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Summary of Significant Accounting Policies - Schedule of Revenue by Major Customers by Reporting Segments (Details) - Sales Revenue, Net [Member] - Customer Concentration Risk [Member]	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Revenues, percentage	100.00%	100.00%
Eni S.P.A [Member]
Revenues, percentage	17.00%	14.00%
Premier Oil UK Limited [Member]
Revenues, percentage	16.00%	47.00%
EGP [Member]
Revenues, percentage	67.00%	0.00%
U.S. Navy [Member]
Revenues, percentage	0.00%	26.00%
Other [Member]
Revenues, percentage	0.00%	13.00%

X

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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