Above is a link to some legislation that might be of interst to you. Just go to the link and click on the tab that says "Versions" and then click on "Engrossed" to see the latest versions. Below is a short explanation I found on the internet.
Oil companies want to expandthe 640-acre spacing because of the length and depth of the drilling.
There has been a committee of people involved in oil and gas drilling as well as representatives for the royalty owners to address this issue. House Bill 1909 is a result of a joint effort that will give guidelines if an operator wishes to do horizontal drilling past the 640-acre spacing. The drilling and production costs, the oil and gas production and the sales proceeds will be allocated to each affected unit in a manner to protect the correlative rights of parties in each unit.
The allocation is a proration between the units based upon the feet of perforations in each of the units. Although one well is being drilled, the portion of the completed horizontal lateral in each unit will be treated as a separate well for that unit.