UNITED STATES DEPARTMENT OF INTERIOR 

GEOLOGICAL SURVEY

Summary of Deep Oil and Gas Wells and Reservoirs in the U.S.

By

1 211 1 T.S. Dyman , D.T. Nielson , R.C. Obuch , J.K. Baird , and R.A. Wise

Open-File Report 90-305

This report is preliminary and has not been reviewed for conformity with 

U.S. Geological Survey editorial standards and stratigraphic nomenclature, 

Any use of trade names is for descriptive use only and does not imply 

endorsement by the U.S. Geological Survey.

^Denver, Colorado 80225 

Reston, Virginia 22092

1990
CONTENTS

Page 

Abs t r ac t............................................................ 1

Introduction........................................................ 2

Data Management..................................................... 3

Data Analysis....................................................... 6

References.......................................................... 11

Tables

Table 1. The ten deepest wells in the U.S. in order of decreasing

total depth............................................ 12

/

2. Total wells drilled deeper than 15,000 ft by depth for

U.S. based on final well completion class.............. 13

2a. Total deep producing wells (producing at or below 

15,000 ft) by depth for U.S. based on final 

completion class....................................... 14

3. Total wells drilled deeper than 15,000 ft by depth

for U.S. based on year of completion................... 15

3a. Total deep producing wells and gas producing wells

(producing at or below 15,000 ft) by depth for U.S.

based on year of completion............................ 19

4. Total wells drilled deeper than 15,000 ft by depth

for U.S. based on region............................... 23

4a. Total deep producing wells and gas producing wells

(producing at or below 15,000 ft) for U.S. by region, 

province, and depth.................................... 24

5. Total drilled feet and average total depth by State 

based on lithology for deep oil producing wells 

(producing at or below 15,000 ft) in the U.S........... 27

6. Total drilled feet and average total depth by State 

based lithology for deep gas producing wells 

(producing at or below 15,000 ft) in the U.S........... 28

7. Total drilled feet and average total depth by State

based on lithology for deep gas and condensate *

producing wells (producing at or below 15,000 ft)

in the U.S............................................. 29
CONTENTS continued.

8. Total drilled feet and average total depth by State 

based on lithology for deep oil producing wells 

with multiple producing horizons (producing at 

or below 15,000 ft) in the U.S......................... 30

9. Total drilled feet and average total depth by State

based on lithology for deep gas producing veils with

multiple producing horizons (producing at or below

15,000 ft) in the U.S.................................. 31

10. Total drilled feet and average total depth by State 

based on lithology for deep gas and condensate 

producing wells with multiple producing horizons 

(producing at or below 15,000 ft) in the U.S........... J32

11. Total drilled feet and average total depth by State 

based on lithology for deep oil and gas producing 

wells (producing at or below 15,000 ft) in the U.S..... 33

12. Summary data for deep fields and reservoirs and

cumulative production by State for reservoirs and 

fields with average depth to production greater than 

15,000 feet............................................ 34

13. Field and reservoir names, discovery dates, producing

formations, and locations of largest and oldest gas 

fields in the U.S. with average depth to production 

greater than 15,000 feet,.............................. 35

11
DEEP OIL AND GAS WELLS AND RESERVOIRS IN THE UNITED STATES FROM THE 

WELL HISTORY CONTROL SYSTEM AND PETROLEUM DATA SYSTEM

By

T.S. Dyraan, D.T. Nielson, R.C. Obuch, J.K. Baird, and R.A. Wise

ABSTRACT

Deep wells and hydrocarbon production are widely distributed in the U.S. 

in rocks of various ages and lithologies. Sixteen thousand six hundred fifty 

wells have been drilled deeper than 15,000 ft in the U.S. since the first 

deep well was drilled in 1920, according to Petroleum Information 

Corporation's Well History Control System (WHCS) as of February 1988. Of 

these 16,650 deep wells, 8,705 were completed as producing wells that could 

be producing oil and (or) gas at any depth (above or below 15,000 ft). Nearly 

as many gas wells exist (6,347) as dry holes (7,090); gas wells are about 

three times more abundant than oil wells (2,181). In the WHCS file, 1,442 

wells have a total depth greater than 20,000 ft.

/

Of these 16,650 deep wells, 7,251 were drilled in the offshore province 

of Louisiana. Of the 2,860 deep wells in the Midcontinent region, 2,211 were 

drilled in the Anadarko basin and 354 in the Ardmore basin. Of the 841 deep 

wells in the Rocky Mountain region, 175 are in the Uinta basin, 136 in the 

Wyoming thrust belt, 113 in the Green River basin, and 100 in the Wind River 

basin. Of the 3,547 deep wells in Mississippi, Alabama, and Florida, 1,876 

were drilled in the Cretaceous-Jurassic trend; and 1,157 wells were drilled 

in the Gulf basin. A total of 19 deep wells have been drilled in the 

Appalachian, Michigan, and Illinois basins.

In the WHCS file, 2,981 producing wells drilled deeper than 15,000 ft 

have a formation at total depth equal to the producing formation. These wells 

represent a minumum number of those that are actually classed as producing 

oil and gas deeper than 15,000 ft; they are referred to as deep producing 

wells and form the basis for statements made in the following discussion* The 

ratio of gas-producing deep wells to total-producing deep wells increases 

with increasing total depth of well. The ratio of gas-producing deep wells of 

total-deep producing wells consistently increases from 72 percent in the 

15,000 to 16,000-ft range to more than 90 percent in the 19,000-ft range. In 

the Rocky Mountain region, deep gas producing wells account for 34 percent of 

the total deep producing wells (265 total wells, 91 gas wells). The Uinta and 

Powder River basins are oil-rich below 15,000 ft whereas the Green River, 

Wind River, Washakie, and Bighorn basins and the Wyoming thrust belt are 

predominantly gas-rich.

Only eight wells classed as producing from reservoirs deeper than 15,000 

ft were completed before 1960, all of which were reported as gas producers. 

The first three wells to produce gas deeper than 20,000 ft were completed in 

1967. The two deepest hydrocarbon producing wells (producing deeper than 

26,000 ft) were completed in 1977 and 1979. Deep gas-producing wells account 

for 70 percent of the total deep .producing wells completed during the 1970 to 

1975 period and over 80 percent completed during the 1976 to 1987 period. For 

all years together, over 90 percent of the wells that are classed as 

producers below 20,000 ft are producing gas.

1
Seventy-five percent of the oil wells completed deeper than 15,000 ft 

produce from clastic rocks (467 wells, 7.6 million drilled feet). The 

greatest depths to clastic reservoirs occur in the New Mexico part of the 

Permian basin (average=18,243 ft). In Utah, 136 deep-producing oil wells 

(over 2 million drilled feet) were completed in clastic reservoirs. Three 

hundred sixty six deep oil wells produce from Tertiary rocks; of these 168 

produce from the Miocene in the Gulf Coast region and 134 from the Paleocene 

and Eocene Wasatch Formation in the Rocky Mountain region. One hundred 

twenty-five deep-producing wells are Jurassic oil producers, 92 of which 

produce from the Smackover Formation.

Over seventy-five percent of the deep wells completed as gas wells have 

produced from clastic rocks (1,740 wells, over 29 million drilled feet). The 

Anadarko basin and the Rocky Mountain region produce deep gas primarily from 

clastic reservoirs (352 wells, 5.6 million drilled feet). In Texas, 55 

percent of the deep-producing wells (377), accounting for more than 7 million 

drilled feet, were completed as producing from carbonate rocks; most of these 

are producing from the Ordovician Ellenburger Group in the Permian basin. 

Texas and Louisiana have more deep wells which produce from carbonate rocks 

than from clastic rocks. Ninety-nine deep producing wells produce from 

carbonate rocks in the Jurassic Smackover Formation in Texas, Alabama, 

Mississippi, and Florida.

3 Approximately 7 billion barrels of oil and 50 trillion ft (TCP) of

nonassociated gas have been produced from 2,007 deep reservoirs through 1985 

according to the Dwight's Energy Data Petroleum Data System (PDS) (Dwights 

Energy Data, 1985). Deep gas accounts for about 8 percent of the U.S. 

cumulative gas production (698 TCP) and deep oil accounts for about 5 percent 

of the U.S. cumulative oil production (143 billion barrels). The 

Midcontinent, Texas, and Gulf Coast regions, totaling 1,900 deep reservoirs, 

account for 95 percent of the cumulative deep oil and gas production in the 

U.S.

Cumulative nonassociated gas production for deep reservoirs discovered 

prior to 1970 equals 9.2 TCP which is 18 percent of the cumulative deep gas 

production in the U.S. Thirty-four of the .260 active deep reservoirs in the 

PDS file were discovered prior to 1970. The oldest reservoirs were discovered 

in the Permian basin and Gulf Coast region.

INTRODUCTION

Drilling activity in the U.S. is rapidly declining because of lower 

worldwide oil prices, and major producing companies are looking outside the 

U.S. for oil and gas exploration prospects. Production from existing wells is 

declining and the U.S. reliance on imported oil is increasing. Even if 

prices were to increase drastically, it would take several years for domestic 

exploration to reach previous levels of intensity.

When the issue of economics is set aside, many drilling frontiers remain 

untapped in the U.S. and deserve a more detailed review. One such drilling 

frontier is deep gas in sedimentary basins. Very little information is 

presently available for deep gas reservoirs. In fact, very few studies have 

been published on the subject. Deep wells are defined for this study as those 

drilled deeper than 15,000 ft. Deep producing wells are those that are

2
producing at or below 15,000 ft. However, more than 16,000 wells have been 

drilled deeper than 15,000 feet in the U.S. since the first deep well was 

drilled in 1920. Deep wells are widely distributed in the U.S. and are 

drilled into rocks of various ages and lithologies. Many of these wells are 

producing gas and oil, much of which occurs below 15,000 feet. Commercial gas 

production has been established in deep reservoirs in a few basins for many 

years. In other basins, only a few deep wells have been drilled, and the gas 

potential of other deeper horizons remains unknown.

The purpose of this study is to present a statistical summary of deep 

wells and reservoirs in the U.S. in order to begin to develop a data base of 

information concerning this potential resource. In this way, geologic and 

engineering factors associated with deep drilling can be defined and a better 

understanding of deep reservoirs can be developed. Data summaries are 

presented in tabular form and discussed sequentially in this report. These 

data summaries are considered preliminary, and no rigorous statistical 

analysis of these data is attempted in this report.

Data were compiled from Petroleum Information Corporation's Well History 

Control System (WHCS) available through February, 1988 (Petroleum Informajtion 

Corporation, 1988) and Dwight's Energydata Petroleum Data System (PDS) 

available through December, 1985 (Dwights Energy Data, 1985). WHCS contains a 

variety of location, identification, and geologic and engineering data for 

approximately two million wells drilled in the U.S. The WHCS file can be used 

for a variety of exploration and research applications and is available to 

the U.S. Geological Survey by contract with Petroleum Information 

Corporation. Since WHCS data are proprietary, publication of complete well 

histories and computer versions of the file is prohibited. However, data can 

be aggregated and published for a variety of applications. PDS data were made 

available to the U.S. Geological Survey by the Gas Research Institute (GRI); 

these data are also proprietary in digital form, but aggregated results may 

be published.

PDS is an oil and gas field and reservoir file originally developed by 

the University of Oklahoma under contract to the U.S. Geological Survey. It 

contains location, identification, and geologic and production data for 

approximately 100,000 fields and reservoirs in the 32 oil and gas producing 

States in the U.S.

This work was conducted in part under contract to Gas Research 

Institute, Chicago, Illinois (Contract No. 5087-260-1607).

DATA MANAGEMENT

Deep wells in this study are defined arbitrarily as those drilled deeper 

than 15,000 feet. In order to easily assemble data for the more than 16,000 

deep wells, a WHCS short file was created by Petroleum Information 

Corporation for the U.S. Geological Survey. This short file contains the 

following data items for each deep well in the WHCS file:

American Petroleum Institute (API) unique well number

Latitude and longitude

Total depth

Initial and final well classification

Completion date

3
WHCS province code

Field name

Age and formation code for first producing formation

Age and formation code for formation at total depth

The API number includes the State and county codes and a 5-digit unique 

identification number for each well in each county. The total depth of the 

well was arbitrarily chosen as the criterion for depth as opposed to true 

vertical depth which was not retrieved for wells in this study. Some wells in 

our data set, particularly those in the Gulf Coast region, deviate from true 

vertical depth and may not actually exceed 15,000 feet.

No effort was made in this study to subdivide wells on the basis of 

initial well classification. All initial well classes were grouped together 

and data summaries were compiled based on final well classification. Initial 

and final well classifications in the WHCS data file as defined by Petroleum 

Information Corporation are as follows: 

Initial well classification and numeric code1. Outpost or extension test

2. Shallow pool test

3. Deeper pool test

4. New pool wildcat

5. New field wildcat

6. Development well

7. Stratigraphic test

8. Core test

9. Injection well 

0. Unclassified well 

G. Gerthermal well

Final well classification and numeric code1. Oil well

2. Gas well

3. Gas and condensate well

4. Multiple completion, oil

5. Multiple completion, gas

6. Multiple completion, gas and condensate

7. Multiple completion, oil and gas

8. Junked and abandoned well

9. Injection or unclassified well

0. Dry hole

S. Suspended

Geologic province summaries in this report were compiled solely on the basis 

of the province codes contained in the WHCS file as defined by Petroleum 

Information Corporation. In some cases, WHCS province boundaries differ from 

province boundaries defined elsewhere. As a result, our data summaries may 

differ slightly with other published summaries.

Only one producing age and formation is identified in the WHCS short 

file for the purposes of this study, namely the first producing formation 

listed in the full WHCS file. In some cases, wells may be producing from 

several formations at different depths. Additional work needs to be done to - 

identify other producing formations both above and below 15,000 feet. Age and

4
formation codes used in this report were also taken directly from the WHCS 

file. Some stratigraphic names may not agree with those in the published 

literature; some WHCS names may be informal names.

The data file contains 16,650 wells of which 8,705 are classed as 

producing wells and 2,981 of the 8,705 producing wells have a formation at 

total depth that is the same as the first producing formation in WHCS. These 

2,981 wells, although a minimum figure, form a subset of wells actually 

producing hydrocarbons below 15,000 feet and will form the basis for some of 

the data summaries in this report. An additional 2,667 wells that are 

classified as producing, have no producing formation or formation at total 

depth identified in the data file. We cannot determine at this time whether 

these wells are producing below 15,000 feet or not. The remaining 3,017 

producing wells of the original 8,705 producing wells have a producing 

formation that is different from the formation at total depth. These wells 

may be producing below 15,000 feet but were not considered for this report. 

The three groups of producing wells (2,981, 2,667, and 3,017 wells) fall 

short of the total producing wells (8,705) by 40 wells; these 40 wells 

represent those dry holes in the file with a producing formation identified. 

We did not determine whether formations other than the formation at total" 

depth are themselves below 15,000 feet.

The WHCS file does contain data errors as does any large data file. For 

example, 33 wells which are identified as dry holes contain both a formation 

at total depth and a producing formation. These 33 wells could indeed be dry 

holes with incorrect data in the producing formation field, or they could be 

producing wells with an incorrect completion class. These errors are not 

considered significant for the purposes of this study. Minor variations in 

well totals for different data tables in this report (e.g. no more than a few 

wells) are due to minor errors introduced into the data set by summarizing 

wells based on different criteria.

Selected deep reservoir data for this study from PDS were stored in a 

second short file. The PDS short file contains the following data items for 

each reservoir or field record in PDS:

Field and reservoir name

State, county, and basin name

Discovery year

Present status of field or reservoir

Porosity and permeability

Lithology of producing formation

Geologic age and name of producing formation

Depth to top of and thickness of producing formation

Trapping mechanism

Driving mechanism

Recovery factor

Proven acreage

Cumulative production totals for oil, gas, and condensate

Field and reservoir data in PDS are actually compilations of well data 

from State agencies and petroleum companies and published field studies, 

Production totals for some States are not compiled by reservoir, and many 

data fields in PDS are empty because some data are simply not available. 

Porosity, permeability, recovery factor, and acreage data are often missing

5
and data summaries by reservoir using these data were not attempted. In many 

cases, data summaries by veil from WHCS may actually be more complete than 

reservoir summaries from PDS. Because of this disparity, 11 summary tables 

were compiled using WHCS data (Tables 1 through 11), whereas only two tables 

were compiled using PDS data (Tables 12 and 13).

Data for more than 16,000 wells and 1,900 reservoirs were stored on a 

VAX 11-780 minicomputer using DATATRIEVE data management software. Well data 

were selectively downloaded to an IBM-PC with a 40 megabyte hard drive. Data 

were sorted and manipulated on the PC using Dbase III+ software. Data fields 

were coded and restructured for easy storage. Well data were manipulated on 

both systems in order to cross check for errors. Data presented in Tables 

1-11 were prepared using both the minicomputer and PC-based systems. 

Reservoir data in Tables 12 and 13 were prepared using only DATATRIEVE on the 

VAX 11-780.

DATA ANALYSIS

Tables 1 through 11 contain data summaries for well data in WHCS. Our 

comments concerning these tables are based solely on observations from the 

tables themselves and do not take into account other wells that have been 

drilled, such as in the Appalachian basin, that do not reside in the WHCS 

file. A rigorous statistical examination of completions should take all wells 

into account.

Table 1 contains identification and location information for the 10 

deepest drill holes in the United States regardless of completion 

classification. All were drilled in the Anadarko and Permian basins of 

Oklahoma and Texas. The deepest well drilled in the U.S., the Lone Star 

Bertha Rogers No. 1, was completed in 1974 as a dry hole in the Anadarko 

basin in Washita County, Oklahoma. The well was drilled as a wildcat to a 

depth of 31,441 ft. The well penetrated the Cambrian Arbuckle Group at 31,236 

ft after almost a year and a half of drilling.

The second deepest well, the Lone Star Earnest Baden No. 1, although 

drilled to more than 30,000 ft, was completed as a gas well in the 

Pennsylvanian Atoka Formation at a depth of approximately 16,500 ft after 

being acidized. The third deepest well, the Hunt Energy 1-9 Cerf Ranch unit, 

was drilled as a wildcat and, although it was suspended, it reported gas in 

the Ordovician Ellenburger Formation at 22,535 ft. Of the remainder, well 

numbers 6 through 8 were drilled and abandoned and well numbers 9 and 10 were 

completed as gas wells. Well no. 9, the McCulloch Oil Easley No. 1, reported 

production from below 15,000 ft.

Table 2 contains well summaries based on completion class for all 16,650 

wells completed to depths below 15,000 feet in WHCS arranged by final 

completion class and depth interval. Of the total number of deep wells in the 

data file (16,650), 1,442 wells have a total depth greater than 20,000 feet. 

Of these, 842 are producing wells, and of these 842 wells, 727 (86 percent) 

are producing gas at any depth. For all wells with total depths below 15,000 

feet, gas wells account for 73 percent of the total producing wells. There 

are nearly as many gas wells (6,347) as dry holes (7,090); gas wells are 

approximately three times more abundant than oil wells. Producing wells and, 

dry holes decrease with increasing depth but the percentage of gas producing

6
wells to total producing wells increases with depth down to the 25,000 ft 

range. The propensity of deep wells to produce gas is related to the relative 

instability of oil in deep, hot reservoirs (C.W. Spencer, U.S. Geological 

Survey, written communication, 1989).

Of the 16,650 wells in the file, 16,173 are exploration or production 

tests. The remaining 477 wells include those wells that were suspended during 

drilling, injection wells, those wells with no completion status (blank), dry 

development wells, and one sulfur test well. The Louisiana Offshore province 

accounts for 7,251 wells of the total 16,650 wells (almost half the file). 

Most of these wells do not include formation data.

Table 2a contains totals for deep producing wells by depth interval 

based on final well classification for the 2,981 wells that have a match in 

producing formation and formation at total depth. This set of wells is 

considered representative of the total of those producing below 15,000 feet. 

Of the 2,981 wells producing below 15,000 feet, 315 are producing below 

20,000 feet. Gas wells outnumber both oil wells and wells producing gas from 

multiple horizons for each depth category. The percentage of gas wells to 

total producing wells also consistently increases for each depth interval 

from a minimum of 72 percent in the 15,000-feet range to more than 90 percent 

in the 19,000-feet range. The gas and condensate, and oil and gas columns 

were not included in the total gas figures.

When Table 2a is compared to Table 2, gas wells producing from

reservoirs below 15,000 feet make up 37 percent of total gas producing wells

that reach a depth of 15,000 feet and which produce at any depth.

The deepest producing oil well was drilled to a depth of 26,391 feet and 

is listed as producing from the Permian Drinkard Formation in the Permian 

basin portion of southeast New Mexico in Lea County. The next deepest oil 

well was drilled to a total depth of 24,441 feet and is identified as 

producing from the Permian Yates Formation in Ward County, Texas. The deepest 

gas well was drilled to a total depth of 26,566 feet into the Ordovician 

Arbuckle Group in Pecos County, Texas. Five additional gas wells were 

reported producing from the Ellenburger Formation below 25,000 feet in the 

Permian basin, Pecos County, Texas, and two more were reported producing from 

the Silurian and Devonian Hunton Group in the Anadarko basin of southwestern 

Beckham County, Oklahoma in the same depth interval. Two hundred and 

ninety-three gas wells are listed in Table 2a as producing below 20,000 feet. 

These gas wells represent a minimum figure which should be added to other 

deep gas wells where the formation at total depth is different from the 

producing formation.

Table 3 contains the number of deep wells by depth interval for the U.S. 

based on year of completion. All well completion classes are included 

together. The first well was completed below 15,000 feet in 1920. Only seven 

deep wells were drilled before 1946. Totals by year indicate a relatively 

continued increase in completions from 1946 through 1966 which peaks in 1966 

when 461 wells were completed. From 1967 through 1976, the trend is somewhat 

flat and varies from 399 to 515 wells. During the period 1977 through 19A82 a 

sharp increase in deep completions occurred. The most prolific year for deep 

completions was 1982 when 1,449 wells were drilled. This increase in wells
completed deeper than 15,000 ft was probably precipitated by the Federal 

deregulation of gas produced from reservoirs deeper than 15,000 ft. There has 

been a continuous decrease in deep drilling since 1982.

When data are combined for each 10-year period, continuous increases in 

completions result, but the rate of increase is less for the 1980's period 

(the WHCS data base used in this study does not include all wells drilled 

during and after 1987). In the 1970's, 12 percent of the completions were 

below 20,000 feet the highest of any decade. During the 1980's (through 

February, 1988), only eight percent were completed below 20,000 feet. The 

deepest well (Lone Star Production Bertha Rogers No. 1, TD=31,441 feet) was 

completed in 1974.

Table 3a contains total deep producing wells and gas producing wells in 

the U.S. based on year of completion. Data for Table 3a were compiled from 

the same set of 2,981 wells producing below 15,000 feet as was used in Table 

2a. Only eight wells producing from intervals below 15,000 feet were 

completed before 1960, all of which were reported as producing gas. The first 

well to produce gas below 20,000 feet was completed in 1967. In that year, 

three wells were completed below 20,000 feet. The deepest oil and gas wells 

(producing below 26,000 feet) were completed in 1979 and 1977, respectively.

When yearly averages are compared, the ratio of gas-producing wells to 

total producing wells ranges from zero to 100 percent. After discounting the 

few wells drilled before 1961, the ratio increases with time. From 1961 

through 1969, the ratio averages less than 50 percent. The ratio increases to 

an average of approximately 65 percent from 1970 through 1975, and again 

increases from 1976 through 1987 to more than 80 percent. For post-1969 

wells, the ratio varies from a low value of 46 percent in 1972 to a high 

value of 89 percent in 1982. However, the ratio ranges from between 46 to 89 

percent for 14 years between 1968 and 1987. The variation in the ratio may be 

due to varying exploration and development strategies due to economics and 

local and regional geology.

For each reported year, the ratio of gas producing wells to total , 

producing wells below 15,000 feet increases with depth. In fact, for all 

years together, more than 90 percent of the producing wells below 20,000 feet 

are producing gas. The most prolific year for completions of deep producing 

wells was 1982 with 329 producing wells, 292 of which were gas wells. The 

number of completions of producing wells increases through time (with minor 

fluctuations in the early years) until 1983 when the number of successful 

wildcats decreased by approximately 40 percent. A similar 40 percent decrease 

in the total number of wells drilled deeper than 15,000 feet is shown on 

Table 3.

Table 4 contains total deep wells for all depth categories in the U.S. 

by province. The table is based on all wells (16,650) and includes dry holes 

and wells that are producing from any depth. The seven provinces are defined 

by groups of basins from WHCS. Basins are aggregated into provinces as they 

are in the WHCS file and province boundaries are often State boundaries. 

Refer to the WHCS Users Manual (Petroleum Information Corporation, 1988) for 

details of basin subdivisions.
Approximately 45 percent of all deep veils in the U.S. were drilled in 

the Louisiana Offshore Province. About 65 percent of the deep veils were 

completed in the Louisiana Offshore and Mississippi Southeast provinces 

together. Only 19 deep wells have been drilled in the Appalachian 

basin-Michigan-Illinois Province, (15 in the Appalachian basin, 2 in the 

Illinois basin, and 2 in the Michigan basin) and 160 in the West Coast-Alaska 

Province. Of the 2,860 deep Midcontinent veils, 2,211 vere drilled in the 

Anadarko basin and 354 in the Ardmore basin. Of the 841 deep wells in the 

Rocky Mountain Province, 175 are from the Uinta basin, 136 from the Wyoming 

thrust belt, 113 from the Green River basin, and 100 from the Wind River 

basin. Of the 3,547 deep wells in the Mississippi Southeast Province, 1,876 

wells were drilled in the Cretaceous-Jurassic trend extending from 

Mississippi eastward to northern Florida; an additional 1,157 wells were 

drilled in the Gulf basin.

Of the seven provinces listed, the Permian basin province has the 

greatest number of wells drilled deeper than 20,000 feet (314 wells) 

representing approximately 26 percent of the total wells deeper than 20,000 

feet; this represents the largest percent of any province. In the Gulf Coast 

province (Louisiana Offshore and Southeast Mississippi Provinces), fewer -than 

three percent of the wells were drilled deeper than 20,000 feet.

Table 4a contains total deep producing wells and gas producing wells in 

the U.S. by province based on depth interval. Data for Table 4a is a subset 

of Table 4 and only includes the 2,981 producing wells used in Tables 2a and 

3a. Province boundaries are the same as those in Table 4 and are taken 

directly from the WHCS file. Of the 5 provinces represented, the Gulf Coast 

Southeast Province contains by far the greatest number of producing wells 

(1,895). The Rocky Mountain Province contains only 265 deep producing wells. 

The Appalachian-Illinois-Michigan Province contains 19 wells drilled deeper 

than 15,000 feet (Table 4), but because all are either dry holes or are 

producing from formations other than the formation at total depth, this 

region is omitted from this table. One hundred and sixty-eight wells 

reported no basin code and are listed separately by depth in Table 4a.

For all depth intervals (below 15,000 ft) and provinces, including 

locations unknown, the ratio of gas to total producing wells is 78 percent. 

For all depths together, the Rocky Mountain province has the smallest 

percentage (34 percent) of deep gas wells to total producing wells (265 total 

wells and 91 gas wells). This figure is somewhat misleading because it is 

strongly biased by the deep oil-rich Uinta and Powder River basins. The Green 

River, Wind River, Washakie, and Bighorn basins and the Wyoming thrust belt 

are predominantly gas producers, but have fewer total wells. The 

California-Alaska province was not compared with other provinces because (1) 

it contains only 7 deep producing wells as defined in the table, and (2) the 

file is incomplete.

The deepest producing wells, namely those producing below 20,000 feet, 

in the Rocky Mountain province are in Cretaceous Shannon Sandstone drilled in 

the Owl Creek Mountains and Wind River basin, Fremont County, Wyoming. The 

two deepest wells in the Midcontinent region are gas producers which were 

drilled into the Cambrian Arbuckle Group and the Silurian-Devonian Hunton 

Group in Wheeler County, Texas, and Beckham County, Oklahoma, respectively. -
The deepest wells in the Gulf Coast Southeast Province are gas wells and 

reside in Terrebonne and Arayelles Parishes, Louisiana. They are both 

producing gas from Miocene strata; no formation data are available for these 

wells. The deepest offshore well is located on the Eugene Island block off 

Louisiana and is producing from Miocene strata at a depth of 21,000 feet.

Table 5 contains total drilled feet by State based on lithology of 

producing formation and average total depths by State for deep oil-producing 

wells. Geologic age data are taken directly from the Petroleum Information 

Corporation age codes in the WHCS well file. Lithology data were compiled by 

the authors from the published literature primarily from State geological 

survey publications. Table 5 data set includes only those producing wells 

with a match in producing formation and formation at total depth. It is the 

same data set used in Tables 2a, 3a, and 4a.

Clastic reservoirs account for approximately 75 percent of the tojial 

drilled feet for oil producing wells drilled below 15,000 feet in the U.S. 

All of the deep oil producing wells in the U.S. reside in the 12 States 

identified in the table. The deepest average depths occur in the Permian 

basin (average = 18,243 feet for New Mexico part of Permian basin).

Louisiana (onshore and offshore together) has the greatest number of 

deep oil wells (228). Louisiana wells produce oil predominantly from clastic 

reservoirs. Florida has the greatest number of producing wells in carbonate 

rocks with 49. Utah has more than two million drilled feet from 136 wells in 

predominantly Tertiary clastic reservoirs.

Three hundred and sixty-four deep oil producing wells are Tertiary 

producers, of which 168 produce from the Miocene in the Gulf Coast region and 

134 from the Wasatch in the Rocky Mountain region. There are 125 Jurassic 

producers in the data set, 92 of which are from Smackover Formation.

Table 6 contains total drilled feet by State based on lithology of 

producing formation and average total depth for deep gas-producing wells. 

Geologic age data are taken directly from the Petroleum Information age codes 

in the WHCS file. Lithology data were compiled by the authors from the 

published literature primarily from State geological survey publications. 

Table 6 data set includes only those producing wells with a match in 

producing formation and formation at total depth. It is the same data set 

used in Tables 2a, 3a, 4a, and 5.

Clastic reservoirs account for more than 29 million drilled feet with 

1,740 wells accounting for approximately 75 percent of the total gas wells 

producing from below 15,000 feet. The distribution by State is similar to oil 

production all the States are represented except Alaska. Louisiana has the 

greatest number of wells (834); these wells produce primarily from clastic 

reservoirs.

Texas has the greatest number of wells producing from carbonate rocks 

with more than 7 million drilled feet (377 wells). This figure represents 

mostly producing wells from the Qrdovician Ellenburger Formation in the .

10
Permian basin. Both Texas and Alabama have more deep carbonate production 

than clastic production. Ninety nine deep wells produce from carbonate rocks 

in the Jurassic Smackover Formation in Alabama, Mississippi, Texas, and 

Florida.

In comparing Tables 5 and 6, there are more gas producing veils (2,265) 

than oil producing wells (589) in the subset of producing wells used here. 

Again in Table 6, most wells are completed in the Tertiary (767), with 37A 

wells in the Cretaceous, and 376 wells in the Pennsylvanian and Permian.

Tables 7 through 11 contain total drilled feet by state based on 

lithology of producing formation, average total depth, and producing 

formations by State for (1) gas and condensate producing wells, (2) oil 

producing wells with multiple producing horizons, (3) gas producing wells 

with multiple producing horizons, (A) gas and condensate producing wells with 

multiple producing horizons, and (5) oil and gas producing wells. Geologic 

age data are taken directly from the Petroleum Information Corporation "age 

codes in the WHCS file. Major lithology data were taken by the authors from 

the published literature primarily from State geological survey publications. 

The data set for Tables 7 through 11 includes only those producing wells with 

a match in producing formation and formation at total depth. It is the same 

data set used in Tables 2a, 3a, 4a, 5, and 6.

Tables 12 and 13 were produced using PDS data based on average depth of 

production greater than 15,000 feet. For some fields with multiple 

reservoirs, shallow reservoirs (less than 15,000 feet deep) were not chosen. 

Table 12 contains production data for the deepest field and reservoir in each 

State. Approximately seven billion barrels of oil and 50 trillion cubic feet 

(TCP) of nonassociated gas have been produced from deep reservoirs through 

1985 according, to PDS data. Deep gas production accounts for approximately 8 

percent of the U.S. total cumulative gas production in the U.S. (698 TCP; 

G.L* Dolton, U.S. Geological Survey, written communication, 1989) ) and deep 

oil production accounts for approximately 5 percent of the total U.S. 

cumulative production (1A3 billion barrels; G.L. Dolton, U.S. Geological 

Survey, written communication, 1989). The Midcontinent, Texas, and the Gulf 

Coast regions account for more than 1,900 deep reservoirs, or more than 95 

percent of the total.

Table 13 contains location and production data where available for the 

oldest and largest fields and reservoirs discovered prior to 1970. Total 

cumulative production (through 1985) of nonassociated gas for reservoirs 

discovered prior to 1970 equals approximately 9.2 TCP which is approximately 

18 percent of the total cumulative deep nonassociated gas production. 

Thirty-four of the 260 active deep reservoirs in the PDS file were discovered 

prior to 1970. The oldest reservoirs were discovered in the Permian Basin and 

Gulf Coast regions.

REFERENCES

Dwights Energy Data, 1985, Petroleum Data System (through 1985): Available 

from Dwights Energy Data Corporation, Oklahoma City, OK 73108.

Petroleum Information Corporation, 1988, Well History Control System (through 

February, 1988): Available from Petroleum Information Corporation, Denver, 

CO. 80122.

11
Table 1. The ten deepest veils in the United States in decreasing order of total d

VHCS data file updated February, 1985. Wells listed regardless of completion cl

and longitude in decimal degrees. Date spudded and completed in month, day, and 

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Operator

Lone Star Prod.

Lone Star Prod.

Hunt Energy Corp.

Gulf Oil Corp.

GHK Corp.

GHK Corp.

Chevron USA

Ralph Love Estate

McCulloch Oil

Napeco Inc.

Well name

#1 Bertha Rogers

#lEarnest R.Baden

1-9 Cerf Ranch

2 Emma Lou Unit #1

#1-34 Duncan

#1-1 Robinson

#1 University 23-3

#1-17 University

#1 Easley

#1 Centurion

Spud date

11/25/72

09/04/70

04/29/79

05/21/78

02/20/81

07/06/81

11/08/78

na

04/05/71

10/05/79

Date 

Completed

04/18/74

10/20/72

09/06/82

07/30/80

01/15/83

01/25/84

06/01/81

/72

09/18/73

06/23/81

Total 

Depth

31,441

30,050

29,650

29,622

29,312

29,241

28,747

28,500

27,050

27,019

Long 

99.19

99.53

102.54

102.56

99.41

99.48

102.65

102.69

99.28

102.75
H 

U)

Table 2. Total deep wells by depth for U.S. based on final completion class. Producing wells may be pro

depth. Blank = unknown final well classification; Dry « dry holes; Oil = oil producing wells; Gas = g

wells; Cond. = condensate producing wells; Gas-Cond. = gas and condensate producing wells; Mul. = wel

from multiple horizons, either oil or gas; Oil-gas = oil and gas producing wells; D/A = drilled and ab

considered dry holes; Inj. = injection wells; Dev. dry - dry development wells; Susp. = wells suspend

completion; Sulf. = sulfur wells; Prod. Total » production, where total producing wells are listed sep

gas producing wells; Prod, gas = wells from gas and multiple gas columns. Depth in intervals of thou

Total gas includes total number of gas producing wells from either single or multiple producing horizo

Final Well Classification

Depth

13-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

2&-29

29-30

30-31

31-32

Blank Dry

6

4

2

1

1

2

1

0

2608

1861

1062

687

332

224

142

90

35

30

12

1

0

2

3

0

1

Oil

944

488

266

125

45

47

21

13

1

1

1

2

1

1

Gas Good.

2047

1428

952

577

322

227

200

190

40

15

11

3

2

0

1

1

0

14

8

15

3

7

17

4

1

1

Oil 

Mul.

127

65

24

5

2

2

0

0

Gas 

Mul.

121

91

41

19

22

15

16

6

Gas 

Cond,

13

12

12

0

3

1

0

0

Oil 

. Gas

37

19

4

3

2

1

0

0

D/A

141

99

55

34

17

17

9

2

2

Dev. 

Inj. Dry

18 0

13 1

12

10

7

2

2

Susp.

172

112

52

29

9

7

8

4

1

0

1

1

Total 

Sulf. wells

6248

4201

2497

1493

769

1 563

403

306

80

46

25

7

3

3

4

1

1

Prod, 

total

3303

2111

1314

732

403

310

241

210

42

16

12

5

3

1

1

1

Prod

Gas 

2168

1519

993

596

344

242

216

1%

40

15

11

3

2

0

1

1

' Total 17 7,090 1,956 6,016 70 225 331 41 66 376 64 1 3% 1 16,650 8,705 6,347
Table 2a. Total deep producing wells by depth in U.S. based on final completion 

class; only includes wells having producing formation same as formation at 

total depth. Data for Table 2a is a subset of Table 2. Oil = oil producing 

wells; Gas = gas producing wells; Cond. = condensate producing wells; Mul. = 

wells producing from multiple horizons, either gas or oil; Oil-gas = oil and 

gas producing wells. Depth in intervals of thousands of feet. Total gas = 

gas and multiple gas column wells. Total wells (= 2,981) does not include 40 

wells from the data file that have a matching producing formation and 

formation at total depth, but which are classed as dry holes or were left 

blank; these wells may be producing but could have an incorrect completion 

class. Percent (%) gas equals percent total producing wells completed as gas 

wells (gas and gas mul. columns combined).

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

Oil

297

165

70

36

9

7

1

2

1

1

GasGas cond.

799 2

498 2

307 6

219

144 1

84 10

74 2

107 1

12

3

7

1

Final Well Classification

GasOil Gas cond. Oil- Total 

mul. mul. mul. gas gas

12 21 1 6 820

4 17 8 6 515

43 3 2 310

9 2 228

1-11 1 155

1 85

1 75

107

12

3

7

1

--

Total 

wells

1138

700

395

266

167

102

78

110

12

4

7

2

% 

gas

72

74

79

86

93

83

96

97

TOTAL 589 2,255 24 21 63 13 16 2,318 2,981

1-4
Table 3. Total deep wells (all completion classes) by depth for U.S. based on 

year of completion. Depth in intervals of thousands of feet. Producing 

wells may be producing at any depth, above or below 15,000 feet. Unknown: 

number of wells that have no year of completion. Years beginning with 

1920. Data incomplete for 1988. Data set does not include 292 wells with 

unknown year of completion.

Depth 1920 1924 1937 1940 1945

15-16 1 12 

16-17 1 1 

17-18 

18-19 

19-20 

20-21 

21-22 

22-23 

23-24 

24-25 

25-26 1 

26-27 

27-28 

28-29 

29-30 

30-31 

31-32

1946 1947 1948 1949

1557 

1 11 

1 1

- 1

Total

Depth 1950

15-16 4

16-17 2

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1951 1952 1953

8 17 19

287

2 3

1 1

1

1954 1955

30 55

14 17

6 10

1 3

1

1

1956

85

47

21

5

1

1957

102

49

14

4

1

2

1

1

1958

101

51

19

6

3

1

Total 6 10 28 31 51 87 159 174 181

15
Table 3. continued

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1959

129

65

24

6

1

1

1

1

1

1

1960

141

56

27

6

2

3

1

1961

137

82

34

7

3

1

1

1962

147

63

44

10

2

1

1963

134

83

37

22

6

3

2

1

1964

130

102

54

27

14

4

4

2

1

1965

146

114

55

20

10

15

4

3

1

1

1966

179

132

59

33

15

13

21

7

2

1967

168

113

63

35

19

13

16

8

2

,,

Total 230 236 265 267 288 338 369 461 437

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1968

169

83

64

33

18

18

12

12

2

1969

157

90

54

24

19

28

8

11

1

2

1970

159

104

59

43

14

25

13

22

1

1

1971

128

98

57

30

28

18

10

27

3

1972

203

134

79

26

22

17

11

18

1

2

1

1

1973

158

108

79

41

20

19

16

23

4

2

1

1

1974

158

95

56

48

27

35

20

15

2

2

1

1

1

1975 1976

137

121

71

66

32

30

21

6

3

149

106

47

64

20

14

20

12

' 2

4

1

1 -

Total 411 394 441 399 515 472 461 487 440

16
Table 3. continued.

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1977

162

128

81

66

32

20

17

9

7

2

1

1

1978

251

189

91

65

39

40

14

10

4

3

1979

233

200

116

82

46

22

25

13

3

5

1

1

1980

293

238

151

79

43

43

29

15

4

1

1

1981

349

306

182

114

74

32

31

19

9

3

2

1

1

1982

412

356

263

176

95

57

41

31

6

6

4

1

1

1983

297

184

159

97

50

32

21

15

5

4

1

2

1984

355

184

96

73

32

18

14

10

6

4

3

1

1985

272

209

132

78

37

15

20

4

2

3

6

1

Total 526 706 747 897 1,123 1,449 867 796 779

Depth 1986 1987 1988

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

172

100

87

48

25

12

7

8

6

1

2

128

75

60

37

14

1

2

2

2

3

3

2

1

1

Total 468 321 10 Unknown= 292; Total= 16,650

17
Table 3. continued.

[Well counts aggregated for 10 year intervals from 1920 

through 1988. The last decade (1980) incomplete.]

Depth 1920

15-16 1

16-17 1

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

Totals 2

1930 1940 1950

21 550

4 262

2 99

27

6

1 6

2

2

1

1

1 1

1 28 957

1960

1508

918

491

217

108

99

68

44

9

3

1

3,466

1970

1738

1283

736

531

280

240

167

155

30

20

6

4

1

1

1

5,193

1980

2281

1655

1132

703

370

211

165

104

40

22

17

3

1

2

4

6,710

+292 unknown year = 16,650
Table 3a. Total deep producing wells by depth in U.S. based on year of

completion; only includes wells having producing formation same as 

formation at total depth. Depth in intervals of thousands of feet. First 

number represents total producing wells for that depth interval and year; 

second number (following dash) represents wells producing gas in that depth 

interval. Gas wells only include WHCS completion codes 2 and 5 (gas and 

multiple gas completions; Petroleum Information Corporation, 1988). Table 

does not include wells that may be producing from intervals greater than 

15,000 feet but where formation at total depth is different from producing 

formation. Data set does not include 292 wells with unknown completion 

year. Data for 1988 incomplete.

Depth 1920 1924 1937 1940 1945 1946 1947 1948 1949

15-16 1-1

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32_________________________________________________________

Totals 1-1

Depth 1950 1951 1952 1953 1954 1955 1956 1957 1958

15-16 1-1 3-3 1-1

16-17

17-18 1-1

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32_________________________________________________

Totals 1-1 4-4 1-1

19
Table 3a. continued.

Depth 1959 1960 1961 1962 1963

15-16 4-4 5-3 5-3 2-1

16-17 1-1 2-2 1-0 3-3

17-18 1-1

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1964 1965 1966 1967

5-0 15-2 9-0

1-1 2-1

1-1 1-0

1-1

1-1

2-2

^

Totals 1-1 6-6 6-3 9-7 2-1 5-0 17-4 16-5

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

31-32

1968

7-3

2-0

4-1

5-1

5-4

8-8

1969

9-5

3-2

2-0

1-0

8-4

3-3

7-7

1970

9-7

7-2

3-1

1-1

5-4

4-3

2-1

16-15

1971

2-1

6-3

7-5

1-1

4-4

1-0

1-1

21-21

2-2

1972

26-9

17-6

13-4

1-1

2-2

2-1

9-9

1-1

1973

18-6

18-6

9-5

6-4

3-2

4-4

3-3

11-11

1-1

1974

39-20

20-12

12-5

10-5

4-4

4-4

3-2

7-7

1975

32-18

38-24

28-17

23-20

8-7

2-1

2-2

1-1

1-1

1976

55-39

39-31

14-12

17-14

5-3

3-3

8-8

3-2

'

Total 31-17 33-21 47-34 45-38 71-33 73-42 99-59 135-91 144-112

20
Table 3a. continued.

Depth 1977

15-16 46-34

16-17 47-39

17-18 22-15

18-19 17-15

19-20 11-9

20-21 6-5

21-22 1-1

22-23 4-4

23-24 1-1

24-25 1-0

25-26

26-27 1-1

27-28

28-29

29-30

30-31

31-32

Total 157-124

Depth 1986

15-16 51-35

16-17 29-19

17-18 16-14

18-19 10-10

19-20 3-3

20-21

21-22 1-1

22-23 1-1

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

1978

85-63

54-42

18-16

12-11

12-11

12-12

2-2

2-2

1-1

1979 1980

82-63 90-70

73-59 57-44

26-26 27-23

20-18 16-15

13-13 17-16

7-5 13-12

3-3 11-11

2-2 4-4

1-1

1-1

1-0

1981

99-82

76-61

46-43

24-21

26-26

10-10

11-11

3-3

2-2

1982 1983

111-93 100-85

72-63 29-23

47-42 28-24

45-41 22-18

25-24 13-13

11-11 5-4

11-11 3-3

5-5 3-3

1-1

1-1

1984

111-81

41-27

19-12

14-12

6-6

2-2

3-3

1-0

2-2

1-1

1-1

1985

75-50

43-30

40-32

16-13

7-6

3-3

4-4

1-1

4-4

198-160 229-191 235-195 297-259 329-292 203-173 201-147 193-143

1987

41-38

16-12

10-10

10-7

2-2

1988

2-2

Total 111-83 79-69 2-2

21
Table 3a. continued. Data totaled by 10 year intervals

Depth 1920

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

Total

Grand total

1930 1940 1950 1960

1-0 5-5 61-21

1-1 14-9

1-1 9-3

1-1

1-0

13-5

9-8

17-17

1-0 7-7 125-64

1970

394-260

319-224

152-106

108-90

67-59

45-38

25-23

76-74

6-6

3-2

1-1

2-1

1,198-884 1

2

1980

678-534

365-281

233-200

157-137

99-96

44-42

44-44

17-16

6-6

1-1

6-6

,650-1,363

,981-2,318

22
Table 4. Total deep wells by depth for U.S. by province. Well completion

classes combined. RKS = Rocky Mountain Province; MDCNT = Midcontinent 

Province; PRM = Permian basin province; APILM = Appalachian- MidcontinentMichigan-Illinois Province; CAAL = West Coast-Alaska Province; LAOF = 

Louisiana Offshore Province; and SEMISS = Mississippi Southeast Province. 

Provinces compiled here are same as WHCS provinces, but SEMISS here 

includes Texas onshore and offshore but not West Texas. Depth in intervals 

of thousands of feet.

Depth

15-16

16-17

17-18

18-19

19-20

20-21

21-22

22-23

23-24

24-25

25-26

26-27

27-28

28-29

29-30

30-31

31-32

Total

RKS

316

227

127

85

36

21

15

8

3

2

1

841

MDCNT

835

677

564

314

158

134

79

37

26

19

8

4

1

2

1

1

2,860

+793

APILM

6

1

5

1

3

1

1

1

19

wells

PRM

307

157

160

129

112

84

101

86

18

10

7

3

1

2

2

1,179

CAAL

75

42

20

11

2

5

3

2

160

not identified by

LAOF

3141

1937

1030

557

303

165

76

30

8

1

3

7,251

province =

SEMISS

1408

1051

489 -

345

92

58

62

21

14

7

3,547

16,650

23
Table 4a. Depth totals for deep producing wells in U.S. by WHCS provinces and basins; only includes wel

formation same as formation at total depth (totals 2,981 wells). Data for Table 4a is a subset of 

basin codes in parentheses in left column taken directly from WHCS and arranged by province (under

Grand total of producing wells includes 168 wells not identified by location. Total number of pro

depth interval is on left and number of gas producing wells is on right. Depths in intervals of th

15,000 and 27,000 feet. Province codes (e.g. BKS for Rocky Mountain region) are same as those in Ta

noted. Gulf Coast SE province includes both LAOF and SEMESS provinces in Table 4.

<

Basin/Province and code 15

1. Rocky Mt. Province (BKS)

Bighorn (114) 1-1

Green River (140) 5-3

Jackson (152) 1-1

Ovl Creek Mts. (172)

Piceance (186) 2-1

Powder River (191) 32-0

Rawlins uplift (194)

Sweetwater Mts. (234)

Uinta (242-248) 50-1

Vashakie (262) 5-5

Wind River (276) 4-4

Wyo. fold belt (289) 21-20

TOTAL: 120-35

16

1-1

2-1

54-1

4-4

5-4

6-6

73-18

17

1-1

1-1

2-2

29-1 5-0

2-2 4-4

8-8 8-8

40-12 20-15

 Depth Interval 

18 19 20 21

1-1

1-0

6-6 4-4

7-6 5-5

22 23 24 2

2. Mid-Continent Province (HXNT)

Amarillo Arch (302) 1-1

Anadarko (306) 118-117

Arbudde Mts. (310) 3-1

Ardmore (312) 9-5

Chautaqua Plat. (327)

Marietta (336)

.Wichita Mts. (363)

TOTAL: 131-124

71-69

3-3

12-12

1-0

87-84

4-4 2-2

54-5434-34

4-4 2-1

5-4 3-3

1-0

1-1

1-1 1-1

69-68 43-41

14-14 4-4 2-2

3-3

3-3 4-4 1-1

1-1

1-1 1-1 2-2

21-21 9-9 6-6

1-1 1-1 1-

1-1 1-1 

1-1 1-1 

1-1 

3-3 2-2 2-2 1-1 
'fable 4a. Continued.

NJ 

171

<

Basin/Provrince and code 15 16

3. Permian basin Province

Central basin

platform (650) 10-8 10-10

Delaware (652) 36-35 9-9

Marathon belt (660) 12-12

Midland (664)

North (666) 19-18 1-1

Pecos arch (668) 1-1

Valverde (676) 3-3 3-3

TOTAL: 81-77 23-23

4. Gulf Coast SB Province

Ark-La/Cret-Jur. (705) 7-7 1-1

MS-FL/Cret-Our. (710) 170-88 154-108

Eocene downdip (725) 2-0 6-4

Gulf Coast (730) 133-130 79-75

E. Texas (740) 20-20 4-4

Texas offshore (760) 14-12 5-3

Louisiana offshore

(770) 44&-321 246-185

N. Gulf of Hex. (777) 1-0

S. Florida (786)

Alabama offshore (945)

TOTAL: 795-578 495-380

17 18

13-13 5-5

14-13 9-9

1-0

1-1 8-8

28-27 2S-22

47-30 62-55

1-0 1-1

29-29 6-6

2-1 1-1

9-8

150-125 10S-82

1-1

1-0

1-0

239-194 74-144

19

20-20

10-10

1-1

3-3

34-34

5-5

2-2

1-1

84-75

93-84

 Depth Internal 

20 21 22 23

9-9 1-1

3-3 14-14 4-4

2-2 14-14 25-25 2-2

4-14 29-29 2£-29 2-2

9-9 3-2 5-5 3-3

3-2 1-1

39-34 22-22 5-3 2-2

3-3 3-3

54-48 29-28 10-8 5-5

24 2

1-0 

20-1

1-1 5-

2-1 5-

1-

1-
Table 4a. Continued.

-Depth IntennalBasin/Province 15 16 17 18 19 20 21 22 23 24 2

5. California-Alaska Province (CA-AL)

Cook Inlet (820) 2-0 1-0

Ventura (904) 1-0

San Joachim (906) 1-0

Calif, offshore (957) 1-1 1-1

TOTAL: 4-1 2-1 1-0

6. Location unknown 7-5 20-9 18-9 6-6 12-10 20-9 14-12 68-67 3-3

TOTAL (without unknown) 1131-815 680-506 377-301 260-222 155-145 82-76 64-63 42-40 9-9 4-3

GRAND TOTAL: 1138-820 700-515 395-310 266-228 167-155 102-85 78-75 110-107 12-12 4-3

7-7 

7-7 
Table 5. Total drilled feet for deep wells by lithology of producing formation, 

and average total depth by State for deep oil-producing wells. Data file 

only includes wells which have a match in producing formation and formation 

at total depth and are producing oil (VHCS final well class = 1). States 

represented by postal code abbreviations. Total drilled feet for both 

clastic and carbonate reservoir formations are listed separately with 

number of wells contributing to the total in parentheses. Producing 

formation(s) or stratigraphic interval with number of wells listed 

regardless of lithology. Producing formation assigned to carbonate or 

clastic based on dominant lithology of formation. In some cases lithology 

of producing part of formation may be different. Lithologic data taken 

from published literature by the authors. Dashes indicate that no wells 

exist with that lithology.

Total drilled feetState Clastic Carbonate Ave depth Formation(s) or unit^(age)

OK 148,427 (9) 47,237 (3)

TX 127,716 (8) 166,555 (9)

NM 41,922 (2) 31,050 (2)

WY 571,027 (37)

CO 15,857 (1) 

UT 2,221,288 (136)

MS 684,030 (42) 475,652 (29)

16,305 Bromide-3 (Ord)

Springer-3 (Penn) 

Arbuckle-2 (Ord) 

Glenn-1 (Penn) 

Atoka-1 (Penn) 

Viola-1 (Ord) 

Boatwright-1 (Penn)

17,310 Pleistocene-4

Austin Chalk-3 (Cret) 

Frio-2 (Olig) 

Ellenburger-2 (Ord) 

Miocene-1 

Yates-1 (Perm) 

Silurian-1 

Edwards-1 (Cret) 

Vicksburg-1 (Olig) 

Cotton Valley-1 (Jur)

18,243 Ellenburger-2 (Ord) 

Morrow-1 (Penn) 

Drinkard-1 (Perm)

15,433 Minnelusa-32 (Penn-Perm) 

Nugget-2 (Jur) 

Dakota-2 (Cret) 

Morrison-1 (Jur)

15,857 Weber-1 (Penn)

16,333 Wasatch-134 (Tert) 

Flagstaff-1 (Tert) 

North Horn-1 (Cret-Tert)

16,333 Smackover-25 (Jur) 

Hosston-25 (Cret) 

Cotton Valley-15 (Jur)
Table 5. continued.

Total drilled feetState Clastic Carbonate Ave depth Formation(s) or unit (age)

AL

FL

LA 3,734,148 (227)

473,411 (29) 

781,093 (49)

19,500 (1)

CA

AK

31,141 (2)

48,005 (3)

Norphlet-2 (Jur) 

Haynesville-1 (Jur) 

Jurassic-1 

Sligo-1 (Cret) 

Cretaceous-1

16,324 Smackover-24 (Jur) 

Norphlet-5 (Jur)

15,940 Smackover-43 (Jur) 

Norphlet-5 (Jur) 

Sunniland-1 (Cret)

16,463 Miocene-167 

Pliocene-32 

Wilcox-10 (Tert) 

Tuscaloosa-8 (Cret) 

Camerina-2 (Tert) 

Planulina-2 (Tert) 

Textularia warreni-2 (Tert) 

Austin Chalk-1 (Cret) 

Woodbine-1 (Cret) 

Cibicides carsteni-1 (Tert) 

Pliocene-Pleistocene-1 

Pleistocene-1

15,570 Temblor-1 (Tert) 

Miocene-1 (Tert)

16,001 Hemlock-2 (Tert) 

Tyonek-1 (Tert)

Total* 7,623,561 (467) 1,994,498 (122)

* minimum number

Total deep wells by geologic age as follows: Ordovician= 10; Silurian = 1; 

Pennsylvanian- Permian = 42; Cretaceous = 45; Jurassic = 125; Tertiary = 366. 

Wells without producing formation data must be aggregated for final results. An 

additional 1248 oil wells with formation at total depth greater than 15,000 feet 

have no producing formation or formation at total depth listed in the data file. 

These wells together average 16,356 total depth and account for 20,412,891 total 

drilled feet. These wells are distributed by State as follows: LA = 637 wells 

and 10,417,890 drilled feet; CA = 11 wells and 188,348 drilled feet; NM = 6 

wells and 94,443 drilled feet; TX = 4 wells and 76,457 drilled feet; and AK = 1 

well and 17,689 drilled feet. These data do not include those wells drilled to 

greater than 15,000 feet that have a formation at total depth different than the 

producing formation. These wells have been omitted from the study even though 

some of them may be producing from depths greater than 15,000 feet.

27a
Table 6. Total drilled feet by lithology of producing formation, and average

total depth by State for deep gas-producing wells. Data file only includes 

wells which have a match in producing formation and formation at total 

depth and are producing gas (WHCS final well class = 2). States represented 

by postal code abbreviations. Total drilled feet for both clastic and 

carbonate reservoir formations are listed separately with number of wells 

in parentheses. Producing formation(s) or stratigraphic interval with 

greatest number of wells listed regardless of lithology. Producing 

formation assigned to carbonate or clastic based on dominant lithology of 

formation. In some cases lithology of producing part of formation may 

be different. Lithologic data taken from published literature by the 

authors. Dashes indicate that no wells exist with that lithology.

 Total drilled feet 

State____Clastic_______Carbonate Ave depth Formation(s) or unit (age)

OK 4,686,325 (274) 475,706 (27) 17,149 Morrow-116 (Penn)

Springer-97 (Penn) 

Atoka-29 (Penn) 

Arbuckle-12 (Ord) 

Hunton-12 (Sil-Dev) 

Boatwright-8 (Penn) 

Goddard-6 (Miss) 

Britt-6 (Penn) 

Bromide-5 (Ord) 

Granite Wash-3 (Penn) 

Simpson-2 (Ord) 

Mississippian-1 

Fortuna-1 (Perm) 

Nichlos-1 (Perm) 

Deese-1 (Penn) 

Morrow sand-1 (Penn)

TX 5,034,002 (313) 7,178,423 (377) 17,699 Ellenburger-227 (Ord)

Wilcox-101 (Tert) 

Fusselman-57 (Sil) 

Morrow-53 (Penn) 

Frio-51 (Tert) 

Vicksburg-43 (Olig) 

Cotton Valley-24 (Jur) 

Miocene-17 

Edwards-16 (Cret) 

Sligo-15 (Cret) 

Hunton-12 (Sil-Dev) 

Devonian-11 

Silurian-7 

Silurian-Devonian-7 

Pleistocene-6 

Yegua-5 (Tert) 

Wolfcampian-4 (Perm) 

Mississippian-4 

Woodbine-3 (Cret) 

Jackson-2 (Tert) 

Jurassic-2 

Atoka-2 (Penn) 

28 Arbuckle-1 (Ord)
Table 6. continued.

 Total drilled feet 

State____Clastic______Carbonate Ave depth Formation(s) or unit (age)

Oil Creek-1 (Ord) 

Stravn-1 (Penn) 

Pennsylvanian-1 

Smackover-1 (Jur) 

Hosston-1 (Cret) 

Lower Cretaceous-1 

Glen Rose-1 (Cret) 

Massive sand-1 (Tert) 

Oligocene-1

NM 802,812 (52) 33,206 (2) 15,481 Morrow-51 (Penn)

Ellenburger-1 (Ord) 

Atoka-1 (Penn) 

Devonian-1

WY 1,119,798 (65) 214,957 (13) 17,112 Shannon-28 (Cret)

Nugget-17 (Jur) 

Bighorn-7 (Ord) 

Madison-6 (Miss) 

Mesaverde-5 (Cret) 

Frontier-4 (Cret) 

Cody-3 (Cret) 

Lance-2 (Cret) 

Fort Union-1 (Cret-Tert) 

Lewis-1 (Cret) 

Ericson-1 (Cret) 

Blair-1 (Cret) 

Dakota-1 (Cret) 

Thaynes-1 (Trias)

CO 32,654 (2) 16,327 Nugget-1 (Jur)

Mancos-1 (Cret)

UT 172,240 (11) 15,658 Nugget-10 (Jur)

Wasatch-1 (Tert)

MS 2,742,598 (165) 620,715 (32) 17,072 Hosston-145 (Cret)

Smackover-29 (Jur) 

Cotton Valley-14(Jur) 

Norphlet-4 (Jur) 

Sligo-3 (Cret) 

James-2 (Cret)

AL 448,372 (26) 1,126,281 (65) 17,303 Smackover-65 (Jur)

Norphlet-26 (Jur)

FL 78,926 (5) 15,785 Smackover-4 (Jur)

Norphlet-1 (Jur)

28a
Table 6. continued.

 Total drilled feet 

State Clastic Carbonate Ave depth Formation(s) or unit (age)

LA 14,126,804 (830

AK

CA 32,648 (2) 

70,721 (4) 17,023 Miocene-564

Tuscaloosa-130 (Cret) 

Pleistocene-42 

Oligocene-11 

Planulina-11 (Tert) 

Hackberry-11 (Tert) 

Cotton Valley-9 (Jur) 

Miogypsinoides-9 (Tert) 

Camerina-6 (Tert) 

Hosston-5 (Cret) 

Nodosaria-5 (Tert) 

Bolivina mexicana-5 (Tert) 

Pleistocene-Pliocene-3 

Marginulina texana-3 (Tert) 

Marginulina-3 (Tert) 

Discorbis-3 (Tert) 

Textularia warreni-3 (Tert) 

James-2 (Cret) 

Siphonina-2 (Tert) 

Wilcox-2 (Tert) 

Massive anhydrite-1 (Cret) 

Austin Chalk-1 (Cret) 

Vbmx (?)-!

Robulus mayeri-1 (Tert) 

Siphonia davisi-1 (Tert)

16,324 Repetto-1 (Tert)

Pico-1 (Tert)

Total* 29,198,253 (1740 9,798,935 (525)1 7,217

* minimum number

Wells without producing formation data must be aggregated for final results. 

Totals by geologic age are as follows: Ordovician = 256; Devonian-Silurian « 

100; Mississippian = 13; Pennsylvanian-Permian = 376; Triassic = 1; Jurassic = 

193; Cretaceous = 388; and Tertiary = 915. An additional 1096 gas wells with 

formation at total depth greater than 15,000 feet have no producing formation or 

formation at total depth listed in the data file. These wells together average 

16,364 total depth and account for 17,935,771 total drilled feet. These wells 

are distributed by State as follows: LA = 1019 wells and 16,701,692 drilled 

feet; NM = 1 well and 16,100 drilled feet; TX = 72 wells and 1,154,555 drilled 

feet; WY = 1 well and 15,896 drilled feet; MS = 1 well and 15,600 drilled feet; 

and AK = 2 wells and 31,928 drilled feet. These data do not include those wells 

drilled to greater than 15,000 feet that have a formation at total depth 

different than the producing formation. These wells have been omitted from the 

study even though some may be producing from depths greater than 15,000 feet.

28b
Table 7. Total drilled feet by State for deep veils by lithology of producing 

formation, and average total depth for deep gas and condensate producing 

wells. Data file only includes wells which have a match in producing 

formation and formation at total depth and are producing gas and condensate 

(WHCS final well class = 3). States represented by postal code 

abbreviations. Total drilled feet for both clastic and carbonate reservoir 

formations are listed separately with number of wells contributing to the 

total in parentheses. Producing formation(s) or stratigraphic interval with 

number of wells listed regardless of lithology. Producing formation 

assigned to carbonate or clastic based on dominant lithology. In some cases 

lithology of producing part of formation may be different. Lithologic data 

taken from published literature by the authors. Dashes indicate that no 

wells exist with that lithology.

 Total drilled feet 

State Clastic Carbonate Ave depth Formation(s) or unit (age)

TX

NM 15,323 (1)

441,976 (23) 19,216 Ellenburger-22 (Ord) 

Pennsylvanian-1

15,323 Morrow-1 (Penn)

Total* 15,323 (1) 441,976 (23) 19,054

* minimum number.

Wells without producing formation data must be aggregated for final results. 

An additional 2 gas and condensate wells with formation at total depth greater 

than 15,000 feet have no producing formation or formation at total depth listed 

in the data file. These wells together average 15,575 total depth and account 

for 31,150 total drilled feet. These wells are distributed by State as follows: 

TX = 2 wells and 31,150 drilled feet. These data do not include those wells 

drilled to greater than 15,000 feet that have a formation at total depth 

different than the producing formation. These wells have been omitted from the 

study even though some of them may be producing from depths greater than 15,000 

feet.

29
Table 8. Total drilled feet by lithology of producing formation, and average 

total depth by State for deep oil-producing wells with multiple producing 

horizons. Data file only includes wells which have a match in producing 

formation and formation at total depth and are producing oil from multiple 

horizons (WHCS final well class = 4). States represented by postal code 

abbreviations. Total drilled feet for both clastic and carbonate reservoir 

formations are listed separately with number of wells contributiong to the 

total in parentheses. Producing formation(s) or stratigraphic interval 

with number of wells listed regardless of lithology of formation. 

Producing formation assigned to carbonate or clastic based on dominant 

lithology. In some cases lithology of producing part of formation may be 

different. Lithologic data taken from published literature by the authors. 

Dashes indicate that no wells exist with that lithology.

 Total drilled feet 

State Clastic Carbonate Ave depth Formation(s) or unit (age)

TX 15,419 (1) 

MS

AL

LA 210,933 (13)

15,419 Yegua-1 (Tert)

80,032 (5) 16,006 Smackover-4 (Jur)

Cotton Valley-1 (Jur)

17,372 (1) 17,372 Smackover-1 (Jur)

16,225 Miocene-7 

Pliocene-5 

Planulina-1 (Tert)

Total* 226,352 (14) 97,404 (6) 16,187

* minimum number.

Wells without producing formation data must be aggregated for final results. 

An additional 152 multiple completion oil wells with formation at total depth 

greater than 15,000 feet have no producing formation or formation at total depth 

listed in the data file. These wells together average 16,145 feet total depth 

and account for 2,420,171 total drilled feet. These wells are distributed by 

State as follows: LA = 152 wells and 2,420,171 drilled feet. These data do not 

include those wells drilled to greater than 15,000 feet that have a formation at 

total depth different than the producing formation. These wells have been 

omitted from the study even though some of them may be producing from depths 

greater than 15,000 feet.

30
Table 9. Total drilled feet by lithology of producing formation, and average

total depth by State for deep gas-producing wells with multiple producing 

horizons. Data file only includes wells which have a match in producing 

formation and formation at total depth and are producing gas from multiple 

horizons (WHCS final well class = 5). States represented by postal code 

abbreviations. Total drilled feet for both clastic and carbonate reservoir 

formations are listed separately with number of wells contributing to the 

total in parentheses. Producing formation(s) or stratigraphic interval with 

greatest number of wells listed regardless of lithology. Producing 

formation assigned to carbonate or clastic based on dominant lithology. In 

some cases lithology of producing part of formation may be different. 

Lithologic data taken from published literature by the authors. Dashes 

indicate that no wells exist with that lithology.

 Total drilled feet 

State

TX

MS

AL

LA

Clastic

62,173 (4)

18,576 (1)

474,016 (29)

Carbonate

224,494 (12)

167,690 (10)

133,282 (7)

Ave depth

17,916

16,933

19,040

16,345

Formation(s) or unit (age)

Ellenburger-12 (Ord) 

Frio-4 (Tert)

Hosston-10 (Cret) 

Cotton Valley-1 (Jur)

Norphlet-5 (Jur) 

Smackover-2 (Jur)

Miocene-23

Pliocene-5 

Pleistocene-1

Total* 554,765 (34) 525,466 (29) 17,146

*minimum number

Wells without producing formation data must be aggregated for final results. 

An additional 128 wells with formation at total depth greater than 15,000 feet 

have no producing formation or formation at total depth listed in the data file. 

These wells together average 16,205 feet total depth and account for 2,074,331 

total drilled feet. These wells are distributed by State as follows: LA = 124 

wells and 2,006,307 drilled feet; TX = 4 wells and 68,024 drilled feet. These 

data do not include those wells drilled to greater than 15,000 feet that have a 

formation at total depth different than the producing formation. These wells 

have been omitted from the study even though some of them may be producing from 

depths greater than 15,000 feet.

31
Table 10. Total drilled feet by lithology of producing formation, and average 

total depth by State for deep gas and condensate producing wells with 

multiple producing horizons. Data file only includes wells which have a 

match in producing formation and formation at total depth and are producing 

gas and condensate (WHCS final well class = 6). States represented by 

postal code abbreviations. Total drilled feet for both clastic and 

carbonate reservoir formations are listed separately with number of wells 

contributiong to the total in parentheses. Producing formation(s) or 

stratigraphic interval with greatest number of wells listed regardless of 

lithology. Producing formation assigned to carbonate or clastic based on 

dominant lithology. In some cases lithology of producing part of formation 

may be different. Lithologic data taken from published literature by the 

authors. Dashes indicate that no wells exist with that lithology.

 Total drilled feet 

State Clastic Carbonate Ave depth Formation(s) or unit (age) 

~TX220,172 (13)16,936Ellenburger-13 (Ord)

Total* 220,172 (13) 16,936

* minimum number.

Wells without producing formation data must be aggregated for final results. 

An additional 128 wells with formation at total depth greater than 15,000 feet 

have no producing formation or formation at total depth listed in the data file.

32
Table 11. Total drilled feet by lithology of producing formation, and average

total depth by state for deep oil and gas producing wells. Data file only 

includes wells which have a match in producing formation and formation at 

total depth and are producing oil and gas (WHCS final well class = 7). 

States represented by postal code abbreviations. Some producing horizons 

may exist below 15,000 feet but are not identified. Total drilled feet for 

both clastic and carbonate reservoir formations are listed separately with 

number of wells contributing to the totalin parentheses. Producing 

formation(s) or stratigraphic interval with greatest number of wells listed 

regardless of lithology of formation. Producing formation assigned to 

carbonate or clastic based on dominant lithology. In some cases lithology 

of producing part of formation may be different. Lithologic data taken 

from published literature by the authors. Dashes indicate that no wells 

exist with that lithology.

 Total drilled feet 

State Clastic Carbonate Ave depth Formation(s) or unit (age)

OK

TX

MS

LA

__

17,000 (1)

212,599 (13)

15,715 (1)

16,800 (1)

15,715

16,800

17,000

16,353

Hunton-1 (Sil-Dev)

Ellenburger-1 (Ord)

Hosston-1 (Cret)

Miocene-9

Pliocene-3

Tuscaloosa-1 (Cret)

Total* 229,599 (14) 32,515 (2) 16,382

* minimum number.

Wells without producing formation data must be aggregated for final results. 

An additional 41 oil and gas multiple completion wells with formation at total 

depth greater than 15,000 feet have no producing formation or formation at total 

depth listed in the data file. These wells together average 15,842.feet total 

depth and account for 649,533 total drilled feet. These wells are distributed by 

State as follows: LA = 39 wells and 615,318 drilled feet; TX = 2 wells and 

34,215 drilled feet. These data do not include those wells drilled to greater 

than 15,000 feet that have a formation at total depth different than the 

producing formation. These wells have been omitted from the study even though 

some of them may be producing from depths greater than 15,000 feet.

33