吸液式降当量循环密度工具及降压机理研究  

Suction-Type ECD Reduction Tool and Its Depressurization Mechanism

作　　者：窦亮彬[1,2,3] 程学彬 彭先波 王婷 陈景杨 方勇[1,3] Dou Liangbin;Cheng Xuebin;Peng Xianbo;Wang Ting;Chen Jingyang;Fang Yong(College of Petroleum Engineering,Xi an Shiyou University;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing);Engineering Research Center of Development and Management for Low to Ultra-Low Permeability Oil&Gas Reservoirs in West China,Ministry of Education)

机构地区：[1]西安石油大学石油工程学院,陕西省西安市710065 [2]中国石油大学(北京)油气资源与探测国家重点实验室 [3]西部低渗—特低渗透油藏开发与治理教育部工程研究中心

出　　处：《石油机械》2025年第2期44-49,58,共7页China Petroleum Machinery

基　　金：陕西省重点研发计划“地层CO_(2)含量随钻定时定量反演机制及预测方法研究”(2024GX-YBXM-503)。

摘　　要：为进一步控制当量循环密度(Equivalent Circulating Density,简称ECD)值,设计了一套高温高压井新型环空降压井下工具——吸液式降ECD工具。利用该工具可以实现当量循环钻井液的井底压力接近其静水压力,进而实现更深的钻井深度。该工具主要由涡轮马达、叶片、环空密封、钻柱组成。其工作原理为:利用其吸液作用及由涡轮提取循环流体液压能量,将能量转化为机械能,进而产生抽吸力来提高井底环空内的钻井液流动能量,降低当量循环密度。基于SolidWorks flow simulation分析模拟了不同钻井液密度、排量、工具尺寸下压降特征变化。模拟结果表明,钻井液密度为1.2 g/cm^(3)时,其降压效果达到了1.95 MPa;钻井液密度为1.5 g/cm^(3)时,降压大约1.8 MPa;钻井液密度为1.8 g/cm^(3)时,降压大约2.39 MPa。钻井液排量为1500~2500 L/min时,最高可降压3.06 MPa。对2种不同工具尺寸(Ф90.5、Ф215.9 mm),钻井液流经吸液式降ECD工具时,压降几乎没有变化,尺寸增大其压降效果略有降低,但对压降影响不大,且主要受等排量下流速的影响。研究结果可为高温高压钻井提供技术参考。To further control the equivalent circulating density(ECD)value,a new type of downhole tool for annulus depressurization in high-temperature and high-pressure(HTHP)wells,i.e.,a suction-type ECD reduction tool,was designed.This tool can be used to allow the bottomhole pressure of the equivalent circulating drilling fluid to approach its hydrostatic pressure,thereby achieving deeper penetration.It mainly consists of turbo motor,blades,annular seal and drill string.It reduces the ECD by using the suction action of the tool to drive the turbine to extract the hydraulic energy of circulating fluid and convert it to mechanical energy,which can generate a suction force to improve the flow energy of the drilling fluid in the bottomhole annulus.Based on the SolidWorks flow simulation,the depressurization behaviors under different drilling fluid densities,displacements and tool sizes were analyzed.According to the simulation results,when the drilling fluid density is 1.2 g/cm^(3),the pressure drop is 1.95 MPa;when the drilling fluid density is 1.5 g/cm^(3),the pressure drop is about 2 MPa;when the drilling fluid density is 1.8 g/cm^(3),the pressure drop is about 2.39 MPa.When the drilling fluid displacement is 1500 to 2500 L/min,the maximum pressure drop can be 3 MPa.At two different tool sizes(90.5 mm,215.9 mm),when the drilling fluid flows through the suction-type ECD reduction tool,almost no change is observed in depressurization.Increasing the tool size just slightly reduces the pressure,and it has little impact on depressurization.The depressurization is mainly affected by the flow rate at the same displacement.The research results provide reference for HTHP drilling.

关 键 词：当量循环密度(ECD) 环空降压 降压工具 吸液式降ECD工具 高温高压 

分 类 号：TE254[石油与天然气工程—油气井工程]