Managed Pressure Drilling Candidate Selection

Managed Pressure Drilling now at the pinnacle of the 'Oil Well Drilling' evolution tree, has itself been coined in 2003. It is an umbrella term for a few new drilling techniques and some preexisting drilling techniques, all of them aiming to solve several drilling problems, including non-productive time and/or drilling flat time issues. These techniques, now sub-classifications of Managed Pressure Drilling, are referred to as 'Variations' and 'Methods' of Managed Pressure Drilling. Although using Managed Pressure Drilling for drilling wells has several benefits, not all wells that seem a potential candidate for Managed Pressure Drilling, need Managed Pressure Drilling. The drilling industry has numerous simulators and software models to perform drilling hydraulics calculations and simulations. Most of them are designed for conventional well hydraulics, while some can perform Underbalanced Drilling calculations, and a select few can perform Managed Pressure Drilling calculations. Most of the few available Managed Pressure Drilling models are modified Underbalanced Drilling versions that fit Managed Pressure Drilling needs. However, none of them focus on Managed Pressure Drilling and its candidate selection alone. An 'Managed Pressure Drilling Candidate Selection Model and software' that can act as a preliminary screen to determine the utility of Managed Pressure Drilling for potential candidate wells are developed as a part of this research dissertation. The model and a flow diagram identify the key steps in candidate selection. The software performs the basic hydraulic calculations and provides useful results in the form of tables, plots and graphs that would help in making better engineering decisions. An additional Managed Pressure Drilling worldwide wells database with basic information on a few Managed Pressure Drilling projects has also been compiled that can act as a basic guide on the Managed Pressure Drilling variation and project frequencies and aid in Managed Pressure Drilling candidate selection

Subchronic exposure to phytoestrogens alone and in combination with diethylstilbestrol - pituitary tumor induction in Fischer 344 rats

<p>Abstract</p> <p>Background</p> <p>Subchronic administration of the potent pharmaceutical estrogen diethylstilbestrol (DES) to female Fischer 344 (F344) rats induces growth of large, hemorrhagic pituitaries that progress to tumors. Phytoestrogens (dietary plant estrogens) are hypothesized to be potential tumor inhibitors in tissues prone to estrogen-induced cancers, and have been suggested as "safer" estrogen replacements. However, it is unknown if they might themselves establish or exacerbate the growth of estrogen-responsive cancers, such as in pituitary.</p> <p>Methods</p> <p>We implanted rats with silastic capsules containing 5 mg of four different phytoestrogens - either coumestrol, daidzein, genistein, or <it>trans</it>-resveratrol, in the presence or absence of DES. We examined pituitary and other organ weights, blood levels of prolactin (PRL) and growth hormone (GH), body weights, and pituitary tissue histology.</p> <p>Results</p> <p>Blood level measurements of the administered phytoestrogens confirmed successful exposure of the animals to high levels of these compounds. By themselves, no phytoestrogen increased pituitary weights or serum PRL levels after 10 weeks of treatment. DES, genistein, and resveratrol increased GH levels during this time. Phytoestrogens neither changed any wet organ weight (uterus, ovary, cervix, liver, and kidney) after 10 weeks of treatment, nor reversed the adverse effects of DES on pituitaries, GH and PRL levels, or body weight gain after 8 weeks of co-treatment. However, they did reverse the DES-induced weight increase on the ovary and cervix. Morphometric examination of pituitaries revealed that treatment with DES, either alone or in combination with phytoestrogens, caused gross structural changes that included decreases in tissue cell density, increases in vascularity, and multiple hemorrhagic areas. DES, especially in combination with phytoestrogens, caused the development of larger and more heterogeneous nuclear sizes in pituitary.</p> <p>Conclusions</p> <p>High levels of phytoestrogens by themselves did not cause pituitary precancerous growth or change weights of other estrogen-sensitive organs, though when combined with DES, they counteracted the growth effects of DES on reproductive organs. In the pituitary, phytoestrogens did not reverse the effects of DES, but they did increase the sizes and size heterogeneity of nuclei. Therefore, phytoestrogens may oppose some but not all estrogen-responsive tissue abnormalities caused by DES overstimulation, and appear to exacerbate DES-induced nuclear changes.</p

The Energetics of Halogenated Ethylenes (Ethynes) and 1,3-Butadienes (Butadiynes): A Computational and Conceptual Study of Substituent Effects and “Dimerization”

The energetics of ethylenes and 1,3-butadienes may be interrelated by the reaction: RHC=CH2 + H2C=CHR\u27 → RHC=CH−CH=CHR\u27 + H2. Shown earlier to be nearly enthalpically thermoneutral for a variety of hydrocarbon cases, we are now interested in the related energetics of halogenated alkenes and alkynes. Using quantum chemical calculations, we have studied this as recast as the isodesmic reactions: 2(H2C=CHX) + H2C=CH−CH=CH2 → p,q-di-X-1,3-butadiene + 2H2C=CH2 2(HC≡CX) + HC≡C−C≡CH → di-X-butadiyne + 2HC≡CH. Here p,q- = 1,3-; 1,4- and 2,3- with X = F, Cl, Br, and I. The halogen and location-dependent deviations from near enthalpic thermoneutrality are discussed

Migrating to the Cloud: IT Application, Database, and Infrastructure Innovation and Consolidation

Whether your company is planning on database migration, desktop application migration, or has IT infrastructure consolidation projects, this book gives you all the resources you'll need. It gives you recommendations on tools, strategy and best practices and serves as a guide as you plan, determine effort and budget, design, execute and roll your modern Oracle system out to production. Focusing on Oracle grid relational database technology and Oracle Fusion Middleware as the target cloud-based architecture, your company can gain organizational efficiency, agility, increase innovation and reduc

A New Driver for Managed Pressure Drilling: Reducing Stuck Pipe Occurence

Differences between mud pressure in a wellbore and pore pressure in high permeability rocks can lead to differential sticking, particularly when drilling deviated wells and encountering mud losses. Several solutions, all challenging, can be used to address this problem. The conventional mitigation has been to manage mud weight (MW) accordingly. However, managed pressure drilling (MPD) offers a promising solution with positive risk-adjusted cost and other benefits. Wells in the E oilfield in southern Iraq are typically drilled overbalanced and therefore often experience a high percentage of non-productive time (NPT) due to differential sticking. This study evaluates the feasibility of using MPD to optimize the drilling process by decreasing mud weight while applying required surface pressure to achieve the target bottom hole pressure (BHP). A software simulation model uses different mud weights to determine required choke surface backp ressure (SBP) to achieve the initial target equivalent circulation density (ECD). Historically, differential sticking has not been a primary driver to justify MPD. However, MPD offers more dynamic and rapid wellbore pressure control by adjusting SBP applied to the annulus for a given MW, and can actually decrease the risk of differential sticking. Instead of shifting MW or changing other drilling parameters, MPD adjusts the required ECD and/or equivalent static density (ESD) based on formation pore pressure gradient. Additionally, MPD directly lowers SBP in the event of mud losses due to high ECD/ESD to decrease the BHP without the need to reduce MW. This paper discusses hydraulic simulation software used to model the drilling development plan. The software optimizes MW and SBP while drilling, making pipe connections, and completing the well. Furthermore, it discusses the sensitivity effects of each parameter on wellbore pressure and provides guidelines for managing pressure by adjusting these variables