Knowledge of drilling geological exploration

Drilling geological exploration is a project to drill holes from the surface to the underground with drilling equipment, and take out soil, cores, cuttings and various liquid and gaseous media for analyzing and studying soil properties, stratigraphic structure and mineral conditions, or for development and construction. On the basis of geophysical and geochemical exploration, it is an engineering and technical method to directly explore ore deposits or carry out mineral development in order to further understand the stratigraphic situation and structure, find out whether there are target ore deposits, including the size, thickness and distribution of mining areas, formation pressure and other geological conditions. In recent years, with the continuous development of drilling technology, horizontal wells, unbalanced wells, slim holes and sidetracking wells have appeared one after another. Geological technicians can almost search and understand the detailed information of ore deposits and strata by analyzing and studying a large number of geological data obtained from drilling engineering.

The knowledge system of drilling geological exploration includes general geological knowledge, drilling engineering knowledge, logging knowledge, logging knowledge, testing knowledge, mineral development knowledge, experimental testing knowledge and so on. This requires us to obtain accurate and complete drilling data as much as possible. It is also necessary to learn to identify and evaluate all kinds of information revealed in single well geological data, which is also the basic quality that a geological university student and geological technician should have.

(A) knowledge of drilling engineering

Drilling engineering is a specialized course in geological colleges. Generally, taking ultra-deep well or oil drilling as an example, the basic principle and drilling technology of drilling are expounded. From the foundation of single well design to the implementation process of drilling engineering, as well as the methods and requirements for obtaining main drilling data and data information in the whole process.

Statistical table of geological drilling data

sequential

The information you need to know mainly includes:

Drilling geological design book.

Observation records.

Geological log.

Well deviation data sheet.

Drilling and coring records.

History.

Drilling geological design is the most important geological data for geologists to understand drilling construction. Its contents include: basic data, well name introduction, drilling properties (whether the well is a scientific exploration well, a parameter well or a development well), well location coordinates, geographical location, structural location, design well depth, target layer, etc. Introduction of regional geological structure; Design basis and drilling purpose; Design stratigraphic profile and coal seam location; Formation pressure prediction and drilling fluid requirements; Obtain geological data and data acquisition requirements, etc.

Some original data, such as casing data and logging instruments, are rarely used for geological research and mineral analysis, and belong to drilling engineering technical data. They are mostly used for studying the improvement of engineering technology, improving drilling efficiency, reducing operation cost and geological construction design of related wells, and analyzing operation accidents.

(2) Geological logging knowledge

Geological record is the geological and technical record accompanying drilling engineering. This kind of record, including written records and equipment records, is the main channel to obtain the geological data of single well drilling. It is divided into cuttings logging, fluorescence logging, drilling fluid logging, gas logging logging, core logging, comprehensive logging and geochemical logging.

There is a set of basic data in logging work, which is necessary to record this well. For example, the coordinates of well location are usually based on WGS-72 system, and areas 3 and 6 are usually displayed on recorded data, which are generally calculated by satellite positioning system and triangulation points. Some use latitude and longitude coordinates alone or at the same time. Well location coordinates and administrative geographical location are the most basic data of a single well. Well location coordinate data is confidential, and its leakage is easy to be hit by missiles or otherwise damaged. Therefore, geological data storage units are generally not allowed to extract or copy data to prevent leaks.

Core logging is an important part of logging work, and core is the most authentic and valuable information to understand strata and coal seams. For example, many geological data of oil and gas fields are obtained by laboratory analysis of cores, such as porosity, permeability, oil saturation, distribution and thickness of oil and gas layers. Through the experimental analysis of cores from several wells, we can understand the distribution law of deposits, accurately calculate reserves, determine reasonable development plans, take corresponding measures according to mineral characteristics to increase mineral production and protect oil and gas reservoirs with cores as the research object.

Cutting logging needs to understand the relationship among well depth, drilling arrival time, later time and sand fishing time, which is an important factor to master the description of cutting depth. When we observe and use the physical data of cuttings, we need to know how to determine the depth of cuttings, which is calculated according to a certain depth interval and cuttings' late time during drilling, salvaged at the mud outlet and returned to the ground with drilling fluid. Debris logging is an important means to establish stratigraphic profile, understand stratigraphic sequence, lithologic combination and mineral display. The most important requirement of cuttings logging is that the depth and later time of drilling tools are accurate. The miscalculation of cuttings depth or the description of cores and cuttings will lead technicians to misjudge the geological horizon and rock properties. Skilled and experienced technicians are not at ease when they read the descriptions of cores and cuttings. They must observe the physical or physical scanning images of the core cuttings, for fear that the logging technicians will give an incorrect description of the core cuttings. Due to the misjudgment of cuttings depth, there may be errors in horizon depth and lithology in mineral development operations, which may easily lead to misunderstanding of mineral resources.

Oil samples, gas samples, water samples or other minerals are also physical data, and their collection has specific requirements. Oil sample: Collect 250ml crude oil sample in drilling fluid tank with special jar; For gas samples, use the degasser in the gas measuring instrument to sample; If there is no gas measuring instrument, sample with drainage gas sampling method and put it in a bottle for sealing; 5ml drilling fluid was taken from the water sample by water loss meter method, and ion determination was carried out on site. After the detailed label is attached to the outside of the sample bottle, some oil samples, gas samples and water samples should be sent to the laboratory for analysis in time, and the other part should be kept as physical data.

Statistical table of data generated by logging engineering

sequential

sequential

The logging geological data to be understood mainly include:

Completion geological summary report (sometimes called completion geological summary).

Comprehensive logging map (cuttings logging, core logging, etc.). ).

Gas mapping.

Comprehensive logging chromatographic analysis record.

Oil, gas and water histogram.

Basic drilling data sheet.

Core log.

Well deviation data sheet.

Among them, the geological report of single well completion is the most frequently used. The main contents of the completion geological report include: preface (introducing the basic situation of the well and the completion of geological tasks, etc. ), drilling logging profile (the influence of drilling conditions on logging quality), drilling results (stratum, structure, coal seam, source-reservoir caprock and formation pressure), conclusions and suggestions (whether the drilling has achieved the geological purpose, geological knowledge and conclusions of the well and existing geology).

When technicians can't quench their thirst or have questions after reading the completion geological summary report, they will refer to relevant comprehensive logging and other maps in detail. A detailed understanding of the logging records of strata and lithology. Many simple mineral exploration and completion geological reports only involve minerals, not other minerals, and many other minerals are found in the mineral description of comprehensive logging data. Therefore, the logging map plays a great role in comprehensively understanding the geological conditions of single wells.

(3) Logging engineering knowledge

Logging engineering is a part of drilling engineering. Only after the drilling project is started can the "logging" construction be carried out in the borehole. Its full name is also called geophysical logging, so geophysical logging data can also be classified as geophysical exploration data. Geophysical logging is indispensable for the exploration of underground minerals, especially in the field of oil and gas exploration, and it is a single well logging data that geological and technical professionals can't wait to check to know whether the well is "brilliant".

Geophysical logging is a technical method to evaluate mineral resources by measuring various physical and chemical parameters of strata with relevant detection instruments in drilled wells. It can be used not only to judge the rock properties of strata, determine the thickness and buried depth of strata, but also to compare strata in drilling area, test the dip angle, dip angle, faults and structural characteristics of strata, not only to detect the physical properties and ore-bearing conditions of reservoirs, but also to study the sedimentary environment, rock mass distribution and special mineral composition, not only to detect the temperature, pressure, tension and oil, gas and water interface of strata, but also to conduct static analysis of strata or deposits. For mineral exploration, logging technology should help exploration technicians solve the following problems: whether there are target minerals underground, how many, whether they can be mined, how long they will be mined, and whether they have industrial value; If the next exploratory well has not been drilled, how will the well location be deployed if drilling continues? If it is a development well, how to arrange the well pattern and so on.

Logging engineering technology is the most widely used technology in oil and gas exploration and development projects. Researchers pay attention to the drilling process. In addition to breakthrough discovery, logging information and its data are the first-line well site information of primary concern. Its role in mineral exploration and development, especially in oil and gas exploration and development can be seen.

In recent years, logging methods have also developed greatly. Electrode logging technology, electromagnetic logging technology, acoustic logging technology, radioactive logging technology and VSP logging technology are widely used. Sometimes a single logging technology is used, and in most cases, the above logging technology is used comprehensively. The emergence of a new generation of scanning imaging and array imaging logging technology has obviously improved the comprehensive geological analysis and logging evaluation ability of complex lithologic deposits and subtle oil and gas reservoirs. Logging instruments have also developed from CLS-3700 numerical control logging to ECLIPS-5700 imaging series logging, which can provide new technical services such as conventional logging, acoustoelectric imaging, dipole acoustic wave, nuclear magnetic resonance and array induction logging. The image provided by imaging logging is often an intuitive display of geological phenomena.

Although electrode logging is out of date, it is still a low-cost electrode logging technology in some shallow wells with low requirements. Moreover, because there are a lot of old data produced by electrode logging in history, it is necessary to know the knowledge of electrode logging technology in the past, so as to develop, utilize, study and excavate the old data of electrode logging and serve for mineral exploration and development and geological research.

With the development in recent years, logging data not only need to be used to evaluate formation lithology, reservoir space and fluid types, but also play an important role in many fields, such as mineral geology research, wellbore stability control of exploration and drilling engineering, pressure prediction, design and optimization of tight reservoir pressure transformation scheme, rapid identification of oil, gas and water layers in open-hole wells of exploration wells, productivity prediction and evaluation, etc. They have contributed to reducing the cost of mineral exploration and development, improving exploration efficiency and mine benefits.

In modern logging technology, we need to know logging knowledge, and the logging data we need to read mainly include electrode logging, electromagnetic logging, acoustic logging and radioactive logging. Gas logging, also known as gas logging while drilling, was carried out in the logging stage, also known as gas logging. According to the current situation of logging technology and equipment in enterprises and the collected logging data, we can choose to learn, understand and accumulate relevant logging knowledge, and compare the reflection characteristics of different lithologic strata and various logging curves in order to understand and use logging data.

Statistical table of main data of logging engineering

sequential

The main logging data to be understood are:

Geological report of logging interpretation.

Comprehensive logging map 1: 200.

Natural gamma logging map 1: 200.

Standard logging map 1: 500.

Cementing quality inspection chart.

Comprehensive interpretation results of imaging logging 1: 200.

Sonic logging 1: 200.

Overview of seismic logging (VSP)

Geothermal logging map.

Reservoir response characteristic map.

Imaging crack analysis diagram.

Deformation bedding imaging map.

Among them, the single well logging interpretation geological report, also known as logging geological summary, is the most frequently used. Geophysical logging is to obtain measurement data through logging equipment and instruments, and draw them into various graphs through processing and interpretation software. Logging interpretation geological report is the interpretation and summary of the result map. When technicians can't quench their thirst or have doubts about reading the geological report of logging interpretation, they will consult the interpretation of relevant logging maps and related logging data. A knowledgeable researcher will directly ask the logging frontline personnel to send back the logging data volume, and use the workstation system to process and interpret the data and read the logging curve. Understand and deal with the underground construction in time, and guide the further exploration, development, research and deployment of the mine.

(4) Geological experiment knowledge

Geological experiment is an integral part of geological and mineral work, which runs through the whole process of geological research, geological prospecting and mineral development. It provides technical services for geological research, prospecting and mineral development, and mineral development experiment is a professional technical work. In order to determine the paleogeographic environment, it is necessary to find out the corresponding paleontology to prove it in the laboratory analysis of physical data such as cores. In order to determine the mineral composition and content, it is necessary to analyze and test the ore, and sometimes it is necessary to simulate the underground environment for mineral development experiments. The results of these geological experiments or laboratory analysis are called experimental reports and laboratory analysis reports. First of all, we must be able to understand the experimental analysis data and corresponding written reports, and then we can conduct exploration and development research of geology and minerals on this basis, and then we can understand and discover them.

Statistical table of geological experiment analysis data

sequential

sequential

The materials to be read mainly include:

Rock mineral appraisal report and analysis result table.

Physical property analysis report and analysis result table.

Paleontological analysis report and analysis result table.

Scanning report and analysis result table of electron microscope.

Absolute age determination report and analysis result table.

Analysis report and analysis data sheet of acid hydrolysis hydrocarbon.

Gas composition analysis report and analysis data sheet.

Oil, gas and water test report and analysis data sheet.

……

The experimental analysis report is generally divided into two parts: the report body part and the analysis data table. The text part explains the geological significance of the data in the data table, and the experimental analysis data table is the laboratory analysis data of the experimental instrument to the sample delivery object or the experimental object. When reading these reports, geologists should read the text first, because it is a geological interpretation conclusion obtained through experiments or laboratory analysis. Secondly, check the laboratory analysis data from the data table, and more often read the text while comparing the laboratory analysis data.

According to the actual needs of research, geological technicians decided to collect samples of physical data and send them to laboratory analysis units for experimental analysis. Generally speaking, they will read the samples they send carefully. Many laboratory analysis researchers will accumulate and analyze the laboratory analysis data of a certain area, write academic articles on the paleogeographic environment and other aspects of the area, discover new paleontological species in the area, and identify paleogeography, climatic environment and ore deposit formation conditions, which will be published in industry journals and attracted much attention.

(5) Test knowledge and trial production knowledge

1. Oil testing

During or after drilling, the coal seam is tested to obtain the relevant parameters of formation pressure and fluid under dynamic conditions, and the formation and related mineral development are evaluated according to the parameters. The main parameters are: oil, gas, aquatic product output, daily production capacity, etc. Flow pressure, formation pressure and production pressure difference; Data of fluid properties and high-pressure physical properties; Formation parameters and formation damage degree; Oil-bearing height and oil-water interface; Test radius, fault interface display, energy supply and reserve parameters, etc.

Statistical table of main data of test engineering

Understand the interpretation of test curve. General curves are divided into six categories: high permeability curve, low permeability curve, high pressure and low permeability curve, low pressure and low permeability curve, pollution blocking curve and energy depletion curve. Compared with logging curves, these test curves have response rules to follow. The test data can be used for early evaluation of ore deposits.

Test data mainly need to know these curve data and test interpretation report. Midway test data mainly include: layered test summary, pressure build-up curve, processing and interpretation report, and high-pressure physical data.

2. Trial production knowledge (taking oil trial production as an example)

Trial mining refers to the trial mining of minerals. It is also called oil testing in the field of oil and gas field development. Take oil testing as an example here. Oil testing is called oil testing geology and technology in academic environment, which is an important procedure from oil and gas exploration to oil and gas field development, and a direct means to find out the oil and gas water distribution and understand the corresponding horizons.

In the process of oil testing after drilling, reservoir protection is a principle that should be followed in oil and gas field development projects. Perforation horizon, well washing and induced injection, production finding, pressure measurement, acidification and fracturing are the key links in the oil testing process.

Statistical table of data mainly produced during oil testing.

Geological data generated by oil testing project mainly need to be read as follows:

Trial production report (also called geological summary of trial production) and drawings, schedules and accessories, such as oil test report and drawings, schedules and accessories. It provides a basis for oilfield development plan.