ABSTRACT

The Crescent Farms Field, on the northern flank of the Terrebonne Trough, is an example of tilted gas-water contacts where there is a variation in the permeability of the reservoir. The forces probably causing these tilts are capillary pressure in low permeability zones, hydrodynamic relationships caused by regional downwarping into the Terrebonne Trough and from local structural deformation, and to some extent, flow potentials created by increasing effects of the weight of overburden. A maximum of 40 feet of tilt in a distance of 1800 feet existed at the commencement of production.

PURPOSE. -- This paper attempts to explain the variation in depth to the gas-water contacts of the Crescent Farms Field as a condition of reservoir dynamics. It is thought that the anomalous attitudes of the gas-water interfaces are best explained as a result of a dynamic fluid system in relation to variable permeabilities, to movement of the beds and to compaction of the sediments. Geologists familiar with the gas-water spatial relationships are not in general agreement with the causes.

DATA. -- The interpretations given here are based on electric log analyses, production and reservoir data, and a small amount of core information. Inasmuch as the terrain is essentially level and the heights of derrick floors about equal, the depths to a common horizon from the top of the kelly bushing were used in determining structural elevations. Depths in side-tracked holes were corrected to vertical equivalents.

LOCATION. -- The Crescent Farms Field is in Terrebonne Parish, Louisiana, 60 miles west of New Orleans, 40 miles north of the Gulf of Mexico and 5 miles west of the city of Houma.