New karst stage judgment method

Abstract

The invention provides a new karst stage judgment method. The karst reservoir is a new field of recent oil and gas exploration and development, and the judgment of karst development stage is the difficulty in a karst reservoir modeling technology at home and abroad. The existing karst stage judgment method mainly takes an exposure marker as basis of judgment, but various karst process forms exist, so that the karst processes caused by factors such as hydrothermal solution are difficult to judge due to the lack of an exposure marker. The invention provides a new method for objectively judging the karst stage by combining a method for judging the filling stage by carbon and oxygen isotopes of karst fillings and a method for judging the karst fluid active stage by inclusion homogenization temperature aiming at the problem of karst stage judgment. A carbon and oxygen isotope discrimination chart and an inclusion homogenization temperature comparison diagram are established by the new karst stage judgment method, so that the karst development stage can be accurately and rapidly judged, the limitation that the traditional karst stage judgment takes the exposure marker as basis is broken through, and the problem that karst stage judgment is difficult under the condition that the underground deep layer is short of exposure marker can be solved.

Description

technical field

[0001] The invention relates to a new karst stage discrimination technology in karst reservoir modeling, which is suitable for judging karst stages in marine carbonate rock basins. Background technique

[0002] Karst reservoir is an extremely important oil and gas reservoir. Recently, a number of important discoveries have been made in the karst reservoirs of marine carbonate rocks in the three major basins of Tarim, Sichuan and Ordos in my country, which have become the most important oil and gas reservoirs in the carbonate rock series. Phase identification has always been a major problem faced by the petroleum geology community.

[0003] Predecessors have carried out a lot of research and exploration in the study of karst reservoirs, and formed a basic method based on exposure signs as the main basis for identification. Commonly used methods include: judging karstification and possible karst stages in the outcrop area through unconformity surfaces and diss...

Examples

Embodiment 1

[0076] Taking the identification of carbonate rock karst stages in the Halahatang area in the northern Tarim Basin as an example, previous studies mainly based on the unconformity on the seismic section. Since the wells drilled in the study area are generally deep and there are few wells, it is difficult to identify The exposed signs can be directly identified on the core to distinguish the karst stage. In the 78 wells in the study area, a total of 22 effective samples were obtained, and the carbon and oxygen isotope values ​​(mainly measured 13 C PDB and δ 18 o PDB ) and inclusion homogeneity temperature data, and using the measured data (Table 4, Table 5), the carbon and oxygen isotope values ​​are calibrated to the carbon and oxygen isotope maps obtained above, and there are distributions in all five areas ( Figure 12 ), indicating that five phases of filling also occurred in the Halahatang area. The average homogeneous temperature distribution map established by using...

Embodiment 2

[0083] Taking the Tahe Oilfield as an example, the karst identification period is explained. Compared with Halahatang, the Tahe Oilfield has relatively more cores, and some of the cores can be identified with exposure signs, but it is still not enough to provide direct evidence for the identification of karst stages. According to the method of the present invention, 32 data carbon and oxygen isotope values ​​(Table 6) are used to calibrate to the established carbon and oxygen isotope map, and 4 regions distributed therein ( Figure 14 ), indicating that the Tahe Oilfield had four stages of filling. However, the average homogeneous temperature distribution map ( Figure 15 )and Figure 9 The comparison shows that there have been four periods of fluid activities in the Tahe River.

[0084] Table 6 Carbon and oxygen isotope data of some rocks in Tahe Oilfield

[0085] hashtag

lithology

δ 13 C (PDB)

δ 18 O(PDB)

hashtag

lithology

δ 13 C ...

technical field

[0001] The invention relates to a new karst stage discrimination technology in karst reservoir modeling, which is suitable for judging karst stages in marine carbonate rock basins. Background technique

[0002] Karst reservoir is an extremely important oil and gas reservoir. Recently, a number of important discoveries have been made in the karst reservoirs of marine carbonate rocks in the three major basins of Tarim, Sichuan and Ordos in my country, which have become the most important oil and gas reservoirs in the carbonate rock series. Phase identification has always been a major problem faced by the petroleum geology community.

[0003] Predecessors have carried out a lot of research and exploration in the study of karst reservoirs, and formed a basic method based on exposure signs as the main basis for identification. Commonly used methods include: judging karstification and possible karst stages in the outcrop area through unconformity surfaces and diss...

Examples

Embodiment 1

[0076] Taking the identification of carbonate rock karst stages in the Halahatang area in the northern Tarim Basin as an example, previous studies mainly based on the unconformity on the seismic section. Since the wells drilled in the study area are generally deep and there are few wells, it is difficult to identify The exposed signs can be directly identified on the core to distinguish the karst stage. In the 78 wells in the study area, a total of 22 effective samples were obtained, and the carbon and oxygen isotope values ​​(mainly measured 13 C PDB and δ 18 o PDB ) and inclusion homogeneity temperature data, and using the measured data (Table 4, Table 5), the carbon and oxygen isotope values ​​are calibrated to the carbon and oxygen isotope maps obtained above, and there are distributions in all five areas ( Figure 12 ), indicating that five phases of filling also occurred in the Halahatang area. The average homogeneous temperature distribution map established by using...

Embodiment 2

[0083] Taking the Tahe Oilfield as an example, the karst identification period is explained. Compared with Halahatang, the Tahe Oilfield has relatively more cores, and some of the cores can be identified with exposure signs, but it is still not enough to provide direct evidence for the identification of karst stages. According to the method of the present invention, 32 data carbon and oxygen isotope values ​​(Table 6) are used to calibrate to the established carbon and oxygen isotope map, and 4 regions distributed therein ( Figure 14 ), indicating that the Tahe Oilfield had four stages of filling. However, the average homogeneous temperature distribution map ( Figure 15 )and Figure 9 The comparison shows that there have been four periods of fluid activities in the Tahe River.

[0084] Table 6 Carbon and oxygen isotope data of some rocks in Tahe Oilfield

[0085] hashtag

lithology

δ 13 C (PDB)

δ 18 O(PDB)

hashtag

lithology

δ 13 C ...

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