Praise be to Allaah.
The scholars differed concerning the wudoo’ of one who suffers from urinary incontinence or passes wind continually. Does he have to do wudoo’ for each obligatory prayer after the time for it begins, and then pray as much as he wants to of naafil prayers, or is it permissible for him to do wudoo’ once and pray all the prayers with it, unless he breaks his wudoo’ in a manner other than his ongoing incontinence?
Abu Haneefah, al-Shaafa’i and Ahmad were of the view that he should do wudoo’ for each prayer after the time for it begins.
Maalik was of the view that it is permissible for the one who is suffering from incontinence to do wudoo’ once and offer all his prayers with it, so long as his wudoo’ is not broken by something other than that ongoing incontinence.
The first view is more on the safe side and is the view of the majority.
See the answer to question no. 22843 for more information.
But if the person who suffers from incontinence breaks his wudoo’ in a manner other than his ongoing problem, then he must repeat wudoo’, and it is not permissible for him to offer any prayer, obligatory or naafil, without doing wudoo’. Al-Bukhaari (6954) and Muslim (225) narrated from Abu Hurayrah (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said: “Allaah does not accept the prayer of any one of you if he breaks his wudoo’ until he does wudoo’.”
The scholars are unanimously agreed that purification from minor impurity is a condition of prayer being valid, and it is not valid without it. See al-Majmoo’ by al-Nawawi (3/139); Majmoo’ al-Fataawa by Shaykh al-Islam Ibn Taymiyah (22/99).
As for what your intention should be in this situation:
You should intend to purify yourself in order to perform the prayer.
It should be noted that it is not prescribed to utter the intention out loud, rather the intention should be formed in the heart.
And Allaah knows best.