depth. The increase and decrease in drift necessary to deviate 

 the wells an average of 1,150 feet at a 3,000-foot vertical depth with the 

 bottom hole vertical were not considered too diflicult. However, the opera- 

 tors were unable to obtain an easement across certain adjoining property, 



