Method of increasing the low shear rate viscosity of well drilling and servicing fluids containing calcined magnesia bridging solids, the fluids and methods of use
申请人:Texas United Chemical Company, LLC.
公开号:EP1698677A2
公开(公告)日:2006-09-06
The invention provides well drilling and servicing fluids, and methods of drilling, completing, or working over a well therewith, preferred fluids comprise an aqueous liquid, a water soluble polymer viscosifier (preferably xanthan gum), a polymeric fluid loss control additive (preferably a partially depolymerized partially crosslinked hydroxyalkyl ether derivative of starch or a hydroxyalkyl ether derivative of a partially crosslinked and partially depolymerized starch), a bridging agent comprising a particulate calcined magnesia that has an Activity Index greater than about 800 seconds, and an additive selected from the group consisting of citric acid, alkali metal salts of citric acid, ammonium citrate, and mixtures thereof in an amount sufficient to increase the low shear rate viscosity of the fluids, preferably from about 0.05-5 ppb, most preferably from about 0.15-3 ppb. The invention further provides a method of increasing the low shear rate viscosity of fluids which contain a water soluble polymer and a calcined magnesia bridging agent which has an Activity Index greater than about 800 seconds.
本发明提供了钻井和修井流体,以及用其钻井、完井或修井的方法,优选的流体包括水性液体、水溶性聚合物粘稠剂(优选黄原胶)、聚合物流体损失控制添加剂(优选部分解聚的部分交联的淀粉羟基烷基醚衍生物或部分交联和部分解聚的淀粉羟基烷基醚衍生物)、架桥剂,包括活性指数大于约 800 秒的微粒煅烧镁,以及选自柠檬酸、柠檬酸的碱金属盐、柠檬酸铵及其混合物组成的组的添加剂,其用量足以增加流体的低剪切速率粘度,优选约 0.05-5 ppb,最优选约 0.15-3 ppb。本发明进一步提供了一种提高流体低剪切速率粘度的方法,该流体含有水溶性聚合物和活性指数大于约 800 秒的煅烧镁架桥剂。