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Premier Minerals Project:
Stacy Field Prospect

  • Introduction
  • Geology
  • Maps
Stacy Field Prospect


Premier Minerals, Inc. is pleased to announce its plans to drill the Peters #1 well in Frio County, Texas. The infill development well will be drilled within the Stacy Field (Olmos) that has produced in excess of 1,200,000 barrels of oil to date. This well will target the well defined Olmos "A" sand and will utilize state of the art technology in the well completion phase of this project.

Utilizing the new Radial Jet Enhancement Technology, we will drill 4 laterals in the Olmos Sand to enhance the ultimate recovery of this relatively tight sand. Utilizing existing core data with only a 20% recovery factor, we have estimated the Peters #1 well could yield 107,760 barrels of oil. This project offers excellent offset drilling opportunities.

Complete geological and engineering details of the project as well as Joint Venture information are included in the following summary. Please take the time to read carefully and feel free to consult with any industry professionals you feel necessary. If there are any questions, feel free to contact your representative or myself and we will be happy to address any questions or concerns that you may have. These interests are offered on a first come first served basis.

Respectfully Submitted,
Frank Gabrysch


Premier Minerals, Inc. has acquired an acreage position in the Stacy (Olmos) Field in Frio County, Texas. The field, which was discovered in 1955, has produced approximately 1.2 million barrels of oil from the Upper Cretaceous, Olmos "A" Sand, which is less than 8% of the original oil in place. The wells produce 24 to 26 gravity oil with very little water. Primary drive mechanism for the reservoir is gravity drainage. At 4,200', the Stacy Field (Olmos "A") sand is an excellent candidate for an enhanced oil recovery project.

Field History

The Stacy (Olmos "A") Field was discovered in 1955 and had been developed by 1961, at which time 38 pumping oil wells had been drilled and completed. Many of these wells flowed at rates up to 80 barrels of oil per day with negligible water. Some of the wells experienced a rapid decline rate, primarily the result of high crude oil viscosity being produced from a low permeability reservoir. However, because many of these wells were fraced causing communication with a water bearing sand a few feet below the productive zone, they were abandoned very early in their life, leaving a large number of the recoverable reserves behind.

Several years after the discovery of the Stacy Field, corrosion caused leaks in the production casing, allowing fresh water from the Carrizo Formation at approximately 2,000' to invade the producing zone in many wells. This invasion by fresh water resulted in formation damage, further reducing producing rates. These casing leaks occurred mainly in wells that were not cemented to the surface.

This hypothesis was confirmed during a recent remedial workover of a well in the field. The Thompson #2 well produced approximately 50,000 barrels of oil and was abandoned after it was believed to have watered out. The two offset wells were still producing water free after having produced over 239,000 barrels of oil combined. The operator performed several squeeze jobs on the casing and the well was put back on pump producing 12 BOPD with very little water. The well could have produced a higher daily volume, had the fresh water leaking from the corroded casing not contaminated the local wellbore. This workover has confirmed that the field has not been efficiently drained.

During the last 30 years producing rates have been extremely stable in the remaining wells. The wells in the field all produce less than a 10% water cut. Gas-Oil ratios are negligible and no secondary gas cap has formed. All of Premier's acreage position sits above the present oil-water contact level and there is no evidence of the oil-water contact moving.

Reservoir Character

The Stacy (Olmos "A") reservoir is formed by a "shale out" of the upper member of the Olmos Sand in an up-dip direction along regionally dipping beds. The productive upper member is separated from a lower water-bearing portion of the Olmos by only a few feet of shale making stimulation by conventional frac treatments almost impossible. With today's technology, well stimulation may be performed by lateral jet drilling 4 drainholes up to 300' from the wellbore with either diesel or 8% KCL water. This should effectively stimulate the reservoir without communication with the lower water bearing member or damage the swelling clays.

Available wireline core data indicates porosity of the Olmos "A" ranges from 20% to 30% with permeability up to 250 millidarcies in the cleanest sand, however, average permeability is probably in the range of 30 to 40 millidarcies. As mentioned, there are indications that the Olmos "A" reservoir may contain clays subject to swelling and permeability may be reduced upon contact with fresh water. Thus, casing leaks early in the life of the field may have contributed to reduced oil production, if these leaks were opposite the fresh water bearing Carrizo Sand.

We have attached a net sand isopach which is the result of data taken from SP curves. This data shows a lobate body of sand extending northward (up dip) from the oil-water contact. At least three fingers of thicker sand trend in a north-south direction within the larger lobe. As evidenced by this map, the best part of the reservoir has not been drained on the Peters lease.


Over the 55 year life of the Stacy (Olmos "A") Field, the low permeable nature of the reservoir in combination with a relatively high viscosity crude oil and low reservoir energy has led to a primary recovery which is only a small portion of the original oil in place. Volumetric calculations indicate that the 1,200,000 barrels of oil recovered up to now represent only about 8% of the in-place oil in the primary producing area. The primary producing area is defined as the reservoir between the 2' contour on the net sand isopach map and the oil-water contact.

Data from the attached net sand isopach indicates that primary producing area contains 16,760 acre feet of productive reservoir covering an area of 1500 surface acres. Core lab calculates 898 barrels of stock tank oil per acre foot originally in place, which would indicate slightly more than 15,000,000 barrels of oil originally in the reservoir.

If an Enhanced Oil Recovery project could increase ultimate recovery to only 20% of original oil in place, an additional 2,900,000 barrels of oil would be produced. An ultimate recovery of 30% of oil in place would yield 3,400,000 barrels of oil over present production. As mapped, the Olmos "A" sand should be about 15 feet thick in the Peters wells. This calculated to 107,760 barrels of recoverable oil per well. The two wells on the Thompson lease with similar sand thickness have recovered over 239,000 barrels of oil (119,500 each).

Enhanced Oil Recovery

Based on the volume of oil recovered from several wells in the field, it seems apparent that given enough time a large portion of the in-place reserves can be produced by primary means. However, higher producing rates are key to economic success. We have based our economics on estimated recoverable reserves utilizing radial jet drilling technology. We feel like we will be able to recover the same amount of reserves in a much shorter period of time. Once the well has been drilled, we will cement the production casing to the surface of the ground to protect the casing from the corrosive shallow fresh water sands. We will then perforate the well and put in on pump for a short time allowing the reservoir to clean up. At this point, we will then drill 4 laterals in the reservoir spaced 90 degrees apart. Each lateral will be approximately 300 feet. We will utilize diesel or 8% KCL water to inhibit any swelling clays.

Olmos Sand waterflood projects in the nearby Big Foot and Charlotte Fields have successfully increased production and ultimate recovery according to Railroad Commission data. Shell Oil Company's Big Foot waterflood project in the Olmos "B" Sand began in 1964 and by 1978 the operator was predicting that an additional 8.7 million barrels of oil would be recovered as a result of their waterflood. Exxon's Charlotte Field waterflood in the "Navarro" Sand, which is the Olmos "A" equivalent, was projected to recover an additional 13 million barrels of oil according to that same 1978 report.

Since reservoir conditions in the Stacy (Olmos "A") Field are similar to the water flooded reservoirs in the Big Foot and Charlotte Field, the Stacy (Olmos "A") should be a viable Enhanced Oil recovery project. The application of radial jet drilling would permit greater well bore exposure and probably increase producing rates substantially.

Stacy Field Reservoir Summary

Field Area 1,500 acres
Field Reservoir Volume 16,760 Ac. Ft.
Reservoir Depth + or - 4,200'
Original Oil in Place + or - 15,000,000 BO
Primary Production to date 1,200,000 BO
Produced Oil as a Percent of
Original Oil in Place
Remaining Recoverable Reserves
@ 30% of Original Oil in Place
3,400,000 BO
Crude Oil Gravity 26 deg API



Location Map of Stacy Field Prospect id= zoomClick image to zoom Production Map of Stacy Field Prospect id= zoomClick image to zoom Structure Map of Stacy Field Prospect id= zoomClick image to zoom ISOPACH Map of Stacy Field Prospect id= zoomClick image to zoom