Hybrid LPG frac

1. A fracturing method comprising:

pumping a first stream of proppant-free liquefied petroleum gas and gelling agent with a first frac pressure pump through a first surface line into a wellhead through a first port of the wellhead;

pumping a second stream of lubricated proppant with a second frac pressure pump through a second surface line separate from the first surface line into the wellhead through a second port of the wellhead that is separate from the first port of the wellhead;

removing fluid from the second stream of lubricated proppant with a proppant intensifier prior to the second stream entering the second port of the wellhead, wherein the proppant intensifier removes fluid from the second stream after the second frac pressure pump;

the first stream and the second stream having respective velocity vector components that are directly opposite to each other both (a) upon exiting the first port and the second port, respectively, and (b) up to a point within the wellhead where the first stream and the second stream meet, thereby combining the first stream and the second stream within the wellhead into a combined stream;

pumping the combined stream into a hydrocarbon reservoir;

pumping a treatment fluid comprising an acid spearhead with the second frac pressure pump into the wellhead, wherein the treatment fluid has a higher density than the first stream, and the treatment fluid is pumped to provide a fluid cap over the combined stream in the hydrocarbon reservoir; and

subjecting the combined stream in the hydrocarbon reservoir to fracturing pressures.

2. The fracturing method of claim 1 in which the lubricated proppant is lubricated with liquid.

3. The fracturing method of claim 2 in which the liquid is ungelled.

4. The fracturing method of claim 2 in which the liquid is gelled.

5. The fracturing method of claim 2 in which the liquid is free of liquefied petroleum gas.

6. The fracturing method of claim 2 in which the liquid comprises liquid hydrocarbons.

7. The fracturing method of claim 6 in which the liquid hydrocarbons comprise seven or more carbons per hydrocarbon molecule.

8. The fracturing method of claim 7 in which the liquid hydrocarbons comprise eighteen or less carbons per hydrocarbon molecule.

9. The fracturing method of claim 1 in which the liquefied petroleum gas further comprises hydrocarbons with four or more carbons per molecule in an amount of more than 50% by volume of the liquefied petroleum gas.

10. The fracturing method of claim 9 in which the hydrocarbon reservoir comprises oil and further comprising:

flowing back injected fluids from the hydrocarbon reservoir; and

supplying the flowback fluids to an oil sales line.

11. The fracturing method of claim 10 further comprising, prior to supplying the flowback fluids to the oil sales line, diluting the flowback fluids with reservoir oil from the hydrocarbon reservoir.

12. The fracturing method of claim 1 in which the liquefied petroleum gas further consists essentially of propane, butane, or propane and butane.

13. The fracturing method of claim 1 in which the first port, the second port, and a wellhead axis form a Y-shape.

14. The fracturing method of claim 1 in which the first port, the second port, and a wellhead axis form a T-shape.