Geology topics

D.S. Oki

Publications and source records attributed to D.S. Oki.

12 recordsLinked to original sources

USGS2005

Comparison of formation and fluid-column logs in a heterogeneous basalt aquifer

Deep observation boreholes in the vicinity of active production wells in Honolulu, Hawaii, exhibit the anomalous condition that fluid-column electrical conductivity logs and apparent profiles of pore-water electrical conductivity derived from induction conductivity logs are nearly identical if a formation factor of 12.5 is assumed. This condition is documented in three boreholes where fluid-column logs clearly indicate the presence of strong borehole flow induced by withdrawal from partially penetrating water-supply wells. This result appears to contradict the basic principles of conductivity-log interpretation. Flow conditions in one of these boreholes was investigated in detail by obtaining flow profiles under two water production conditions using the electromagnetic flowmeter. The flow-log interpretation demonstrates that the fluid-column log resembles the induction log because the amount of inflow to the borehole increases systematically upward through the transition zone between deeper salt water and shallower fresh water. This condition allows the properties of the fluid column to approximate the properties of water entering the borehole as soon as the upflow stream encounters that producing zone. Because this condition occurs in all three boreholes investigated, the similarity of induction and fluid-column logs is probably not a coincidence, and may relate to aquifer response under the influence of pumping from production wells.

Groundwater↗

USGS2000

Estimating formation properties from early-time oscillatory water levels in a pumped well

Hydrologists often attempt to estimate formation properties from aquifer tests for which only the hydraulic responses in a pumped well are available. Borehole storage, turbulent head losses, and borehole skin, however, can mask the hydraulic behavior of the formation inferred from the water level in the pumped well. Also, in highly permeable formations or in formations at significant depth below land surface, where there is a long column of water in the well casing, oscillatory water levels may arise during the onset of pumping to further mask formation responses in the pumped well. Usually borehole phenomena are confined to the early stages of pumping or recovery, and late-time hydraulic data can be used to estimate formation properties. In many instances, however, early-time hydraulic data provide valuable information about the formation, especially if there are interferences in the late-time data. A mathematical model and its Laplace transform solution that account for inertial influences and turbulent head losses during pumping is developed for the coupled response between the pumped borehole and the formation. The formation is assumed to be homogeneous, isotropic, of infinite areal extent, and uniform thickness, with leakage from an overlying aquifer, and the screened or open interval of the pumped well is assumed to fully penetrate the pumped aquifer. Other mathematical models of aquifer flow can also be coupled with the equations describing turbulent head losses and the inertial effects on the water column in the pumped well. The mathematical model developed in this paper is sufficiently general to consider both underdamped conditions for which oscillations arise, and overdamped conditions for which there are no oscillations. Through numerical inversion of the Laplace transform solution, type curves from the mathematical model are developed to estimate formation properties through comparison with the measured hydraulic response in the pumped well. The mathematical model is applied to estimate formation properties from a singlewell test conducted near Waialua, Oahu, Hawaii. At this site, both the drawdown and recovery showed oscillatory water levels in the pumped well, and a step-drawdown test showed that approximately 86% of the drawdown is attributed to turbulent head losses. Analyses at this site using late-time drawdown data were confounded by the noise present in the measured water levels due primarily to nearby irrigation wells and ocean tides. By analyzing the early-time oscillatory recovery data at the Waialua site, upper and lower bounds were placed on the transmissivity, T, storage coefficient, S, and the leakance of the confining unit, K′/B′. The upper and lower bounds on T differ by a factor of 2. Upper and lower bounds on S and K′/B′ are much larger, because drawdown stabilized relatively quickly after the onset of pumping.

Journal of Hydrology↗

USGS1998

Estimating formation properties from early-time recovery in wells subject to turbulent head losses

A mathematical model is developed to interpret the early-time recovering water level following the termination of pumping in wells subject to turbulent head losses. The model assumes that turbulent head losses dissipate immediately when pumping ends. In wells subject to both borehole storage and turbulent head losses, the early-time recovery exhibits a slope equal to 1/2 on log-log plots of the recovery versus time. This half-slope response should not be confused with the half-slope response associated with a linear flow regime during aquifer tests. The presence of a borehole skin due to formation damage or stimulation around the pumped well alters the early-time recovery in wells subject to turbulent head losses and gives the appearance of borehole storage, where the recovery exhibits a unit slope on log-log plots of recovery versus time. Type curves can be used to estimate the formation storafivity from the early-time recovery data. In wells that are suspected of having formation damage or stimulation, the type curves can be used to estimate the 'effective' radius of the pumped well, if an estimate of the formation storativity is available from observation wells or other information. Type curves for a homogeneous and isotropic dual-porosity aquifer are developed and applied to estimate formation properties and the effect of formation stimulation from a single-well test conducted in the Madison limestone near Rapid City, South Dakota.A mathematical model is developed to interpret the early-time recovering water level following the termination of pumping in wells subject to turbulent head losses. The model assumes that turbulent head losses dissipate immediately when pumping ends. In wells subject to both borehole storage and turbulent head losses, the early-time recovery exhibits a slope equal to 1/2 on log-log plots of the recovery versus time. This half-slope response should not be confused with the half-slope response associated with a linear flow regime during aquifer tests. The presence of a borehole skin due to formation damage or stimulation around the pumped well alters the early-time recovery in wells subject to turbulent head losses and gives the appearance of borehole storage, where the recovery exhibits a unit slope on log-log plots of recovery versus time. Type curves can be used to estimate the formation storativity from the early-time recovery data. In wells that are suspected of having formation damage or stimulation, the type curves can be used to estimate the `effective' radius of the pumped well, if an estimate of the formation storativity is available from observation wells or other information. Type curves for a homogeneous and isotropic dual-porosity aquifer are developed and applied to estimate formation properties and the effect of formation stimulation from a single-well test conducted in the Madison limestone near Rapid City, South Dakota.

Journal of Hydrology↗

USGS1996

Drilling, construction, and caliper-log data for wells 3-3204-01, Kaheaka exploratory well, Oahu, Hawaii

The Kaheaka exploratory well (State well number 3-3204-01) was drilled about 3.3 miles southeast of the town of Haleiwa. The well is on agricultural land in the Waialua ground-water area. The well penetrates about 67 feet into a basalt aquifer. Well-construction data, logs of drilling notes, geologic descriptions for the samples, and caliper-log data are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, and aquifer-test data from wells 3-3307-20 and -21, Thompson Corner exploratory wells I and II, Oahu, Hawaii

The Thompson Corner exploratory wells I and II (State well numbers 3-3307-20 and -21) were drilled near Thompson Corner, about 2.2 miles south-southwest of the town of Haleiwa. The wells are located on agricultural land in the Waialua ground-water area. The wells are about 50 feet apart and penetrate about 90 feet into the ground water. Aquifer tests were conducted using well 3-3307-20 as a pumping well and well 3-3307-21 as an observation well. Well-construction data, logs of drilling notes, geologic descriptions for the samples, and aquifer-test data are presented for the wells. The wells are two of twelve exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, caliper-log, and specific-conductance data for well 3-3406-12, Twin Bridge Road deep monitor well, Oahu, Hawaii

The Twin Bridge Road deep monitor well (State well number 3-3406-12) was drilled about 2,000 feet northeast of Weed Circle in the town of Haleiwa. The well is on agricultural land. The well penetrates through the freshwater lens and into the freshwater-saltwater transition zone of the Waialua ground-water area to an elevation of -596 feet below mean sea level. Well-construction data, logs of drilling notes, geologic descriptions for the samples, caliper-log, and specific-conductance data are presented for the well. The well is one of 12 exploratory wells drilled in the north- central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling and construction data for well 3-3406-13, Kaamooloa exploratory well, Oahu, Hawaii

An exploratory well (Hawaii State well number 3-3406-13) was drilled about 1.6 miles south of the town of Haleiwa. The well is located on agricultural land within the Waialua ground-water area. The well penetrates about 20 feet into a basalt aquifer to an elevation of -10 feet. Well construction information and logs of drilling notes and geologic descriptions for the samples are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, and caliper-log data for wells 3-3406-14 and -15, Helemano exploratory wells I and II, Oahu, Hawaii

The Helemano exploratory wells I and II (State well numbers 3-3406-14 and -15) were drilled near Weed Circle, about 3,000 feet south of the town of Haleiwa. The wells are located on agricultural land in the Waialua ground-water area. The wells penetrate through sedimentary deposits (caprock) and into a basalt aquifer. Both wells have short open intervals cased with well screen at the bottom of the hole, and are cased and sealed through the caprock and basalt to the well screen. The shallow well, Helemano exploratory well I, penetrates about 10 feet into the basalt aquifer below the contact of the caprock and basalt. The deep well, Helemano exploratory well II, penetrates about 210 feet into the basalt aquifer. The deep well has a 20-foot open interval at the bottom. Well construction data, logs of drilling notes, geologic descriptions for drill samples, and caliper-log data are presented for the wells. The wells are two of twelve exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling and construction data for well 3-3407-37, Kiikii exploratory well, Oahu, Hawaii

The Kiikii exploratory well (State well number 3-3407-37) was drilled about 1.4 miles southwest of the town of Haleiwa and 4,000 feet west- southwest of Weed Circle. The well is on agricultural land in the Waialua ground-water area. The well penetrates through sedimentary deposits (caprock) and into the underlying basalt aquifer. Well-construction data, logs of drilling notes, and geologic descriptions for the samples are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July, 1993 and May, 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, and caliper-log data for well 3-3505-25, North Lower Anahulu exploratory well, Oahu, Hawaii

The North Lower Anahulu exploratory well (State well number 3-3505-25) was drilled about 1.4 miles east-northeast of the town of Haleiwa. The well was drilled on agricultural land in the Kawailoa ground-water area. The well was drilled from an elevation of about 232 feet above mean sea level and penetrates about 22 feet into a basalt aquifer. Well-construction data, logs of drilling notes, geologic descriptions for the samples, and caliper-log data are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July, 1993 and May, 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, and caliper-log data for well 3-3505-26, Opaeula exploratory well, Oahu, Hawaii

The Opaeula exploratory well (State well number 3-3505-26) was drilled about 1.2 miles east- southeast of the town of Haleiwa. The well is located on agricultural land in the Waialua ground-water area. The well was drilled at an elevation of about 287 feet above mean sea level and penetrates about 75 feet into a basalt aquifer. Well-construction data, logs of drilling notes, geologic descriptions for the samples, and caliper-log data are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗

USGS1996

Drilling, construction, caliper-log, and specific-conductance data for well 3-3604-01, Kawailoa deep monitor well, Oahu, Hawaii

The Kawailoa deep monitor well (State well number 3-3604-01) was drilled about 1.9 miles east- northeast of the town of Haleiwa. The well is on agricultural land in the Kawailoa ground-water area. The well penetrates through the freshwater lens and into the freshwater-saltwater transition zone to an elevation of -392 feet below mean sea level. Well-construction data, logs of drilling notes, geologic descriptions for the samples, specific-conductance and caliper-log data are presented for the well. The well is one of 12 exploratory wells drilled in the north-central Oahu area between July 1993 and May 1994 in cooperation with the Honolulu Board of Water Supply.

Open-File Report↗