1. n. [Drilling Fluids]
A drilling-mud additive used to control fluid loss in water muds ranging from freshwater to saturated-salt to high-pH lime muds. Starches have thermal stability to about 250°F [121°C]. They are subject to bacterial attack unless protected by high salinity or bactericide. Drilling-grade natural starch has API/ISO specifications for quality. Starches are carbohydrates of a general formula (C6H10O5)n and are derived from corn, wheat, oats, rice, potatoes, yucca and similar plants and vegetables. They consist of about 27% linear polymer (amylose) and about 73% branched polymer (amylopectin). The two polymers are intertwined within starch granules. Granules are insoluble in cold water, but soaking in hot water or under steam pressure ruptures their covering and the polymers hydrate into a colloidal suspension. This product is a pregelatinized starch and has been used in muds for many years. Amylose and amylopectin are nonionic polymers that do not interact with electrolytes. Derivatized starches, such as pregelatinized starches, are used in drill-in fluids, completion fluids and various brine systems as well as in drilling-mud systems. The use of starch typically causes a minimal increase in viscosity while effectively controlling fluid loss.
一种钻井泥浆添加剂，用于控制水泥中的流体损失，从淡水到饱和盐到高pH石灰泥。淀粉具有约250°F [121°C]的热稳定性。除非受到高盐度或杀菌剂的保护，否则它们会受到细菌侵袭。钻井级天然淀粉具有API / ISO质量标准。淀粉是通式（C 6 Hn的碳水化合物，并且衍生自玉米，小麦，燕麦，大米，马铃薯，丝兰和类似的植物和蔬菜。它们由大约27％的线性组成聚合物（直链淀粉）和约73％支化聚合物（支链淀粉）。这两种聚合物在淀粉颗粒中缠绕在一起。颗粒是不溶于冷水，但在热水中或下浸泡蒸汽 压力破裂其覆盖物和聚合物水合成胶体悬浮液。该产品是预糊化淀粉，已在泥浆中使用多年。直链淀粉和支链淀粉是不与电解质相互作用的非离子聚合物。衍生化淀粉，例如预糊化淀粉，用于钻井液，完井液和各种盐水系统以及钻井泥浆系统。淀粉的使用通常导致最小的增加粘度有效控制流体损失。
