Changes in Completion Strategy Unlocks Massive Jurassic Coalbed Methane
Resource Base in the Surat Basin, Australia

Johnson, Raymond L.; Scott, Stephen H.; Herrington, Michael

doi:10.2523/101109-ms

Cited by 5 publications

(1 citation statement)

References 8 publications

(10 reference statements)

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“…Generally, hydraulic fracturing resulted in low productivity wells in the early pilot areas of the Surat Basin and produced wellbore failures in the Undulla Nose area, which led to the development of an alternative under-reamed, open-hole completion as the primary completion method for WSG wells (Johnson, Scott and Herrington 2006). However, as appraisal programs moved away from the more prolific Undulla Nose area, some areas of variable and lower permeability were encountered; this required reevaluation of the traditional WSG completion method and consideration of implementing hydraulic fracturing to improve production.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Hydraulic Fracture Effectiveness in a Coal Seam Gas Reservoir from Surface Tiltmeter and Microseismic Monitoring

et al. 2010

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In developing new coalbed methane (CBM) or coal seam gas (CSG) fields or reservoirs, the effect of many parameters are important in understanding the success or potential areas for improvement of hydraulic fracturing treatments. Estimating fracture geometry relative to the reservoir architecture is critical to understanding production variability. The Walloon Coal Measures, in the Surat Basin of Eastern Queensland, Australia, are a complex reservoir containing interbedded sandstone, siltstone, carbonaceous shale and coal seams where initial attempts at hydraulic fracturing in early pilot areas of the Surat Basin yielded poor results. Thus, when a hydraulic fracturing program was planned for this reservoir, it was decided to integrate a group of diagnostics that would be useful in understanding past results as well as deriving future improvements.Data is presented from two wells in the Walloon Sub Group (WSG) where tiltmeters and microseismic monitoring were used to evaluate fracture effectiveness relative to the reservoir architecture and to assist further design work. The treatments carried out in the studied wells were typical of CSG frac treatments used in other producing areas, incorporating stages of treated, gelled and crosslinked-gelled water with increasing concentrations of sand, up to six (6) lbm/gal. During the treatments, complex fractures were inferred based on analyses of data from both tiltmeter and microseismic monitoring methods. The collaborative data set for these wells also included a large amount of other analyses and diagnostic data. It was only possible to fully explain the treatment results through the combination of multiple diagnostics and an in-depth understanding of how the created fracture interacted with the complex reservoir and stress environment.In this paper, we outline the steps used to plan the monitoring program and describe how geological data was integrated to better understand the results observed during the treatments. We describe each of six (6) stages performed across the two wells, and how the diagnostics did or did not support the overall conclusions as to the effectiveness of each stage. Finally, this paper presents a logical framework to evaluate and integrate these technologies for use in future CSG well stimulation.2 SPE 133063 growth that would limit fracture extension or might lead to wellbore failures following hydraulic fracturing (Jeffrey et al. when a program to incorporate hydraulic fracturing was considered, it was decided that an integrated diagnostics program would be essential in understanding the fracture geometry and overall stress environment in order to improve treatment designs and to help understand past treatment results. Ridgewood Frac Pilot AreaThe area of investigation, the Ridgewood pilot (see Figure 2), was drilled on a localized structural high that appears to be a southwestern continuation of the Kogan Anticline. This area was investigated to determine if enhanced natural fracturing and associated higher permeability might exist east of the...

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Section: Introductionmentioning

confidence: 99%

Evaluating Hydraulic Fracture Effectiveness in a Coal Seam Gas Reservoir from Surface Tiltmeter and Microseismic Monitoring

et al. 2010

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Chapter 12 Specialist Completions

Bellarby¹

2009

Developments in Petroleum Science

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Evaluating Hydraulic Fracture Geometry from Sonic Anisotropy and Radioactive Tracer Logs

Scott¹,

Johnson²,

Datey³

et al. 2010

SPE Asia Pacific Oil and Gas Conference and Exhibition

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In developing a new field or reservoir, many parameters are important in understanding the success or possible areas for improvement in hydraulic fracturing. Estimating fracture geometry is essential to effectively calibrate a reservoir model to production results. Radioactive (RA) tracers have been used in hydraulic fracturing treatments to infer fracture dimensions. Three stable isotopes (i.e. Scandium, Iridium and Antimony) were used in various parts of the treatment to understand the progression of hydraulic fracture growth. Advanced sonic anisotropy logging tools, using a broader range of frequency acquisition, were used to enable shear measurement in cased hole environments over a wide range of interbedded coal, shale and sandstone sequences both before and after the hydraulic fracture treatment. Amplitude and anisotropy changes after a hydraulic fracture have been measured using sonic anisotropy logging and used to infer fracture height. Finally, the sonic anisotropy can be evaluated above and below the perforated interval and investigate hydraulic fracture height growth away from the wellbore, potentially visualising a greater distance than available with RA tracers. We will show how sonic anisotropy and radioactive tracer logging methods can be used to better understand the fracture geometry and aid further design work. The paper will present data from two (2) wells in the Walloon Coal Measures of the Surat Basin where both RA tracers and sonic anisotropy logs were used to infer fracture dimensions. Both wells used a combination of treated water stages, containing low concentrations of proppant, followed by borate-crosslinked gelled water stages with higher concentrations of proppant. This project contained a large amount of other hydraulic fracturing diagnostics including treatment pressure history- matching, microseismic monitoring and surface tiltmeters. In this paper we will note how those diagnostics compared with the results presented herein, but their results are discussed in greater detail elsewhere (Johnson et al. 2010a). Generally, the results indicate good agreement between these two fracture diagnostic methods and the authors will illustrate the complimentary nature of these diagnostics in gaining a fuller understanding of fracture height, especially in environments of complex fracture development.

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Changes in Completion Strategy Unlocks Massive Jurassic Coalbed Methane Resource Base in the Surat Basin, Australia

Cited by 5 publications

References 8 publications

Evaluating Hydraulic Fracture Effectiveness in a Coal Seam Gas Reservoir from Surface Tiltmeter and Microseismic Monitoring

Evaluating Hydraulic Fracture Effectiveness in a Coal Seam Gas Reservoir from Surface Tiltmeter and Microseismic Monitoring

Chapter 12 Specialist Completions

Evaluating Hydraulic Fracture Geometry from Sonic Anisotropy and Radioactive Tracer Logs

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