Increase In Exploratory Drilling Research Articles

Oil and Gas Developments in Southeastern States in 1983

Total drilling activity in Mississippi, Alabama, Florida, and Georgia, including both exploratory and development wells, decreased 8.9% from 855 in 1982 to 779 in 1983. However, exploratory drilling in the southeastern states in 1983 increased 7.2%. Exploratory tests totaled 357 versus 333 tests in 1982, and 52 were successfully completed for a 14.6% success rate. This compares to 46 successful completions and a 13.8% success rate in 1982. The shallow Eocene Wilcox trend in southwest Mississippi accounted for 39.8% of exploratory tests in the southeastern states during 1983. This active trend had 11 new-field discoveries compared to only 6 new-field discoveries in 1982. The Paleozoic trend of northeast Mississippi and northwest Alabama had 17 new-field discoveries compared with 16 the previous year. This trend represented 18.4% of the exploratory drilling activity in the southeast. The Jurassic trend had 4 new-field discoveries for a 50.0% decline relative to 1982 when 8 new-field discoveries were made. The Jurassic accounted for 17.4% of the total exploratory effort in the southeast in 1983. The Upper Cretaceous, Lower Cretaceous, and Miocene trends accounted for 12.9%, 8.1%, and 3.4%, respectively, of the total explor tory tests. Six new-field discoveries were reported in the Upper Cretaceous, 2 in the Lower Cretaceous, and 3 in the Miocene. Seismic activity was down 18.1% as crew-week totals dropped from 1,306 in 1982 to 1,070 in 1983. Oil and gas production also showed a decline. Oil production decreased 12.1%, and gas production decreased 7.9%. In 1984, a modest increase in exploratory drilling can be expected. Most of the activity will be concentrated in the Wilcox, Paleozoic, and Jurassic trends. These 3 trends represented approximately 75% of the exploratory activity in the southeastern states in 1983, and a similar level of activity in these trends is expected to occur in 1984. Natural gas exploration below 15,000 ft will continue to be slow because of continuing poor economic conditions for deep gas. Seismic activity should show a modest improvement in 1984 as companies attempt to improve prospect inventories. The increase in seismic activity will be accompanied by an increase in acreage availability as 3- and 5-yr term lease blocks taken during the boom years of 1979-81 expire. Even with increased exploratory activity, 1984 oil and gas production in the southeastern states will show a decline relative to 1983 unless a number of significant discoveries are made. The independents and smaller companies will continue to conduct the bulk of the exploratory drilling in the southeastern states.

Arkansas, Northern Louisiana, and East Texas

During 1980, the level of activity in all three CSD districts covered by this report, Arkansas, North Louisiana, and East Texas, surpassed the 1979 level of drilling activity, which was at the highest level during the past 10 years. All three districts have had a large development drilling increase. Arkansas had a slight increase in exploratory drilling, while the north Louisiana and east Texas exploratory drilling level had a more sizable increase. Success ratios in exploratory drilling increased slightly in both east Texas and Arkansas. As to development drilling success, both north Louisiana and east Texas had an increase, while the Arkansas development drilling success declined.

Developments in Eastern Canada in 1979

In Eastern Canada 245 wells, not including 10 lost holes, were drilled for oil and gas during 1979. Of this total, 90 wells were classed as exploratory, 144 as development, and 11 were drilled for various service and storage purposes. The total meterage drilled in Eastern Canada amounted to 177,623.3. The production of natural gas in Eastern Canada increased 29.4% in 1979, whereas oil production dropped 1.2%. A total of approximately 399,353,200 cu m of natural gas and 96,118.6 cu m of oil was produced from southwestern Ontario and New Brunswick. Additional production from Lake Erie, coming on stream, accounted for the rise in natural gas production figures. All phases of exploration increased in Quebec, the Maritimes, and Atlantic offshore during 1979; 23 exploratory wells were completed, 2 of which had been suspended in 1978. Of this total, 3 dry holes were drilled in Nova Scotia; 9 wells were drilled in Quebec, which resulted in 8 dry holes and 1 suspended well; 11 wells were drilled in the Atlantic offshore, which resulted in 1 gas well, 5 dry holes, 4 suspended wells, and 1 well testing at year end. This represents a 61.5% increase in exploratory drilling for the area. In southwestern Ontario, 67 exploratory and 144 development wells, not including 10 lost holes, were drilled in 1979; 15 of the 67 exploratory wells were completed as producers (3 oil, 12 gas) for an exploratory success rate of 21.4% (including 3 lost holes). Of the 144 development wells, 78 were completed as producers (5 oil, 73 gas) for a development success rate of 51.7% (including 7 lost holes). The overall success rate for southwestern Ontario for 1979 was 42.1%, down 5.2% from 1978. An increase in development drilling in Lake Erie (up 63.8%), accompanied by an even greater percentage of offshore development dry holes, accounted for the decline in the overall success ratio. This trend may continue, as it is anticipated that the 1980 drilling season in Ontario will surmount that o 1979.

Developments in Eastern Canada in 1978

The production of natural gas in Eastern Canada increased 21.66% in 1978, whereas the production of oil dropped 1.4%. A total of approximately 308,564,600 cu m of natural gas and 97,314.7 cu m of oil was produced from southwestern Ontario and New Brunswick. Most of the increase in natural gas production is the result of additional wells within Lake Erie being placed on-stream this past year. Exploratory drilling increased slightly in Quebec and the Atlantic provinces, but geophysical activity remained constant. During 1978, 12 exploratory tests were completed: 5 were drilled in Quebec, which resulted in 3 dry holes and 2 suspended wells and 7 were drilled offshore on the Scotian and Labrador Shelves, resulting in 6 dry holes and 1 gas well. In southwestern Ontario, 64 exploratory and 99 development wells were drilled in 1978. This represents an increase of 10 exploratory wells, but a 15-well decrease in development drilling. The increase in exploratory drilling has lowered the exploratory success rate from 40.74% in 1977 to 28.13% in 1978. Five pinnacle reefs (3 gas, 2 oil) were discovered in Lambton County during 1978. The 1 Ordovician gas discovery in Kent County has continued to stimulate deeper tests southwest of the province. An active drilling program, begun in Bruce, Huron, and Perth Counties by several major companies, had no success by year end. Continued success in the development drilling program within Lake Erie has accounted for the high percentage (59%) of development wells there. It appears that this patte n will continue into 1979.

Developments in Canada in 1976; "gas becomes king"

The year of 1976 was a record drilling year. A total of 5,561 wells were drilled, an increase of 1,456 wells over the previous year. Exploratory wells totalled 2,459, an increase of 49.5% and development wells totalled 3,690, an increase of 39.3% over 1975. There were 183 oil discoveries and 1,126 gas discoveries for an exploratory success ratio of 53.2%. In development drilling, 566 oil wells and 2,502 gas wells were completed for a success ratio of 83.3%. The majority of exploratory drilling was in Alberta, where 2,132 exploratory wells were drilled. In this province, exploration was concentrated on natural gas with numerous trends being followed. Very high prices were paid for acreage favorable for natural gas exploration and development. Intense development of the shallow Cretaceous Bluesky Sand gas play continued in the Keg River area of northern Alberta. There was also a major deep drilling program under way, centred on Devonian, Triassic and Lower Cretaceous gas accumulations of the deeper part of the Alberta basin and on the thrust fault structures of the Foothills belt. In Alberta, there was also a large development well program aimed at placing the numerous known gas fields on production. There was a significant increase in exploratory drilling on favorable gas trends in British Columbia. Emphasis was on the Devonian Slave Point formation at moderate depths in the Helmet area and on two deep Foothills trends. The majority of drilling in Saskatchewan was for Lower Cretaceous heavy oil in the western part of the province. An interesting Winnipegosis (Middle Devonian) discovery was made in the eastern part of Saskatchewan, which holds some promise of establishing a new trend. In Manitoba, there was a minor amount of exploration for Mississippian oil. The only continuing exploration in the Arctic was by Panarctic Oils, who concentrated on building up reserves in areas where oil or gas had already been found. This resulted in major extensions and a new deep zone being found in the Hecla gas field, which has now reached giant status. A third producer was drilled in the Bent Horn oil field on Cameron Island. In the onshore Mackenzie Delta, two oil discoveries were made and offshore in the Beaufort Sea there were two gas discoveries. In Ontario, exploration for and development of shallow Silurian gas plays continued at the same level as the previous year. A major part of this activity was in the offshore waters of Lake Erie. In Quebec, exploratory drilling by SOQUIP for natural gas in the St. Lawrence lowlands resulted in two extensions to a previous Trenton discovery at St. Flavian near Quebec City. Ten wells were drilled in the offshore area of Eastern Canada, of which five were on the Scotian Shelf, one in the Cumberland Basin and five on the Labrador Shelf. One gas discovery, Eastcan Snorri J-90, resulted from this drilling. Geophysical activity was at a somewhat higher level than last year, but did not show any trend towards increasing as the year progressed. Production of liquid hydrocarbons was again down about 11% from the previous year. There were further reductions in export of oil to the United States but with the completion of the Ontario-Montreal pipeline, oil began flowing to Quebec. On the other hand, natural gas production increased by 8%, the increase being mainly from Alberta fields. Proven and probable reserves of crude oil continued their decline and natural gas liquid reserves also declined slightly. However, for the third year running, gas reserves increased. Proven reserves after production rose by 1.31 Tcf while probable reserves rose by 4.89 Tcf, the latter increase resulting largely from the inclusion of more large Arctic Island reserves.

Developments in Four Corners-Intermountain Area in 1975

Total drilling in Four Corners-Intermountain area during 1975 was up considerably over 1974. The increase came in both exploratory and development drilling. Success ratios also were higher. Some increase in exploratory drilling is indicated for 1976.

Developments in North-Central Texas in 1974

Rapid expansion of drilling in North-Central Texas during 1974 produced a 32% increase in well completions compared with the previous year. The impact of rising crude oil and natural gas prices caused a 25% increase in exploratory drilling, and a 35% increase in development wells. Rapidly rising costs and critical shortages of equipment characterized almost all phases of operations. The exploratory-well success ratio remained at a high level (26%). Gas-well discoveries again exceeded new-oil discoveries. Gas exploration activity was concentrated in the Fort Worth basin. Oil production declined 5.1%, a decrease of 4,190,800 bbl from 1973.

Developments in Eastern Canada in 1974

The production of natural gas and petroleum in Eastern Canada declined sharply in 1974. A total of 7,762, 551 MCFG and 746,000 BO was produced. This is a production decrease of 20% gas and 8.6% oil from 1973. In Eastern Canada geophysical activity and exploratory drilling declined as compared with 1973. Some acreage was released in Quebec and in the offshore areas of Hudson Bay, the Atlantic, and the Labrador Sea. Seven dry holes were completed on inland areas, 3 dry holes offshore in Hudson Bay, 3 indicated gas discoveries, and 17 dry holes in the Atlantic and Labrador Sea regions. In southwestern Ontario, 80 exploratory tests and 60 development wells were drilled in 1974, 4 more development wells than in 1973. Silurian exploratory drilling, both onshore and in Lake Erie, increased significantly although Silurian development drilling remained almost the same as the previous year. The overall increase in exploratory drilling is reflected in a 26% increase in total footage drilled. Three gas-bearing Silurian reef structures in Lambton County and an Ordovician (Trenton) gas discovery in Aldborough Township, Elgin County, were the most significant discoveries in 1974. In Quebec, 7 dry exploratory tests were drilled. No data are available on geophysical work done during the year. Onshore in the Atlantic provinces (New Brunswick, Nova Scotia, and Newfoundland) there was no exploratory drilling. Offshore activity was relatively active with 20 completions, 9 less than in 1973. Of the 20 tests, 17 were drilled in the Atlantic, 2 in the Labrador Sea and 1 in the Gulf of St. Lawrence. Three wells are classified as discoveries. In the offshore region, 23.5 crew-months of geophysical work was completed. The total area under permit for oil and gas exploration in the offshore decreased by 51 million acres.

Developments in Southeastern States in 1974

Onshore 1974 drilling activity in Mississippi, Alabama, Florida, and Georgia increased 9.7% from 1973. A total of 566 tests was drilled compared to 516 in 1973. A 20.9% increase in exploratory drilling was recorded as 370 tests were reported, 64 more than in 1973. Development activity continued to decline, however, as 196 tests were drilled in 1974 down from 210 in 1973. A total of 20 new-field discoveries was completed, 3 less than the 1973 total. New-field success rate was low at 6.1%. Exploration increased considerably in the Wilcox trend of southwestern Mississippi and it replaced the Jurassic as the leading drilling trend. Drilling for Jurassic objectives was the lowest since 1968, but some of the more significant discoveries were reported in this interval. The Paleozoic trend in the Black Warrior basin was the third most active drilling area, followed by the Upper Cretaceous, but important discoveries were lacking in both trends. Activity dropped in the Lower Cretaceous trend but 2 important discoveries were recorded and increased interest in this trend is expected in 1975. Drilling in the Mafla offshore area began at about midyear and approximately 15 Tertiary and Cretaceous tests were drilled. Only 1 successful wildcat was announced and this was less than 1 mi from established production in the Louisiana offshore area. The remaining offshore wildcats were disappointingly dry, including 2 on the huge Destin anticline of offshore Florida panhandle. Deeper Jurassic sections were not penetrated offshore in 1974. Seismic activity declined in the southeastern states in 1974. Much of the activity was detailed work supplementing data acquired in previous years. Important leasing activity occurred in the Lower Cretaceous trend and along the coastal counties of Mississippi, Alabama, and Florida panhandle where the deep Jurassic was the primary objective. Overall, however, no extensive blocks were assembled and leasing appeared to be mainly a continuation of efforts started in the previous 2 years. Total drilling activity is predicted to increase slightly in 1975 because of an expected rise in exploratory drilling. However, this forecast is based on the availability of rigs and pipe, plus continued economic incentives. Conditions or policies adversely affecting these factors could lead to a decline in drilling activity.

North American Drilling Activity in 1972

Total drilling activity in North America increased in 1972 compared with 1971. The year is further highlighted by a substantial increase in new-field wildcat drilling and discoveries. During 1972 the oil industry drilled more than 29,500 mi of hole in 33,005 wells. Compared with 1971 this is an increase of 7.8% in footage and 6.2% in wells. Canada showed the greatest increase in both footage and wells, approximately 17%. The 28,755 wells in the United States represent an increase of 5.3% over 1971 drilling. Mexico, however, reports a decrease for this year, 431 wells compared with 516 for the previous year. The Canadians report an eye-opener increase of 65% in new fields discovered, 137 in 1972 compared with 83 reported in 1971. The United States also reports a substantial increase of 30.5% in new fields discovered, 566 compared with 434. These 566 new fields found estimated ultimate reserves of 585 million bbl oil and 5.0 Tcf gas. Both reserve figures represent increases compared with 1971 data, 2.8% for oil and 3.2% for gas. Success of new-field wildcat drilling continues to remain a constant of approximately 10%. For 1972 it was 11.1%. The statistical data for 1972 reemphasize the fact that the number of new-field wildcat discoveries increases proportionately to the increase in exploratory drilling.

Developments in Alaska in 1971

Alaska's petroleum exploration and development activity was virtually at a standstill during 1971. Only 6 exploratory and 29 development wells were drilled for declines of 78.6% and 49.2%, respectively. One discovery was made on the Arctic Slope; for the third consecutive year, none was made in the Cook Inlet basin. No wells were drilled in Alaska's other major basins. Geophysical and surface geologic investigations totaled 94.5 crew-months, down 45.7% from 1970. Oil production decreased 5.8% and gas production increased 4.7%. Cumulative state production at year end totaled approximately 396,396,757 bbl of oil and 884,992,139 Mcf of gas, of which 356,854,769 Mcf is casinghead gas. Cumulative petroleum industry investments in Alaska through 1971 are estimated to be in excess of $3 billion; 24 competitive state oil and gas lease sales alone have brought bonus payments of $998,107,679. No federal lease sales were conducted, and at year end total Federal land under oil and gas lease was 5,326,815 acres, down 13.7%. Two new Arctic Slope federal units were approved. One competitive state lease sale was held in the Cook Inlet basin. State lands under oil and gas lease at year end totaled 3,945,222 acres, down 5.0%. Vigorous industry opposition by the many conservation and environmental groups throughout the country is the cause of this sharp decline in activity. Over 95% of Alaska's 375 million acres remain locked up by the Federal land freeze, and construction on the proposed trans-Alaska pipeline had not started at year end because of lack of a construction permit. The forecast for 1972 is for a twofold increase in exploratory drilling, a slight decline in development drilling, and a sharp drop in surface geologic and geophysical investigations. Production should remain near the 1971 level with no real increase to be expected until Prudhoe Bay field wells go on production. State and federal lands under oil and gas lease will also decline during 1972. Additional geologic and geophysical investigations directly or largely applicable to petroleum resource evaluation in Alaska during 1971 included 12 crew-months by the U. S. Geological Survey and a 43,932-sq mi aeromagnetic survey by the Alaska Division of Geological Survey.

Developments in Upper Gulf Coast of Texas in 1969

There was a pronounced increase in exploratory drilling in the Upper Gulf Coast of Texas in 1969. The total of 441 wells drilled marked a 37% increase from the 1968 total. This increase was evident in all exploratory classifications, and the success ratio of all exploration wells drilled was 1:5. There was a very slight decline in development drilling compared with 1968, but the success percentage showed an increase. The Eocene remained the most actively explored trend in 1969, but the largest gain in exploratory activity was registered in the Miocene trend. Most of this increase was accounted for by the offshore Texas area, where 86 wells were drilled in order to evaluate recently leased federal and state offshore tracts. Seismic activity in Texas Rairoad Commission Dist ict 3 continued the drop which commenced in 1967.

Exploration in Oklahoma and Panhandle of Texas in 1969

A strong increase in exploratory drilling and success was experienced in 1969. Development drilling was also up. Geophysical activity declined markedly, and land activity remained at about the same level as last year. The Anadarko basin continued to receive major emphasis in all of the above categories as the deep drilling campaign continued along with a high level of shelf and hinge line drilling.

Developments in Upper Gulf Coast of Texas in 1968

Exploratory drilling in Texas Railroad Commission District 3 decreased in 1968, but new-field discoveries increased. The success ratio of all exploratory wells was 1:6. A total of 596 development wells was drilled, with a 69% success. The Eocene became the most actively explored trend in 1968 and continued to be the most successfully drilled trend. Seismic activity in both the onshore and offshore continued to decrease. There was an increase in exploratory drilling but a decrease in development drilling in the offshore.

Developments in Arkansas, North Louisiana, and East Texas in 1965

During 1965 there were 359 wells drilled in Arkansas, a decline of 7.9% from 1964. Of the successful completions, 113 were oil productive and 46 were gas productive. From these successes, 8 new oil fields, 2 new gas fields, and major extensions to 3 gas fields were established. All of the gas discoveries and extensions were in the Arkoma basin of northern Arkansas. The overall drilling program in Arkansas was 44.3% successful; wildcat wells were 12.0% successful. Total footage drilled was 1,530,240, a decline of 4.5% from 1964. Increased geophysical activity and strong leasing activity indicate an increase in exploratory drilling in 1966. In North Louisiana, 2,640 wells were drilled, 299 less than in 1964. There were 1,220 oil wells completed, 300 gas wells, and 1,120 dry holes. Wildcatting accounted for 348 completions. Total footage drilled was 9,854,958, an increase of 1,171,028 ft. from 1964. The number of fields discovered was much less than the number for 1964. A total of 13 new oil fields and 2 new gas fields was discovered, compared with 22 oil fields and 6 gas fields for 1964. There were 8 oil fields discovered in Concordia Parish, 2 in LaSalle, 1 in Caddo, 1 in Catahoula, and 1 in DeSoto. Gas discoveries were made in DeSoto and Sabine Parishes. Eleven of the oil discoveries were in the Wilcox Group reservoirs, and 1 each was in the Paluxy Sand and Pettet Formation. Two gas fields were discovered in reservoirs of the Tuscaloosa and Tokio Formations. Increased geophysical work and much stronger leasing activity indicate an increase in exploratory drilling in 1966. In East Texas, 229 wildcats and 824 field wells were drilled, an increase of 49 wells above 1964. However, new-field discoveries totaled only 15, a decrease of 6. New-pool discoveries made a substantial gain, but geophysical activity and acreage acquisition decreased. The major interest continues to be in the Smackover trend and in field development in the Sabine uplift area.

Developments in Arkansas and North Louisiana in 1963

This report covers that part of the Gulf Coastal Province located in North Louisiana and Arkansas, and the Paleozoic area of northwestern Arkansas. The District includes 26 parishes of North Louisiana and all of Arkansas. There was an over-all increase in drilling activity in 1963 as compared with the previous years. North Louisiana had a record-breaking year in the number of wells drilled. This was due to an increase in development drilling in the Wilcox trend and Saratoga-Annona Chalk areas of Sabine and Caddo Parishes. There was also an increase in exploratory drilling. Arkansas showed an increase in development and a decrease in exploration drilling activity. Fourteen new fields were discovered in North Louisiana and 5 new fields were discovered in Arkansas. Sandstones of the Wilcox formation accounted for the largest number of new-field discoveries in North Louisiana. Four of the new-field discoveries in South Arkansas were in the Nacatoch, Meakin, and Baker sands and the Smackover limestone. In North Arkansas the discovery was in the Atoka (Pennsylvanian) sand. The most important exploration activity in Arkansas was in search of gas in the Arkoma basin in the northwestern part of the state. Exploratory drilling was active in the Wilcox areas in the eastern part of North Louisiana, and in the western part the Saratoga and Annona Chalk areas were most active. Exploration activity will probably remain about the same during 1964 as was present in 1963. Arkansas' most important activity will be centered in the Arkoma basin while activity in North Louisiana will again be centered in the Wilcox, Sligo, Hosston-Cotton Valley, and Saratoga-Annona Chalk areas.

Developments in Montana, North Dakota, and South Dakota in 1962

Over-all exploratory activity was down slightly in Montana in 1962; however, the discovery ratio improved. The widespread occurrence of new-field discoveries and an improved success ratio reflect the increased confidence oil men have in the potential of vast unexplored areas of Montana. Eastern Montana is expected to receive high interest and much activity in 1963. The Powder River Basin extension into Montana will continue to receive exploratory attention, commenced in 1961 and 1962. North Dakota in 1962 experienced a modest increase in exploratory drilling. Wildcat success ratios were only fair, compared with national averages, but the area continues to reflect high development and extension success ratios. The industry-wide attitude of exploratory retrenchment, which affected North Dakota in 1961, continued to prevail in 1962. Developments in 1963 are expected to follow the same general pattern as in 1962, with some improvement expected as a result of better marketing economics in some areas. For the second successive year South Dakota failed to register a wildcat exploratory success. However, there is a sustained exploratory interest in South Dakota, as indicated by continued leasing and sporadic exploratory drilling.

Developments in Louisiana Gulf Coast in 1960

The Louisiana Gulf Coast, as treated in this analysis, consists of the 38 southern parishes and the 16 adjacent continental shelf areas offshore. Production is obtained from sediments ranging in age from Cretaceous to Pleistocene. The 2,251 development and exploratory wells drilled in 1960 are favorably comparable in number and in results with those of 1959. Of the 769 exploratory wells, 44.4% were successful. The Southeast District continued to be the most important in both development and exploratory drilling. The Offshore District had a 69.4% increase in exploratory drilling. Of the 50 new-field discoveries (42 onshore, 8 offshore) the most important are: South Chauvin field, Terrebonne Parish; Pierre Pass field, Assumption Parish; and Eugene Island Block 100 field. The most important of the 292 new pools and extensions include Buck Point field, Vermilion Parish, and South Pass Block 27 field. Leasing continued to be very active with large blocks of acreage being assembled and traded. Subsurface geology increased in importance as more well control became available. Seismic exploration continued to be extensive. In 1960, the high level of activities recorded in 1957 and 1959 was maintained.

Developments in Montana, North Dakota and South Dakota in 1957

Substantial increase in exploratory drilling in North Dakota during 1957 resulted in a success ratio of 19.8% In Montana little change was noted in total holes drilled and the success ratio as compared with 1956. Crude production increased 5,356,000 bbls. in Montana and 1,692,000 bbls. in North Dakota over 1956. Pine Unit field of eastern Montana became the largest producer in the Williston basin, with a 1957 production of 5,347,608 bbls.

Developments in North Texas in 1956

There was a substantial increase in exploratory drilling during 1956 but development drilling remained almost the same. The success ratio reflected this as it was down from 31% to 17% for exploratory wells, but remained nearly the same for development wells. Crude production increased by about 3,500,000 bbls. over 1955.