Abstract

With the trend of inferior quality of onshore oil and gas resources in China, the main old oil fields have generally entered a period of ultra-high water cut, and oil and gas fields have entered a new stage of deep and refined development. Digital transformation and intelligent development have become inevitable choices. This article analyzes the current status and trends of international intelligent oilfield technology development, as well as the digital construction status and intelligent exploration progress of onshore oil and gas field production in China. It is pointed out that China's future smart oil and gas fields should focus on building a new smart oil and gas production ecosystem, improving the intelligence level of the whole basin of oil and gas production under complex working conditions, developing the reservoir engineering integrated production technology of automatic matching between the injection and production ends of oil reservoirs, developing advanced intelligent completion technology and intelligent coordinated control system, and realizing the transformation of complex oil reservoir production from "lagging control" to "real-time optimization".

Article Overview

The construction of intelligent oil fields aims to focus on establishing a comprehensive perception, automatic control, intelligent prediction, and optimized decision-making production technology management system in the field of oil and gas production, deeply integrating advanced information technology with traditional oil and gas production business, and continuously promoting digital transformation and intelligent development to drive high-quality development of the oil and gas industry. Advanced technologies such as hydraulic control, electric control, electro-hydraulic integrated control, and wireless signal transmission control have been developed in intelligent well completion abroad. However, intelligent well completion systems are complex, difficult to construct, and have high investment costs, making them only suitable for high-yield wells. Major international oil companies are rapidly promoting the application and practice of intelligent technology in the field of oil and gas production. Although some new technologies have made breakthroughs, overall they are still in the stage of exploration direction and technical preparation. Although China's intelligent oilfield construction started relatively late compared to foreign oil companies, it has made rapid progress and achieved great results. Guided by innovative development concepts, major Chinese oil companies are vigorously implementing digital transformation in the field of onshore oil and gas production.

China has also made certain progress in the digital transformation and intelligent exploration of onshore oil and gas field production. We have built an oil and gas production IoT system for production operations and achieved full coverage of onshore oil and gas fields in China. We have established a standardized and unified oil and gas production management platform, which comprehensively perceives production objects such as oil and gas wells, metering rooms, and oil and gas station warehouses through a combination of sensing, communication networks, and advanced computing technologies. Production data and equipment status information are centrally managed and controlled in the production command center and production control center, effectively supporting the management of oil and gas production processes.

China has focused on conducting intelligent technology experiments based on hydraulic control and electric control for layered injection and production; conducting research and practice on the collaborative operation of injection and production wellbore and ground for the "multi energy complementary" microgrid; Exploring the production optimization and control technology of injection and production units based on digital twins, and forming various types of layered injection and production intelligent control technologies. In terms of single technology, its level is already relatively close to foreign technology, but there is still a need for research in underground signal transmission and intelligent measurement and control. The successful application of the "staggered peak pumping scheduling" and "multi energy complementary" collaborative adaptive control technology in the Changqing Oilfield of PetroChina has filled the gap in the collaborative optimization technology of the "wind-light-electricity" microgrid pumping well group production at home and abroad, providing innovative theories and leading technical support for promoting oilfield production intelligence, cost reduction, efficiency increase, and green low-carbon.

China's future intelligent oil and gas production technology will focus on expanding the entire industrial chain of oil and gas production, enriching the series of real-time monitoring, diagnosis and warning, optimization decision-making, and intelligent control technologies for layered injection and production, and improving the intelligence level of the entire basin of oil and gas production under complex working conditions; Develop an integrated intelligent production system for oil reservoir engineering that automatically matches injection and production ends; Develop advanced hydraulic control, all electric control, electro-hydraulic integrated control, wireless transmission control and other intelligent completion technologies and intelligent coordinated control systems to realize the transformation of complex reservoir production from "lag control" to "real-time optimization".

1.Current Status of International Digital Oil and Gas Field Technology Development

Layered injection and production technology is an important technical means for solving interlayer and planar contradictions, fully developing medium and low permeability reservoirs, reducing ineffective water circulation, and realizing the potential tapping of remaining oil during the high water cut stage of oil fields. The rapid development of injection and production technology abroad has reached the level of refined and intelligent control of layered injection and production. In the 1960s, Acro developed a Programmable Logic Controller (PLC) to control the water injection pump; In the late 1980s, BP began using automated controlled water injection technology for oilfield development; In the 1990s, Shell began using intelligent completion technology to develop oil fields.

The layered water injection process in foreign countries is relatively simple, and water distribution mainly uses wellhead flow regulators and downhole flow regulators for quantitative water distribution, generally without the need for downhole flow testing. The foreign layered oil recovery technology is represented by vertical well bridge plug sealing technology, inflow control technology, and intelligent completion technology, mainly applied to horizontal wells and high-yield vertical wells. In recent years, a new type of adaptive flow control technology has been proposed, with the core component being the Adaptive Inflow Control Device (AICD). AICD can achieve automatic recognition of the ratio of oil, water, and gas, as well as automatic adjustment of valve opening, thereby achieving layered section mining that integrates water control, gas control, and oil increase. At present, the number of FloSure AICD used worldwide has exceeded 42000, widely used in the North Sea, North America, the Middle East, Southeast Asia and other regions.

Typical intelligent completion systems in foreign countries currently include the InForce system of Baker Hughes, the SmartWell system of Halliburton, and the SCRAMS system of Welldynamics, which have been applied on a certain scale in high-yield wells around the world. However, the intelligent completion system is complex, difficult to construct, and costly to invest, making it only suitable for high-yield wells. Major international oil companies, such as Shell, BP, Saudi Arabian National Petroleum, Norwegian National Petroleum, Schlumberger, and Halliburton, are rapidly promoting the application of intelligent technology in the field of oil and gas production, with a focus on real-time remote monitoring of oil and gas wells, equipment reliability warning, and optimization of reservoir production monitoring; Integrate and implement solutions in various fields, shifting from individual intelligence to overall intelligence in key areas, with the aim of improving the efficiency of reservoir, oil well, facility management, and production operations.

In short, although some foreign oil and gas companies have made breakthroughs in new technologies, they are still in the stage of exploratory direction and technical preparation, mainly focusing on improving daily production technology. There has not been a large-scale and wide-ranging system action, no updated oil and gas development main technology, and no large-scale and mature commercial applications have been launched.

2.Progress and Challenges in Digital Construction of Onshore Oil and Gas Fields in China

Compared with foreign oil companies, the construction of smart oil fields in China started relatively late, but has made rapid progress and achieved great results. In recent years, China's petroleum industry has been facing severe challenges such as the deterioration of oil resource grade and the entry of the main old oil fields into the stage of ultra-high water cut development. Guided by innovative development concepts, major domestic oil companies are vigorously implementing digital transformation.

2.1 Established a Production IoT System Covering Onshore Oil and Gas Fields

After more than 10 years of construction and development, the construction of the Internet of Things for onshore oil and gas production in China has basically achieved basic functions such as data collection perception, data transmission aggregation, and data application. The construction of the "cloud end" architecture of the Internet of Things system for oil and gas production has been completed, achieving full connectivity of the Internet of Things in the oil and gas production business chain. 

The perception layer and control layer of the oil and gas production Internet of Things system are composed of various perception and control devices installed on the process flow of oil and gas wells, pipeline networks, station warehouses, etc., to achieve comprehensive perception of the production status of a single well and automatic control of various devices; The wireless heterogeneous network composed of wireless sensor networks, private networks, and public wireless technology constitutes the transmission layer of the system, which can achieve reliable data transmission; The application layer can achieve functions such as real-time monitoring of production dynamics, statistical analysis of production data, real-time diagnosis of production conditions, prediction of production trends, intelligent optimization of production parameters, centralized display of key alarms, and production scheduling command management. Among them, the introduction of IoT devices and network management systems can self diagnose and manage various sensing devices and transmission networks, while mobile intelligent applications can achieve functions such as IoT device installation, work order distribution for operation and maintenance, work reporting, data interaction with IoT devices, and application, making the management of oil and gas production more digital.

With the deepening of oilfield intelligent construction, the "cloud end" architecture is difficult to meet the real-time requirements, and needs to achieve fast edge computing and real-time response on the site. Therefore, a new architecture of the Internet of Things system for oil and gas production is proposed to support the intelligent acquisition of well pads and edge computing in the operation area, which effectively coordinates the analysis and decision-making of field data from the cloud to the well station, realizing the comprehensive perception, reliable transmission Smart applications.

2.2 Developed Refined and Intelligent Injection and Production Technology

Faced with the trend of inferior oil and gas resource grade in China, the main old oilfields have generally entered the stage of ultra-high water cut development, with a focus on developing refined and intelligent layered injection and production technology, which has improved reservoir recovery rate and development efficiency. 

(1) .We have established an adaptive flow regulation and water control completion method and technical system that can improve the balanced inflow profile of complex reservoirs, thereby improving the controlled reserves and recovery efficiency of a single well. Underground intelligent separate production and injection can increase the recovery rate by 15% and reduce operating costs by 50%; The adaptive flow regulation and water control completion technology for improving the balanced inflow profile of complex reservoirs can achieve maximum single well production capacity, increase production capacity by 23%, increase the opening rate of oil and water wells by 15.3%, and save oil production costs by 15.5%.

(2) .A fourth generation layered water injection process with the technical connotation of "measuring while injecting" has been formed, achieving online monitoring and intelligent control of injection layer pressure, flow rate and other parameters. The adaptive online measurement and adjustment decision control technology for layered water injection wells has been applied on a large scale in Daqing and Changqing oilfields, and the completion rate of layered water injection allocation has increased by 9.21 percentage points.

(3) .A series of technologies have been formed, including "self spraying layered production allocation", "mechanical production well water plugging", "hydraulic adjustable layer", and "intelligent separate production". Intelligent separate production technologies represented by pre installed cable layered oil production and vibration wave control layered oil production have been demonstrated and applied in oil fields.

(4) .A series of processes and intelligent equipment have been formed for low-pressure water outlet gas reservoirs, including bubble discharge, pressurized gas lift, and plunger gas lift. They have been applied on site with a scale of over 500000 wells, increasing natural gas production by nearly 2×10¹⁰ cubic meters, effectively promoting a leapfrog growth in natural gas production.

(5) .We have created an optimization model for variable speed drive in beam pumping wells and a fully coupled implicit iterative solution method with electric machine rod pump as boundary conditions. We have invented a flexible energy feedback control device for pumping wells and established an optimization control technology for variable speed flexible drive in pumping wells, effectively improving the economy and safety of oil well production. The application shows that the average power saving rate of the pumping well is 15.84%, the average peak torque is reduced by 16.04%, and the system efficiency is improved by 7.88 percentage points, completely eliminating negative torque and negative power generation.

(6) .The pioneering "optimization model for staggered peak pumping scheduling of pumping well groups" and "multi energy complementary microgrid production collaborative control technology" have been successfully applied in Changqing Oilfield of PetroChina, and have achieved good results, filling the gap in collaborative optimization technology for production of "wind light electricity" microgrid pumping well groups at home and abroad. The load rate of the pumping well motor has increased from 19% to 30%, and the comprehensive energy saving rate has reached 40.94%. On the premise of ensuring that the oil well production does not decrease, the daily electricity saving of the well exceeds 30 kW·h.