Extended-Time Conductivity Testing of Proppants Used for Multi-Stage Horizontal Completions

The American Petroleum Institute Recommended Practice 19-D (2018) is the current industry standard for conductivity testing of proppants used in hydraulic fracturing. Similar to previous standards from both the API and ISO, it continues the practice of measuring a "reference" long-term conductivity after 50-hours of time at a given stress. The fracture design engineer is then left to estimate a damage factor to apply over the life of the well completion based on correlations or experience. This study takes four standard proppants used for multi-stage horizontal well completions in North America and presents test data over 250-days of "extended-time" at 7,500 psi of effective stress. The API RP 19-D procedure was followed for all testing, but extended for 250-days duration for the four proppant types: 40/70 mesh mono-crystalline "White" sand, 40/70 mesh multi-crystalline "Brown" sand, 100 mesh "Brown" sand, and 40/70 mesh Light Weight Ceramic (LWC). The 7,500 psi stress condition was chosen to replicate initial stress conditions for a 10,000 feet deep well with a 0.75 psi/ft fracture gradient - typical of unconventional resource plays such as the Bakken formation of North Dakota or the Delaware Basin in west Texas. Results presented provide a measure of the amount of damage occurring in the proppant pack due to time at stress. To the authors’ knowledge, there has never been any extended-time conductivity data published for multiple proppant types over the timeframe completed in this study - despite the obvious need for this understanding to optimize the stimulation design over the full life of the well. Results for the four proppant types are presented as conductivity curves as a function of time for the 250-days of testing. Pack degradation is shown to follow a semi-log decline. Late time continued degradation for all materials is extrapolated over the life of a typical well (40 years), and compared to extended-time particle size distribution and crush data to explain the results observed. Extended-time data such as this 250-day study have never been published on proppants such as these despite the fact that fracture conductivity has a major impact on the productive life of a well and the ultimate recovery of hydrocarbons from the formation. The data presented should be of great interest to any engineer involved with completion designs, or reservoir engineers assessing the productive life and ultimate recovery in the formation since economic optimization is primarily driven by the interplay of fracture length/area with extended-time in-situ fracture conductivity.

Optimasi K-Klasterisasi Ketahanan Pangan Kabupaten Jember Menggunakan Metode Elbow

Clustering is a process of grouping data based on similarities or similarities with other members in a group. Food security is the condition of a country to provide food for individuals, which does not conflict with beliefs, religion and culture and leads a healthy, active and productive life. Food instability and food insecurity can be caused by many factors, one of which is natural disasters. In 2020, Jember Regency experienced 121 natural disasters. Determination of the optimal K value is done to get the right number of group divisions from the clustering process, in this case using the elbow method. The data used in the clustering process are sub-districts in Jember Regency using transient attributes or natural disaster events. Based on the results of sub-district data grouping from the number of clusters k=1 to k=10, the optimal k value was found at the value of k = 4 with the SSE (Sum of Square Error) value = 24,809.

Contradictory regimes of practice: Constructs and discourses in an open prison

Using concepts from Kelly and Foucault, analysis of interviews in the mid-1990s with staff in an English open prison explores how contrasting discourses are reconciled. Two superficially antagonistic discursive formations within prison practice are described: a discourse of discipline/control and an ethic of reform and reclaiming “spoiled” criminals for good and productive life. While rhetorically at odds, they are reconciled in the working practices of prison staff, with discipline as a necessary precondition for reform. The open prisons stand for the rehabilitative ethic and the staff are proud of their work, but by the 1990s prison policy had begun to dissociate itself from promises of reform, in response to research conclusions that residential care was ineffective. This case study shows how discourses survive when they are disowned by their “owners.” The research has wider implications for an understanding of hierarchical relationships between discourses and construct-sets that prescribe different practices.

Fleckscore system of exterior evaluation as a more accurate indirect predictor of longevity in Slovak Simmental dairy cows

The goal of the work was to discover the influence of conformation traits evaluated by the Fleckscore system on the length of productive life of Slovak Simmental dairy cows. Evaluation of body conformation traits according to the Fleckscore system was performed on 3 452 cows. The relationship of individual traits to longevity was analysed using the Weibull proportional hazard model. The results confirmed that smaller and longer cows, which were well muscular and with a deeper body, had a lower risk of early culling than cows in the reference group. Hock angularity, pastern and hoof height scored with low or high marks were associated with an early culling of cows. In terms of the length of productive life, a slightly more elastic pattern is required. Cows with a deeper udder and a stronger and tighter fore udder attachment, which were also average in notching and height central ligament and centrally placed teats, reached a longer productive life.

Genetic factor affecting the milk production of mares

The article presents the results of studies to establish the influence of the record productivity of mothers’ mares on milk yield and the duration of productive life of mares-daughters of the Lithuanian heavy draft breed. It was found that the high level of milk productivity of mothers during the period of highest lactation (up to 4000 kg of milk) enabled their daughters to become leaders already during the first lactation. With an increase in the record milk yields per lactation in mothers, the heritability coefficient in mother-daughter pairs decreased and turned into negative values. The daughters of mares with record milk yields of up to 8000 are the most dairy among their contemporaries. The research results indicate that intensive milk production of mares during the first lactation can cause a reduction in the terms of their economic use due to the large loads on the developing fragile animal organism. The highest rates of productive life, number of lactations and life-long milk yield were obtained from daughters whose mothers had record milk yields per lactation from 7000 kg to 8000 kg of milk.

Length of productive life the cows of Simmental breed

The purpose of the research was to assess the duration of the length of productive life of Simmental cows. Methods. The research was carried out on Simmental cows bred in 14 regions of the Russian Federation, the total livestock was 8 832 heads. The calculation of the heritability coefficients and correlation (genetic and paratypic) was carried out by using the programs RENUMF90 and REMLF90. Results. A fairly strong relationship was established between the duration of a productive life (months) and the age of culling (lactations) r = +0.795, the length of productive life (months) and lifetime productivity within the range of +0.669…+0.714. However, the relationship between the age of culling (lactations) and lifetime productivity is moderate, from +0.261 to +0.316. A moderate negative relationship was obtained between the age of culling (lactations) and milk yield per first lactation from –0.472 to –0.486. The average relationship was found between milk yield per first lactation and lifetime productivity from +0.567 to +0.588. Cows of the Altai Territory (3.08 lactations or 61.6 months), the Republic of Mordovia (3.38 lactations or 62.4 months) and the Lipetsk region (3.40 lactations or 65.7 months) were distinguished by low age of culling. While the greatest length of productive life was noted in animals and Bryansk (5.48 lactations or 86.9 months) and Irkutsk regions (4.57 lactations or 77.1 months). Bryansk (23 630 kg of milk), Tyumen (18 156 kg) and Irkutsk (17 751 kg) regions occupied the leading positions in lifetime productivity of cows in the sample, while the outsiders were the regions of traditional cattle breeding - Altai Territory (12658 kg of milk), the Republic of Bashkiria (12 482 kg). Scientific novelty. For the population Simmental cattle of the Russian Federation, for the first time, an assessment of selection and genetic parameters of lifelong productivity and length of productive life of Simmental cows was carried out, depending on the breeding region.

Effect of Calving Difficulties and Calf Mortality on Functional Longevity in Polish Holstein-Friesian Cows

Longevity is one of the functional traits that considerably affect dairy herd profitability. A Weibull proportional hazards model was used to evaluate the impact of difficult calvings and calf stillbirths on cow functional longevity, defined as length of productive life corrected for milk production. The data for analysis comprised calving ease and calf mortality scores of 2,163,426 calvings, 34.4% of which came from primiparous cows. The percentage of male calves was 53.4%. Calving ease was scored as “without assistance” (34.44%), “with assistance” (62.03%), “difficult—hard pull” (3.39%), and “very difficult, including caesarean section” (0.14%). Calf mortality scores were “live born” (94.21%) and “stillborn or died within 24 h” (5.79%). The Weibull proportional hazards model included classes of calving ease or calf mortality scores × parity (1, ≥2) × sex of calf as time-dependent fixed effect. The model also included time-dependent fixed effects of year × season, parity × stage of lactation, annual change in herd size, fat yield and protein yield, time-independent fixed effect of age at first calving, and time dependent random herd × year × season. In first-parity cows, very difficult birth of a bull or heifer increased the relative risk of culling, respectively, 2.18 or 1.26 times as compared with calving without assistance. In later parities, the relative risk of culling related to very difficult calving was 2.0 times (for male calves) and 1.33 times (for female calves) higher than the relative risk of culling associated with calving without assistance. Calf mortality showed a negative impact on longevity in both heifers and cows. First-parity stillbirth increased the relative risk of culling depending on sex of calf by 18% in females and by 15% in males; in later parities the increase of the relative risk of culling was lower (by 7% for females, 9% for males). Difficult calvings and their consequences, especially in primiparous cows, may negatively influence dairy herd profitability by reducing the length of cows’ productive life.

Optimization of Control Line Encapsulation Based on Numerical Simulations of Shock and Vibration

Control line integrity is fundamental to ensure operability of intelligent completion systems. Damage to control lines can normally occur during string deployment (by shock), or during productive life (by vibration-related fatigue). This work aimed to investigate how encapsulation will affect control line survivability throughout their entire life cycle. Numerical simulations were carried out using geometrical arrangements of control lines typically found in completion valves and tubings. For installation loads, lines were submitted to shock simulations, both inside and outside of protection clamps. The role of flatpack material was studied, as to which kind of material would better absorb impact energy. For productive life loads, the flow-induced vibration was taken into account for high-rate injector wells. Vibration loads were based on force results obtained by Computational Fluid Dynamics (CFD). Structural Finite Element Analysis (FEA) was performed to obtain local tensions to estimate productive life of lines.

Design of Free Stalls for Dairy Herds: A Review

Lying is an important behavior of dairy cattle. Cows should spend more than 50% of a day lying as it has a high impact on their milk yield and animal welfare. The design, size, and flooring properties of the free stalls influence the time cows spend lying, the way they lie down, and their rising movements. The purpose of this review is to provide an overview of the currently available information with the aim to assist farmers and advisors to come to an optimal design of the free stalls. The design of the free stalls should enable the cows to move and lie in positions as natural as possible. Cows should rest, with all parts of the body, on a clean, dry and soft bed, be able to stretch their front legs forward, lie on their sides with unobstructed space for their neck and head, and rest with their heads against their flanks without hindrance from a partition. When they stand, they should not be hindered by neck rails, partitions, or supports. A comfortable place for cows to lie down helps cows to stay healthy, improve welfare, and increase milk yield. Hence, the probability of a longer productive life for the cows increases and the number of replacements per year decreases.

Relationship between reproductive capacity and productive longevity of cow

One of the most critical tasks of modern dairy farming is to extend the time of productive use of cows. Studies have shown that the studied herd’s economic benefit ranged from 1005 to 3693 days and averaged 1864. The lifetime milk yield of the cows averaged 20746 kg and lifetime milk fat was 735.4 kg. On the first day of economic use, 10.2 kg of milk was obtained, and on the first day of lactation, the figure was significantly higher at 20.8 kg. The most extended use period for a cow was found to be 1903 days. The average open days were 91-120 days. The highest lifetime productivity was obtained from this group of animals, which was 21909 kg of milk. A further reduction or increase in the length of open days was accompanied by a decrease in economic use and a decrease in the productive life of the cows. When open days were too long (more than 120 days), the productive life of the cows was reduced to 1875 days, and milk productivity was also reduced to 20562 kg of milk. According to the research results, the abundant lifetime life of cows increases with the duration of inter calving period from 11 to 13 months from 14939 to 26582 kg. It was found that productive life milk yield and milk fat decreased with a more extended period between calvings. The age of the first calving had no significant effect on the duration of economic use of the cows. Individuals with first calving at 30 months of age and more excellent than 1993.2 days were best on this trait. However, the highest productive life was shown by animals whose age at first calving was 26-27, 9 months.