Real Time Borehole Stability Monitoring and Pre-drill Model Calibration using LWD Sonic — A Case Highlight.

2015 ◽  
Author(s):  
Sophia Weaver ◽  
Xiaohui Xiao ◽  
Rob Vines
Keyword(s):  
Model Calibration ◽  
Weight Optimization ◽  
Borehole Stability ◽  
Acoustic Data ◽  
Stability Monitoring ◽  
Development Costs ◽  
Stability Model ◽  
Logging While Drilling ◽  
Geophysical Log ◽  
Productive Time

Abstract Borehole instability challenges can account for a significant percentage of non-productive time and associated costs in drilling. This is even more so in deepwater subsea wells due to high development costs coupled with the subsurface complexities associated with turbidite reservoirs. Pre-drill borehole stability studies in this field case were performed by evaluating offset well history and geophysical log data and calibrating these against direct well measurements and drilling experiences, with the objective of recommending the appropriate mud weight. However, the validation of the pre-drill borehole stability model derived from sonic data taken in the only offset well in the field was deemed necessary for effective borehole stability monitoring in this case. Additionally, the inability to run wireline in a highly deviated well fuelled the need for acoustic data acquisition using logging-while-drilling (LWD). Sonic data was acquired by LWD (a first in the field) and this aided mud weight optimization to successfully drill the well to TD without any borehole stability problems. This paper describes the application of this solution to managing well delivery uncertainties in a deepwater field and highlights the process, results and lessons from the event to aid future applications.

Joint inversion of logging-while-drilling multipole acoustic data to determine formation shear-wave transverse isotropy

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. D121-D132
Author(s):  
Yang-Hu Li ◽  
Song Xu ◽  
Can Jiang ◽  
Yuan-Da Su ◽  
Xiao-Ming Tang
Keyword(s):  
Shear Wave ◽  
Joint Inversion ◽  
Transverse Isotropy ◽  
Synthetic Data ◽  
Flexural Wave ◽  
Inversion Method ◽  
S Wave ◽  
Acoustic Data ◽  
Wave Data ◽  
Logging While Drilling

Seismic-wave anisotropy has long been an important topic in the exploration and development of unconventional reservoirs, especially in shales, which are commonly characterized as transversely isotropic ([TI] or vertical TI [VTI]) media. At present, the shear-wave (S-wave) TI properties have mainly been determined from monopole Stoneley- or dipole flexural-wave measurements in wireline acoustic logging, but the feasibility of those obtained from logging-while-drilling (LWD) acoustic data needs to be established. We have developed a joint inversion method for simultaneously determining formation S-wave transverse isotropy and vertical velocity from LWD multipole acoustic data. Our theoretical analysis shows that the presence of anisotropy strongly influences LWD Stoneley- and quadrupole-wave dispersion characteristics. Although the monopole Stoneley and quadrupole waves are sensitive to the formation S-wave TI parameters, they suffer from the typical nonuniqueness problem when using the individual-wave data to invert parameters alone. Thus, the respective dispersion data can be jointly used to estimate the formation S-wave TI properties. By the joint inversion, the nonuniqueness problem in the parameter inversion can also be effectively alleviated. The feasibility of the method has been verified by the processing results of theoretical synthetic data and field LWD acoustic-wave data. Therefore, the result offers an effective method for evaluating VTI formation anisotropy from acoustic LWD data.

The Benefits of Logging While Drilling (LWD) for Formation Evaluation in the Dulang West Field

1998 ◽  
Vol 1 (06) ◽  
pp. 496-503
Author(s):  
Zarool Hassan Bin Tajul Amar
Keyword(s):  
Gamma Ray ◽  
Cost Savings ◽  
Sufficient Information ◽  
Neutron Density ◽  
Borehole Stability ◽  
Formation Evaluation ◽  
Petrophysical Analysis ◽  
Measurement While Drilling ◽  
Logging While Drilling ◽  
Competitive Pricing

Summary Ever since the first electric log was run in 1927, the oil industry relied on wireline-conveyed logging for the acquisition of formation data for petrophysical analysis. It was not until 1978 that the first measurement while drilling (MWD) tools were introduced in the field. The industry did not pay too much attention to them then because they did not offer sufficient information for petrophysical analysis. Furthermore, the reliability of such tools was notimpressive and their cost was unattractive. However, over the last 6 years, the drilling services industry has shifted its focus from just directional MWD to a complete directional and logging while drilling (LWD) package. The LWD tools that are built into special drill collars provide measurements of resistivity, neutron, density, and gamma ray. Significant improvements in the reliability of the tools and competitive pricing, as compared to conventional wireline logging, has offered advantages in running LWD in fields that have drilling and completion constraints (e.g., borehole stability) or difficult well trajectories. This paper discusses the benefits to Petronas Carigali of using LWD for formation evaluation. In the development of the Dulang West field, LWD was used extensively to acquire formation log data. The quality of the data and cost savings are addressed. A comparison between the wireline-conveyed and LWD data acquired in this field is also presented. The acquisition of formation data by use of LWD in Dulang West has made a significant contribution to the overall cost per barrel of oil produced, without compromising data quality. P. 496

Mud Weight Optimization to Reduce Non-Productive-Time While Drilling Through Shale/Carbonate Sequence of UAE: A Case Study

2015 ◽  
Author(s):  
GuiFen Xi ◽  
Nabila labbassen ◽  
Bader Saif Al Badi ◽  
Thierry Francis Lecoq ◽  
Hassan Al-Husseiny Afifi ◽  
...  
Keyword(s):  
Weight Optimization ◽  
Carbonate Sequence ◽  
Productive Time

Borehole Stability and Field Stress Analysis with Azimuthal Logging-while-Drilling Technology: A Case History

2015 ◽  
Author(s):  
Shaikh Abdul Azim ◽  
Sankar Chowdhuri ◽  
Mohammad Raffi Madar Sahib ◽  
Tarek Abdel Gawwad Mohammad ◽  
Anar Abdulkarim ◽  
...  
Keyword(s):  
Stress Analysis ◽  
Case History ◽  
Borehole Stability ◽  
Field Stress ◽  
Drilling Technology ◽  
Logging While Drilling
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