"理想充填理论"—d90经验规则在昆2井中的应用

昆2井是中油集团公司部署在柴达木盆地北缘昆特依凹陷潜伏1号构造上的一口重点探井,完钻井深为5950m。地质结构复杂,属喷、漏、塌、缩、卡高危地层。经与中国石油大学(北京)合作,在成膜钻井液的基础上,根据理想充填理论,引入封堵剂,进而增强地层的承压能力,以满足高压盐水层的施工要求。在研究分析地层岩性、物性、敏感性和损害因素的基础上,根据地层孔隙度、渗透率、岩性、井底温度及开钻顺序,将钻井液分为低温中孔高渗封堵成膜钻井液、中温中孔中渗封堵成膜钻井液、高温中孔中低渗封堵成膜钻井液,并在钻进过程中根据地层孔隙度,应用d90规则调整封堵粒子(超细碳酸钙、磺化沥青、聚合醇、有机硅醇)和成膜剂加量。昆2井井壁稳定,无复杂与事故,顺利完成了钻探任务。

The Application of the "Ideal Packing Theory"- d90 Empirical Rule in Well Kun-2

Well Kun-2 is a key exploration well located in the No. 1 structure in Kunteyi depression in the north of the Chaidamu Basin. The drilled depth of this well is 5950 meters. Being geologically complicated, almost all downhole problems, such as blowout, mud losses, borehole sloughing, tight hole, and pipe sticking can be found in drilling this well. In cooperation with University of Petroleum (Beijing), a new technology using the so-called "ideal packing theory" was developed. A plugging agent was introduced into a film-forming drilling fluid to increase the pressure-bearing of the formations, so that drilling operation would be done successfully in high-pressure saltwater formations. Formation lithology, physical properties, sensitivity and damaging factors were studied. The drilling fluids used were classified as: Low-temperature medium-porosity high-permeability plugging filming-forming mud, Medium-temperature medium-porosity medium-permeability plugging filming-forming mud, and High-temperature medium-porosity medium to low-permeability plugging filming-forming mud, according to the formation porosity, permeability, lithology, bottom hole temperatures and drilling sequences. During drilling, the d90 empirical rule was adopted to define the plugging particles (such as ultra-fine calcium carbonate, sulfonated asphalt, poly gly col, or organo silicon. ) and the concentration of film-formaing agents, based on the formation porosities. A gauge hole was obtained in Well Kun-2, using this technology, and the well was successfully completed.