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Title: The use of wireline pressure measurements to refine reservoir description, Main Body B waterflood, Elk Hills oil field, Kern County, California

Conference · · AAPG Bulletin (American Association of Petroleum Geologists); (United States)
OSTI ID:5254044
 [1];  [2];  [3];  [4]
  1. Bechtel Petroleum Operations, Inc., Tupman, CA (United States)
  2. Scientific Software Intercomp, Bakersfield, CA (United States)
  3. Dept. of Energy, Los Angeles, CA (United States)
  4. Chevron, USA, San Ramon, CA (United States)

The Main Body B, one of five large Stevens sand reservoirs at Elk Hills, occupies the eastern half of the 31S anticline. Early in the production history of this reservoir, the Elk Hills unit initiated peripheral water injection to maintain reservoir pressure. Water injection has proceeded at a rate approximately equal to the voidage created by oil and gas production and has moved water upstructure creating an oil bank. Bechtel Petroleum Operations Inc., the current unit operator, drills five to ten new wells each year to fully exploit this oil bank. In 1985, the unit added wireline pressure measurements to the open-hole logging programs of these infill wells for the purpose of evaluating the net effect of injection into and production from the Main Body B reservoir. A typical well provides the opportunity to obtain 8-10 pressures from the Main Body B. To date, the Unit has measured wireline pressures in more than two dozen wells. The wireline measurements have shown a broader than expected range of formation pressures (1,600 {plus minus} psi to 4,200 {plus minus} psi). The pressures show that this is a layered reservoir with little vertical pressure communication between some of the layers. In some parts of the reservoir, wireline pressures indicate horizontal continuity of the layers between wells and in other areas pressure differences between adjacent wells may indicate faults or cementation barriers. Permeabilities calculated from the sampling drawdown are the same order of magnitude as brine permeabilities obtained from core and show that higher-pressured layers of the reservoir have lower permeability. These observations fundamentally alter performance evaluation of the Main Body B waterflood.

OSTI ID:
5254044
Report Number(s):
CONF-9103128-; CODEN: AABUD
Journal Information:
AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:2; Conference: American Association of Petroleum Geologists (AAPG)/Society of Economics, Paleontolgists, and Mineralogists (SEPM)/Society of Exploration Geophysicists (SEG)/Society of Professional Well Log Analysts (SPWLA) Pacific Section annual meeting, Bakersfield, CA (United States), 6-8 Mar 1991; ISSN 0149-1423
Country of Publication:
United States
Language:
English