Petrophysics of the Lance and Upper Mesaverde Reservoirs at Pinedale Field, Sublette County, Wyoming, USA

Cluff, Suzanne G.; Cluff, Robert M.; Hallau, Daniel; Sharma, Ryan

doi:10.1306/13511895m1073635

Cited by 2 publications

(9 citation statements)

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“…Porosity is considered main controlling factor on permeability (Cluff and Cluff, 2004). However, this study demonstrates that permeability is dependent upon dominant pore size rather than total porosity.…”

Section: Discussionmentioning

confidence: 69%

“…The main productive reservoirs of Jonah are the Lance and Mesaverde sandstones, which have a collective porosity range of 1 to 12% (Cluff and Cluff, 2004). Porosity is locally reduced by cementation by quartz, chlorite, kaolinite, illite and sparse ferroan calcite decreases pore throat size, clog pores and restricts fluid flow (DuBois et al, 2004).…”

Section: Challenges In Net-pay Calculations and Hydraulic Fracturingmentioning

confidence: 99%

“…However, gamma ray is not a good mineralogy indicator. In addition, according to Cluff and Cluff (2004), 6% porosity was considered as the cut off to distinguish reservoir rocks and non-reservoir rocks. The summary of the problems that I will address in my work to improve net-pay calculation are:…”

Section: Problem Statementmentioning

confidence: 99%

“…Sandstones exhibit 1-12% porosity ranges and are considered main productive formations (Cluff and Cluff, 2004). Traditionally, 75 API units of gamma ray cut off were used to differentiate sandstone from siltstone and mudstone (DuBois et al, 2004).…”

Section: Common Rock Classificationmentioning

confidence: 99%

“…There is a general decreasing behavior in permeability that associated with porosity decrease. A linear regression is used to find general correlation between porosity and permeability close to in-situ reservoir effective stress condition (Cluff and Cluff, 2004):…”

Section: Common Rock Classificationmentioning

confidence: 99%

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Rock typing of tight gas sands: A case study in Lance and Mesaverde formations from Jonah field

Aliyev

Saidian

Prasad

et al. 2016

Journal of Natural Gas Science and Engineering

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The Jonah field is one of the biggest tight gas sand fields in the Green River basin. Production profiles from its deeper sections show high liquid hydrocarbons close to the Pinedale anticline, especially in Mesaverde and Lance formations. To assess the potential of condensate production, new approaches for rock classification are needed that will allow us to differentiate between discontinuous sandstone layers and the interbedded siltstones. Currently, the only cutoff used is for gamma ray: rocks below 75 API are designated as sandstones.Although, significant porosity and permeability variations occur within the sandstone zones, the only criterium used to differentiate between reservoir and non-reservoir rocks is porosity: sandstones with porosity > 6% are considered reservoir quality rocks. Porosity is considered main controlling factor on permeability. A 6% porosity cut off in sandstones was used in net-pay calculations. However, hydraulic rock typing demonstrates permeability is dependent on main pore throat radius, rather than porosity. This study presents rock typing for tight sandstones and siltstones with an understanding of petrophysical properties such as pore structure, porosity, permeability, and cementation.I studied 14 samples from the Mesaverde and Lance Formations with lithologies varying from clean sandstone to mudstone. X-ray diffraction (XRD) mineralogy and mercury injection capillary pressure (MICP) were measured for all samples. NMR transverse relaxation times (T 2 ) at 2 MHz were also measured for 10 water saturated samples. Nitrogen adsorption tests were performed on 8 samples. Ultrasonic velocities from 10 samples were measured at different confining pressure conditions. Thin section petrography was used to analyze the cementation and pseudomatrix clay effects on pore and pore throat size.MICP data are used to subdivide rocks into three groups based on pore throat size distribution: reservoir sandstones, non-reservoir sandstone and siltstone/mudstone. Dominant pore throat size for reservoir and non-reservoir sandstones are 400 and 100 nm, respectively.iii In order to apply pore throat size rock typing to downhole measurements, NMR pore size classification is used to identify formations. Pore size from NMR demonstrated equivalent behavior to pore throat size from MICP. The logarithmic mean values of T 2 transverse relaxation times for reservoir, non-reservoir sandstone and siltstone/mudstone are 22.2 ms, 3.4 ms and 0.29 ms, respectively. Clear separation of reservoir sandstone, non-reservoir sandstone and siltstone is seen based on compressibility behavior from compressional velocity during initial pressure loading. Reservoir sandstone demonstrates the highest compressibility. In addition, siltstone and mudstone were separated based on log differential pore volume distribution from N 2 adsorption data.Based on pore size distribution data, four main rock types are identified in Lance and Mesaverde formations in Jonah field. Rock typing based on gamma ray and porosity logs can be con...

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Section: Discussionmentioning

confidence: 69%

Section: Challenges In Net-pay Calculations and Hydraulic Fracturingmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Common Rock Classificationmentioning

confidence: 99%

Section: Common Rock Classificationmentioning

confidence: 99%

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