Industry Standard Procedures Research Articles

Estimation of pore-type distribution utilizing petrophysical data and rock physics modeling on an Iranian carbonate reservoir

Pore types in carbonate reservoirs are more complex than their sandstone counterparts due to the wide spectrum of their depositional environments and their more complicated post-depositional processes. This means that a good knowledge of pore types is vital in determining carbonate formation’s elastic and reservoir properties. This study aims to develop a multi-physics approach to determine pore-type variations in a carbonate reservoir using well log information from one of the oilfields of the Abadan Plain in southwest Iran. Firstly, we determined lithology, porosity, and fluid content by interpreting conventional well logs (gamma ray, resistivity, density, neutron, photoelectric, and P-wave sonic). Then, nuclear magnetic resonance data were used to determine different pore types within the Main Ilam and Sarvak formations. We distinguished between clay, micro, meso, and macro pore types. We confirmed our interpretation results using thin sections, scanning electron microscopy photographs, and pore-size distribution on the available core plugs. Finally, a carbonate rock physics model was employed to model sonic velocities using petrophysical interpretation along with pore-type determination results. A good match between modeled and measured sonic velocities confirmed that using nuclear magnetic resonance data for pore-type determination can reasonably estimate pore-type variations needed for rock physics modeling. The standard industry procedure for carbonate rock physics modeling uses sonic logs, core data, or thin sections to determine pore types. We offer a substitute approach with reasonable accuracy for pore-type modeling needed for carbonate rock physics modeling. We modeled pore types independently from sonic velocity and used them to predict P-wave velocity with a correlation coefficient of 92 and 64 percent accuracy in the Main Ilam and Sarvak formations.Graphical abstract

PHYTOCHEMICAL ANALYSIS AND ESTIMATION OF ANTI OXIDANT POTENTIAL OF PHYTOSOMES FORMULATIONS OF MORINDA LUCIDA BENTH

Introduction: Lucid morinda (L) A medium-sized evergreen tree of the Morinda genus, the Benth (M. lucida, Rubiaceae) is a tropical West African rainforest plant that is also known as the Brimstone tree. In several West African nations, it is utilized in traditional medicine to cure a variety of human ailments. Phytosomes are freshly developed herbal formulations that have superior bioavailability and effects than traditional phyto molecules or botanical extracts because they are more readily absorbed. The goals of the current study were to evaluate ethanolic leaf extract of M. lucida's phytosomes, in vitro antioxidant properties, qualitative and quantitative phytochemical analyses, and phytosome formation. Methods: The ethanolic plant extract and cholesterol-containing phospholipids were used to make the phytosome. The entrapment efficiency, particle size and size distribution, optical microscopic research, stability tests, and in vitro dissolution investigations were used to characterize phytosomes. Alkaloids, glycosides, sterols, phenols, terpenoids, tannins, and saponins were found by phytochemical examination. Results: The ethanolic leaf extract of M. lucida contained 0.721 mg of total phenols and 0.464 mg of total alkaloids per 100 mg. Using industry-standard procedures, the ethanolic leaf extract's in vitro antioxidant activity was evaluated against the DPPH assay technique. Combining phospholipids and M. lucida can have a synergistic impact, which can be measured using the DPPH model for free radical scavenging activity. The optimised batch F10's particle size and entrapment efficiency were found to be 223.30±0.41 nm and 76.46±0.61 nm, respectively. Conclusion: It can be employed as a targeted medicine delivery system in the future for applications such as liver, brain, heart, etc. protection. The use of novel approaches rather than traditional methods for delivering herbal drugs increases the bioavailability of polar extracts and boosts patient compliance. Peer Review History: Received: 28 October 2022; Revised: 27 November; Accepted: 3 January 2023, Available online: 15 January 2023 Academic Editor: Dr. Gehan Fawzy Abdel Raoof Kandeel, Pharmacognosy Department, National Research Centre, Dokki, 12622, Giza, Egypt, gehankandeel9@yahoo.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. George Zhu, Tehran University of Medical Sciences, Tehran, Iran, sansan4240732@163.com Dr. Hasniza Zaman Huri, University of Malaya Medical Centre, Kuala Lumpur, hasnizazh@ummc.edu.my Similar Articles: NUTRITIONAL COMPOSITION, CONSTITUENTS, AND ANTIOXIDANT ACTIVITY OF POWDER FRACTIONS OF FICUS DICRANOSTYLA MILDBREAD LEAVES IN VITRO ASSESSMENT OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF EXTRACTS OF YEMENI FAGONIA SCHWEINFURTHII HADIDI CYTOTOXIC EFFECT, ANTIOXIDANT POTENTIAL, AND PHYTOCHEMICAL STUDY OF THE ETHYL ACETATE EXTRACT OF PLEIOGYNIUM TIMORENSE SEEDS

Mineralogical and Micro-structural Investigation into the Mechanical Behaviour of a Soft Calcareous Mudstone

The construction industry in Abu Dhabi is thriving and its coastline has some of the most ambitious structures in the world. Whilst the subsurface evaporitic and calcareous soft rocks of this region are of great geological interest, they are relatively poorly understood from a geotechnical engineering perspective, forcing foundation designs to be overly conservative. Understanding the stiffness of the underlying geology at small strains is of great importance for the accurate estimation of ground movements around excavations and foundations, and yet routine post-SI laboratory testing programmes tend to focus on basic rock mechanics tests such as UCS tests. These procedures are generally unsuitable for use with calcareous rocks due to their friable and moisture sensitive nature, and rarely obtain parameters representative of actual in situ behaviour. The calcareous mudstone investigated in this paper has mechanical and structural characteristics falling between those of a soil and those typical of a rock and, as such, requires a geotechnical testing approach that combines methods from both soil and rock mechanics disciplines. The mineralogical, micro-structural and mechanical characteristics of this lithology have been examined via a suite of testing techniques, including XRPD, SEM, advanced triaxial with bender elements, along with industry standard procedures. Shearing, tensile and consolidation behaviours have been explored. Examination of the micro- and macro-scale features of this material shows it to be highly structured, with strength and stiffness being controlled by inter-granular bonding of Dolomite grains, as well as by mean effective stress state and rate of strain. The presence of fibrous Palygorskite acts to reduce the degree of bonding, causing specimens rich in this clay mineral to have a more ductile mechanical behaviour.

217 Assessment of the dissolution characteristics of Rumensin® 90 and Monovet® 90

Abstract Continued evaluation of physical attributes of monensin Type A medicated articles is needed to keep customers apprised of product characteristics. Two randomly chosen lots of Rumensin® 90 (P1 and P2) and Monovet® 90 (A1 and A2) with dates of manufacture between May and September 2019 were used to evaluate dissolution properties according to US Pharmacopeia in vitro procedures and FDA guidance for interpretation of dissolution data. A synthetic rumen fluid (lacking microorganisms) that simulated an animal fed a high-forage diet (pH = 6.8) was used in Exp. 1, whereas a synthetic rumen fluid simulating an animal fed a high-concentrate diet (pH = 5.5) was used in Exp. 2. Samples were added to dissolution vessels containing 1 L of the appropriate media and maintained at 39°C with constant stirring (250 rpm). Aliquots (10 mL) were collected after 15, 30, 45, 60, 90, 120, 240, 360, and 480 min, filtered, and subsequently analyzed for monensin by HPLC procedures. The Rumensin lot with the lowest dissolution was designated as the reference (P2); A1 and A2 were compared to this reference using f1 and f2 test statistics computed following FDA guidance. Dissolution profile comparisons were considered statistically different if the f1 statistic was > 15 and the f2 statistic was < 50. In both experiments, Monovet dissolution profiles were lower than Rumensin profiles. In Exp. 1, f1 = 45 and 50 and f2 = 23 and 20 for A1 and A2, respectively. Likewise in Exp. 2, f1 = 41 and 27 and f2 = 31 and 41 for A1 and A2, respectively. Although the Monovet and Rumensin dissolution profiles were deemed similar in the studies used for FDA approval of Monovet, these data indicate that they are not similar using the most recent industry-standard procedures.

A rigorous general workflow for accurate prediction of carbonate and sulphide scaling profiles in oil and gas wells

Prediction of pH-dependent carbonate and sulphide scale in oil and gas operations is of major importance to allow effective mitigation strategies to be put in place. Nevertheless, there is not a standard industry procedure which clearly describes how to obtain scale prediction profiles starting from commonly available field data. This work presents a clear and systematic step-by-step procedure to obtain carbonate and sulphide scale prediction profiles from the reservoir to the first stage of separation using commonly available field data, thus closing the gap between surface and subsurface three phase calculations. As presented here, any suitable aqueous phase mineral chemistry model can be used with any Pressure/Volume/Temperature (PVT, phase prediction) software to carry out these calculations and the models used here are referenced.

Speed simulation of bypass hole PIG with a brake unit in liquid pipe

Periodic pigging of oil and gas pipelines for dewatering, cleaning and inspecting has become a standard industry procedure. A pigging operation requires the pipeline inspection gauge (PIG) to move at a nearly stable, moderate speed; otherwise, inspection data could be missed, and the PIG could break down. In this paper, a brake unit for the active control of the PIG speed and the working principle of the brake unit are presented. Two cases are discussed in this paper to present the characteristics of the brake unit. The speed governing equations of each case are simplified and solved using a numerical solution utilizing the Euler-Cauchy method. The results from the two studies indicate that an undesirably high travel speed of a PIG can be prevented because the drag force of the brake increases sharply with increases in PIG travel speed. A PIG would travel with more stability and at slower speeds when utilizing the brake unit. Moreover, the number of wheels on the brake unit has a great impact on the results because the more wheels that are present, the higher the control force of the brake unit.

Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

Microrobotized blasting improves the bone-to-textured implant response. A preclinical in vivo biomechanical study

This study evaluated the effect of microrobotized blasting of titanium endosteal implants relative to their manually blasted counterparts. Two different implant systems were utilized presenting two different implant surfaces. Control surfaces (Manual) were fabricated by manually grit blasting the implant surfaces while experimental surfaces (Microblasted) were fabricated through a microrobotized system that provided a one pass grit blasting routine. Both surfaces were created with the same ~50µm average particle size alumina powder at ~310KPa. Surfaces were then etched with 37% HCl for 20min, washed, and packaged through standard industry procedures. The surfaces were characterized through scanning electron microscopy (SEM) and optical interferometry, and were then placed in a beagle dog radius model remaining in vivo for 3 and 6 weeks. The implant removal torque was recorded and statistical analysis evaluated implant system and surface type torque levels as a function of time in vivo. Histologic sections were qualitatively evaluated for tissue response. Electron microscopy depicted textured surfaces for both manual and microblasted surfaces. Optical interferometry showed significantly higher Sa, Sq, values for the microblasted surface and no significant difference for Sds and Sdr values between surfaces. In vivo results depicted that statistically significant gains in biomechanical fixation were obtained for both implant systems tested at 6 weeks in vivo, while only one system presented significant biomechanical gain at 3 weeks. Histologic sections showed qualitative higher amounts of new bone forming around microblasted implants relative to the manually blasted group. Microrobotized blasting resulted in higher biomechanical fixation of endosteal dental implants and should be considered as an alternative for impant surface manufacturing.

Numerical simulation of contact force on bi-directional pig in gas pipeline: At the early stage of pigging

Periodic pigging of oil and gas pipelines for dewatering, cleaning and inspecting is a standard industry procedure. Predicting the motion of a pig to estimate its velocity, position and required driving pressure is essential before pigging. To enhance these predictions, the frictional force between pig and pipeline is a key determinant and insufficient understanding of the frictional force characteristics leads to significant inaccuracies. As the frictional force acting parallel to the pipeline wall plane is a function of contact force in the radial direction, a 2D axisymmetric nonlinear finite element model was proposed to predict the contact force experienced by bi-directional pig by using ANSYS. The impacts of four parameters (including interference, thickness, chamfer dimension and clamping rate of the sealing discs) on the contact force and the deflection angle of the sealing disc are studied at different differential pressures over the pig. Results obtained in this study shows that the thickness of the sealing disc has the greatest impact on contact force of the bi-directional pig, followed by the chamfer dimension, then the clamping rate and finally the interference. A linear relationship between the contact force and the differential pressure can also be observed from the results. Research findings on the characteristic of contact force and deflection angle of sealing disc may provide useful information for the formulation of theoretical or mathematical models to predict the frictional force on the pig, and pigging risks may be efficiently reduced by establish mitigating strategies on the basis of prediction.

An experimental evaluation of the probe dynamics as a probe pig inspects internal convex defects in oil and gas pipelines

The periodic pigging of oil and gas pipelines for dewatering, cleaning and inspection has become a standard industry procedure. The probe pig is the most typical tool for contact-testing in oil and gas pipelines. The dynamic behavior of the probe as it inspects convex defects has been investigated using a home-built inspection system. The probe dynamics differed in the uphill and downhill sections, and the trajectory of the probe was asymmetrical. A bouncing phenomenon was found in the exit region of the convex defect. The experimental results indicated that both the speed and the spring pre-tightening elastic force are closely related to the inspection precision. This study provides a reference for analyzing probe dynamic behavior and improving its inspection precision.

Adaptation of WorkFace Planning for construction contexts

WorkFace Planning (WFP) is a construction industry best practice aimed at improving productivity on industrial construction projects. It is now a common requirement in the construction contracts of industrial projects in Alberta. Since its debut, the implementation of WFP in different project contexts has not been formally studied. Construction project contexts differ greatly and have an impact on the effectiveness of implementation of any industry standard procedure. The purpose of this paper is to present a framework for identifying the context variables that warrant changes to the industry standard WFP procedures and to illustrate how these variables require the adaptation of WFP within an organization and on a project. The framework is illustrated with a case study of an organization and a project, which found that modifications to the standard WFP procedures were made at both the organization and project levels during implementation, based on certain organization and project characteristics. These modifications to the standard WFP procedures, coupled with the organization and project char- acteristics identified, are of value to the future implementation of WFP in specific contexts. Furthermore, the methodology used in this study to investigate the adaptation of WFP is useful in studying the adaptation of other industry best practices for different construction contexts.

Experimental study on dynamics of rotatable bypass-valve in speed control pig in gas pipeline

Periodically pigging of oil and gas pipelines for dewatering, cleaning and inspecting becomes a standard industry procedure. Speed control unit is needed to control the speed of the pig and keep it work at a moderate constant speed, especially in the large diameter and high pressure gas pipelines. Rotatable bypass-valve is a necessary part in speed regulating unit, which is used to control the speed of pig by changing the amounts of the bypass flow across the pig body. However, the dynamics of the bypass-valve is complexity and indeterminacy during bypassing. As a result, in this paper, an experiment facility is set up to simulate the real working condition and get the dynamic characteristics of bypass-valve. The relationship among the torque, the opening of bypass-valve and the differential pressure over bypass-valve can be obtained in this experiment, which can provide the references to make control algorithm for speed control pig.

Thermal insulation requirements and new cardboard packaging for chilled seafood exports

Three expanded polystyrene (EPS) boxes with different thermal resistance (R-value), a box-in-box type cardboard prototype and commercial EPS boxes were packed with fish using standard industry procedures and subjected to a simulated airfreight temperature regime replicating commercial practice. The Quality Index Method was used to assess the fish quality. The boxes with lower R-values did not have a measurable negative effect on the quality compared to the commercial EPS box. There was also no measurable difference in quality between fish stored in the corners or centre of all the boxes. For another experiment a double fluted cardboard prototype and commercial EPS boxes were filled with ice and subjected to a constant temperature regime to determine their R-value. The second prototype had slightly lower R-values than commercial EPS boxes. However, the double fluted wall structure might limit the foldability and manufacturability and will need to be further investigated.

Graphene-based Li-ion hybrid supercapacitors with ultrahigh performance

There is a growing demand for hybrid supercapacitor systems to overcome the energy density limitation of existing-generation electric double layer capacitors (EDLCs), leading to next generation-II supercapacitors with minimum sacrifice in power density and cycle life. Here, an advanced graphene-based hybrid system, consisting of a graphene-inserted Li4Ti5O12 (LTO) composite anode (G-LTO) and a three-dimensional porous graphene-sucrose cathode, has been fabricated for the purpose of combining both the benefits of Li-ion batteries (energy source) and supercapacitors (power source). Graphene-based materials play a vital role in both electrodes in respect of the high performance of the hybrid supercapacitor. For example, compared with the theoretical capacity of 175 mA·h·g−1 for pure LTO, the G-LTO nanocomposite delivered excellent reversible capacities of 207, 190, and 176 mA·h·g−1 at rates of 0.3, 0.5, and 1 C, respectively, in the potential range 1.0–2.5 V vs. Li/Li+; these are among the highest values for LTO-based nanocomposites at the same rates and potential range. Based on this, an optimized hybrid supercapacitor was fabricated following the standard industry procedure; this displayed an ultrahigh energy density of 95 Wh·kg−1 at a rate of 0.4 C (2.5 h) over a wide voltage range (0–3 V), and still retained an energy density of 32 Wh·kg−1 at a high rate of up to 100 C, equivalent to a full discharge in 36 s, which is exceptionally fast for hybrid supercapacitors. The excellent performance of this Li-ion hybrid supercapacitor indicates that graphene-based materials may indeed play a significant role in next-generation supercapacitors with excellent electrochemical performance.

Limit analysis of the undrained bearing capacity of offshore pipelines

The ultimate bearing capacity of a rigid, plane-strain pipe segment embedded in undrained clay is studied using numerical limit analysis. The pipe is considered to be ‘wished in place' at invert penetrations ranging from zero to five pipe diameters, thus providing coverage of both on-bottom (partially embedded) and trenched (fully embedded) offshore pipelines. The soil is modelled as a rigid-plastic Tresca material with either uniform strength or strength proportional to depth. The effects of soil weight, interface roughness and interface tensile capacity are investigated in a systematic manner. All calculations are performed using the finite-element limit analysis code OxLim, which uses adaptive mesh refinement to compute tightly bracketed lower- and upper-bound plasticity solutions. The velocity fields from the upper-bound analyses provide the corresponding failure mechanisms. The paper initially focuses on purely vertical loading (penetration and uplift), and then addresses combined vertical and horizontal loading. A comprehensive set of design curves and failure envelopes is presented, with the results explained in terms of the changing failure mechanisms. These results are immediately applicable in practice. In particular, current industry-standard procedures for design against pipeline upheaval are critically reviewed, and are shown to have potentially unconservative shortcomings.

Recent Developments in Speed Control System of Pipeline PIGs for Deepwater Pipeline Applications

Pipeline infrastructures normally represent high cost of investment and the pipeline must be free from risks that could cause environmental hazard and potential threats to personnel safety. Pipeline integrity such monitoring and management become very crucial to provide unimpeded transportation and avoiding unnecessary production deferment. Thus proper cleaning and inspection is the key to safe and reliable pipeline operation and plays an important role in pipeline integrity management program and has become a standard industry procedure. In view of this, understanding the motion (dynamic behavior), prediction and control of the PIG speed is important in executing pigging operation as it offers significant benefits, such as estimating PIG arrival time at receiving station, planning for suitable pigging operation, and improves efficiency of pigging tasks. The objective of this paper is to review recent developments in speed control system of pipeline PIGs. The review carried out would serve as an industrial application in a form of quick reference of recent developments in pipeline PIG speed control system, and further initiate others to add-in/update the list in the future leading to knowledge based data, and would attract active interest of others to share their view points. Keywords—Pipeline Inspection Gauge (PIG), In Line Inspection Tools (ILI), PIG motion, PIG speed control system

Mapping QTL for fatty acid composition that segregates between the Japanese Black and Limousin cattle breeds

The objective of this study was to search for quantitative trait loci (QTL) that segregate between Japanese Black and Limousin cattle breeds and affect relative amounts of saturated (SFA), mono-unsaturated (MUFA) and poly-unsaturated (PUFA) fatty acids. Six F1 Japanese Black-Limousin cross bulls were joined with 121 F1 females over a three-year period to produce 328 F2 progeny. Calves, aged from 450 to 641 d (average 561 d), were harvested using standard industry procedures. After aging, 2.54 cm thick steaks were cut from the posterior end of the wholesale rib, frozen at –20 °C, and held for determination of fatty acid composition. Percentages of the individual fatty acids were classified into percentages of SFA, MUFA and PUFA. Two hundred seventeen microsatellite markers covering the 29 bovine autosomes were assayed and QTL were identified by least squares regression. Genome-wise significant QTL with additive effects on SFA (-0.61 ± 0.19%), MUFA (0.93 ± 0.19%) and PUFA (-0.52 ± 0.11%) were observed near the centromere of BTA2. Also observed were five QTL indicative of dominance effects on: MUFA (BTA9, 119 cM, -1.87 ± 0.72%; BTA22, 47 cM, 1.85 ± 0.60%) and PUFA (BTA9, 54 cM, -1.49 ± 0.42%; BTA10, 38 cM, 1.20 ± 0.35%; and BTA15, 14 cM, 1.11 ± 0.36%). Based on these results, we conclude that it may be possible to improve the healthfulness of beef by manipulating fatty acid composition using genetic markers and appropriate crossbreeding systems. Keywords : Beef, fatty acids, Japanese Black, Limousin, quantitative trait loci, Wagyu South African Journal of Animal Science Vol. 38 (2) 2008: pp. 126-130

A New Technique for Identifying Synchronous Resonances Using Tip-Timing

Non-contact measurement of vibration at turbomachinery rotor blade tips using blade tip-timing has become an industry-standard procedure. Current research focuses on analysis methods for interpretation of the measured vibration data from a limited number of probes. The methods are classified by the form of the vibration they can identify. Identification of asynchronous response amplitude and frequency is well documented. Whilst a method for identifying maximum synchronous resonance amplitude has existed since the early 1970s, there is no published evidence of a method for directly identifying frequency or engine order using a small number of probes. This paper presents a new analysis method for identifying synchronous resonance engine order using two tip-timing vibration measurements. The measurements are made at different locations on the turbomachinery casing using a minimum of two probes. A detailed description of the method and results from its practical application are given. The potential of the method to identify the amplitude and frequency of close modes, not possible with current methods, is demonstrated. The effect of blade mistuning on the accuracy of the method is investigated. Existing synchronous response analysis methods and the new method presented here give the response amplitude and frequency after the resonance has been traversed. Real-time identification of synchronous response amplitude and frequency would allow tip-timing to be used as a safety monitor of all blades. Real-time methods, their limitations and practical application are discussed. The future use of tip-timing as the dominant vibration measurement system is discussed with reference to experience on measurements made solely with tip-timing on assemblies with undefined vibration characteristics. [S0742-4795(00)02602-8]

Systematic error in genetic evaluation of miles city line 1 hereford cattle resulting from preadjustment for age of dam.

Differences in preweaning growth of calves nursing 2- and 3-yr-old dams compared with contemporaries nursing older dams are accentuated in the Miles City Line 1 Hereford herd relative to age-of-dam (AOD) effects implied by preadjustment of 205-d weight in national cattle evaluation. Mixed-model analyses of 205-d weight that fit random individual direct effects and maternal genetic and permanent environmental effects on 4,998 calves were conducted to 1) determine the magnitude of residual AOD effects after preadjustment (PA) using industry-standard procedures and 2) compare changes in genetic predictions resulting from either PA or simultaneous adjustment (SA) for AOD. Expressed as differences from the 5- to 10-yr-old age effect, simultaneously estimated AOD effects were 45 +/- 1, 19 +/- 1, 6 +/- 1, and 19 +/- 3 kg for 2, 3, 4, and 11+ AOD classes, respectively. Comparable estimates of residual AOD effects after PA were 20 +/- 1, 6 +/- 1, 1 +/- 1, and 14 +/- 3 kg. Rank correlations of direct (BVd) and maternal (BVm) breeding values (BV) for 205-d weight from the analysis using PA with BV predicted using SA for AOD were .98 and .77, respectively. Estimated genetic trends were also affected by the method of accounting for AOD effects. One hundred fifty replicate simulations of 205-d weights with pedigree, fixed effect, and variance-covariance structures corresponding to the experimental population were used to establish correlations (r) of predicted BV with underlying true values. The r of predicted BVd with true values were reduced less than .02 by PA compared to SA in accounting for AOD. However, r of predicted BVm with true values were reduced more than .13 by PA compared to SA in accounting for AOD. These data indicate potential for systematic error in genetic evaluations that apply standard adjustments for AOD to 205-d weight.

Experimental Study of Fracturing Fluid Loss

Abstract This paper describes experimental work for the filtration characterization of common hydraulic fracturing fluids. The concept of filter-cake resistance is introduced and elements of visco-elastic theory are used for the interpretation of observed phenomena. Important conclusions from this work include relationships between filter-cake leakoff coefficient and polymer loading and predictive models for filter-cake leakoff behavior for specific polymer loads, temperature and differential pressure. The results can be incorporated into any robust model to account for fluid leakoff during hydraulic fracture execution. Introduction Fracturing fluid loss is a composite of several effects. Of these, the filter-cake properties play a critical role for leakoff control during a fracture treatment(1–7). The objective of this work was to investigate properties of filter-cake leakoff and ultimately their impact from the pressure history of a fracture treatment. This can permit a rational basis for combining the effects of different fluid-loss control mechanisms. In order to isolate filter-cake properties, experiments using filter-paper were done. Experiments conducted in accordance with previous work(1,2) using constant pressure differentials across filter-cakes have revealed no essential contradictions on the influence of temperature, pressure and polymer loading. Relationships between the leakoff coefficient and fracturing pressure can thus be developed. Experiments, though, with pressure histories simulating both the pumping and closure phase of a fracture treatment yielded findings which required a new interpretation. A generalized empirical interpretation for describing the cake filtration is offered here covering both the fracturing and closing periods. Visco-elastic theory hints towards this interpretation. For clarity and brevity, the filter-cake leakoff coefficient will be denoted as wall coefficient. Procedures and Basic Relations The experiments were conducted with a high-pressure, high temperature filter press commonly used for static fluid-loss testing. A zirconate-crosslinked HPG-polymer solution, prepared according to standard industry procedures, was used as the fracturing fluid system. Filtrates were collected continuously and crosslinked polymer was clear and had the Newtonian properties of plain water. Evaporation was prevented by cooling the effluent. Sufficient duplicate experiments were performed to ensure the quality of the resulting data. Basic leakoff theory for filtercakes defines the filtrate volume By(3): Equation (1) (Available In Full Paper) and the wall coefficient by: Equation (2) (Available In Full Paper) where V is the filtrate volume per unit area, t = time, Sp = spurt loss, k = cake permeability, b = constant of deposition, Δp = pressure differential and µ> ƒ = viscosity of the filtrate. The constant of deposition is defined as: Equation (3) (Available In Full Paper) where V> ƒ the filtrate volume and Ve is the cake volume. A plot of the filtrate volume vs. > √r results in a straight line where the wall coefficient is directly related to the slope by: Equation (4) (Available In Full Paper) The correction of measured filtrate volumes for spurt loss ensures that all straight lines have the same point of origin, which is advantageous for a clear comparison of the straight-line slopes. This procedure was employed for the analysis of filte