Analytical reproducibility and abundances of major elements and sedimentary components in cores from the Sisquoc, Monterey, and Point Sal Formations, Union Newlove 51 well, Orcutt oil field, onshore Santa Maria Basin, California

1989 ◽  
Author(s):  
C.M. Isaacs ◽  
J.E. Taggart ◽  
L.L. Jackson ◽  
Norman Scott
Keyword(s):  
Major Elements ◽  
Oil Field ◽  
Santa Maria Basin ◽  
Santa Maria

scholarly journals A slow earthquake in the Santa Maria basin, California

1992 ◽  
Vol 82 (5) ◽  
pp. 2087-2096
Author(s):  
Hiroo Kanamori ◽  
Egill Hauksson
Keyword(s):  
Sedimentary Basins ◽  
Tectonic Stress ◽  
Oil Field ◽  
Period Range ◽  
Santa Maria Basin ◽  
Motion Data ◽  
Radiated Energy ◽  
Field Evidence ◽  
Regional Tectonic ◽  
Santa Maria

Abstract An ML = 3.5 earthquake near Santa Maria, California, was recorded by the Southern California Seismic Network and a TERRAscope station at Santa Barbara (SBC) on 31 January 1991. The waveform of this event is dominated by 2- to 5-sec waves, and is different from that of ordinary events with similar size. Inquiries into operations in several oil fields in the area revealed that hydro-fracturing at a pressure of about 80 bars was being done at a depth of 100 to 300 m in the Orcutt oil field in the Santa Maria basin from about 9 to 11 a.m. on 31 January and the earthquake occurred in the afternoon. Field evidence of 30-cm displacement to a depth of 300 m was reported. The field evidence as well as the first-motion data indicates that the event had a thrust mechanism with the P axis in the NNE - SSW direction, which is in agreement with the regional stress field. From the analysis of the SBC record and the field evidence, we conclude that the source must be shallower than 1 km and the ratio of the radiated energy to the seismic moment is about 6.2 × 10−7, one to two orders of magnitude smaller than that of ordinary earthquakes. The occurrence of this earthquake demonstrates that release of regional tectonic stress in shallow sediments can yield significant seismic radiation at periods of a few seconds, the period range of engineering importance for large structures, and has important implications for excitation of long-period ground motions from large earthquakes in sedimentary basins.

A gravity model of the basement structure in the Santa Maria Basin, California

Geophysics ◽  
1986 ◽  
Vol 51 (5) ◽  
pp. 1127-1140 ◽  
Author(s):  
Paul M. Kieniewicz ◽  
Bruce P. Luyendyk
Keyword(s):  
Short Wavelength ◽  
Large Scale ◽  
Bouguer Anomaly ◽  
Three Dimensional ◽  
Average Density ◽  
Structure Model ◽  
Basement Structure ◽  
Santa Maria Basin ◽  
Clastic Rocks ◽  
Santa Maria

The Santa Maria Basin in southern California is a lowland bounded on the south by the Santa Ynez River fault and on the northeast by the Little Pine‐Foxen Canyon‐Santa Maria River faults. It contains Neogene sedimentary rocks which rest unconformably on a basement of Cretaceous and older clastic rocks. Analysis of over 4 000 gravity stations obtained from the Defense Mapping Agency suggests that the Bouguer anomaly contains a short‐wavelength component arising from a variable‐density contrast between the basin’s Neogene units and the Cretaceous basement. A three‐dimensional inversion of the short‐wavelength component (constrained by wells drilled to basement) yields a structure model of the basement and the average density of the overlying sediments, assuming that the basement does not contain large‐scale density variations. The density anomalies modeled in the Neogene sediments, showing higher densities in the basin troughs, can be related to diagenetic changes in the silica facies of the Monterey and Sisquoc formations. The basement structure model shows the basin as composed of parallel ridges and troughs, trending west‐northwest and bounded by steep slopes interpreted as fault scarps. The basin is bounded on the west by a north‐south trending slope which may also represent a fault scarp.

scholarly journals Hydrogeochemistry and groundwater mixing close to an oil field: an example from Asmari karstic aquifer, Khuzestan, Iran

2017 ◽  
Vol 18 (2) ◽  
pp. 357-370 ◽  
Author(s):  
H. Rouhi ◽  
N. Kalantari
Keyword(s):  
Saline Water ◽  
Flow Direction ◽  
Groundwater Resources ◽  
Relative Concentration ◽  
Major Elements ◽  
Oil Field ◽  
Water Salinity ◽  
Karstic Aquifer ◽  
Volume Percentage ◽  
Bromide Ion

Abstract Both carbonate (as the oil-gas reservoir) and evaporite rocks (as caprock) coexist in the Masjed Soleyman oil field. The Asmari karstic aquifer is formed within Oligo-Miocene carbonate rocks in the south of the oil reservoir. A mixing between fresh karstic groundwater and oil-field brines is to be expected because of underground migration of the brines toward the aquifer. This process can reduce the groundwater quality by both increasing the water salinity and by adding hydrocarbon and sulfur contaminants into the groundwater. Tembi river contains saline water that can affect groundwater resources. Leaking of these brines into the aquifer was distinguished using total dissolved solids, the relative concentration of major elements, bromide ion (as a trace element), total organic carbon, ion ratios, and mixing curve diagrams. The polluted zone was determined by tracking the hydrochemistry changes across the groundwater flow direction. The volume percentage of different water sources in mixed groundwater was calculated and validated using PHREEQC software. The results revealed that the contribution of the oil-field brine in the groundwater is much lower than the salty river brine, but even this low amount has a considerable impact on water quality by increasing water salinity and adding hydrocarbon and sulfur into the groundwater.

scholarly journals Circulation in the Santa Maria Basin, California, during 1998

2004 ◽  
Vol 109 (C11) ◽  
Author(s):  
Kyoko Ohashi
Keyword(s):  
Santa Maria Basin ◽  
Santa Maria
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