Numerical Simulation of Mud Invasion and Its Array Laterolog Response in Deviated Wells

Deng, Shaogui; Li, Zhiqiang; Fan, Yiren; Chen, Hua

doi:10.1002/cjg2.1496

Cited by 9 publications

(5 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If a quantitative relation is established between mud invasion and reservoir permeability, it is unnecessary to consider the complex factors that affect permeability. Mud invasion affects array-induced logging, and the invasion depth can be inverted using array-induced responses (Deng et al, 2010). However, the detection precision is poor owing to the low working frequency of the logging equipment.…”

Section: Introductionmentioning

confidence: 99%

Model and method of permeability evaluation based on mud invasion effects

Zhou

Meng

et al. 2015

Appl. Geophys.

View full text Add to dashboard Cite

The evaluation of permeability in reservoir assessment is a complex problem. Thus, it is diffi cult to perform direct evaluation permeability with conventional well-logging methods. Considering that reservoir permeability signifi cantly affects mud invasion during drilling, we derive a mathematical model to assess the reservoir permeability based on mud invasion. A numerical model is fi rst used to simulate the process of mud invasion and mud cake growth. Then, based on Darcy's law, an approximation is derived to associate the depth of mud invasion with reservoir permeability. A mathematical model is constructed to evaluate the reservoir permeability as a function of the mud invasion depth in time-lapse logging. Sensitivity analyses of the reservoir porosity, permeability, and water saturation are performed, and the results suggest that the proposed model and method are well suited for oil layers or oil-water layers of low porosity and low permeability. Numerical simulations using fi eld logging and coring data suggest that the evaluated and assumed permeability data agree, validating the proposed model and method.

show abstract

Section: Introductionmentioning

confidence: 99%

Model and method of permeability evaluation based on mud invasion effects

Zhou

Meng

et al. 2015

Appl. Geophys.

View full text Add to dashboard Cite

show abstract

“…The simulated mud invasion time was 7 d, considering that the time from drilling to logging is approximately 7 d, and the invasion depth and invasion zone resistivity were obtained. The finite element forward model [38,39] was applied to calculate the array lateralog responses of the simulation area [40][41][42]. In Figure 12, the fifth track is the comparison between the measured and simulated value of array lateralog responses.…”

Section: Array Laterolog Response and Mud Invasionmentioning

confidence: 99%

Analyzing the Origin of Low Resistivity in Gas-Bearing Tight Sandstone Reservoir

Jiang

Jian

et al. 2021

Geofluids

View full text Add to dashboard Cite

Complex characteristics exist in the resistivity response of Gs reservoirs in the central inversion belt of the Xihu Sag, East China Sea Basin. Some drilling wells have confirmed the existence of abnormally low resistivity in gas reservoirs of the area; and the electrical logging response was unable to reflect fluid properties of the reservoir accurately. Therefore, it is necessary to analyze the origin of the low resistivity and determine its controlling factors. Based on experimental data of core analysis and numerical simulations of mud invasion, this study thoroughly explores the origin of low resistivity in the subject gas-bearing reservoir considering both internal and external factors. The results indicated that when there is no or a low degree of mud invasion, the fine lithology, complex pore structure, additional clay mineral conductivity, and high content of pyrite are the main internal factors driving the conditions present in the studied gas reservoir. When mud invasion occurs, the invasion of highly saline mud is the main external cause of low resistivity. The numerical simulation results indicated that a formation with good permeability and high overbalance pressure has a deep invasion depth. The resistivity around the well is obviously reduced after the invasion, and low resistivity would form easily. Combined with actual data of several wells, the main influencing factors of the reservoir’s electrical characteristics were analyzed, and the main controlling factors of low resistivity in the gas reservoirs are given. This study provides valuable support for studying the low-contrast complex reservoir conductivity mechanism. The study also offers novel ideas for accurate calculation of saturation and the meticulous evaluation of reservoir for subsequent studies.

show abstract

“…We adopt the two-phase (water and oil) isothermal Darcy flow equations to describe how the invasion behavior disturbs the fluid saturation and pressure distributions over time in the near-well formation [8]. The salinity mixing between the low-salinity mud water and the high-salinity in-situ formation water can be described by the convective-diffusive equation, which is actually a multi-component issue [9].…”

Section: A Mud Invasion Modellingmentioning

confidence: 99%

Associating borehole radar logging data with petrophysical properties in a mud-contaminated reservoir: Can we converse disadvantage to advantage?

Zhou¹,

Giannakis

Giannopoulos

et al. 2019

10th International Workshop on Advanced Ground Penetrating Radar

View full text Add to dashboard Cite

Logging engineers deem mud invasion a harm and attempt to eliminate its impact on logging data. However, from our point of view, the mud-contaminated parts of the formation do also carry some valuable information, notably with regard to the key hydraulic properties. Therefore, if adequately characterized, the invasion effects, in turn, could be utilized for reservoir estimation. Typically, the invasion depth critically depends of the formation porosity and permeability. To achieve this objective, we propose to use borehole radar to determine the mud invasion depth considering a high spatial resolution of ground-penetrating radar (GPR) compared with the conventional logging tools. We implement numerical investigations on the feasibility of this approach. The simulations imply that a timelapse radar logging is able to extract EM reflection signals from mud invasion front, and the invasion depth and EM velocity can be estimated by the downhole measurement of one source and two receivers. We find that there exists a positive correlation between the estimated invasion depth and permeability curves, and a negative correlation between the estimated velocity and porosity curves. We suggest that borehole radar has potential to estimate permeability and porosity of oil reservoirs, wherein the mud invasion effect is positively utilized.

show abstract

Numerical Simulation of Mud Invasion and Its Array Laterolog Response in Deviated Wells

Cited by 9 publications

References 8 publications

Model and method of permeability evaluation based on mud invasion effects

Model and method of permeability evaluation based on mud invasion effects

Analyzing the Origin of Low Resistivity in Gas-Bearing Tight Sandstone Reservoir

Associating borehole radar logging data with petrophysical properties in a mud-contaminated reservoir: Can we converse disadvantage to advantage?

Contact Info

Product

Resources

About