Proppant Placement in the Barnett Shale When Perforations are Selected in Like-Rock

2021 ◽  
Author(s):  
Tracy Juarez ◽  
Caleb Francis ◽  
Stephanie Freels ◽  
Brian Sinosic ◽  
Kevin Wutherich
Keyword(s):  
Gamma Ray ◽  
Fluid Distribution ◽  
Barnett Shale ◽  
Accelerometer Data ◽  
Mechanical Specific Energy ◽  
Rock Types ◽  
Sonic Log ◽  
Pump Rate ◽  
Cluster Efficiency ◽  
Pulsed Neutron

Abstract In previous frac designs, proppant tracer logs revealed poor proppant distribution between clusters. In this study, various technologies were utilized to improve cluster efficiency, primarily focusing on selecting perforations in like-rock, adjusting perforation designs and the use of diverters. Effectiveness of the changes were analyzed using proppant tracer. This study consisted of a group of four wells completed sequentially. Sections of each well were divided into completion design groups characterized by different perforating methodologies. Perforation placement was primarily driven by RockMSE (Mechanical Specific Energy), a calculation derived from drilling data that relates to a rock's compressive strength. Additionally, the RockMSE values were compared alongside three different datasets: gamma ray collected while drilling, a calculation of stresses from accelerometer data placed at the bit, and Pulsed Neutron Cross Dipole Sonic log data. The results of this study showed strong indications that fluid flow is greatly affected by rock strength as mapped with the RockMSE, with fluid preferentially entering areas with low RockMSE. It was found that placing clusters in similar rock types yielded an improved fluid distribution. Additional improved fluid distribution was observed by adjusting hole diameter, number of perforations and pump rate.

Physics, applications, and limitations of borehole neutron-gamma density measurements

Geophysics ◽  
2019 ◽  
Vol 84 (1) ◽  
pp. D39-D56 ◽  
Author(s):  
Mathilde Luycx ◽  
Carlos Torres-Verdín
Keyword(s):  
Environmental Effects ◽  
Gamma Ray ◽  
Vertical Resolution ◽  
Neutron Detectors ◽  
Density Measurements ◽  
Gamma Density ◽  
Limited Applicability ◽  
Empirical Density ◽  
Cesium 137 ◽  
Pulsed Neutron

Radioactive chemical sources can pose security, health, and environmental risks when used to estimate rock porosity in situ. The oil industry has been developing solutions to eliminate radioactive chemical sources in borehole nuclear logging. Pulsed neutron generators have successfully replaced chemical sources in neutron tools, but cesium-137 is still mainly used for borehole density measurements. Neutron-activated gamma-ray measurements (neutron-gamma) are a possible alternative to radioactive chemical sources in density tools. Despite recent advances, the measurement faces challenges regarding density accuracy across diverse solid and fluid rock compositions and nonnegligible sensitivity to borehole environmental effects. We have examined a theoretical, albeit realistic, logging-while-drilling neutron-gamma density (NGD) tool operating with two inelastic gamma-ray detectors and two fast neutron detectors. With a strong emphasis on measurement physics and source-sensor design, the tool delivers density accuracies comparable to those of gamma-gamma density (GGD) tools with [Formula: see text] error in shale-free formations and [Formula: see text] in shale and shaly formations. Our work also compares NGD with GGD in terms of depth of investigation (DOI), vertical resolution, and sensitivity to borehole environmental effects to determine optimal logging conditions. NGD accuracy is limited in the presence of standoff. With inputs of caliper and mud type, empirical density corrections can be applied up to 0.64 cm (0.25 in) standoff. NGD also has limited applicability in thinly bedded formations with maximum vertical resolution of 76 cm (2.5 ft). However, the measurement outperforms GGD in the presence of invasion because its DOI is twice as large.

QUALITATIVE ANALYSIS OF SPECTRAL GAMMA RAY DATA AS A TOOL FOR FIELDWIDE AND REGIONAL STRATIGRAPHIC CORRELATION, ENDERBY TERRACE, CARNARVON BASIN, WESTERN AUSTRALIA

2001 ◽  
Vol 41 (1) ◽  
pp. 449
Author(s):  
A.P. Clare ◽  
A.J. Crowley
Keyword(s):  
Western Australia ◽  
Gamma Ray ◽  
Petroleum Industry ◽  
Stratigraphic Correlation ◽  
Environment Impact ◽  
Rock Types ◽  
Subsurface Environment ◽  
Detailed Assessment ◽  
Well Correlation ◽  
Carnarvon Basin

The use of wireline and core spectral gamma data as a tool for defining clay types and mineral assemblages in the subsurface environment has been widely used for many years within the petroleum industry. However, the qualitative use of radiometric data for interpreting rock types as used with airborne surveys in the mineral industry has not undergone detailed assessment as a well correlation tool.Applying the principles of qualitative airborne radiometric interpretation to the assessment of wireline spectral gamma ray data has proved extremely useful as a well correlation tool in the Carnarvon Basin of Western Australia. Data is presented from the Stag Field detailing the application of the technique as an effective fieldwide correlation tool. The sandstone reservoirs exhibit mineralogical variation and individual sand packages can be discontinuous. However, the major shale packages are laterally continuous and individual shales show remarkable character consistency over several kilometres. Such character continuity has proved a valuable correlation tool for confirming and refining the stratigraphic packages observed in the Cretaceous section of Stag.Success on the Stag Field led to application of the technique for regional correlations on the Enderby Terrace. The results of regional work show that correlations still hold when the technique is applied to correlations of over 70 km even though some lateral variation due to provenance and depositional environment impact on clay types was evident. Hence this qualitative approach of wireline log evaluation has proved an effective and valuable correlation tool.

APPLICATIONS OF THERMAL MULTIGATE DECAY PULSED NEUTRON LOGS IN UNUSUAL DOWNHOLE LOGGING ENVIRONMENTS

1985 ◽  
Vol 25 (1) ◽  
pp. 265
Author(s):  
Sami O. Ajam ◽  
V.E. Rahal
Keyword(s):  
Gamma Rays ◽  
Cross Sections ◽  
Gamma Ray ◽  
Decay Curve ◽  
Drill Pipe ◽  
Paper Briefly ◽  
Gamma Ray Detectors ◽  
Porosity Ratio ◽  
Pulsed Neutron ◽  
Capture Cross Sections

The Thermal Multigate Decay (TMD) logging system utilizes a pulsed 14 Mev generator and two gamma ray detectors to obtain measurements of the capture cross sections of downhole formations. The composite decay curve from both formation and borehole capture gamma rays is detected, and is separated into the two individual components : sigma formation and sigma borehole. The resulting sigma formation measurement is only minimally affected by borehole conditions, especially in cased wells.In addition to sigma formation and sigma borehole, the TMD system generates a dual-spaced porosity ratio and several other parameters which provide information on log quality, borehole parameters, and tool stability. These features can be used to assist the log analyst in understanding the down- hole borehole environment as well as formation characteristics. Under appropriate conditions, the TMD log can also provide production logging information relating to fluid movement in or near the wellbore.The paper briefly reviews the TMD logging system, after which it concentrates on log examples in unusual borehole conditions : logs run across intervals where borehole conditions change; logs run in air filled boreholes; logs run in badly washed out boreholes; logs run through stuck drill pipe/ collars; logs run in flowing wells. The supplemental TMD curves in these situations identify the presence of gravel packs and packers, changes in borehole fluid salinity, possible communication between zones, and water and oil producing perforations. Gas in the borehole can also be clearly differentiated from gas in the formation.

A new method for calculating bulk density in pulsed neutron-gamma density logging

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. D219-D232
Author(s):  
Hu Wang ◽  
Wensheng Wu ◽  
Tianzhi Tang ◽  
Ruigang Wang ◽  
Aizhong Yue ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Pair Production ◽  
Bulk Density ◽  
Density Estimation ◽  
Measurement Accuracy ◽  
Gamma Ray ◽  
Estimation Algorithm ◽  
Gamma Density ◽  
Pulsed Neutron

Formation density is one of the most important parameters in formation evaluation. Radioisotope chemical sources are used widely in conventional gamma-gamma density (GGD) logging. Considering security and environmental risks, there has been growing interest in pulsed neutron generators in place of the radioactive-chemical source in using bulk-density measurements. However, there still is the requirement of high accuracy of the neutron-gamma density (NGD) calculation. Pair production is one of the factors influencing the accuracy of the results, which should be considered. We have adopted a method, based on the difference between the inelastic gamma-ray response of high- and low-energy windows, to reduce the impact of pair production upon calculating the bulk density. A new density estimation algorithm is derived based on the coupled-field theory and gamma-ray attenuation law in NGD logging. We analyze the NGD measurement accuracy with different mineral types, porosity, and pore fluid and determine the influence of the borehole environment on NGD logging. The Monte Carlo simulation results indicate that the improved processing algorithm limits the influence of the mineral type, porosity, or pore fluid. The NGD measurement accuracy is ±0.025 g/cm3 in shale-free formations, which is close to the GGD measurement (±0.015 g/cm3). Our results also show that the borehole environment has a significant impact on NGD measurement. Therefore, it is necessary to take the influence of the borehole parameters into account in NGD measurements. Combined with Monte Carlo simulation cases, we evaluate the application results of the new density estimation algorithm in various model wells.

A pulsed neutron gamma-ray system for Mars rover missions

2005 ◽  
Author(s):  
J.I. Trombka ◽  
R.D. Starr ◽  
J. Groves ◽  
H. Akkurt ◽  
L.G. Evans ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Mars Rover ◽  
Pulsed Neutron

Semiautomated geologic mapping using self-organizing maps and airborne geophysics in the Brazilian Amazon

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. K17-K24 ◽  
Author(s):  
Cleyton de Carvalho Carneiro ◽  
Stephen James Fraser ◽  
Alvaro Penteado Crósta ◽  
Adalene Moreira Silva ◽  
Carlos Eduardo de Mesquita Barros
Keyword(s):  
Gamma Ray ◽  
Gold Mineralization ◽  
Brazilian Amazon ◽  
Geophysical Data ◽  
Self Organizing Map ◽  
Self Organizing Maps ◽  
Spectrometric Data ◽  
Rock Types ◽  
Geologic Map ◽  
Self Organizing

A self-organizing map (SOM) approach has been used to provide an integrated spatial analysis and classification of airborne geophysical data collected over the Brazilian Amazon. Magnetic and gamma ray spectrometric data were used to extract geophysical signatures related to the spatial distribution of rock types and to produce a geologic map over the prospective Anapu-Tuerê region. Particular emphasis was given to discriminating and identifying rock types, and the processes related to gold mineralization, which are known to occur in the Anapu-Tuerê region. SOM was able to identify and map distinctive geophysical signatures related to the various geologic units identified on the published geologic map. Furthermore, SOM was able to identify and enhance very subtle signatures derived jointly from the magnetic and gamma ray spectrometric data that could be related to geologic processes present in the area. These results demonstrate the effectiveness of using SOM as a tool for geophysical data analysis and for semiautomated mapping in regions such as the Amazon.

scholarly journals MAGNETIC SUSCEPTIBILITY AND GAMMA-RAY SPECTROMETRY ON DRILL CORE: LITHOTYPE CHARACTERIZATION AND 3D ORE MODELING OF THE MORRO DO PADRE NIOBIUM DEPOSIT, GOIÁS, BRAZIL

2015 ◽  
Vol 33 (2) ◽  
Author(s):  
Marta Henriques Jácomo ◽  
Tereza Cristina Junqueira Brod ◽  
Augusto Cesar Bittencourt Pires ◽  
José Affonso Brod ◽  
Matheus Palmieri ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Late Cretaceous ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Drill Core ◽  
Carbonatite Complex ◽  
Central Brazil ◽  
Rock Types ◽  
Drill Holes ◽  
Fresh Rock

ABSTRACT. The Morro do Padre niobium Deposit, in the Late-Cretaceous Catal˜ao 2 alkaline-carbonatite complex, central Brazil, consists of stockworks of nelsonite and carbonatite dykes intruded into Precambrian phyllites, quartzites, and amphibolites. A gamma-ray spectrometry and magnetic susceptibility petrophysical survey was conducted on the cores of 73 drill holes in fresh-rock, producing a total of 1295 geophysical samples. Nelsonite, the host rock of the niobium mineralization in the Morro do Padre Deposit, has a characteristic geophysical signature, with higher gamma-ray spectrometry counting rates and magnetic susceptibility values, compared to other rock types. The studied nelsonites may be divided into N1 and N2 types. N2 nelsonite is richer in K, U and Th than N1. Carbonatites are divided into magnetic (C1) and nonmagnetic (C2) varieties. The nonmagnetic carbonatites can be subdivided into C2a and C2b. The C2a carbonatite is richer in K, U and Th than C2b, which is consistent with the presence of apatite and/or monazite in the former. The geophysical 3Dmodeling has shown that the main mineralized body is elongated in the E-W direction. It is about 100 m wide and 300 m long with a maximum depth of approximately 850 m reached by drilling.Keywords: 3D ore modeling, niobium ore, applied geophysics, alkaline rocks, nelsonite. RESUMO. O depósito de nióbio do Morro do Padre no complexo carbonatítico alcalino de Catalão 2 do Cretáceo Superior, região central do Brasil, consiste em stockworks de nelsonito e diques de carbonatito intrudidos em filitos pré-cambrianos, quartzitos e anfibolitos. A pesquisa petrofísica de gamaespectrometria e de susceptibilidade magnética foi realizada em testemunhos de 73 furos de sondagem em rocha fresca, produzindo um total de 1.295 amostras. Nelsonito, a rocha hospedeira da mineralização de nióbio no depósito Morro do Padre, tem uma assinatura geofisica característica, com maiores taxas de radiação gamaespectrométrica e maiores valores de susceptibilidade magnética em comparação com outros tipos de rochas. Os nelsonitos estudados podem ser divididos em N1 e N2. O nelsonito N2 é mais rico em K, U e Th do que o N1. Carbonatitos são divididos em magnéticos (C1) e não magnéticos (C2). Os carbonatitos não magnéticos podem ser subdivididos em C2a e C2b. O carbonatito C2a é mais rico em K, U e Th do que o C2b, o que é consistente com a presença de apatita e/ou monazita na composição minerológica. O modelamento 3D revela um corpo principal de nelsonito mineralizado, alongado segundo a direção E-W. Este é cerca de 100 m de largura e 300 m de comprimento, com uma profundidade máxima de 850 m.Palavras-chave: modelamento 3D de minério, minério de nióbio, geofísica aplicada, rochas alcalinas, nelsonito.

scholarly journals MAGNETOMETRIC AND GAMMA-RAY SPECTOMETRY EXPRESSION OF SOUTHWESTERN SÂO FRANCISCO BASIN, SERRA SELADA QUADRANGLE (1:100.000), MINAS GERAIS STATE

2012 ◽  
Vol 30 (4) ◽  
pp. 445 ◽  
Author(s):  
Humberto Luis Siqueira Reis ◽  
Maria Sílvia Carvalho Barbosa ◽  
Fernando Flecha de Alckmim ◽  
Antonio Carlos Pedrosa Soares
Keyword(s):  
Gamma Ray ◽  
Low Frequency ◽  
Geological Mapping ◽  
Weathering Processes ◽  
Rock Types ◽  
High K ◽  
Minas Gerais State ◽  
Basement High ◽  
Tectonic Features ◽  
Low K

Localizada na porção sudoeste da Bacia do São Francisco, a área abrangida pela Folha Serra Selada (1:100.000) contém rochas sedimentares deformadas do Grupo Bambuí (Neoproterozoico), localmente recobertas, em pronunciada discordância, pelos sedimentos e depósitos vulcanoclásticos/epiclásticos cretáceos dos grupos Areado e Mata da Corda, respectivamente. Os dados aerogeofísicos mostram dois domínios magnetométricos principais. Um deles é caracterizado por anomaliasde baixa frequência (ABF), aparentemente relacionadas a estruturas do embasamento pré-cambriano local. O outro é marcado por anomalias de alta frequência (AAF),representando os depósitos vulconoclásticos/epiclásticos do Grupo Mata da Corda. O Grupo Bambuí exibe teores de K e Th intermediários a altos (1 a 3% e 10 a 16ppm, respectivamente), enquanto os teores de U giram em torno de 2,5 ppm. Esse dados mostram algumas variações, geralmente influenciadas pela distribuição dos diferentes litotipos, feições estruturais e ocorrência de emanações de hidrocarbonetos. Os sedimentos do Grupo Areado, por sua vez, mostram baixos conteúdos deK, Th e U (<1%, <10 ppm e <2 ppm, respectivamente). As rochas do Grupo Mata da Corda e coberturas associadas têm teores muito baixos de K (subtraços) e altas concentrações de Th e U (>20 ppm e >3 ppm, respectivamente). Estes valores parecem sofrer grande influência dos processos de intemperismo. As análises realizadas confirmam a grande aplicabilidade dos levantamentos aerogeofísicos no mapeamento geológico e constituem excelentes ferramentas no entendimento do cenário tectônico e dos depósitos de hidrocarbonetos da região sudoeste da Bacia do Sâo Francisco. ABSTRACT: Located in the southwestern portion of São Francisco Basin, the region covered by the Serra Selada quadrangle (1:100.000) contains deformed rocks ofthe Neoproterozoic Bambuí Group, unconformably overlain by Cretaceous sedimentary and volcaniclastic rocks of the Areado and Mata da Corda groups, respectively. The aerogeophysical data shows two main magnetometric domains. A low frequency anomalies domain is apparently related to deep structures of Precambrian basement. High frequency anomalies represent the volcaniclastic/epiclastic deposits of Mata da Corda Group. The Bambuí Group exhibits intermediate-to-high K and Th contents (1 to 3% and 10 to 16 ppm, respectively), while U-levels are around 2.5 ppm. Significant changes in these values are caused by the distribution of rock types, tectonic features and hydrocarbon exudations. Areado Group sediments show low K (<1 %), low Th (<10 ppm) and low U (<2 ppm). Mata da Corda Group volcanics and associated covers exhibit very low K (sub-traces), and high Th and U concentrations (>20 and 3 ppm, respectively). These values seem to be strikingly influenced by weathering processes. The performed analyses confirm the applicability of aerogeophysical data in geological mapping, and represents an important tool for the studyof both the tectonic scenario and hydrocarbon accumulations in south western São Francisco Basin.Keywords: magnetometry, gamaespectrometry, Serra Selada Quadrangle, São Francisco Basin.

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