If a person swears an oath concerning one matter and repeats the oath, then breaks it, he has to offer one expiation. If a person makes repeated oaths concerning several different matters and breaks the oaths, he has to offer expiation for each oath.
Ibn Qudaamah (may Allah have mercy on him) said:
If he repeatedly swears an oath concerning one matter, such as if he said: By Allah, I shall attack Quraysh; by Allah, I shall attack Quraysh; by Allah, I shall attack Quraysh -- then he breaks the oath, he only has to offer one expiation.
Something similar to this was narrated from Ibn ‘Umar, and it was the view of al-Hasan, ‘Urwah and Ishaaq.
It was also narrated from ‘Ata’, ‘Ikrimah, al-Nakha‘i, Hammaad and al-Awzaa‘i.
End quote from al-Mughni, 11/204.
It says in al-Iqnaa‘ (4/337):
Whoever repeatedly swears an oath concerning one matter, such as saying “By Allah, I shall not eat; by Allah, I shall not eat,” only offers expiation once.
The scholars of the Standing Committee for Issuing Fatwas said:
If oaths are sworn repeatedly, if they have to do with one matter, one expiation is sufficient, such as if one says, “By Allah, I shall not speak to So and so,” and he repeats that a great deal, that he speaks to him. If what is mentioned in the oath is different types of things, such as if he says, “By Allah I shall not speak to So and so,” then he speaks to him, and he says, “By Allah, I shall not travel to such and such a place,” then he goes there… and so on – (in such cases) he has to offer expiation for each oath. End quote.
Fataawa al-Lajnah (23/50)
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
If you swore a number of different oaths, if it had to do with one matter, then one expiation will be sufficient for you, but if they had to do with several different matters, that you should offer expiation for each oath. End quote.
Liqa’ al-Baab al-Maftooh (115/13),
Based on that, what appears to be the case is that in your oath you swore two different things: to stay up all night until you became thirsty and to stay up until you became tired, and you broke your oath in both cases, so you have to offer two expiations.
For detailed information on the expiation for breaking an oath (kafaarat yameen), please see the answer to question no. 45676.
And Allah knows best.