Evangeline Section Meeting on Drilling and Production Practices on the Gulf Coast, 24 April, Lafayette, Louisiana
The advantages or secondary recovery of oil by high pressure gas injection have be an recognized by the Petroleum Industry for a number or years. In 1951,Atlantic initiated the first high pressure gas injection project in the Block 31 Field or West Texas. Although the Neale Project was started some rive years later, due to its smaller size is now nearer completion than the Block 31project.
The 10,400' Sand originally contained an estimated 3.7 million stock tank barrels or oil. At initiation or Gas Injection 290,000 barrels or oil had been recovered by primary production. Estimated ultimate recovery by primary was 600,000 barrels or 16% of original in place oil. The balance or the primary reserve has now been recovered and the project is well into the secondary phase.
Neale Field is located in Beauregard Parish in extreme west central Louisiana. The structure is an east-west trending anticline on the down thrown side or a down-to-the-south regional fault as shown in Figure 1. The only other fault recognized in the vicinity or the field is a small one on the south flank which parallels the regional fault. This fault is beyond the productive limits or the field but may effect water movement from the south. Dip rates within the productive limits are approximately 20'/1000' or 1. An oil-water contact at 10,250' subsea in the 10,400' Sand limits production in all directions with a maximum 30' oil column. The productive area or the 10,400' Sand is about 2000acres with an average eight feet of net sand.
There are eleven producing Wilcox Sands in the field ranging in depth from 8300–11600'. The first Wilcox Sand at 8300' is the only one with a strong waterdrive and it has had by far the best primary history. The other ten oil and gas producing sands are all below 10,000' and are Middle Wilcox. The 10,400' Sand is the third Sand of the Middle Wilcox Series and might be considered typical. It is a tight, shaly, fine to medium grain band stone, having a low permeability, high irreducible water saturation and contains a highly volatile oil. Table No. 1 is a summary of reservoir data for the 10,400' Sand.