CORE LABORATORIES

UNION OIL COMPANY OF CALIF.
SIDEWALL CORE ANALYSIS
"McKITTRICK FRONT" 418 WELL
CYMRIC FIELD
KERN COUNTY, CA
CL FILE #92021

PERFORMED BY:
CORE LABORATORIES
3430 UNICORN ROAD
BAKERSFIELD, CA 93308
(805) 392-8600

FINAL REPORT PRESENTED
MARCH 31, 1992

PROGRAM PARTICIPANTS:

DATA REDUCTION AND ANALYSIS:
William R. Cooper
Project Geologist

REVIEWED BY:
Jeffry L. Smith
Laboratory Supervisor

INTRODUCTION

Core Laboratories was requested to perform a core analysis study, on behalf of Union Oil Company of California, upon sidewall core samples recovered from the Cymric Field, Kern County, California. Presented herein are the results of this study.

The report is divided into two sections. The first section identifies the requested procedures and tests. The second section contains a tabular presentation of the Dean Stark data.

These sidewall core samples are also being used for ASET analysis, and the data will be presented in Rock Catalog format at a later date.

We appreciate this opportunity to be of service and hope these data prove beneficial in the development of this reservoir.

DESCRIPTION OF SERVICES

Sample Preparation (Dean Stark Analysis)
The sidewall cores were cleaned of drilling mud and trimmed to right cylinders. The samples were then inserted into thin-walled metal jackets and fitted with 120 mesh end-screens. The jackets were seated to the samples, under hydrostatic loading, at a pressure of 400 psig.

Extraction and Saturation Determinations (Dean Stark Analysis)
Oil and water were extracted by Dean Stark methods using toluene. Additional hydrocarbon extraction was performed with methylene chloride using a soxhlet apparatus. The extracted samples were dried in a humidity controlled oven at 145ûF and 45% relative humidity until stable weights were attained, and then cooled to laboratory temperature in sealed zip-lock bags. Following porosity and permeability measurements, the humidified samples were dried in a convection oven at 240ûF until stable weights were again obtained. The samples were then cooled to laboratory temperature in a desiccator and weighed. The difference between the humidified and the dry sample weights were used to correct the initial Dean Stark water volumes for water derived from clay dehydration during the extraction.

Oil and water saturations were calculated by Dean Stark methods by using Equations 1 and 2.

So = [((Wl - Wh - H20)/Do)/Vp] x 100 (1)

Sw = [H20/Vp] x 100 (2)

Where:
SO = Oil Saturation, Percent
Sw = Water Saturation, Percent
Wl = Natural Weight
Wh = Extracted and Humidity Dried Weight
H20 = Extracted Water, Density Assumed 1.0 gm/cc
(Water volume corrected for clay dehydration in Dean Stark)
Do = Density of Oil, Density Assumed 24 APIû
Vp = Pore Volume Humid

Grain Density (Dean Stark Analysis)
Grain volume determinations were performed upon the humidified samples according to Boyle's Law utilizing the extended range helium porosimeter. Grain density was calculated using Equation 3.

Dma = Mg/Vg (3)

Where:
Dma = Grain Density Humid
Vg = Grain Volume Humid
Mg = Grain Mass Humid

Porosity (Dean Stark Analysis)
The samples were loaded into a hassler type core holder and a confining pressure equal to 250 psi was applied. Direct pore volume measurements were made according to Boyle's Law methods with helium as the gaseous medium. Porosity was calculated using Equation 4.

phi = [Vp/(Vp + Vg)] x 100 (4)

Where: phi = Porosity, Percent
Vg = Grain Volume
Vp = Pore Volume

Permeability to Air (Dean Stark Analysis)
Permeability determinations were made following the pore volume determinations with pressure release. Calculations were performed using Darcy's Equation for compressible fluids, Equation 5.

Pa vg (1000)		Qa L 2
______________________	x	_______	(5)
(Pl - P2)[(P1 + P2)/2]		Vb
2

Where:
Ka = Permeability to Air
vg = Gas Viscosity
P1 - P2 = Differential Pressure
(Pl + P2)/2 = Mean Pressure
Pa = Atmospheric Pressure
Qa = Flow Rate
L = Length
Vb = Bulk Volume

Sample Disposition
Upon completion of the ASET work, the residual samples will be shipped to Union's geological sample warehouse in Brea California as per clients request.