Low Permeability Gas-Bearing Sandstone Reservoirs Characterization from Geophysical Well Logging Data: A Case Study of Pinghu Formation in KQT Region, East China Sea

Gao, Feiming; Xiao, Liang; Zhang, Wei; Cui, Weiping; Zhang, Zhiqiang; Yang, Erheng

doi:10.3390/pr11041030

Cited by 5 publications

(4 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This theoretical relation can be well-used to express the variation between pore structure and cementation exponent, especially for tight rocks with porosities lower than 8%. The theoretical relation raised by has been verified to be widely usable in different types of tight reservoirs [40]. In this study, using the resistivity experimental data that are displayed in Figures 16 and 17, we also analyze the effect of pore structure to cementation exponent in Chang 8 Formation of Shunning Region and determine that the cementation exponent is heavily affected by porosity.…”

Section: Water Saturation Calculationmentioning

confidence: 89%

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Li,

Xiao,

et al. 2023

Processes

Self Cite

View full text Add to dashboard Cite

The role of the horizontal well in developing unconventional oil and gas reservoirs is particularly significant. Different from vertical wells, horizontal wells are greatly affected by many factors, e.g., well track, surrounding mudstone, resistivity, and pore structure heterogeneity in horizontal and vertical directions. These make it difficult to evaluate reservoir parameters and determine optimized test layers. In order to improve formation evaluation in horizontal wells, it is necessary to carry out the research of analyzing formation anisotropy, predict physical property parameters, and classify formation to determine high-quality intervals. In this study, taking Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin as an example, 40 core samples were drilled and applied for nuclear magnetic resonance (NMR), mercury injection capillary pressure (MICP), and resistivity experiments. The porosity, permeability, resistivity, and pore structure anisotropy are analyzed. Results illustrate that the physical properties and pore structure in horizontal direction are superior to vertical direction. Meanwhile, NMR log loses its role in pore structure characterization in horizontal wells. Afterward, methods of correcting interval transit time (DT) and resistivity anisotropy are raised, and models of predicting formation physical property parameters, such as porosity, permeability, and water saturation, are established. A parameter, named as the formation type indicator (FTI), is proposed to reflect reservoir oil-bearing properties and pore structure. Finally, our target horizontal intervals are classified into four types, and the highest-quality “sweet spot” is determined.

show abstract

Section: Water Saturation Calculationmentioning

confidence: 89%

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Li,

Xiao,

et al. 2023

Processes

Self Cite

View full text Add to dashboard Cite

show abstract

“…The K s can be obtained by using Equation (6). In order to calculate K fa , K d and K m also need to be determined.…”

Section: Array Acoustic Loggingmentioning

confidence: 99%

“…However, the complex interplay between depositional and post-depositional "diagenetic" attributes obliterates the petrophysical characteristics of sandstone reservoirs resulting in a tight pore. Combined with the influence of logging conditions and reservoir factors, the sensitivity of the logging response to pore fluid is reduced and complex oil and water layers, such as high-resistivity water layers and low-resistivity oil layers, are often misjudged or missed, which seriously restricts the economic benefits of the oilfield [4][5][6]. Nowadays, the research on the fluid identification method of complex oil and water layers in tight sandstone reservoirs has become an important topic in oilfield exploration and development [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Fluid Identification Method of Nuclear Magnetic Resonance and Array Acoustic Logging for Complex Oil and Water Layers in Tight Sandstone Reservoir

Bai,

Tan,

et al. 2023

Processes

View full text Add to dashboard Cite

In order to improve the logging interpretation accuracy for complex oil and water layers developed in tight sandstone reservoirs, this study takes the Chang 8 member of the Yanchang Formation in the Huanxian area as the research object, and two new fluid identification methods were constructed based on nuclear magnetic resonance (NMR) logging and array acoustic logging. Firstly, the reservoir characteristics of physical properties and conductivity were studied in the research area, and the limitations of conventional logging methods in identifying complex oil and water layers were clarified. Then, the sensitive parameters for identifying different pore fluids were established by analyzing the relationship between NMR logging and array acoustic logging with different pore fluids. On this basis, the fluid identification plate, composed of movable fluid apparent diffusion coefficient and effective porosity difference (Da-Δφe) by NMR logging data of D9TWE3 observation mode, and the other fluid identification plate, composed of apparent bulk modulus of pore fluid and elastic parameter sensitive factor (Kf-Fac), were constructed, respectively. Finally, these two fluid identification methods were used for reservoir interpretation of actual logging data. This study shows that the two new fluid identification methods constructed by NMR logging and array acoustic logging can effectively eliminate the interference of rock skeleton on logging interpretation, which make them more effective in identifying complex oil and water layers than the conventional logging method. Additionally, the two methods have their own advantages and disadvantages when used separately for interpreting complex oil and water layers, and the comprehensive interpretation of the two methods provides a technical development direction for further improving the accuracy of logging the interpretation of complex oil and water layers.

show abstract

“…Meanwhile, also raised a statistical model to predict various saturation exponent from NMR logging to optimize the Archie's equation. These proposed models had been verified to be usable in certain reservoirs (Gao et al, 2023;Li et al, 2023). However, the widely applicability was questionable.…”

Section: Introductionmentioning

confidence: 99%

Estimation of water saturation based on optimized models in tight gas sandstone reservoirs: A case study of Triassic Xujiahe Formation in northwestern Sichuan Basin

Xia,

Han,

Xie

et al. 2024

Preprint

View full text Add to dashboard Cite

Water saturation estimation faced a great challenge in tight gas sandstone reservoirs because of the effect of pore structure and strong heterogeneity to rock resistivity. The classic Archie’s equation cannot be always well used. To quantify the effect of pore structure to rock resistivity in tight gas sandstones, taking the Triassic Xujiahe Formation of northwestern Sichuan Basin as an example, 35 core samples were recovered and applied for resistivity experiments in laboratory under the simulated formation temperature and pressure environment, and 18 of them were simultaneously applied for nuclear magnetic resonance (NMR) and high-pressure mercury injection (HPMI) experimental measurements. Relationships between rock pore structure and resistivity parameters were analyzed. The results clearly illustrated that cementation exponent (m) and saturation exponent (n) were heavily affected by pore structure. Rocks with superior pore structure contained relative higher cementation exponent and lower saturation exponent, and vice versa. Afterwards, we raised a parameter of pore size index, which was defined as the ration of macropore and micropore percentage contents, to reflect rock pore structure, and established a model to calculate optimal saturation exponent from NMR data. Meanwhile, various cementation exponent prediction model was also raised by combining with porosity and irreducible water saturation (Swirr). By combining with calculated cementation exponent and saturation exponent, we optimized the Archie’s equation to predict water saturation in our target tight gas sands. Field examples illustrated that the predicted cementation exponent and saturation exponent matched well with core-derived results. The absolute errors between predicted cementation exponent and saturation exponent with core-derived results were lower than 0.05 and 0.07, separately. By using the optimized Archie’s equation, water saturations were precisely predicted from well logging data in our target tight gas sandstone reservoirs.

show abstract

Low Permeability Gas-Bearing Sandstone Reservoirs Characterization from Geophysical Well Logging Data: A Case Study of Pinghu Formation in KQT Region, East China Sea

Cited by 5 publications

References 48 publications

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Fluid Identification Method of Nuclear Magnetic Resonance and Array Acoustic Logging for Complex Oil and Water Layers in Tight Sandstone Reservoir

Estimation of water saturation based on optimized models in tight gas sandstone reservoirs: A case study of Triassic Xujiahe Formation in northwestern Sichuan Basin

Contact Info

Product

Resources

About