Foreign service providers to the petroleum operations must associate to Mozambican natural or juridic persons majority-owned by Mozambican nationals. Similarly, foreign persons providing services to mining operations must associate themselves with Mozambican natural or legal persons [assuming majority-owned by Mozambican nationals as per the definition under the Law No. 21/2014 on Oil].
"Article 2
Object
This Law establishes the rules for the granting of rights to carry out petroleum operations in the Republic of Mozambique and beyond its borders insofar as it is in accordance with international laws.
[…]
CHAPTER IV - PETROLEUM OPERATIONS
Article 26
Subjects
1. Mozambican or foreign legal entities that are registered in Mozambique, and who demonstrate that they have the technical capability and adequate financial resources for the effective conduction of petroleum operations may be holders of the right to carry out petroleum operations.
2. Foreign legal entities which directly or indirectly hold or control legal entities that own rights under a concession contract, shall be established, registered and administered under a transparent jurisdiction.[...]
4. Mozambican legal entities as well as foreign legal entities that associate with Mozambican legal entities shall have a pre-emption right in the granting of concession contracts. 
[...]
Article 41
Acquisition of goods and services
1. The acquisition of goods or services by the petroleum operations right holders, above a set amount, must be made through public tender and this must be published in the means of communication of greater incidence to the larger publication newspapers of the country and on the internet page of the respective right holders.
2. Single or collective foreign entities that provide services to the petroleum operations must associate to single or collective Mozambican persons.[...]
4. The petroleum operations right holders must give preference to local products and services when comparable, in terms of quality, to the international materials and services that are available in time and in the quantities required and when the price, including taxes, is not over by ten percent to the price of the available imported goods.
[....]
Annex - DEFINITIONS [...]
o) “Mozambican person” – any legal entity incorporated and registered pursuant to the Mozambican legislation with its headquarters in the country and having at least fifty one percent of its share capital held by national citizens or controlled by Mozambican citizens, or Mozambican public or private companies or institutions.
p) National collective person – is the one registered in Mozambique and has its head office and effective management in national territory and the capital of which is predominantly national.
q) National single person – single person of Mozambican nationality. [...]
bb) Transparent jurisdiction – is understood as jurisdictions whereby the Government, in an independent manner, may verify the ownership, management and control, fiscal situation of a foreign legal person who wishes to participate or participates in petroleum operations.[...]" (Law No. 21/2014 on Oil  [unofficial translation])
Law No. 21/2014 on Oil [unofficial translation]
[<a href="https://www.vda.pt/xms/files/v1/Newsletters/2014/Petroleum_Law_translation.pdf">Law</a>]