Log interpretation method of water flooding degree in mixed reservoirs based on sedimentary microfacies and lithofacies

Abstract

The present invention provides a logging interpretation method for water flooding degree of mixed reservoirs based on sedimentary microfacies and lithofacies, including: carrying out fine correlation and division of strata; conducting classification research on sedimentary microfacies-lithological facies; establishing each facies zone According to the four-property relationship chart, a log interpretation model suitable for the study area was established according to the sedimentary microfacies-lithological facies, and the actual data were processed based on the sedimentary microfacies-lithological facies discrimination model. On this basis, various types of Differences in reservoir logging interpretation; using entropy weight-based quantitative evaluation method for water-flooded layers to study water-flooded status of mixed reservoirs, establish comprehensive evaluation criteria for water-flooded layers in mixed reservoirs, and classify water-flooded oil layers , summed up the water flooding mode of the target interval. This method improves the degree of production and ultimate recovery of out-of-control reserves in mixed reservoirs, effectively reduces the decline in oilfield production, prolongs the stable production period of oilfields, significantly improves the ultimate recovery of oil reservoirs, and has achieved significant development effects and benefits.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a log interpretation method for water flooding degree of mixed reservoirs based on sedimentary microfacies and rock facies. Background technique [0002] Regarding the study of diamictite, Mount first proposed the concept of "mixed sediments" in 1984, which is used to describe the product of mixed deposition of terrigenous clastics and carbonates, and the term "diamictite" was derived from Yang Chaoqing and Sha Qingan proposed in 1990 to characterize this special sedimentary phenomenon that diamictite refers to a type of sedimentary rock in which terrigenous clastics, carbonate particles and mortar are mixed together, and is a typical terrigenous clastic rock and Types of transition between carbonate rocks. After 2000, Guo Fusheng et al. proposed to use the term "mixed strata" to characterize the interbedded or interbedded mixed deposits of terrigenous clas...

AI Technical Summary

Problems solved by technology

Especially in limestone-sandstone mixed reservoirs, the degree of recovery is lower, and the distribution of remaining oil is more complicated. Therefore, the interpretation of water flooding degree of mixed reservoirs is urgently needed in tapping the remaining oil potential of mixed reservoirs. have been resolved, but the importance of interpreting the extent of water flooding in mixed reservoirs has not yet received enough attention

[0008] Various oil and gas fields at home and abroad have carried out a lot of research work on the evaluation of water-flooded formations, and great progress has been made in logging interpretation of water-flooded formations in clastic rock reservoirs, but the evaluation of water-flooded degree of mixed reservoirs has been Neglected, still in a qualitative and semi-quantitative state, there is no mature method to evaluate the water flooding degree of mixed reservoirs

[0009] Existing logging evaluation methods for water-flooded zones fail to fully combine logging, geological, and oilfield development data. Existing methods rely too much on empirical formulas and ignore the impact of water injection development on the original model

[0010] Judging from the current research situation at home and abroad, the logging evaluation of water-flooded formations has been relatively mature, but the evaluation of water-flooded degree of mixed reservoirs has been neglected. The new research field mainly refers to the mixed deposition of terrigenous clastics and carbonates in the same depositional environment, covering three geological phenomena of diamictite, diamictive strata and sporadic mixing, so in diamictive reservoirs Due to its complex geological characteristics in the study, it is extremely difficult to evaluate the degree of flooding

[0011] The main reason for this problem is that there are great difficulties in the combination of dynamic and static research in the evaluation of flooding degree.

Geology, well logging, oilfield development dynamic data, etc. have not been fully utilized so far, have not reached a very good practical stage, and have not achieved major breakthroughs and results

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