scholarly journals Geothermal Gradient And Heat Flow Maps Of Offshore Malaysia: Some Updates And Observations

2021 ◽  
Vol 71 ◽  
pp. 159-183
Author(s):  
Mazlan Madon ◽  
◽  
John Jong ◽  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Deep Water ◽  
Oil And Gas ◽  
Geothermal Gradient ◽  
Flow Probe ◽  
Geothermal Gradients ◽  
Heat Flows ◽  
Flow Maps ◽  
Tectonic Settings

An update of the geothermal gradient and heat flow maps for offshore Malaysia based on oil and gas industry data is long overdue. In this article we present an update based on available data and information compiled from PETRONAS and operator archives. More than 600 new datapoints calculated from bottom-hole temperature (BHT) data from oil and gas wells were added to the compilation, along with 165 datapoints from heat flow probe measurements at the seabed in the deep-water areas off Sarawak and Sabah. The heat flow probe surveys also provided direct measurements of seabed sediment thermal conductivity. For the calculation of heat flows from the BHT-based temperature gradients, empirical relationships between sediment thermal conductivity and burial depth were derived from thermal conductivity measurements of core samples in oil/gas wells (in the Malay Basin) and from ODP and IODP drillholes (as analogues for Sarawak and Sabah basins). The results of this study further enhanced our insights into the similarities and differences between the various basins and their relationships to tectonic settings. The Malay Basin has relatively high geothermal gradients (average ~47 °C/km). Higher gradients in the basin centre are attributed to crustal thinning due to extension. The Sarawak Basin has similar above-average geothermal gradients (~45 °C/km), whereas the Baram Delta area and the Sabah Shelf have considerably lower gradients (~29 to ~34 °C/km). These differences are attributed to the underlying tectonic settings; the Sarawak Shelf, like the Malay Basin, is underlain by an extensional terrane, whereas the Sabah Basin and Baram Delta east of the West Baram Line are underlain by a former collisional margin (between Dangerous Grounds rifted terrane and Sabah). The deep-water areas off Sarawak and Sabah (North Luconia and Sabah Platform) show relatively high geothermal gradients overall, averaging 80 °C/km in North Luconia and 87 °C/km in the Sabah Platform. The higher heat flows in the deep-water areas are consistent with the region being underlain by extended continental terrane of the South China Sea margin. From the thermal conductivity models established in this study, the average heat flows are: Malay Basin (92 mW/m2), Sarawak Shelf (95 mW/m2) and Sabah Shelf (79 mW/m2). In addition, the average heat flows for the deep-water areas are as follows: Sabah deep-water fold-thrust belt (66 mW/m2), Sabah Trough (42 mW/m2), Sabah Platform (63 mW/m2) and North Luconia (60 mW/m2).

scholarly journals Evaluation of geothermal energy resources in parts of southeastern sedimentary basin, Nigeria

2021 ◽  
Vol 23 (1) ◽  
pp. 195-211
Author(s):  
I.M. Okiyi ◽  
S.I. Ibeneme ◽  
E.Y. Obiora ◽  
S.O. Onyekuru ◽  
A.I. Selemo ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Heat Flow ◽  
Curie Point ◽  
Geothermal Energy ◽  
Sedimentary Basin ◽  
Geothermal Gradient ◽  
Geothermal System ◽  
Magnetic Vector ◽  
Geothermal Gradients ◽  
Vector Inversion

Residual aeromagnetic data of parts of Southeastern Nigerian sedimentary basin were reduced to the equator and subjected to magnetic vector inversion and spectral analysis. Average depths of source ensembles from spectral analysis were used to compute depth to magnetic tops (Z), base of the magnetic layer (Curie Point t Depth (CPD)), and estimate geothermal gradient and heat flow required for the evaluation of the geothermal resources of the study area. Results from spectral analysis showed depths to the top of the magnetic source ranging between 0.45 km and 1.90 km; centroid depths of 4 km - 7.87 km and CPD of between 6.15 km and 14.19 km. The CPD were used to estimate geothermal gradients which ranged from 20.3°C/km to 50.0°C/km 2 2 and corresponding heat flow values of 34.9 mW/m to 105 mW/m , utilizing an average thermal conductivity -1 -1 of 2.15 Wm k . Ezzagu (Ogboji), Amanator-Isu, Azuinyaba, Nkalagu, Amagunze, Nta-Nselle, Nnam, Akorfornor environs are situated within regions of high geothermal gradients (>38°C/Km) with models delineated beneath these regions using 3D Magnetic Vector Inversion, having dominant NW-SE and NE-SW trends at shallow and greater depths of <1km to >7 km bsl. Based on VES and 2D imaging models the geothermal system in Alok can be classified as Hot Dry Rock (HDR) type, which may likely have emanated from fracture systems. There is prospect for the development of geothermal energy in the study area. Keywords: Airborne Magnetics, Magnetic Vector Inversion, Geothermal Gradient, Heat Flow, Curie Point Depth, Geothermal Energy.

Inversion of bottom‐hole temperature data: The Pineview field, Utah‐Wyoming thrust belt

Geophysics ◽  
1988 ◽  
Vol 53 (5) ◽  
pp. 707-720 ◽  
Author(s):  
Dave Deming ◽  
David S. Chapman
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Heat Flow ◽  
Random Noise ◽  
Synthetic Data ◽  
Element Model ◽  
Geothermal Gradient ◽  
Oil Field ◽  
Conductive Heat ◽  
Bottom Hole

The present day temperature field in a sedimentary basin is a constraint on the maturation of hydro‐carbons; this temperature field may be estimated by inverting corrected bottom‐hole temperature (BHT) data. Thirty‐two BHTs from the Pineview oil field are corrected for drilling disturbances by a Horner plot and inverted for the geothermal gradient in nine formations. Both least‐squares [Formula: see text] norm and uniform [Formula: see text] norm inversions are used; the [Formula: see text] norm is found to be more robust for the Pineview data. The inversion removes random error from the corrected BHT data by partitioning scatter between noise associated with the BHT measurement and correction processes and local variations in the geothermal gradient. Three‐hundred thermal‐conductivity and density measurements on drill cuttings are used, together with formation density logs, to estimate the in situ thermal conductivity of six of the nine formations. The thermal‐conductivity estimates are used in a finite‐element model to evaluate 2-D conductive heat refraction and, for a series of inversions of synthetic data, to assess the influence of systematic and random noise on the inversion results. A temperature‐anomaly map illustrates that a temperature field calculated by a forward application of the inversion results has less error than any single corrected BHT. Mean background heat flow at Pineview is found to be [Formula: see text] (±13 percent), but is locally higher [Formula: see text] due to heat refraction. The BHT inversion (1) is limited by systematic noise or model error, (2) achieves excellent resolution of a temperature field although resolution of individual formation gradients may be poor, and (3) generally cannot detect lateral variations in heat flow unless thermal‐conductivity structure is constrained.

A heat flow profile across the Sverdrup Basin, Canadian Arctic Islands

Geophysics ◽  
1989 ◽  
Vol 54 (2) ◽  
pp. 171-180 ◽  
Author(s):  
F. W. Jones ◽  
J. A. Majorowicz ◽  
A. F. Embry
Keyword(s):  
Heat Flow ◽  
Canadian Arctic ◽  
Ground Surface ◽  
Geothermal Gradient ◽  
Flow Profile ◽  
Heat Flows ◽  
Boundary Temperature ◽  
Sverdrup Basin ◽  
Base Boundary ◽  
Rock Analysis

An average geothermal gradient of 25 ± 5 mK/m and an average heat flow of [Formula: see text] have been determined for 16 out of 20 analyzed wells along a profile across the Sverdrup Basin in the Canadian Arctic. These estimates, based on deep bottom‐hole temperature (BHT) data from exploration wells and the permafrost base boundary temperature, together with assumed heat conductivities from net rock analysis, are surprisingly low and disagree with previously published results based on shallow data. The differences may be due to the dramatic changes in boundary temperature conditions from moderate subsea conditions to ground‐surface low temperatures as a result of marine regression. Because of these effects, it appears that deep BHT temperature data are valuable in providing information about the deep heat flow. The heat flows thus determined indicate that the basin has approached thermal equilibrium.

Implications of coalification levels, Eureka Sound Formation, northeastern Arctic Canada

1977 ◽  
Vol 14 (7) ◽  
pp. 1588-1597 ◽  
Author(s):  
R. M. Bustin ◽  
L. V. Hills ◽  
P. R. Gunther
Keyword(s):  
Brown Coal ◽  
Bituminous Coal ◽  
Geothermal Gradient ◽  
High Heat ◽  
Ellesmere Island ◽  
Sediment Thickness ◽  
Arctic Canada ◽  
Heat Flows ◽  
Tectonic Settings ◽  
Maximum Temperatures

The rank of coal in the Eureka Sound Formation on Ellesmere and Axel Heiberg Islands ranges from brown coal to high volatile bituminous coal, based on reflectance determinations. Reflectance values from coals adjacent to the Stolz Fault, Axel Heiberg Island, are higher than in adjacent areas and may be related to abnormally high heat flows resulting from evaporite diapirism at depth, from the effect of overthrusting, or both. Regional reflectance values indicate that there is no correlation between the degree of coalification and the age of the strata, suggesting differing depths of burial and tectonic settings. Comparison of the coalification gradient at Fosheim Peninsula, Ellesmere Island, with that of the Téjon area of California permits estimation of a geothermal gradient which can be used for calculation of preorogenic sediment thickness. Maximum temperatures derived from the degree of coalification (100 °C at Fosheim) suggest that the sediments are within the zone of initial oil maturity.

scholarly journals Assessment of the interval heat flow and thermal resistance at the Faltu-1 well, Borno basin, NE Nigeria

2021 ◽  
Vol 27 (2) ◽  
pp. 153-169
Author(s):  
S. Ali ◽  
K. Mosto-Onuoha
Keyword(s):  
Heat Flow ◽  
Oil And Gas ◽  
Thermal Resistivity ◽  
Reservoir Rocks ◽  
Heat Flows ◽  
Vertical Heat ◽  
Fluid Convection ◽  
Flow Heat ◽  
Magmatic Intrusions ◽  
Migration Pathways

The heat flowing through horizons in the Faltu-1 well, Borno Basin, NE Nigeria was calculated from their thermal conductivities and geothermal gradients with the aim of determining whether or not it is uniform, and if not, the depths where it is diverted, and the possible heat diversion process. The interval heat flow was assessed to be non-uniform. While fluid convection is adjudged to be the major heat diversion mechanism within the Chad Formation with minor heat refraction, the reversed is adjudged to be the situation for the underlying Kerri Kerri Formaton within which increasing sand content with depth is also predicted, with the lower interval predicted to be the Gombe Formation. Patterns of disruptions to the vertical heat flow within the Fika Formation were inferred to suggest rhythmic bedding of shale and sand beds that could serve as both source and reservoir rocks. Magmatic intrusions that impacted the maturation of organic matter into oil and gas also provided necessary entrapment structures and possible migration pathways. The Gongila and Bima Formations each has single disruption of the heat flows that are attributed to refraction. In the case of the Gongila Formation, the disruption is between the early-deposited more sandy and laterdeposited more shaley lithologies in the marine transgression of the area, while in the case of the Bima, it is between the more shaley Upper and more sandy Middle Bima Formations. Analysis of the Bullard plots also revealed disruptions to the vertical heat flow that are attributed either to convecting fluids or to heat refraction and diffraction. Two such disrupting heat advections were identified within the Chad Formation with the first being attributed to convection, while the other is attributed to a combination of both. Two similar disruptions for the Kerri Kerri Formation were attributed largely to lithological variations with minor contributions from convection of fluids. While unable to discern the rhythmic bedding, the five disruptions of the Bullard plot for the Fika Formation and one each for the Gongila and Bima Formations were interpreted to indicate similar features inferred from interval heat flow plots. Keywords: Interval heat flow, heat convection, heat diffraction, thermal resistivity, shaliness

HEAT FLOW IN WEST TEXAS AND EASTERN NEW MEXICO

Geophysics ◽  
1956 ◽  
Vol 21 (4) ◽  
pp. 1087-1099 ◽  
Author(s):  
Eugene Herrin ◽  
Sydney P. Clark
Keyword(s):  
Thermal Conductivity ◽  
New Mexico ◽  
Heat Flow ◽  
Rock Salt ◽  
Geothermal Gradients ◽  
West Texas ◽  
Thermal Conductivity Of Rock

Geothermal gradients are examined in West Texas and eastern New Mexico, and it is found that the gradients in the salt section of the Permian Salado formation are nearly uniform throughout the region. The values range from 7.70 to 9.00°C/km. Measured values of the thermal conductivity of rock salt are reviewed, and it is concluded that this quantity is most likely to be about [Formula: see text] cal/cm sec °C., with an estimated uncertainty of ten percent. From these figures, the heat flow is found to be [Formula: see text] in this region.

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