Page 260 - Annual Report 2020

5.7 Supplementary oil and gas information – unaudited continued
Drilling and other exploratory and development activities
The number of crude oil and natural gas wells drilled and completed for each of the last three years was as follows:

Net exploratory wells Net development wells
Productive Dry Total Productive Dry Total Total
Year ended 30 June 2020
Australia − − − − − − −
United States (1) − − − − 1 1 1
Other (2) 1 1 2 1 − 1 3
Total 1 1 2 1 1 2 4
Year ended 30 June 2019
Australia − − − 1 − 1 1
United States (1) 1 − 1 33 − 33 34
Other (2) 4 2 6 − − − 6
Total 5 2 7 34 − 34 41
Year ended 30 June 2018
Australia − − − 1 − 1 1
United States (1) 1 1 2 84 1 85 87
Other (2) − − − − − − −
Total 1 1 2 85 1 86 88
(1) Includes Onshore US assets net productive development wells of nil (2019: 33; 2018: 84) and net dry development wells of nil (2019: nil; 2018: 1). Onshore US assets
had nil net exploratory wells in 2020, 2019 and 2018.
(2) Other is primarily comprised of Algeria, Mexico and Trinidad and Tobago.
The number of wells drilled refers to the number of wells completed at any time during the respective year, regardless of when drilling was
initiated. Completion refers to the installation of permanent equipment for production of oil or gas, or, in the case of a dry well, to reporting
to the appropriate authority that the well has been abandoned.
An exploratory well is a well drilled to find oil or gas in a new field or to find a new reservoir in a field previously found to be productive of oil
or gas in another reservoir. A development well is a well drilled within the limits of a known oil or gas reservoir to the depth of a stratigraphic
horizon known to be productive.
A productive well is an exploratory, development or extension well that is not a dry well. Productive wells include wells in which hydrocarbons
were encountered and the drilling or completion of which, in the case of exploratory wells, has been suspended pending further drilling
or evaluation. A dry well (hole) is an exploratory, development, or extension well that proves to be incapable of producing either oil or gas
in sufficient quantities to justify completion as an oil or gas well.
Oil and gas properties, wells, operations, and acreage
The following tables show the number of gross and net productive crude oil and natural gas wells and total gross and net developed and
undeveloped oil and natural gas acreage as at 30 June 2020. A gross well or acre is one in which a working interest is owned, while a net
well or acre exists when the sum of fractional working interests owned in gross wells or acres equals one. Productive wells are producing
wells and wells mechanically capable of production. Developed acreage is comprised of leased acres that are within an area by or assignable
to a productive well. Undeveloped acreage is comprised of leased acres on which wells have not been drilled or completed to a point that
would permit the production of economic quantities of oil and gas, regardless of whether such acres contain proved reserves.
The number of productive crude oil and natural gas wells in which the Group held an interest at 30 June 2020 was as follows:
Crude oil wells Natural gas wells Total
Gross Net Gross Net Gross Net
Australia 353 176 162 54 515 230
United States 61 24 − − 61 24
Other (1) 59 22 8 4 67 26
Total 473 222 170 58 643 280
(1) Other is primarily comprised of Algeria and Trinidad and Tobago.
Of the productive crude oil and natural gas wells, 133 (net: 62) operated wells had multiple completions.
Developed and undeveloped acreage (including both leases and concessions) held at 30 June 2020 was as follows:
Developed acreage Undeveloped acreage
Thousands of acres Gross Net Gross Net
Australia 2,152 823 766 279
United States 98 36 844 800
Other (1)(2) 146 57 3,926 3,445
Total 2,396 916 5,536 4,524
(1) Developed acreage in Other primarily consists of Algeria and Trinidad and Tobago.
(2) Undeveloped acreage in Other primarily consists of Barbados, Canada, Mexico and Trinidad and Tobago.
Approximately 833 thousand gross acres (411 thousand net acres), 1,089 thousand gross acres (655 thousand net acres) and 264 thousand
gross acres (256 thousand net acres) of undeveloped acreage will expire in the years ending 30 June 2021, 2022 and 2023 respectively,
if the Group does not establish production or take any other action to extend the terms of the licences and concessions.

258 BHP Annual Report 2020