哈德地区长裸眼双台阶水平井钻井液技术

塔里木哈德地区石炭系地层深度为5005－5015m，两个油层厚度均为1－2m，属低压，低渗透油气藏，3000m以上地层胶结疏松,岩性差，泥岩水化造浆严重，极易发生阻卡事故；3000m以下地层易漏，井壁易垮塌，因此，直井段钻进时，在钻井液中加入足量的封堵剂和防塌剂，保证井壁稳定，在造斜段和水平段采用低粘度，低切力聚磺混油钻井液体系；并随着井温升主，不断补充抗温处理剂和润滑剂，降低摩阻，减少托压和阻卡事故的发生；进入油气层前，在聚磺混油钻井液中加入大量的乳化沥青，SMP－1和超细碳酸钙，利用屏蔽暂堵技术，防止固相颗粒进入储层，减少对储层的损害，应用结果表明，低粘度，低切力聚磺混油钻井液体系具有很强的抑制性和携砂能力，润滑性能好，性能稳定，完全满足了长裸眼，双台阶水平井钻工程的要求，避免了井下复杂情况的发生。

Drilling fluid technology of two-step horizontal well in the long-ope

Reservoirs in the carboniferous system of 5005-5015 m in Hade area of Tarim are low pressured and low permeable, with oil bearing thickness of 1-2 m. The formations over 3000 m are loose and unconsolidi-fied, shale hydration and mud making always lead to stuck pipe. Lost circulation and hole caving are likely to take place under 3000 m. When drilling the vertical hole, sufficient plugging agent and shale hydration inhibitor are added to hold wellbore stabilization, and polysulfonate oil mixing drilling fluid of low viscosity and low shearing rate is used in the kicking off section and horizontal interval, and high temperature additive and lubricant are added steadily to reduce friction resistance and stuck pipe thereby. Before hitting the pay zone, temporary plugging technology involves using of large volume of emulsified asphalt, SMP-1 and super-fine calcium carbonate is adopted, to keep the solids from entering formation and minimize formation damage. The polysulfonate drilling fluid system proves to have strong shale inhibition and cuttings transportation, better lubricity and stable performances, and it is good for drilling the horizontal well with long-open hole.