Your silent request is not unheard by God. He hears even the prayers that are never spoken aloud, the quick cry of the heart that rises in a moment of need. Scripture shows this when a man stood before a king and in his heart offered a silent prayer for favor, and God answered. Your Father knows what you need before you ask Him, so prayer is not informing Him of something He does not know. It is consenting to Him, opening the door for Him to do what He has long desired to do in your life without violating your will.
It is not the length of a prayer or the amount of time spent that makes it valid. The prayers recorded in the Bible are often very short. What matters is that it is fervent and from the heart. The Scripture says the effectual fervent prayer of a righteous person avails much, and it gives Elijah as an example of a man whose earnest prayer was answered. That same promise is for you. We are agreeing with you in prayer, for Jesus said that if two or three agree on earth concerning anything, it shall be done.
Prayer rests on relationship. Jesus taught His disciples to pray, Our Father, and that address makes all the difference. If He is your Father through faith in Jesus Christ, you have the right to come to Him and He hears you. If that relationship is not yet settled, the first prayer God desires to hear is, God be merciful to me, a sinner, which establishes that relationship through Christ alone and opens the way to all other prayer. We pray to the Father in the name of Jesus, not to get our own will done, but to see His will done on earth as it is in heaven. The wisest prayer any of us can pray is, Lord, work out Your perfect will in my life.
God also wants to bless you and keep His hand upon you and keep you from evil, and He delights to answer those who seek Him. Like Daniel, who was a man of the Word and a man of prayer and who prayed faithfully even when it could cost him his life, and like David who poured out his complaint and showed the Lord his trouble, you can bring your unspoken burden to Him with confidence. He will minister comfort and assurance to your heart as you wait before Him. Prayer is worship, it is awe before His greatness, and it is also trust.
We are praying for you now, that the Lord would hear the voice of your supplication, that He would show you His ways and teach you His paths as Psalm 25 prays, and that you would know the full joy of spending time with the Father and seeing His answer. May His will be done in this silent matter, and may you know His blessing, His guidance, and His peace in Jesus name.