rules such as TWQB 130.01.67.007 (1) (a-b), RRC 051.02.02.020 (B), and State 

 water quality standards. These rules are applicable to all oil and gas activi- 

 ties regardless of whether the action is on private, State, or Federal holdings. 

 The rules deal mainly with reporting spills, cleanup procedures, disposal of 

 spoil and waste material, and precautions against fire. 



Upland drilling sites. In upland areas, or on very firm marsh soils, a 

 pad is constructed at the wellsite. Usually the equipment to build the pad is 

 the same used in road building. Trees and brush are cut and dozers enter the 

 site to clear the vegetation away. Site dimensions vary somewhat, depending on 

 the equipment used and depth to be drilled. Typical site dimensions are 97 by 

 122 m (320 by 400 ft). The topsoil may be removed and placed elsewhere, though 

 this is unusual. The area is graded to plan specifications, and occasionally 

 fill may be hauled in. After the surface is leveled, it may be compacted. At 

 the wellsite a cellar may be excavated to contain the blowout preventer; however, 

 most modern rigs are designed to place the preventer at ground level. 



Many new sites use steel tanks as circulating pits, mud reserve pits, and 

 shaker holding pits. In some cases the cuttings are temporarily stored and 

 hauled away, but more frequently these pits are built into the floor of the 

 wellsite with earthen dikes bulldozed up from the earth at the site. Depending 

 on the soil type, the pits may have to be lined with plastic sheeting or other 

 impervious materials. However, in fine-textured soils, no lining is generally 

 necessary, unless the mud contains toxic chemicals or is oil based. The levee 

 height for the pits is usually 1 to 1.5 m (3 to 5 ft); they are placed close to 

 the rig. Large rectangular pits hold cuttings and reserve mud; smaller rectan- 

 gular subpits serve other functions. 



The area at the wellsite (excluding the pits) is usually surfaced with 

 crushed stone or shell, since much vehicular activity will take place. The 

 shell is leveled and, generally, a finished pad will have an elevation of a 

 foot or so above the surrounding land. Some small drainage ditches may be dug 

 if surface drainage in the area will be a problem. 



Marsh drilling sites. On marsh soils, it used to be the practice to 

 create large elevated pads by digging out borrow and making a mound. This 

 created large pits, encouraging marsh draining and further erosion. In most 

 spots now, the rigs are located on board rig mats directly on the marsh surface. 

 After the road or dike-building equipment finishes the road to the wellsite, a 

 dragline enters the area. A ring levee around the entire site is built using 

 borrow from pits outside the levee. The outside dimensions of the levee are 

 usually no larger than 120 by 120 m (400 by 400 ft). Some drillers specify 

 that vegetation must be stripped from the marsh surface where the levee will be 

 placed to decrease the leakage of water through the levee. The levee is built 

 up to 1.5 to 2 m (5 to 6 ft) and undergoes the same shrinkage as the spoil 

 banks previously described. 



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