The extraction characteristics of shale gas are: initially, it is produced through casing, and production capacity fluctuates after 5-12 months. In the second stage, the process of using oil pipes for drainage and gas production is adopted, and the liquid carrying effect is significant. This stage lasts for about 3-9 months. Subsequently, the decline rate of shale gas production increased, the liquid carrying effect was poor, and there was severe bottomhole fluid accumulation. Further implementation of assisted drainage technology is required at this stage. After large-scale operation demonstration, foam drainage gas production process has low cost, quick effect, and good effect of recovery and stable production. The traditional method of adding fuel requires a significant investment in human resources, involves a lot of manual intervention, is labor-intensive and costly, and has low cost-effectiveness.

In response to this, the company has organized a professional team to conduct research and optimization on the foam injection process. Based on years of practical experience closely related to oil and gas fields and new energy development and production, an intelligent foam injection device based on the Internet of Things has been developed, which effectively combines remote control systems with foam injection agent injection processes, achieving intelligent, accurate, and reliable prediction and fault warning of gas well production, increase in production, and stable production trends, greatly reducing the labor intensity of workers.

This product has been in operation for 4 years since the company's first generation product, Bubble Drainage, entered the Southwest Oil and Gas Field in 2016. The technology has been iteratively updated year by year, striving to match the current production process to the greatest extent possible. As of December 2019, our company has deployed a total of 23 sets of equipment and laid 104 single wells in the Southwest Block. Including Southwest Oil and Gas Field Changning Shale Gas Project Department, East China Oil and Gas Branch Nanchuan Shale Gas Project Department, Zhejiang Oilfield Southwest Gas Production Plant, Southwest Oil and Gas Field Shunan Gas Mine and other mining areas.

Taking the product used in a certain homework area as an example, its product framework is shown in the following figure:

Main features of the product:

(1) The sensor of the intelligent bubble discharge and filling device collects various parameters such as oil pressure, sleeve pressure, water content, gas production, etc. in real time, and transmits the collected data to the intelligent controller through wired or wireless networks;

(2) The intelligent controller realizes preliminary data parsing, uploading, and data interaction with the cloud server to obtain the optimization results of the single well injection system, guiding the intelligent foam injection device to achieve real-time adjustment of injection concentration ratio, dosage, and injection cycle.

(3) The intelligent foam drainage control system deploys foam drainage and injection control software on the cloud server to provide injection algorithm services and real-time data monitoring and management for foam drainage wells within its jurisdiction.

(4) Users can input a specified website or mobile intelligent device through a browser to view real-time injection volume, injection cycle, gas and water production, historical data, equipment failure alarms, and diagnostic analysis of wells anytime and anywhere. They can remotely understand the production and production increase status of wells within their jurisdiction and assist in production decision-making.

Taking the implementation of bubble discharge technology on Changning H12 platform as an example. Since the implementation of foam drainage gas production process on February 23, 2019, the water production has tended to be balanced, the decline rate of gas production has gradually decreased, and the differential pressure of oil casing has been stable. Effectively curbing the significant decline in shale gas production and achieving long-term stable production. (As shown in the legend below)

Since 2016, the foam drainage process has been implemented in the Ning 201 well area of Changning block, and the device has achieved 35000 hours of uninterrupted operation