scholarly journals Laboratory measurement of directional permeability trends. Project 61031 special core analysis report

1982 ◽  
Author(s):  
W. Rose
Keyword(s):  
Laboratory Measurement ◽  
Core Analysis ◽  
Directional Permeability ◽  
Special Core Analysis

Whole Core Analysis - Experience and Challenges

2005 ◽  
Vol 8 (06) ◽  
pp. 460-469 ◽  
Author(s):  
Mehdi M. Honarpour ◽  
Nizar F. Djabbarah ◽  
Krishnaswamy Sampath
Keyword(s):  
Electrical Properties ◽  
Capillary Pressure ◽  
Carbonate Rocks ◽  
Water Saturation ◽  
Core Analysis ◽  
Confining Stress ◽  
X Ray ◽  
X Ray Imaging ◽  
Directional Permeability ◽  
Special Core Analysis

Summary Whole-core analysis is critical for characterizing directional permeability in heterogeneous, fractured, and/or anisotropic rocks. Whole-core measurements are essential for heterogeneous reservoirs because small-scale heterogeneity may not be appropriately represented in plug measurements. For characterization of multiphase-flow properties (special core analysis) in heterogeneous rocks, whole-core analysis is also required. Few commercial laboratories are equipped to conduct routine measurements on whole cores up to 4 in. in diameter and up to 8 in. long and, importantly, under simulated reservoir net confining stress (NCS). Special whole-core analyses are rarely conducted because of the difficulties associated with establishing a representative water saturation in drainage capillary pressure experiments and measuring directional effective permeabilities. Electrical properties also can be measured on whole cores to determine porosity and saturation exponents for situations in which resistivity tools are used in horizontal or highly deviated wells. In this paper, we provide an overview of routine and special core-analysis measurements on whole cores. Results from selected heterogeneous sandstone and carbonate rocks will be discussed. We also will show how the results relate to data obtained from plug analysis, with particular emphasis on directional absolute permeability, trapped-gas and fluid saturations, and the effect of NCS. Finally, we will describe a novel apparatus for special core analysis on whole cores and provide examples of the capabilities of the system. In this paper, we will present:• Recommended techniques for the determination of directional absolute and effective permeability and for establishing initial water saturation in whole cores.• Improved understanding of the effect of scale (sample size) on the measured properties.• Description of a novel whole-core apparatus with measurement of fluid-saturation distribution using in-situ saturation monitoring. Introduction Reservoir rocks are heterogeneous, especially carbonate rocks, in which more than 50% of the world's hydrocarbon reserves are deposited. Fig. 1 shows an example of variability in rock characteristics as observed in a carbonate-rockout crop in Oman. The heterogeneous nature of these rocks tends to become more apparent as attempts are made to measure their petrophyscal properties at various scales. An example of permeability variation in a plug from a carbonate formation is shown in Fig. 2. Single-phase air permeability varies by three orders of magnitude over the distance of a few centimeters in this core plug. This dual-porosity behavior impacts the spontaneous-imbibition performance significantly (Fig. 3). Technology at Commercial Laboratories Selected commercial laboratories have capabilities to appropriately clean and prepare whole cores, perform core X-ray imaging, and measure basic properties such as directional permeability and porosity under a maximum confining stress of 5,000 psi. Available technologies for imaging, sample preparation, and routine core analysis are summarized in the following sections. Special-core-analysis capabilities at commercial laboratories are rare. Only one or two laboratories are capable of measuring primary-drainage gas/water capillary pressure and gas/water or oil/water electrical properties on whole cores at confining stress. Whole-Core Imaging and Screening Whole-core photography and X-ray imaging provide information about surface features and internal structure. The computed tomography (CT) scan provides evidence of fractures, vugs, and heterogeneities as indicated by the extent in the variation of CT density. X-ray fluoroscopy and CT are two of the most practical X-ray scanning techniques used to characterize core-level heterogenieties and to explain their effect on horizontal and vertical permeabilities. CT-scanning algorithms should often be modified to obtain images free of artifacts and with better than0.5-mm horizontal and 1-mm vertical resolutions.

Rekonstruksi dan Validasi Data Permeabilitas Relatif Untuk Proses History Matching Dalam Simulasi Reservoir Pengembangan Lapangan X

2015 ◽  
Vol 4 (2) ◽  
pp. 44-52
Author(s):  
Novia Rita ◽  
Tomi Erfando
Keyword(s):  
History Matching ◽  
Core Analysis ◽  
Black Oil ◽  
Special Core Analysis

Sebelum suatu model reservoir digunakan, terlebih dahulu dilakukan history matching atau menyesuaikan kondisi model dengan dengan kondisi reservoir. Salah satu parameter yang perlu disesuaikan adalah permeabilitas relatif. Untuk melakukan rekonstruksi nilai permeabilitas relatifnya dibutuhkan data SCAL (Special Core Analysis) dari sampel core. Langkah awal rekonstruksi adalah dengan melakukan normalisasi data permeabilitas relatif (kr) dan saturasi air (Sw) dari data SCAL yang berasal dari tiga sampel core. Setelah dilakukan nomalisasi, dilakukan denormalisasi data permeabilitas relatif yang akan dikelompokkan berdasarkan jenis batuannya. Setelah dilakukan history matching menggunakan black oil simulator, data denormalisasi tersebut belum sesuai dengan kondisi aktual. Selanjutnya digunakan persamaan Corey untuk rekonstruksi kurva permeabilitas relatifnya. Hasil dari persamaan tersebut didapat bahwa nilai kro dan krw jenis batuan 1 sebesar 0,25 dan 0,09 kemudian nilai kro dan krw untuk jenis batuan 2 sebesar 0,4 dan 0,2. Nilai permeabilitas dari persamaan Corey digunakan untuk melakukan history matching, hasilnya didapat kecocokan (matching) dengan keadaan aktual. Berdasarkan hasil simulasi, nilai produksi minyak aktualnya adalah 1.465.650 bbl sedangkan produksi dari simulasi adalah 1.499.000 bbl. Artinya persentase perbandingan aktual dan simulasinya adalah 1,14% yang dapat dikatakan cocok karena persentase perbedaannya di bawah 5%.

scholarly journals A new framework for selection of representative samples for special core analysis

2020 ◽  
Vol 5 (3) ◽  
pp. 210-226 ◽  
Author(s):  
Abouzar Mirzaei-Paiaman ◽  
Seyed Reza Asadolahpour ◽  
Hadi Saboorian-Jooybari ◽  
Zhangxin Chen ◽  
Mehdi Ostadhassan
Keyword(s):  
Core Analysis ◽  
Representative Samples ◽  
Special Core Analysis ◽  
New Framework ◽  
Selection Of

Multiphase Flow Under Heterogeneous Wettability Conditions Studied by Special Core Analysis and Pore-Scale Imaging

SPE Journal ◽  
2019 ◽  
Vol 24 (03) ◽  
pp. 1234-1247 ◽  
Author(s):  
Shuangmei Zou ◽  
Ryan T. Armstrong
Keyword(s):  
Multiphase Flow ◽  
Relative Permeability ◽  
Flow Regimes ◽  
Wettability Alteration ◽  
Core Analysis ◽  
Pore Scale ◽  
End Effect ◽  
The Impact ◽  
Capillary End Effect ◽  
Special Core Analysis

Summary Wettability is a major factor that influences multiphase flow in porous media. Numerous experimental studies have reported wettability effects on relative permeability. Laboratory determination for the impact of wettability on relative permeability continues to be a challenge because of difficulties with quantifying wettability alteration, correcting for capillary-end effect, and observing pore-scale flow regimes during core-scale experiments. Herein, we studied the impact of wettability alteration on relative permeability by integrating laboratory steady-state experiments with in-situ high-resolution imaging. We characterized wettability alteration at the core scale by conventional laboratory methods and used history matching for relative permeability determination to account for capillary-end effect. We found that because of wettability alteration from water-wet to mixed-wet conditions, oil relative permeability decreased while water relative permeability slightly increased. For the mixed-wet condition, the pore-scale data demonstrated that the interaction of viscous and capillary forces resulted in viscous-dominated flow, whereby nonwetting phase was able to flow through the smaller regions of the pore space. Overall, this study demonstrates how special-core-analysis (SCAL) techniques can be coupled with pore-scale imaging to provide further insights on pore-scale flow regimes during dynamic coreflooding experiments.

State of the Art Special Core Analysis Program Design and Results for Effective Reservoir Management, Dukhan Field, Qatar

2009 ◽  
Author(s):  
Jonathan Paul Meissner ◽  
Fred Horng Lieh Wang ◽  
James Gregory Kralik ◽  
Mohamed Naguib Abdul Majid ◽  
Mohd Ismail Omar ◽  
...  
Keyword(s):  
Program Design ◽  
State Of The Art ◽  
Reservoir Management ◽  
Core Analysis ◽  
Analysis Program ◽  
Special Core Analysis

Improvements in the Selection Criteria for the Representative Special Core Analysis Samples

2006 ◽  
Vol 9 (06) ◽  
pp. 647-653 ◽  
Author(s):  
Shameem Siddiqui ◽  
Taha M. Okasha ◽  
James J. Funk ◽  
Ahmad M. Al-Harbi
Keyword(s):  
Capillary Pressure ◽  
Relative Permeability ◽  
Selection Criteria ◽  
Sample Selection ◽  
Upper Jurassic ◽  
Carbonate Reservoir ◽  
Core Analysis ◽  
Core Samples ◽  
Representative Samples ◽  
Special Core Analysis

Summary The data generated from special-core-analysis (SCAL) tests have a significant impact on the development of reservoir engineering models. This paper describes some of the criteria and tests required for the selection of representative samples for use in SCAL tests. The proposed technique ensures that high-quality core plugs are chosen to represent appropriate flow compartments or facies within the reservoir. Visual inspection and, sometimes, computerized tomography (CT) images are the main tools used for assessing and selecting the core plugs for SCAL studies. Although it is possible to measure the brine permeability (kb), there is no direct method for determining the porosity (f) of SCAL plugs without compromising their wettability. Other selection methods involve using the conventional-core-analysis data (k and f) on "sister plugs" as a general indicator of the properties of the SCAL samples. A selective technique ideally suited for preserved or "native-state" samples has been developed to identify reservoir intervals with similar porosity/permeability relationships. It uses a combination of wireline log, gamma scan, quantitative CT, and preserved-state brine-permeability data. The technique uses these data to calculate appropriate depth-shifted reservoir-quality index (RQI) and flow-zone indicator (FZI) data, which are then used to select representative plug samples from each reservoir compartment. As an example application, approximately 400 SCAL plugs from an Upper Jurassic carbonate reservoir in the Middle East were tested using the selection criteria. This paper describes the step-by-step procedure to select representative plugs and criteria for combining the plugs for meaningful SCAL tests. Introduction The main goal of coring is to retrieve core samples from a well to get the maximum amount of information about the reservoir. Core samples collected provide important petrophysical, petrographic, paleontological, sedimentological, and diagenetic information. From a petrophysical point of view, the whole-core and plug samples typically undergo the following tests: CT scan, gamma scan, conventional tests, SCAL tests, rock mechanics, and other special tests. The data are combined to get information on heterogeneity, depth shift between core and log data, whole-core and plug porosity and permeability, porosity/permeability relationship, fluid content (Dean-Stark), RQI, FZI, wettability, relative permeability, capillary pressure, stress/strain relationship, and compressibility. The petrophysical data generated in this way play important roles in reservoir characterization and modeling, log calibration, reservoir simulation, and overall field production and development planning. Among all the petrophysical tests, the SCAL tests (which include wettability, capillary pressure, and relative permeability determination) are critical and time-consuming. A reservoir-condition relative permeability test can sometimes run for several months when mimicking the actual flow mechanisms taking place in the field. Therefore, it is very important to design these tests properly and, in particular, to select the samples that ensure meaningful results. In short, the samples must be "representative samples," which can capture the overall variability within the reservoir in a more scientific way. Unfortunately, the most important aspect of all SCAL procedures, the sample selection, is one of those least discussed. According to Corbett et al. (2001), API's RP40 (Recommended Practices for Core Analysis) makes very little reference to sampling; similarly, textbooks on petrophysics do not have sections on sampling. The Corbett et al. paper reviewed the statistical, petrophysical, and geological issues for sampling and proposed a series of considerations. This has led to the development of a method (Mohammed and Corbett 2002) using hydraulic units in a relatively simple clastic reservoir. In this paper, some issues related to sample-selection criteria (with special focus on carbonate reservoirs) will be discussed. A large data set of conventional, whole-core, and special-core analyses on a well in an Upper Jurassic carbonate reservoir was used to characterize representative samples for SCAL tests.

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