革新钻井液技术以促进干热岩产业化开发

Innovate drilling fluid technology to promote the development of hot dry rock industrialization

摘要:

我国干热岩资源丰富，利用系数高，可为电力提供稳定基础荷载，被认为是能够担负起能源革命重任的可再生清洁能源，其规模开发对我国实现“碳达峰和碳中和”具有重要意义。然而，经历近半个世纪，目前世界范围内仅有少量利用EGS技术开发的干热岩示范项目有微量发电，实现产业化目标尚有许多技术瓶颈。通过研究EGS开发过程和钻井液技术，笔者提出：EGS钻井过程中存在钻井液漏失。因此，钻井液组分自身、钻井液与岩屑或井壁岩石、钻井液与热储裂缝表面岩石，在高温高压下会发生各种理化反应，生成新的物质。这些新的物质可能会沉淀在井壁和裂缝表面，甚至可能与井壁或裂缝表面岩石固结成一体，降低裂缝的有效空间，甚至封堵裂缝，且难以清除，使热储导流能力极大降低，难以达到发电要求的流量。因此，革新钻井液技术理念，研究EGS高温高压环境下钻井液组分和岩屑与温压之间的相互关系及其对钻井液性能的影响，利用先进的计算机数据统计、分析和计算技术，对钻井液性能、钻井液在井筒的流动特性以及钻井液与热储岩石的配伍性进行精准预测和控制，避免或减少钻井液漏失以及钻井液在热储环境下与岩石的反应，消除钻井液对热储伤害，提高渗透率，可能是干热岩产业化的技术突破。

关键词:干热岩;产业化;渗透率;钻井液;储层伤害

Abstract:

China is rich in hot dry rock resources which has a high utilization factor and can provide a stable base load for electricity. It is considered to be a renewable and clean energy capable of shouldering the important task of energy revolution. Its large-scale development is key to achieve "carbon peak and carbon neutrality". However， after nearly half a century， only a small number of hot dry rock demonstration projects of EGS in the world have a little power generation， and there are still many technical bottlenecks in achieving the goal of industrialization. By studying the EGS development process and drilling fluid technology， the author proposes that there is drilling fluid loss during EGS drilling. Therefore， the components of the drilling fluid itself， the drilling fluid and cuttings or the rock on the well wall， the drilling fluid and the surface rocks of the reservoir， will undergo various physical and chemical reactions under high temperature and high pressure to generate new substances. These new substances may precipitate on the well wall， and may even be consolidated with the well wall or the surface of the fracture. This reduces the effective space of the fracture， or even seals the fracture， and is difficult to remove； thus， decreasing the reservoir permeability greatly and leading to difficulty in gain the flow rate for power generation. Therefore， it may be a technological breakthrough in the industrialization of hot dry rock to innovate the concept of drilling fluid technology， study the relationship between drilling fluid components and cuttings and temperature and pressure under EGS environment and their influences on drilling fluid performance， and precisely predict and control the drilling fluid performance， the flow characteristics of the drilling fluid in the wellbore， and the compatibility of the drilling fluid with the reservoir rock with advanced computer data statistics， analysis and calculation techniques so as to avoid or reduce the loss of the drilling fluid and the reaction of the drilling fluid with the rock， and eliminate the reservoir damage and increase permeability.

Key words:hot dry rock;industrialization;permeability;drilling fluid;reservoir damage