CN114741390B

CN114741390B - Lithology profile dividing method based on real-time drilling parameters

Info

Publication number: CN114741390B
Application number: CN202210335249.2A
Authority: CN
Inventors: 李战奎; 谭忠健; 郭明宇; 苑仁国; 徐鲲; 张恒; 罗鹏; 崔国宏; 刘松宇; 刘广明; 张学斌; 李鸿儒
Original assignee: China National Offshore Oil Corp CNOOC; CNOOC Energy Technology and Services Ltd
Current assignee: China National Offshore Oil Corp CNOOC; CNOOC Energy Technology and Services Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2024-11-01
Anticipated expiration: 2042-03-31
Also published as: CN114741390A

Abstract

The invention discloses a lithology section dividing method based on real-time drilling parameters, which solves the problems of difficult construction of the lithology section of a Bohai sea recent stratum and low section coincidence rate. The invention can quickly and accurately construct lithology section, saves labor cost and time, saves unnecessary logging items and logging time, obviously improves the drilling time and has obvious economic benefit.

Description

Lithology profile dividing method based on real-time drilling parameters

Technical Field

The invention belongs to the technical field of petroleum exploration, and particularly relates to a lithology section dividing method based on real-time drilling parameters.

Background

With the rapid development of drilling operation, the drilling operation period of a newly-tied shallow exploratory well is continuously shortened, the rhythm is continuously accelerated, the on-site geological logging operation is compact and important, on the other hand, the newly-tied stratum gas measurement value is low, the abnormal amplitude is not obvious, the representativeness of returned rock debris is poor, and the like, which are the phenomenon that the logging of the newly-tied exploratory well is common, so that the problem of low logging profile compliance rate is outstanding, a lot of troubles are caused to logging data quality and later interpretation work, on the other hand, the progress of science and technology makes the intelligent geological logging become a future unblockable trend, and the requirement of establishing an automatic rapid logging method is increasingly obvious, so that a method capable of improving the shallow logging profile compliance rate is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a lithology section dividing method based on real-time drilling parameters. The method uses the sand index SI and the torque to meet, when the torque meets the right side of the sand index SI, the formation lithology is sandstone, otherwise, the formation lithology is mudstone. The method is used for deep excavation of logging data, can reduce the influence of interference factors and improve the quality of on-site real-time logging profile. The method has good application effect, the coincidence rate of the section obtained by intersection and the final correction section is high, and particularly, the coincidence rate of the section of the bottom main objective interval exceeds 90 percent. The technology of the invention is applied in semi-intelligentization at present, combines a medium-method logging system, realizes the intersection of a real-time SI index curve and a real-time torque, rapidly constructs a preliminary lithology section by the system, and performs final lithology homing by combining on-site supervision with the data of cuttings logging, gas logging and the like, thereby greatly improving the accuracy and timeliness of geological logging section establishment.

The invention is realized by the following technical scheme:

A lithologic section dividing method based on real-time drilling parameters is carried out according to the following steps:

Integrating the collected drilling parameter data into a table, and obtaining parameters (min/m), weight on bit (t) and torque (kN.m) required by formation profile construction related to lithology judgment;

Step two, constructing a real-time parameter sand index SI formula, wherein the details of the formula are as follows: si=w (1+a) x T (1+b) x R (1+c). Wherein W is weight on bit, t; t is torque, KN.m; r is min/m when drilling; a, b, c are the weight of each parameter, and no unit exists;

Step three, carrying out operation of a normalization coefficient K, and defining a K value adjustment method as the ratio of SI median (or average value) to torque T median (or average value) in the depth range of lithologic dividing section, namely

And fourthly, under the general condition of the shallow stratum, the stratum level change and the K value need to be adjusted once before and after the drilling fluid performance conversion.

And fifthly, adjusting the SI index threshold range in the software graph according to the calculated K value, wherein the torque determination threshold range is 0-X, and the SI index threshold range is 0-K.X.

Step six, putting the SI index curve and the torque T curve obtained by calculation in the same graph in software, and carrying out intersection filling to form a graph;

and seventhly, filling yellow when the torque curve and the SI are in forward intersection, wherein the representative stratum lithology is sandstone, filling green representative lithology when the torque curve and the SI are in reverse intersection is mudstone, performing curve intersection quality control by adjusting the parameter coefficient K value, and adjusting the threshold range of the SI formula so as to realize quick adjustment of the curve.

In the technical scheme, the drilling parameter data are integrated in a table, the data acquired by the logging sensor are automatically stored in a database, the drilling parameters are extracted from the database, and the data are calculated and processed by editing formulas in the logging database.

In the technical scheme, WOB is weight on bit, which represents the weight of the drill rod and the drilling tool applied at the bottom of the well, and the unit is ton (t); TRQ is torque, which represents the torque required by the rotation of a drill bit during drilling, and is expressed in kilonewtons per meter (KN per meter); ROP is the time in minutes per meter (min/m) required to drill 1 meter per drill.

In the technical scheme, the method is completed by using geological exploration mapping software such as RISExpress or Geofence.

Compared with the prior art, the invention has the advantages that:

Drawings

FIG. 1 is a DrillingLog plate of the present invention.

Fig. 2 shows the results of the present invention.

Other relevant drawings may be made by those of ordinary skill in the art from the above figures without undue burden.

Detailed Description

The technical scheme of the invention is further described below with reference to specific embodiments.

Examples

Step one, acquiring data of drilling parameters by a logging sensor, entering a logging database, and directly calling and selecting the required drilling parameters from the on-site logging database according to the requirement: drilling time (min/m), drilling pressure (t) and torque (KN.m);

step two, calculating a sand index si=weight on bit torque while drilling;

TABLE 1

Well	Depth	Rop	Wob	Torque	SI
						Well name	Depth of	Drilling time	Weight on bit	Torque moment	Sand index
BZ-1 well	500.00	1.38	0.40	1.06	0.5851
						BZ-1 well	501.00	0.95	1.20	1.13	1.2882
BZ-1 well	502.00	1.09	1.40	1.17	1.7854
						BZ-1 well	503.00	3.38	0.90	0.60	1.8252
BZ-1 well	504.00	0.69	0.40	0.65	0.1794
						BZ-1 well	505.00	0.73	0.80	0.83	0.4847

Step three, calculating a normalization coefficient K comprises the following two methods:

Definition of the definition For example, the selected interval is D-Dm, D is the interval top depth and D is the interval bottom depth. The normalized coefficient k=si median (or average)/torque T median (or average). In general, the K value needs to be adjusted once before and after the performance of the drilling fluid is converted, and the K value needs to be adjusted once for the stratum horizon change.

TABLE 2

Step four, adjusting the SI index threshold range in the software graph according to the calculated K value, wherein the torque determination threshold range is 0-X, and the SI index threshold range is 0-K.X;

Examples: as shown in FIG. 1, the torque T is in the range of 0-10 KN.m, and the K value is 3.0 by the final calculation, so the sand index SI is in the range of 0-30 KN.m. (FIG. 1)

Remarks: k value adjustment: if the slurry is converted and the stratum is changed, the K value needs to be calculated again, and the newly calculated K value is applied to the newly drilled well section to adjust the value range of the SI index.

Fifthly, dividing lithology sections of the SI index and the torque T curve in the same graph according to the intersection condition of the two parameter curves in the graph, filling the intersection part with yellow when the torque curve and the SI index curve are intersected in the forward direction, wherein the lithology of the stratum is represented by sandstone, filling the intersection part with green when the torque curve and the SI index curve are intersected in the reverse direction, and carrying out lithology section fine adjustment by combining an observation sample fished in the field. (FIG. 2)

The foregoing has described exemplary embodiments of the invention, it being understood that any simple variations, modifications, or other equivalent arrangements which would not unduly obscure the invention may be made by those skilled in the art without departing from the spirit of the invention.

Claims

1. The lithology section dividing method based on the real-time drilling parameters is characterized by comprising the following steps of:

Integrating the collected drilling parameter data into a table, and obtaining parameters required by formation profile construction, namely drilling time min/m, drilling weight t and torque kN.m, which are related to lithology judgment;

Step two, constructing a real-time parameter sand index SI formula, wherein the details of the formula are as follows:

si=w (1+a) x T (1+b) x R (1+c), where W is weight on bit, T; t is torque, KN.m; r is min/m when drilling; a, b, c are the weight of each parameter, and no unit exists;

Step three, calculating a normalization coefficient K, and defining a K value adjusting method as the ratio of SI average value to torque Taverage value in the lithology dividing section depth range, namely

Step four, under the shallow stratum, the stratum level change and the K value need to be adjusted once before and after the drilling fluid performance conversion;

Fifthly, adjusting the SI index threshold range in the software graph according to the calculated K value, wherein the torque determination threshold range is 0-X, and the SI index threshold range is 0-K.X;

2. The lithology section dividing method based on real-time drilling parameters according to claim 1, wherein: the drilling parameter data are integrated in a table, the data acquired by the logging sensor are automatically stored in a database, the drilling parameters are extracted from the database, and the data are calculated and processed by editing formulas in the logging database.

3. The lithology section dividing method based on real-time drilling parameters according to claim 1, wherein: WOB is weight on bit, which represents the weight of the drill rod and the drill tool applied at the bottom of the well in tons;

TRQ is torque, which represents the moment required by the rotation of a drill bit during drilling, and the unit is kilonewton-meters; ROP is the time in minutes per meter required for drilling, representing 1 meter per drill.

4. The lithology section dividing method based on real-time drilling parameters according to claim 1, wherein: the method is accomplished using RISExpress or Geofence geological survey mapping software.