| Lowstand, siliciclastic turbidite and submarine fan deposits within the Leonardian Bone Spring Formation have proved to be prolific targets for horizontal drilling across the northern portion of the Delaware Basin. Reservoir sandstones in this area are very fine grained, with porosities of 8--12%, permeabilities of 1--2 md and water saturations between 40% and 60%. In Big Eddy, James Ranch and Poker Lake New Mexico Federal Units, a new target for horizontal drilling, the Harkey Mills Sandstone, is proposed, which may have production comparable to the Second Bone Spring Sandstone. There are currently four horizontal wells producing form the Harkey Mills Sandstone in Willow Lake West field (T24-25S, R27E) in south-central Eddy County, New Mexico, approximately 13 miles to the west of Poker Lake Unit. Within a 3-year period, these wells have a combined cumulative production of approximately 176 MBO and 708 MMCF of gas.;The Harkey Mills Sandstone is a lowstand submarine fan deposit incased in the Second Bone Spring Carbonate, between the Second and Third Bone Spring Sandstones. Using a network of stratigraphic and structural cross sections, the Harkey Mills Sandstone was correlated and then mapped throughout Big Eddy, James Ranch and Poker Lake Federal Units in Eddy and Lea Counties, southeast New Mexico, encompassing a total area of approximately 870 mi2 (2250 km2). Based on well log analysis from 625 wells, the Harkey Mills Sandstone can be subdivided into a slope fan, a basin-floor fan, and a modified lowstand wedge deposit that was sourced from the Northwest Shelf and distributed across the Federal Units with a regional dip to the southeast. The best reservoir rock occurs within the apex of turbidite channel deposits proximal to the slope fan, with net thicknesses up to 80 ft. containing at least 8% porosity and Rt values between 5 and 12 ohms. Trapping mechanisms are primarily stratigraphic, produced by upslope pinchouts and lateral porosity variations. Total Organic Carbon measurements and Rock-Eval Pyrolysis, from sidewall core samples from two wells in the Big Eddy Unit, indicated that the Harkey Mills Sandstone averages 2. 1% TOC, and is oil and gas prone with Type II and III kerogen.;This new target for oil and gas was identified in the Bone Spring Formation, in the Big Eddy Unit, using various exploration techniques. Similar strategies and concepts can be used to extend the Bone Spring play to other regions in the Delaware Basin and may be used as a model to explore for similar lowstand submarine fan deposits. |
