Simulation of Artificially Fractured Wells With Single-Well Models

As the new operator of the Mahakam Block started in 2017, Pertamina Hulu Mahakam (PHM) were challenged to ramp up operations in order to combat massive production decline. At the same time, reducing well cost was also a paramount importance to ensure that the economic targets of the wells were achieved following the reduction of well stakes. One of the remaining unsolved enigmas is how to achieve No Wait-on-Cement (NO WOC) on surface diverter section as this will create a lot of rig time saving both on single well and batch operations. The project begins with several different kinds of proposal until the best solutions were identified fulfilling safety, simplicity of operations and acceptable cost and finally were put in place with very satisfying results. The main key principle is conversion wellhead stages following well architecture while there were several modifications of casing hanger, adapter, additional materials & modified procedure. Rig time saving, additional operational gain and a promising new “breakthrough” of drilling technique become a significant impact of the successful effort. Now the method has become a standard in PHM operations and has already been integrated to SDI (Standard Drilling Instruction). The merit of this endless hard work could possibly be gained by other operators as it will create more added values both tangible and intangible.

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Gas-Water Flow Behaviour During Mutual Displacement in Porous Media

The Open Fuels & Energy Science Journal ◽

10.2174/1876973x01710010013 ◽

2017 ◽

Vol 10 (1) ◽

pp. 13-22

Author(s):

Renyi Cao ◽

Junjie Xu ◽

Xiaoping Yang ◽

Renkai Jiang ◽

Changchao Chen

Keyword(s):

Porous Media ◽

Relative Permeability ◽

Gas Storage ◽

Fluid Distribution ◽

Water Displacement ◽

Phase Zone ◽

Two Phase ◽

Flow Process ◽

Single Well ◽

Mutual Displacement

During oilfield development, there exist multi-cycle gas–water mutual displacement processes. This means that a cycling process such as water driving gas–gas driving water–water driving gas is used for the operation of injection and production in a single well (such as foam huff and puff in single well or water-bearing gas storage). In this paper, by using core- and micro-pore scales model, we study the distribution of gas and water and the flow process of gas-water mutual displacement. We find that gas and water are easier to disperse in the porous media and do not flow in continuous gas and water phases. The Jamin effect of the gas or bubble becomes more severe and makes the flow mechanism of multi-cycle gas–water displacement different from the conventional water driving gas or gas driving water processes. Based on experiments of gas–water mutual displacement, the changing mechanism of gas–water displacement is determined. The results indicate that (1) after gas–water mutual displacement, the residual gas saturation of a gas–water coexistence zone becomes larger and the two-phase zone becomes narrower, (2) increasing the number of injection and production cycles causes the relative permeability of gas to increase and relative permeability for water to decrease, (3) it becomes easier for gas to intrude and the invaded water becomes more difficult to drive out and (4) the microcosmic fluid distribution of each stage have a great difference, which caused the two-phase region becomes narrower and effective volume of gas storage becomes narrower.

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SaQuant: a real-time PCR assay for quantitative assessment of Staphylococcus aureus

BMC Microbiology ◽

10.1186/s12866-021-02247-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Colin Wood ◽

Jason Sahl ◽

Sara Maltinsky ◽

Briana Coyne ◽

Benjamin Russakoff ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Sensitivity And Specificity ◽

Pathogen Detection ◽

Limit Of Detection ◽

Future Research ◽

Limit Of Quantification ◽

Pathogen Prevalence ◽

Single Well ◽

Effective Public Health ◽

Detection And Quantification

Abstract Background Molecular assays are important tools for pathogen detection but need to be periodically re-evaluated with the discovery of additional genetic diversity that may cause assays to exclude target taxa or include non-target taxa. A single well-developed assay can find broad application across research, clinical, and industrial settings. Pathogen prevalence within a population is estimated using such assays and accurate results are critical for formulating effective public health policies and guiding future research. A variety of assays for the detection of Staphylococcus aureus are currently available. The utility of commercial assays for research is limited, given proprietary signatures and lack of transparent validation. Results In silico testing of existing peer-reviewed assays show that most suffer from a lack of sensitivity and specificity. We found no assays that were specifically designed and validated for quantitative use. Here we present a qPCR assay, SaQuant, for the detection and quantification of S. aureus as might be collected on sampling swabs. Sensitivity and specificity of the assay was 95.6 and 99.9 %, respectively, with a limit of detection of between 3 and 5 genome equivalents and a limit of quantification of 8.27 genome equivalents. The presence of DNA from non-target species likely to be found in a swab sample, did not impact qualitative or quantitative abilities of the assay. Conclusions This assay has the potential to serve as a valuable tool for the accurate detection and quantification of S. aureus collected from human body sites in order to better understand the dynamics of prevalence and transmission in community settings.

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