中南大学学报（自然科学版）2016，Vol.47Issue(11)：3832-3838,7.DOI:10.11817/j.issn.1672-7207.2016.11.029
复合盐层井壁失稳机理及防塌钻井液技术
Wellbore instability mechanism and wellbore stabilizing drilling fluid technique for drilling compound salt formation
摘要
Abstract
In order to solve the wellbore instability problem when drilling compound salts formation in A&M Oilfield in the border of Iran and Iraq, the fabric and physical-chemical properties of compound salts were tested by X-ray diffraction, scanning electron microscope, hot rolling dispersion test and linear swelling test, and wellbore instability mechanism was analyzed. A multivariate cooperation principle for stabilizing the wellbore in compound salts drilling was designed, which includes enhancing the performance of sealing and consolidating borehole, enhancing the inhibition on dissolution and hydration of compound salts, balancing chemical potential and activity, and maintaining reasonable density of drilling fluid to support the wellbore. According to the principle, the sealing additives and salts mixture consisting of organic and inorganic salts were optimized, and the high density (2.3 g/cm3) multi-component salts drilling fluid for drilling compound salts was formed. The results show that the rheological property of the drilling fluid is good. As a result, the equivalent circulating density can be well controlled. The low fluid loss volume (7.0 mL) at 120 ℃ and 3.5 MPa indicate the excellent filtration property of the drilling fluid. The recovery rates of different kinds of compound salts rocks are up to approximately 90% in the drilling fluid, indicating the excellent inhibition property of the drilling fluid on dissolution and dispersion of compound salts. The drilling fluid can seal fractures of 200μm in width, and the bearing capacity is up to at least 5.5 MPa, which indicates that the drilling fluid has excellent sealing property while drilling, and can meet the requirement of compound salts drilling.关键词
复合盐层/井壁失稳/溶解/多元复合盐/钻井液/裂缝Key words
compound salts formation/wellbore instability/dissolution/multi-component salts/drilling fluid/fractures分类
能源科技引用本文复制引用
赵欣,邱正松,张永君,周国伟,黄维安..复合盐层井壁失稳机理及防塌钻井液技术[J].中南大学学报（自然科学版）,2016,47(11):3832-3838,7.基金项目
国家科技重大专项(2011ZX05030-005-07)；国家自然科学基金资助项目(51374233)(Project(2011ZX05030-005-07) supported by the National Science and Technology Special Grant （2011ZX05030-005-07）
Project(51374233) supported by the National Natural Science Foundation of China) （51374233）
