- المجال: Oil & gas
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A class of polymers added to a drilling-grade clay mineral during grinding, or added directly into a clay-based mud system, to enhance the clay's rheological performance. In concept, clay-extender polymers achieve the type of rheology needed for fast drilling with fewer colloidal solids and lower viscosity at high shear rate (at the bit). This is the concept of a "low-solids, nondispersed mud" system. Extenders are usually long-chain anionic or nonionic polymers that link clay platelets together in large networks. Anionic polymers are highly effective but can be precipitated by hardness ions. Nonionic polymers are less effective but also much less sensitive to hardness ions. Excessively long, linear polymers may break up under mechanical shearing. Either by precipitation or breakup, extender polymers can quickly become ineffective if poorly chosen and used improperly. A drilling-grade clay that has no extender is that which meets the standard for API nontreated bentonite. API bentonite and OCMA-grade API bentonite usually contain extender polymers.
Industry:Oil & gas
A class of muds that contain potassium ion (K<sup>+</sup>) dissolved in the water phase. Potassium muds are the most widely accepted water mud system for drilling water-sensitive shales, especially hard, brittle shales. K<sup>+</sup> ions attach to clay surfaces and lend stability to shale exposed to drilling fluids by the bit. The ions also help hold the cuttings together, minimizing dispersion into finer particles. The presence of Na<sup>+</sup> ions counteracts the benefits of K<sup>+</sup> ions and should be minimized by using fresh water (not sea water) for make-up water. With time, Na<sup>+</sup>, Ca<sup>+2</sup> and other ions accumulate from ion exchange with clays, making the mud less effective, but regular treatment to remove Ca<sup>+2</sup> improves polymer function. Potassium chloride, KCl, is the most widely used potassium source. Others are potassium acetate, potassium carbonate, potassium lignite, potassium hydroxide and potassium salt of PHPA. Use of bentonite clay is restricted because of its strong affinity for K<sup>+</sup>. Instead, various polymers are used. XC polymer and PHPA are used for rheology. For fluid-loss control, mixtures of starch and polyanionic cellulose are often used. CM starch, HP starch, carboxymethylcellulose and sodium polyacrylate (SPA) are also used. PHPA is widely used for shale encapsulation. Potassium, lime and starch-like polymers have also been used as potassium mud systems. Although three API methods exist for determining the K<sup>+</sup> ion concentration, the centrifuge method (for K<sup>+</sup> >5000 mg/L) is the most accepted field method, and essential for daily monitoring of potassium in a mud. Regular additions of potassium salt maintain shale stability. K<sup>+</sup> ion is rapidly consumed while drilling shallow, soft and highly dispersive (gumbo) shales, but maintaining sufficient K<sup>+</sup> ion to stabilize gumbo can become expensive when drilling large holes. Researchers, notably Dr. Dennis O'Brien and Dr. Martin Chenevert (while at Exxon Production Research), evaluated different shales, their clay mineralogy and the concentration of K<sup>+</sup> needed to stabilize them. Potassium muds above about 1 wt. % K<sup>+</sup> ion usually fail the mysid shrimp (US EPA) bioassay test. Therefore, K-muds currently find low acceptance in offshore drilling in USA waters. <br><br>Reference:<br>O'Brien DE and Chenevert ME: "Stabilizing Sensitive Shales with Inhibited Potassium-Based Drilling Fluids," Journal of Petroleum Technology 25, no. 9 (September 1973): 1089-1100.
Industry:Oil & gas
A chemical with the formula NaHCO<sub>3</sub>. It is called bicarb at the drilling rig and is used to treat cement contamination in water mud. When cement hydrates, substantial amounts of lime, Ca(OH)<sub>2</sub>, are produced. As the cement sets, less free lime is available. When partially set cement is drilled with a water mud, Ca<sup>+2</sup> and OH<sup>-</sup> ions are leached into the mud, often causing problems associated with clay flocculation and polymer precipitation. Bicarb can be added, either as a pretreatment or over a period of time, to remove the Ca<sup>+2</sup> in the form of insoluble CaCO<sub>3</sub> while simultaneously neutralizing OH<sup>-</sup> ions with the H<sup>+</sup> ion in the bicarb molecule.
Industry:Oil & gas
A chemical with the formula Na<sub>2</sub>CO<sub>3</sub>. It is called soda ash at the drilling rig and is used to treat most types of calcium ion contamination in freshwater and seawater muds. For cement contamination, sodium bicarbonate is used. Calcium ions from drilling gypsum or anhydrite, CaSO<sub>4</sub>, cause clay flocculation and polymer precipitation and lower pH. A soda-ash treatment is appropriate for gypsum contamination because caustic soda, NaOH, is not needed to raise pH. This is also generally the case with hard water influxes into water muds.
Industry:Oil & gas
A chemical with formula CaO, commonly called quick lime or hot lime. When hydrated with one mole of water, it forms slaked lime, Ca(OH)<sub>2</sub>. Quick lime is used in preference to slaked lime at oil mud mixing plants because it generates heat when it becomes slaked with water and therefore speeds up emulsification by the reaction to form calcium fatty-acid soap.
Industry:Oil & gas
A chemical with formula Ca(OH)<sub>2</sub>, commonly called slaked lime. Lime is used in lime muds and as a treatment to remove carbonate ions. It is used as a stabilizing ingredient in oil- and synthetic-base mud, essential to formation of fatty-acid soap emulsifiers. It is an alkaline material that can be carried in excess to neutralize hydrogen sulfide (H<sub>2</sub>S) and carbon dioxide (CO<sub>2</sub>).
Industry:Oil & gas
Химического вещества, используемого в подготовке и обслуживании из нефти - или синтетические база бурового раствора, который образует эмульсии воды в нефти (Инвертировать эмульсия). Эмульгатор нефти грязь снижает межфазное натяжение между нефтью и водой, которая позволяет стабильных эмульсий с небольшой капли формироваться. Исторически нефти грязи эмульгаторы были классифицированы как первичной и вторичной. Вторичные эмульгаторов обычно не используется только для того, чтобы сделать стабильной масляной грязи. Эмульгаторы может быть кальция мыла жирных кислот из различных жирных кислот и известь или производные амидов, амины, amidoamines и imidazolines, сделанные реакции жирных кислот и различных соединений этаноламина. Эти эмульгаторы окружают капли воды, как инкапсуляции фильм, с компонентом жирных кислот в масляной фазы. Эмульгатор молекул, которые не могут соответствовать вокруг капель формы кластеров (мицелл) в масляной фазы или адсорбируются тел. Эмульсии капли нефти грязи ведут себя как небольшой осмотической ячейки. Эмульгатор вокруг капли действует, как полупроницаемой мембраны, через которые вода может двигаться, но ионы не могут пройти. Таким образом, масло грязи имеют специальные возможности (какие воды грязи не имеют) для контроля воды Трансфер от капель и просто регулируя соленость в водной фазе масляной грязи.
Industry:Oil & gas
Химикат, используемый для сломать эмульсии (то есть, чтобы отделить две фазы). Тип деэмульгатора выбран зависит от типа эмульсии, нефти в воде или вода в нефти. Деэмульгаторы используются в химическом анализе нефтяных и синтетических растворов и для лечения производства углеводородов.
Industry:Oil & gas
A chemical whose molecular structure can envelop and hold a certain type of ion in a stable and soluble complex. Divalent cations, such as hardness ions, form stable and soluble complex structures with several types of sequestering chemicals. When held inside the complex, the ions have a limited ability to react with other ions, clays or polymers. Ethylenediamine tetraacetic acid (EDTA) is a well-known sequestering agent for the hardness ions, such as Ca<sup>+2</sup>, and is the reagent solution used in the hardness test protocol published by API. Polyphosphates can also sequester hardness ions. The addition of sodium acid pyrophosphate (SAPP) to a cement-contaminated mud renders the calcium ions essentially nonreactive with clays in the mud. As a side benefit, SAPP also lowers mud pH. Sequestering is not the same as precipitation because sequestering does not form a solid.
Industry:Oil & gas
Поток образования газа в затрубное пространство между обсадной колонны и стенкой скважины. Кольцевые газовые потоки возникают при недостаточно гидростатическое давление, чтобы удержать газ. Они могут произойти в бесцементным интервалы и даже укрепил разделы при плохом Бонд цемента. После вяжущие, как цемент начинает затвердевать, гель как структура формы которые эффективно поддерживает твердый материал в цементный раствор. Однако в этот начальный период желирующий, цемент имеет нет значительных сил. Таким образом с материалом тела (веса), теперь поддерживаются структурой геля, эффективная плотность шлама, что водохранилище опыт падает довольно неожиданно плотность воды смесь цемента, который обычно пресная вода, чья плотность — 8. 34 lbm/галлон, или градиент 0. 434 psi/фут высоты вертикального столбца. Для уменьшения потока газа кольцевой были разработаны различные химические добавки.
Industry:Oil & gas
