DZ/T 0080-2010Specifications for geophysical logging of coal (English PDF)

3.9 Determination of logging geological tasks

3.9.1 The determination of logging geological tasks shall be based on the requirements of overall exploration geological task, combined with the ability of logging technology to solve the geological problem, defined in the overall exploration design in the relevant logging technology chapters and logging engineering design.

4.1 Basic requirements

4.1.1 Design is the basis for guiding and implementing data collection, processing, interpretation, report preparation, result submission of logging work.

The project leader shall organize the relevant logging technicians to prepare it according to this specification and project contract requirements.

4.2 Requirements for preparation of design

4.2.1 Main content of the text part

4.2.2 Main attached drawing

4.2.3 For general small (determined according to the actual situation of each

province) or lower level (pre-censored) survey projects, it may, based on the actual conditions, appropriately brief or only compile the logging part of the geological exploration design.

4.3 Review, approval, modification of design

4.3.1 The design shall be reviewed by the overall project undertaker in accordance with this specification and the overall project survey design, reported to the project supervisory unit for approval. Logging engineering design that has not been approved for inspection shall not be used as a basis for logging operations.

4.5 Test work

4.5.1 Where the geological-geophysical characteristics are not fully grasped and new methods and techniques need to be studied or promoted, it shall carry out the test work on the reference holes or representative drill holes, to determine effective logging parameters and interpretation law.

4.5.2 The reference hole must be cored in full hole. The length adoption rate of rock and coal core shall be higher than 75% and 90% respectively.

4.5.3 It shall prepare the test plan before the test. It shall prepare the test summary in time after the test.

5.1 Logging notice

5.2 Logging preparation

5.2.1 It shall, based on the design requirements, the drilling exploration data of the borehole to be tested, the logging data of adjacent hole, analyze the geological conditions of the borehole.

5.2.2 Check the working status of the instrument on site and follow the

requirements of Table B.3 in Appendix B to fill in the inspection results. At the same time, the data related to the adjustment and test must be recorded in digital and monitored records, meanwhile the corresponding charts shall be drawn and well kept.

5.3 Drilling preparation

5.3.1 There shall be more than 10 m of open space in front of the drill floor of the well site. It shall ensure the smooth entry and exit of the logging vehicles.

5.3.2 The final hole’s depth must ensure that all downhole instruments can measure 5 m below the lowest level of the target. The final hole’s diameter shall be 20 mm larger than the outer diameter of the well.

5.4 Well site layout

5.4.1 Logging equipment shall be properly placed. The distance between the winch and the wellhead shall be greater than 10 m and can be viewed through.

5.4.2 The downhole cable shall pass through the center of the orifice. The ground wheel’s groove shall be perpendicular to the axis of the winch drum and aligned with the midpoint of the drum.

6.1 Original record

6.1.1 The original record shall generally include.

6.1.3 Digital record

6.1.4 Original monitoring and playback of the well site

6.1.5 Preliminary interpretation of coal-seam well site

6.2 Measuring range

From 5 m ~ 10 m below the deepest target layer to 10 m ~ 20 m of the depth of the wellhead. Special intervals are carried out as required by the design or logging notice.

6.3 Sampling interval

The sampling interval for the target interval is not more than 5 cm. The sampling interval for other intervals are not more than 10 cm. Special logging methods shall be determined based on the required measurement accuracy and instrument performance and specified in the design.

6.4 Collection method

6.7 Quality evaluation and acceptance of original data

6.7.1 The quality evaluation of the original data is carried out by combining single-hole single-parameter evaluation with single-hole comprehensive evaluation.

6.7.2 The quality evaluation of the single-parameter raw data is divided into four levels. A, B, C and wasted. See Table 3 and Table 4 for the quality standard indicators of each level.

7.1 Natural gamma logging

7.1.1 The natural gamma’s count rate is in cps (pulse/second). After scale calibration, the natural gamma’s unit is pA/kg.

7.2 Compensation density logging

7.2.1 The count rate units of long source distance and short source distance

are cps (pulse/second). The compensation density unit after processing calculation is g/cm3.

7.2.2 Before the instrument is downhole, use the inspection device to measure the response value of the long source distance and the short source distance.

It is compared with the base reading. The relative error is not more than 3%.

7.5 Acoustic time difference logging

7.5.1 The unit of time difference is µs/m; and the speed unit is m/s.

7.5.2 Before the instrument is downhole or used for logging, it is inspected in the steel pipe (or aluminum pipe). The difference between the response value and the standard value shall not exceed 8 µs/m.

7.5.3 In the well segment of the regular well wall, the beating caused by non- stratigraphic factors shall not exceed 4 times per 100 meters. It is not allowed to appear on the target layer (except for hole-diameter expansion).

7.6 Sound amplitude logging

7.6.1 The unit of the sound amplitude recording curve is mV. After the relative evaluation standard scale is established, the unit is %.

7.6.2 The curve amplitude of the free casing section of the well is calibrated to be 100%.

7.16 Well temperature logging

7.16.1 The well temperature’s unit is °C.

7.16.2 The instrument shall be inspected before downhole. The checkpoint shall be not less than two. At given two points, the temperature difference shall be greater than 5 °C. The measured value differs not more than 1 °C from the given value.

8.1 Processing of logging data

8.1.1 Pre-processing of logging data

8.1.2 Processing of logging data

8.1.2.1 When the logging data subjected to filtering, it shall select reasonable filtering methods and parameters.

8.1.2.2 When calculating physical quantities, it shall use the latest scale data and correct various influencing factors.

8.1.2.3 It shall produce the frequency cross plots, Z-value plots or other statistical charts.

8.2 Interpretation of single-hole data

8.2.1 Logging borehole shall be subjected to full-hole geological interpretation.

The principle of interpretation shall be reasonable and the basis shall be sufficient.

8.2.2 Study the geological and geophysical characteristics and laws of the

construction area. Select appropriate lithology identification and stratification methods.

8.2.3 Interpretation of coal-seam

8.3 Whole-area study

8.3.1 Carry out statistics and analysis of logging physical property data of coal

and rock-layers in the whole-area, study their physical characteristics, changing rules and particularities.

8.3.2 Analyze the influencing factors of coal and rock-layer properties and

logging curves; study and determine the methods for correcting the influencing factors.

8.3.3 Study and summarize the methods and rules of qualitative, fixed-

thickness, quantitative interpretation of the work area.

8.3.4 Comparative analysis of coal and rock-layer

It must use three or more qualitative and fixed-thickness physical parameters to determine the coal and rock-layer contrast.

8.3.6 Coal-seam analysis

Based on the comparison data of coal and rock-layers, establish the geological plane of the main recoverable coal-seams, to analyze the distribution characteristics and variation laws of coal-seams.

9.1 Basic requirements

9.1.1 For the submission of logging results, it shall extensively collect and study the relevant information such as logging, geology, hydrology, ground geophysical exploration and drilling in the construction area and adjacent areas.

9.2 Preparation, submission, acceptance of single-hole result

specification

9.2.1 Before the preparation of the single-hole interpretation result specification, the technical person in charge of the preparation shall, based on the design requirements and combining the regional geophysical characteristics and the actual conditions of the logging work, draw up a practical outline based on this specification.

9.2.2 Main content of the text part

9.3.4 Main contents of the attached form parts of the professional technical

report

9.3.5 For general small (determined according to the actual situation of each

province) or lower level (pre-censored) survey projects, the professional technical report may be simplified appropriately according to the actual situation or only the logging part of the geological exploration report may be prepared.

9.3.7 Acceptance and approval of professional technical reports.

9.3.7.1 The acceptance of professional technical reports shall generally be carried out in four stages. preliminary review, comment, review, approval.

......