DRILLING SITE ON A NATIONAL SEASHORE REQUIRED EXTRA ENVIRONMENTAL PRECAUTIONS

Mike Hunt
Bright & Co.
San Antonio

The comprehensive planning required for a well drilled on a National Seashore resulted in a trouble-free operation that minimized effects on a very sensitive environmental area. The procedure for obtaining approval from the National Park Service for this exploration well was very detailed and time consuming.

Bright & Co., San Antonio, drilled the Dunn-McCampbell No. 1 on the Padre Island National Seashore in Kleberg County in South Texas earlier this year. The Padre Island National Seashore, a unit of the National Park System, is a barrier island located 10 miles south of Flour Bluff and extends approximately 70 miles to the Mansfield Channel.

Congress created the Padre Island National Seashore in 1962 through a law which preserves undeveloped U.S. seashore. Although the federal government owns all surface lands in the National Seashore, the majority of the subsurface oil and gas rights are owned by the Dunn-McCampbell heirs.

Development of the private oil and gas rights may occur in the National Seashore area as long as operators comply with National Park Service regulations of Title 36, Code of Federal Regulations Part 9, Subpart B. These regulations require operators to submit a plan of operations. Operators must also comply with Texas Railroad Commission regulations.

PLAN OF OPERATIONS

Under the National Park Service regulations, a plan of operations must contain the following:

Lease and ownership information
Maps of the lease and maps showing the location of the proposed operations
Description of area geology
Timetable of operations
Description of the proposed operations, including the construction of the location, the drilling program, the completion program, and the proposed production facilities
Spill control plan
Reclamation plan
Affidavits, statements, and permits
Description of natural resources
Description of archaeological and cultural resources
Description of social and economic environments
Environmental consequences
Alternative methods of operations
Discussion of the proposed plan of operations as related to the unit's statement of management.

Bright & Co. submitted its plan of operations to the National Park Service on July 7, 1994, and obtained approval on Sept. 30, 1994.

Under an approved plan of operations, an operator must file a performance bond before undertaking any operations on the ground. The performance bond is equal to the estimated cost to reclaim the location, plus the estimated cost of cleanup, in case an oil spill occurs. The maximum performance bond requirement for the estimated total cost of the above items was $200,000.

WELL SITE

Because the proposed access road to the location required that 19 nontidal wetlands (total area of 0.4 acres) be filled, a permit from the U.S. Corps of Engineers was required. As compensatory mitigation for the 0.4 acres of wetlands filled, the operator was required to create 0.8 acres of wetlands. The 0.8 acres of wetlands were constructed by excavating to tidal flat elevation a portion of an existing road that went to an abandoned well at Murdock Pass field.

The Corps of Engineers permit was submitted on Mar. 1, 1994, and approval was obtained on Nov. 9, 1994. The Corps of Engineers permit and the environmental portion of the plan of operations were prepared by Belaire Consulting Inc. in Rockport, Tex.

The access road to the location was reached by driving approximately 6 miles south along the beach, from the end of the paved road at Malaquite Beach. The length of the newly constructed access road to the location was 1.63 miles. The fill for the low areas on the access road was obtained from the mitigation site.

The 14-ft wide access road was constructed with 6 in. of compacted caliche. The project required 7,600 tons of caliche, which was hauled 85 miles from a caliche pit near Mathis, Tex.

The 300-ft x 300-ft drilling pad had a 3-ft high ring levee around its perimeter. The drilling pad was also made of 6 in. of compacted caliche. An 18-mil polyethylene liner (200 ft x 110 ft) was installed on top of the caliche pad and under all of the rig equipment, mud tanks, and pipe racks. A berm was constructed around the perimeter of the liner, and the drilling pad was sloped so that all liquid discharge onto the liner would drain to the cellar.

The cellar was constructed from an 8-ft diameter corrugated metal pipe. The bottom of the cellar was 6 ft below the surface of the caliche pad. After the 14-in. conductor pipe was driven in, the bottom of the cellar was cemented with concrete. A centrifugal pump was used to pump out to the mud tanks any liquid that accumulated in the cellar.

These precautions,to contain and collect any discharge of liquids were required because Padre Island has a shallow freshwater aquifer approximately 4 ft below the ground surface. The water from the aquifer collects in shallow ponds on the island and is the main source of drinking water for wildlife there. Therefore, the National Park Service requires groundwater monitoring wells at the production facility site to determine if any contaminants enter the groundwater.

Mesa Drilling Inc.'s Rig No. 4 drilled the well. The rig was well suited for this environmentally sensitive area. The rig was a diesel-electric SCR (silicon controlled rectifier) unit with a very low noise level. The rig was also very mobile, with the majority of the components wheel mounted, thereby reducing the number of loads required to be mobilized along the beach.

The rig's small footprint lessened the required polyethylene liner size. The engines for the generators were equipped with oil drip pans, and the electric motors for the mud pumps and draw works virtually eliminated the chance of an oil leak.

A closed-loop mud system was used to collect the drill cuttings. The closed-loop system consisted of a Derrick Flo-Line Cleaner (supplied by the rig), a high-G mud cleaner, and a decanting centrifuge. The drill cuttings were collected in 85- bbl-capacity boxes, mounted on railroad tracks (Fig. 2). After a box was filled with drill cuttings, it was sealed and loaded on a truck and then hauled to a disposal site at Ingleside, Tex.

DRILLING PROGRAM

The drilling program consisted of the following:

Conductor pipe (14 in.) was driven to 98 ft using a diesel hammer.
A 12-in. hole was drilled to 1,746 ft, and 9 5/8-in. surface casing was run and cemented to surface.
An 8 3/4-in. hole was drilled to 8,900 ft measured depth (8,167 ft true vertical depth). A chrome-free lignosulfonate mud was used. The maximum mud weight was 9.9 ppg.
The well had to be drilled directionally because the bottom hole location was under a large wetlands area. The well was kicked off at 1,830 ft, and the angle was built at 2/100 ft to 29 with an azimuth of 313.
The angle was held to total depth. A majority of the angle-holding portion of the hole was drilled with an 8 3/4-in. polycrystalline diamond compact bit, which averaged 58 ft/hr and did an excellent job of holding angle and direction.
The main target was the Frio Marg A sand at 7,506 ft true vertical depth and a vertical section of 2,770 ft.
The well was drilled in 14 days. The well was logged at 8,900 ft measured depth with an induction-density-neutron log.
There were no productive zones in the well, and the well was plugged and abandoned.
The caliche location and access road were removed. The ground surface was restored to its original contours and was reseeded with native grass.