Imaging Radial Distribution of Water Saturation and Porosity Near the Wellbore by Joint Inversion of Sonic and Resistivity Logging Data

Abstract Multidepth electromagnetic logging tool is considered as traditional measurements of formation resistivity estimation while drilling. When considering data in wells with high angles trajectory, more than 70 degrees, the resistivity measurements could be affected by several factors associated with geological conditions and logging tool specifications. As the result, during water saturation estimation formation properties could be distorted, which will lead to significant effect of reservoir properties assessment and the design of the horizontal well completion. Within the framework of this paper, various methods of influence on the resistivity readings will be considered, especially with cross boundary effects and reservoir formations with anisotropy. At the same time, propagation resistivity logging technologies while drilling with interpretation and boundary propagation technologies will be observed, which has tilted azimuthal oriented receivers for geosteering service of horizontal wells and additionally helps with take into account of boundary enflurane on standard resistivity logging.

Download Full-text

Estimation of dynamic petrophysical properties of water-bearing sands invaded with oil-base mud from the interpretation of multiple borehole geophysical measurements

Geophysics ◽

10.1190/geo2012-0006.1 ◽

2012 ◽

Vol 77 (6) ◽

pp. D209-D227 ◽

Cited By ~ 4

Author(s):

Zoya Heidari ◽

Carlos Torres-Verdín

Keyword(s):

Capillary Pressure ◽

Relative Permeability ◽

Radial Distribution ◽

Apparent Resistivity ◽

Water Saturation ◽

Estimation Method ◽

Petrophysical Properties ◽

Fluid Saturation ◽

Irreducible Water Saturation ◽

Geophysical Measurements

Nonmiscible fluid displacement without salt exchange takes place when oil-base mud (OBM) invades connate water-saturated rocks. This is a favorable condition for the estimation of dynamic petrophysical properties, including saturation-dependent capillary pressure. We developed and successfully tested a new method to estimate porosity, fluid saturation, permeability, capillary pressure, and relative permeability of water-bearing sands invaded with OBM from multiple borehole geophysical measurements. The estimation method simulates the process of mud-filtrate invasion to calculate the corresponding radial distribution of water saturation. Porosity, permeability, capillary pressure, and relative permeability are iteratively adjusted in the simulation of invasion until density, photoelectric factor, neutron porosity, and apparent resistivity logs are accurately reproduced with numerical simulations that honor the postinvasion radial distribution of water saturation. Examples of application include oil- and gas-bearing reservoirs that exhibit a complete capillary fluid transition between water at the bottom and hydrocarbon at irreducible water saturation at the top. We show that the estimated dynamic petrophysical properties in the water-bearing portion of the reservoir are in agreement with vertical variations of water saturation above the free water-hydrocarbon contact, thereby validating our estimation method. Additionally, it is shown that the radial distribution of water saturation inferred from apparent resistivity and nuclear logs can be used for fluid-substitution analysis of acoustic compressional and shear logs.

Download Full-text

Inversion of low-induction number conductivity meter data to predict seasonal saturation variation

Geophysics ◽

10.1190/geo2010-0378.1 ◽

2011 ◽

Vol 76 (6) ◽

pp. F395-F406 ◽

Cited By ~ 2

Author(s):

Adam Smiarowski ◽

James Macnae ◽

Glen Bann

Keyword(s):

Electrical Conductivity ◽

Half Space ◽

Water Saturation ◽

Joint Inversion ◽

A Priori ◽

Field Measurements ◽

Bottom Layer ◽

Near Surface ◽

South Wales ◽

Better Than

Our research introduced a method to monitor saturation in the near surface. In agricultural settings, methods measuring electrical conductivity can provide useful information about soil type, moisture content, and salinity extent. Electrical conductivity meters have been used in a number of studies to determine soil properties in a qualitative sense. We examined the range of structures in which the use of low-induction number instruments can be used successfully to determine layered-earth electrical conductivity. We used an inversion routine which employs a Bayesian modification to the ridge-regression technique with a priori conductivity assumptions typical of agricultural areas. We performed joint inversion of horizontal and vertical dipole configurations at two coil separations for layer over half-space models with electrical properties of silt, loam, clay, and saline waters. Generally, the inversion code resolved layer thickness to better than 25% and electrical conductivity to better than 20% if the layer is less than 3-m thick. We then inverted field measurements acquired in salt-scalded areas in the Yass River Valley, New South Wales, Australia, to determine a layer over a half-space. With Kennedy’s formulation concerning the relationship between porosity, water saturation and electrical conductivity, we used the field results to predict autumn water saturation for the top layer to be 13% and the bottom layer to be 15%. In the spring, we used the field results to predict saturation of 50% for the top layer and 51% for the bottom layer, leading to a seasonal variation in soil saturation of approximately 36%. Predicted saturation was spatially consistent across the traverse line, suggesting that the developed methodology was successful.

Download Full-text

Research on Pseudo-2D Joint Inversion of TEM and CSAMT Based on Well Log Constraint

Journal of Environmental and Engineering Geophysics ◽

10.32389/jeeg20-052 ◽

2021 ◽

Vol 26 (1) ◽

pp. 61-70

Author(s):

Dong Yi ◽

Cheng Jiulong ◽

Xue Junjie ◽

Wen Laifu ◽

Chen Tao ◽

...

Keyword(s):

Joint Inversion ◽

Well Log ◽

Inversion Process ◽

Water Abundance ◽

Rock Formation ◽

Transient Electromagnetic ◽

Geological Situation ◽

Resistivity Logging ◽

Successive Over Relaxation ◽

Inversion Calculation

The transient electromagnetic method (TEM) and controlled-source audio-frequency magnetotellurics method (CSAMT) are commonly used in detecting water abundance of rock formation and faults in coal mines. However, these methods show low accuracy, given the multiplicity of their inversion results, especially for areas with minor differences in lithology and electrical property. To improve the accuracy of electromagnetic exploration, a pseudo-2D joint inversion is performed. The objective function of this pseudo-2D joint inversion is established, and the joint inversion process is constrained by resistivity logging data. Afterward, the symmetric successive over-relaxation (SSOR) is used to realize the pseudo-2D joint inversion calculation of TEM and CSAMT with well log constraint. The effectiveness of joint inversion is verified by combining synthetic and field data. Results show that the pseudo-2D joint inversion results of TEM and CSAMT with well log constraint correspond to the actual geological situation. Compared with either TEM or CSAMT, joint inversion has a significantly better capability of reflecting water abundance in rock formation and faults.

Download Full-text

Inversion-Based Method Integrating Sonic and Resistivity Logging Data for Estimation of Radial Water Saturation Profile and Porosity Near the Wellbore

10.2118/170609-ms ◽

2014 ◽

Author(s):

Sushil Shetty ◽

Lin Liang ◽

Terek M. Habashy ◽

Vanessa Simoes ◽

Austin J Boyd ◽

...

Keyword(s):

Water Saturation ◽

Resistivity Logging ◽

Saturation Profile

Download Full-text

Joint Inversion of Ground-Penetrating Radar and Seismic Velocities for Porosity and Water Saturation in Shallow Sediments

Journal of Environmental and Engineering Geophysics ◽

10.2113/jeeg21.3.105 ◽

2016 ◽

Vol 21 (3) ◽

pp. 105-119 ◽

Cited By ~ 5

Author(s):

Abdullatif A. Al-Shuhail ◽

Ademola Adetunji

Keyword(s):

Ground Penetrating Radar ◽

Water Saturation ◽

Joint Inversion ◽

Seismic Velocities ◽

Shallow Sediments ◽

Ground Penetrating

Download Full-text

Direct reservoir parameter estimation using joint inversion of marine seismic AVA and CSEM data

Geophysics ◽

10.1190/1.2194510 ◽

2006 ◽

Vol 71 (3) ◽

pp. C1-C13 ◽

Cited By ~ 109

Author(s):

G. Michael Hoversten ◽

Florence Cassassuce ◽

Erika Gasperikova ◽

Gregory A. Newman ◽

Jinsong Chen ◽

...

Keyword(s):

Water Saturation ◽

Joint Inversion ◽

Hydrocarbon Exploration ◽

Rock Properties ◽

Parameter Estimates ◽

Angle Of Incidence ◽

Model Errors ◽

Inversion Algorithm ◽

Fluid Saturation ◽

Reservoir Parameter

Accurately estimating reservoir parameters from geophysical data is vitally important in hydrocarbon exploration and production. We have developed a new joint-inversion algorithm to estimate reservoir parameters directly, using both seismic amplitude variation with angle of incidence (AVA) data and marine controlled-source electromagnetic (CSEM) data. Reservoir parameters are linked to geophysical parameters through a rock-properties model. Errors in the parameters of the rock-properties model introduce errors of comparable size in the reservoir-parameter estimates produced by joint inversion. Tests of joint inversion on synthetic 1D models demonstrate improved fluid saturation and porosity estimates for joint AVA-CSEM data inversion (compared with estimates from AVA or CSEM inversion alone). A comparison of inversions of AVA data, CSEM data, and joint AVA-CSEM data over the North Sea Troll field, at a location for which we have well control, shows that the joint inversion produces estimates of gas saturation, oil saturation, and porosity that are closest (as measured by the rms difference, the [Formula: see text] norm of the difference, and net values over the interval) to the logged values. However, CSEM-only inversion provides the closest estimates of water saturation.

Download Full-text

Field examples of the joint petrophysical inversion of resistivity and nuclear measurements acquired in high-angle and horizontal wells

Geophysics ◽

10.1190/geo2013-0355.1 ◽

2014 ◽

Vol 79 (3) ◽

pp. D145-D159 ◽

Cited By ~ 5

Author(s):

Olabode Ijasan ◽

Carlos Torres-Verdín ◽

William E. Preeg ◽

John Rasmus ◽

Edward Stockhausen

Keyword(s):

Gamma Ray ◽

Water Saturation ◽

Joint Inversion ◽

Resistivity Measurement ◽

Well Logs ◽

Electrical Anisotropy ◽

High Angle ◽

Natural Gamma ◽

Well Trajectory ◽

Well Log Analysis

A recently introduced interpretation workflow has confirmed that inversion-based interpretation is more reliable than conventional well-log analysis in high-angle (HA) and horizontal (HZ) wells because the former accounts for well trajectory and shoulder-bed effects on well logs. Synthetic examples show that the inversion workflow could improve the estimation of hydrocarbon volumes by 15% and 10% in HA and HZ intervals, respectively. Using field examples of thinly interbedded calcite-cemented siltstone formations, we document results of the joint petrophysical inversion of logging-while-drilling multisector nuclear (neutron porosity, density, natural gamma ray, photoelectric factor) and multiarray propagation resistivity measurement for improved formation evaluation in HA/HZ wells. Under the assumption of multilayer formation petrophysical models, the inversion approach estimates formation properties by numerically reproducing the available measurements. Subsequently, inversion-derived hydrocarbon pore volume is calculated for assessment of reservoir pay. Application of the joint inversion-based interpretation in challenging field examples highlights petrophysical characteristics such as capillary trends or water saturation variations in a hydrocarbon column influenced by reservoir quality and formation electrical anisotropy which otherwise remain inconspicuous with conventional and quick-look interpretation of well-logs.

Download Full-text