Uncovering the mystery of "weak signal" formations——Record of the development of logging evaluation technology for weak signal oil and gas layers of Petrochemical Jingwei Company

A few days ago, Sinopec Jingwei Co.
, Ltd.
Zhongyuan Measurement & Control Co.
, Ltd.
used the weak signal oil and gas layer logging evaluation technology to accurately evaluate the lacustrine shale gas reservoir in the Puluye 1 well in the Puguang area, providing a favorable and detailed exploration basis for lacustrine oil and gas development.

.

This technology won the third prize of the Group's scientific and technological progress in 2020

Six years to sharpen a sword

Grind a sword in six years grind a sword in six years

Weak signal oil and gas layers refer to oil and gas layers in which logging data show weak oil and gas response during drilling.
Logging evaluation methods are extremely difficult to identify oil and gas reserves, and oil and gas layers that can obtain industrial oil and gas flow after being put into production
.

With the development of the oil and gas industry, global oil and gas exploration has gradually developed into oil and gas reservoirs with tight lithology, large mud intrusion, and poor logging oil and gas response characteristics such as oil shale.
The previous logging data interpretation and evaluation technology can no longer meet the complex requirements.
The changing geological requirements have severely restricted the fine exploration and development of oil and gas resources
.

In order to improve the accurate identification of this type of oil and gas layers and better serve the oil and gas exploration and development, in February 2014, Zhongyuan Measurement and Control Company organized scientific and technological research forces to conduct research on the logging evaluation technology of weak signal oil and gas layers with the Dongpu Sag as the research work area
.

　　In the logging data repository covering an area of ​​700 square meters, there are the logging curve data maps of nearly 10,000 wells since the development of the Dongpu Oilfield in 1976, like finding a needle in a haystack.
Where do you start? At that time, Zhongyuan Measurement & Control Co.
, Ltd.
Explain that the research team led by Zhao Junfeng, director of the Computing Center, decided to change its mindset from "finding a needle in a haystack" to "fishing in a field
.

" They are divided into blocks, first find out the dry, poor, or unsolved layers that were once weak signals, and then go to the Geological Institute and the oil production plant to find out whether these reservoirs have oil test records, and then combine drilling, logging, and logging.

　　They conducted standardized analysis of the lithology, physical properties, electrical properties and other characteristics of these reservoirs, and carried out secondary fine processing and interpretation to find out the reservoir characteristics and laws of weak-signal oil and gas layers, and construct oil and gas layers of different types of storage spaces The evaluation model finally formed a set of weak-signal oil and gas layer logging evaluation technology, and obtained 4 types of complex lithology logging identification methods, 3 types of weak-signal oil and gas layer logging response modes, and 5 new types of weak-signal oil and gas layer logging identification methods.
8 research results including methods
.

At this point, the mystery of the "weak signal" formation has finally been unveiled

　　First try

　First test of edge　First test of edge

　　"Fang 2 well tested oil according to our interpretation and conclusions to obtain high-yield industrial oil flow, which strengthened the research team's confidence in winning
.

" Research team member Hou Liyun said happily

　　Well Fang 2 is an appraisal well deployed in Fangliji in the western subsag zone of Dongpu Depression in Zhongyuan Oilfield
.

After drilling, the logging and geological oil and gas showed extremely weak and low resistivity values.

　　The interpreters of the research team used the weak signal oil and gas layer logging evaluation technology to interpret and evaluate the well, respectively explaining the oil and gas layer, the oil-water layer and the oil-bearing water layer
.

In February 2015, Fang 2 well tested oil and obtained high-yield industrial oil and gas flow.

　　Subsequently, they actively promoted the weak signal identification technology in major domestic oil and gas fields, and successively applied and analyzed them in 200 wells in 6 petroliferous basins in China, and realized low-resistance and low-differential oil layers in the Bohai Bay, low-resistance oil and gas layers in Tarim, and Sichuan.
Accurate identification of low-resistance gas layers, Ordos tight sandstone gas layers, Yin'e tight oil and gas layers, and Songliao shale oil layers.
The accuracy rate of logging identification for weak-signal oil and gas layers reached 92.
6%
.

On April 19, 2020, the technology was well applied in Pulu 3, a key exploration well for continental exploration in Puguang Exploration Area.

　　Huashan tournament

Huashan on the sword Huashan on the sword

　　On June 23, 2020, the Ministry of Science and Technology of China Petroleum & Chemical Corporation invited top experts in logging interpretation of the group company to form an appraisal committee to appraise the technical achievements of the "weak signal oil and gas reservoir logging identification technology" completed by Zhongyuan Measurement & Control Company
.

At the appraisal meeting, experts debated the results from the theoretical basis, innovative points, and application and promotion of the new method of oil and gas reservoir identification.

　　In order to participate in the evaluation of the results, the technical research team made sufficient preparations, sorted out and sorted out the research results in the past six years, and collected comparative data on the application effects of 200 wells in six petroliferous basins
.
In the end, the appraisal committee agreed that the results reached the international advanced level and filled the domestic technological gap
.

　　Central Plains measurement and control data interpreters always take "serving for oil and gas exploration and development and building a domestic first-class processing and interpretation center" as their work goal, and have carried out a series of technical research on bottlenecks that restrict oil and gas exploration and development
.
In the past three years, the company has established a total of 17 scientific research projects on data interpretation at bureau level and above; it has formed weak signal oil and gas layer logging identification, gas storage logging evaluation and dynamic monitoring, using logging data to determine drilling fluid loss horizons, Five core technologies including horizontal well dynamic monitoring and shale oil and gas logging evaluation; two National Energy Administration industry standards have been formulated to realize the "one book" of interpretation methods
.
The project has also contributed to major oil and gas discoveries in major domestic petroliferous basins such as the Bohai Bay Basin, Ordos Basin, Tarim Basin, and Sichuan Basin
.