Application status and research progress of shale reservoirs acid treatment technology

Natural Gas Industry B

Fengjun Bai¹  Jianhui Li²  Nianyin Li³  Zhifeng Luo³  Jinxing Dai³  Pingli Liu³ 

[1] Changqing Downhole Technical Operation Company, CNPC Chuanqing Drilling Engineering Co. Ltd., Xi'an 710018, China;Oil & Gas Technology Research Institute of PetroChina Changqing Oilfield Company, Xi'an 710018, China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu 610500, China;

关键词: Shale reservoirs;    Acid treatment technology;    Stimulation;    Stimulation mechanism;    Research status;   

DOI  :  10.1016/j.ngib.2016.06.001

来源: DOAJ

【 摘 要 】

In recent years, shale oil and gas development has been thriving in China. However, the shale oil and gas production always suffers a rapid decline. Based on the analysis of a large amount of former theories and experiences, a summary of acid treatment stimulation methods in shale oil and gas is presented, and the acid stimulation mechanism is analyzed. The mainstream technique in acid treatments includes: acid wash, matrix acidizing, prop fracturing with acid preflush, and multi-stage alternate-inject acid fracturing. The main stimulation mechanism of acid treatment can be summarized into 3 categories: a) the influence on shale matrix, namely the acid-induced increase of porosity and permeability, and reduce of wetting property of shale; b) the influence on rock mechanical properties, namely shale brittleness and toughness, and even Young Modulus to some degree; c) the influence on fractures' conductivity, caused by the fact that acid dissolves calcite-enrichment area in priority, and then increases roughness on fracture surface. In room temperature and atmospheric pressure, acid reduces fractures' conductivity, while in pressurized condition, the acid-soaked fractures' conductivity is higher than the conductivity of non-acid-soaked fractures. These knowledges would provide useful reference for furthering stimulation techniques and processes in shale oil and gas development.

【 授权许可】

Unknown