How to Calculate XIRR for a company with

[lazabby]

I'm trying to calculate XIRR for an oil company from the perspective of an equity investor. The initial investment say is $21 million. For the 1st five months net income and cash flow is negative. In month six oil revenues begin coming in but net income and cash flow is still negative due to drilling and overhead costs. Each month a new oil well is added producing oil revenues. By month 12 net income is positive but cash flow is still negative. By month 14 cash flow is positive. Would XIRR be calculated using gross oil revenue, net income, or cash flow? How would it be calculated? Attached is spreadsheet

[shg]

I would think the pot that investors get paid out of, which is cash flow.