Enhanced In-Situ Stress Profiling With Microfracture, Core, and Sonic-Logging Data

Ahmed, Usman; Markley, Marvin E.; Crary, Steve

doi:10.2118/19004-pa

Cited by 22 publications

(7 citation statements)

References 18 publications

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“…The preferred method for estimating the horizontal stresses is to use a strain-corrected log-based approach [5][6][7][8][9][10] in which the horizontal strain is kept constant. The method utilizes measured horizontal stress data from microfrac or LOT's in combination with RMP's, pore pressure and temperature, to calculate a "tectonic" strain.…”

Section: Methodsmentioning

confidence: 99%

Log-Based Pore Volume Compressibility Prediction-A Deepwater GoM Case Study

Wolfe¹,

Russell²,

Luise³

et al. 2005

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractPore Volume Compressibility (PVC) is one of the most important parameters for proceeding with project sanctioning. An accurate estimation of pore volume compressibility of reservoir rocks is essential for compaction evaluation, reservoir drive determination, reserves estimates, reservoir pressure maintenance, casing collapse analyses, and production forecasting. This information is then used in modeling the reservoir and calculating the economic value of the project. Thus, obtaining credible indications of this value early in the well evaluation process is invaluable. Unfortunately, this data is usually required long before a conventional core can be obtained and mechanical rock properties measured. Furthermore, cores are only available at discrete points along the wellbore requiring the data to be extrapolated to the missing sections.To accommodate the need for this data early in the project and to circumvent the short comings of core-based information gaps in the wellbore, a cost effective approach that utilizes common wireline data is used to obtain a continuous profile of the pore volume compressibility with depth shortly after wireline logging operations have concluded. The method employs a log-based mechanical property program that simulates triaxial loading to obtain static elastic moduli as well as rock strength. The resulting rock mechanical properties are then converted into their uniaxial strain equivalents and used to determine the pore volume compressibility. The process is repeated for several drawdown stages with the condition that the deformations are contained within elastic limits. This yields the complete reservoir compaction trend as a function of reservoir depletion.The log-based model was recently validated by comparing with lab-derived results from an offset well in deepwater Gulf of Mexico. The results indicate that the uniaxial pore volume compressibility obtained from the log-based method matches well with the results obtained in the laboratory. This fact suggests that the log-based approach should be utilized with a high degree of confidence to determine the PVC in the absence of core data, insufficient depth coverage of the cores, and/or to validate the core results.

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Section: Methodsmentioning

confidence: 99%

Log-Based Pore Volume Compressibility Prediction-A Deepwater GoM Case Study

Wolfe¹,

Russell²,

Luise³

et al. 2005

Proceedings of SPE Annual Technical Conference and Exhibition

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“…Evaluating in-situ stresses and fracture systems from the DSI-BCR shear-wave anisotropy log may have practical applications in petroleum related problems, such as, hydraulic fracturing, reservoir performance, sand-control and sandproduction prediction, waterflooding, well optimum placement, fault detection and hydrocarbon migration (Endo, 1997, Sulbaran, 1999, Klimentos, 1999, Ahmed, 1989, Akbar, 1994, Ramos, 1994, Whitehead, 1987, and Nolen-Hoeksema, 1994.…”

Section: Using Imaging Tools For Carbonate Rock Evaluationmentioning

confidence: 99%

Enhanced Productivity in a Heavy Oil Reefal Reservoir as a Result of Improved Reservoir Characterization

Hani¹,

Theodore²,

Taher³

et al. 2000

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe Nullipore reservoir in the fields of Egypt's General Petroleum Company (GPC) is a heavy oil reefal reservoir located in the Gulf of Suez area. The Nullipore formation is characterized by a high degree of heterogeneity, which, in addition to the high oil viscosity, has made it difficult to locate and drain oil effectively. This was further complicated by the lack of accurate seismic and geological data. For these reasons, the reservoir had been traditionally considered only as a secondary or backup prospect. Recently, an approach was initiated, based on the use of innovative logging techniques for better reservoir characterization as well as production data analysis for better understanding of reservoir dynamics. This has led to the realization that the reservoir's productivity is primarily controlled by the flow contribution from natural fractures. New horizontal wells were hence planned and completed on the basis of the newly acquired information with excellent results. Moreover, older wells were recompleted using the data acquired from these horizontal wells, leading to large increases in production.This paper describes the methods used to locate the natural fractures that lead to the majority of production in the Nullipore reservoir. Central to these are the fracture detection logs and log-analysis methods employed. It also details how new wells can be put in place to intercept these fractures and effectively drain the oil.

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“…The key mechanical properties of wellbore wall rock for calculation of stress profiles based on the uniaxial strain theory, such as Poisson's ratio, overburden and pore pressure, can be determined using acoustic logs including compressional and shear wave velocities together with density log. The horizontal minimum stress profile of wellbores can be calculated using the proposed relationship based on the uniaxial strain theory, with inclusion of poroelasticity, as follows (Ahmed et al 1991):…”

Section: Introductionmentioning

confidence: 99%

Determination of minimum and maximum stress profiles using wellbore failure evidences: a case study—a deep oil well in the southwest of Iran

Molaghab

Taherynia

Aghda

et al. 2017

J Petrol Explor Prod Technol

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The main objective of this paper is estimating the horizontal stresses and calibration of the log-derived horizontal stress profiles in deep oil wells according to their wall failure evidences, including both compressive (breakouts) and tensile failures (drilling-induced tensile fractures). Estimation of the horizontal stress profiles using well logs is one of the standard methods in the oil industry. Another method for estimating horizontal stresses is analyzing failure evidences in the wellbore wall. By integrating these two methods, a practical strategy was followed in this research to determine the horizontal stress profiles. By this strategy, minimum and maximum horizontal stress profiles are determined in such a way that the stress concentration at the wellbore wall at the tensile fracture identified depths, exceeds the formation tensile strength, while at the breakouts identified depths it exceeds the compressive strength of the formation. An advantage of this procedure is that does not require to measure in situ stresses. Also, due to the presence of a large number of breakouts and the induced fractures detected in different zones of a deep wellbore, log-derived stress profile calibration is done using the stress state in different zones that causes to increase the accuracy and reliability of the obtained horizontal stress profile. The proposed solution was applied to determine the horizontal stress profiles in a deep oil well in the southwest of Iran as a real case.

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Enhanced In-Situ Stress Profiling With Microfracture, Core, and Sonic-Logging Data

Cited by 22 publications

References 18 publications

Log-Based Pore Volume Compressibility Prediction-A Deepwater GoM Case Study

Log-Based Pore Volume Compressibility Prediction-A Deepwater GoM Case Study

Enhanced Productivity in a Heavy Oil Reefal Reservoir as a Result of Improved Reservoir Characterization

Determination of minimum and maximum stress profiles using wellbore failure evidences: a case study—a deep oil well in the southwest of Iran

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