U.S. operators are stepping up their horizontal drilling program, targeting more fields and formations.
Here's what's happening:
- Union Pacific Resources Co., Fort Worth, a major Cretaceous Austin chalk participant in the Giddings area of South Texas, plans to drill at least 50 horizontal wells this year in the chalk. UPRC also will drill six or seven horizontal wells in Cretaceous Niobrara in Wyoming and Colorado, where it holds about 1.2 million net acres, and participate in five horizontal wells in Mississippian Bakken shale in Montana and North Dakota, where it has about 70,000 net acres.
- Belden & Blake Energy Co., North Canton, Ohio, used a high angle well to reach reserves under a waste dump in Ohio.
- Merrion Oil & Gas Corp., Farmington, N.M., is applying horizontal drilling to a watered out San Juan basin oil reservoir.
- The U.S. Department of Energy is drilling a deep slant/horizontal well to tight gas sands and coals in the Piceance basin of Colorado and sharing the cost of a shallow horizontal well to watered out Pennsylvanian Bartlesville sands in Northeast Oklahoma.
- Horizontal drilling may be the impetus behind a lease play developing in Pueblo and El Paso counties northeast of Pueblo, Colo. Meridian Oil Inc., Savant Resources Inc., and Severance Oil & Gas Ltd., all of Denver, have acquired a combined 170,000 acres in the area, Petroleum Information Corp. reported.
The attraction appears to be fractured Cretaceous Pierre shale, which produces in Florence-Canon City field in Fremont County, Colo., 40 miles west.
Ensign Oil & Gas Inc., Denver, has drilled or participated in several directional wells to Pierre in that particular field.
- On the international scene, Argentina's Perez Companc reported completion of seven high angle wells in 1989 in Piedras Coloradas oil field in Mendoza Province in Argentina.
UPRC'S PROGRAM
UPRC plans to drill as many as 50 wells in 1990 in the Austin chalk, said William L. Adams, chairman and chief executive officer.
The company's 165,000 acres leased or under commitment in the South Texas chalk trend, makes it one of the largest players there.
It will increase operations to 10 rigs at yearend 1990 from five rigs at present.
Adams said average recoveries from UPRC's Austin chalk wells will exceed 200,000 bbl of oil equivalent (BOE), including more than 100,000 bbl in the first year of production.
The company's average horizontal well costs $1 million to drill and complete, twice the cost of a vertical well.
Ultimate recovery is three to four times that of a vertical well.
The company will operate mostly in Brazos, Burleson, Fayette, Gonzalez, Robertson, and Washington counties and to a lesser extent in Frio and LaSalle counties in the Pearsall area.
GIDDINGS RESULTS
UPRC has drilled 16 Giddings field Austin chalk wells
since December 1988 through first quarter 1990. Production averages a combined 5,900 b/d of oil equivalent, with 5,000 BOE net to UPRC.
The most productive well, completed in March 1990, flowed 1,201 b/d of oil and 3 MMcfd of gas through a 3%4 in. choke with 850 psi flowing tubing pressure.
UPRC's chalk wells have had vertical depths of 7,200-9,500 ft, maximum horizontal displacement of 3,183 ft, and average displacement of 2,321 ft.
Ten of the 16 wells flowed without stimulation or artificial lift. Four were stimulated with a water fracture procedure pioneered by UPRC in the field for vertical and horizontal wells. All four treatments were successful.
UPRC has drilled more than 200 successful vertical wells in the chalk since 1979.
The company said it is estimated that more than 6,300 vertical wells have been completed in the Austin chalk since 1933, most of them in the early 1970s, and 1980s.
Total production has been about 475 million bbl of oil equivalent.
APPLICATIONS VARY
Onshore operators are aiming horizontal drilling technology at various operating conditions in Ohio and New Mexico.
Belden & Blake drilled a high angle well to Silurian Clinton near Alliance in Stark County, Ohio, in late 1989 and was moving in to start oil and gas production in mid-April with the lifting of frost laws.
The 72 angle well was drilled to develop reserves believed to underlie a waste dump where no surface access was allowed. Several other deviated wells are being planned to tap the deposit.
The well, drilled to about 5,100 ft subsea and deviated about 1,000 ft, penetrated about 3 ft of Clinton per vertical foot.
"The well was drilled practically trouble free with a polymer brine using a bent housing downhole motor, measurement while drilling equipment, and perforated with a gun mounted on rollers to transit the medium radius curved hole section," said Charles Haynes, vice-president, operations.
Merrion plans to drill several horizontal wells in Jurassic Entrada fields during the next few years.
Merrion placed its first horizontal oil well, 15-2H Federal, on production last month in Papers Wash field, McKinley County, N.M., in the San Juan basin.
It produced 187 b/d of oil and 779 b/d of water from Entrada sand at 5,180 ft.
Five vertical wells have produced 1.3 million bbl of oil from the field, and all but one have been shut in due to excessive water production. That left behind about 3.2 million bbl of oil, or nearly 70% of original oil in place.
SLANT/HORIZONTAL WELL
DOE is involved with horizontal wells in Colorado and Oklahoma.
It spudded a horizontal well near Rifle, Colo., Apr. 10 to be drilled vertically, at high angle, and horizontally to interbedded tight gas sandstones and coals (OGJ, Dec. 25, 1989, p. 26).
The Mesaverde group tight sands in western Colorado are believed to contain 420 tcf of gas, about two thirds of it in lenticular sands.
CER Corp., Las Vegas, is main contractor on the 3 year, $4.3 million project. Adcor Inc., Denver, is drilling contractor.
DOE also is funding a horizontal well in depleted Flat Rock field, Osage County, Okla., to tight Bartlesville sandstone.
The well will be drilled on an Osage tribal lease owned by Rougeot Oil & Gas Corp., Tulsa, a privately held independent producer that drilled a horizontal well in the same field last year.
DOE plans to publish results of the well drilled with government funds to show other independents horizontal drilling is economic in shallow reservoirs in mature stages of depletion.
The horizontal well, complete with acid cleanup job, is expected to cost $213,000, including $153,000 in DOE funds. A vertical Bartlesville well in the area costs about $40,000.
ARGENTINE WELLS
Baker Hughes Drilling Systems, Houston, under contract to Perez Companc, drilled and completed seven high angle wells during March-December 1989 to a low permeability tuffaceous sandstone reservoir in Argentina's Piedras Coloradas field.
No production information was disclosed.
The wells, averaging 7,544 ft deep, took an average 30 days to drill and complete. Horizontal displacement ranged from 984 to 1,968 ft.
Maximum angles of inclination were 77-84 from vertical.
Drilling reached a maximum buildup of 18/100 ft, with the average being 14/100 ft.
The wells were drilled with a low solids polymer mud in the reservoir, completed with slotted liner, and acidized.
Producing zone is 13-20 ft thick with 1-1.5 md permeability.
Copyright 1990 Oil & Gas Journal. All Rights Reserved.