Recognition method for underground single ancient channel under condition of dense well pattern

Abstract

The invention discloses a recognition method for an underground single ancient channel under the condition of a dense well pattern. By adoption of an analogy method, field outcrop observation results are used for guiding recognition of the underground single ancient channel, and a model fitting geological thinking method is embodied. Through application of the recognition method in a Sulige gas field, quantitative description results are applied to three-dimensional geological modeling and serve as constraint conditions to enable the model consistency rate to be remarkably increased. According to the recognition method for the underground single ancient channel under the condition of the dense well pattern, aiming at morphological characteristics of the single ancient channel, dense well pattern drilling data are sufficiently utilized, tedious work of sedimentary micro-phase interpretation conducted on a single well is avoided, the phenomenon that the seismic datum longitudinal resolution ratio is not enough for determining is avoided, and the recognition method has the characteristic of being convenient to operate. According to application of the recognition method in the Sulige gas field, recognition accuracy of vertical sand bodies is improved to be less than 8 m from being 15-20 m, the original quantitative description results achieve quantification, the results are applied to three-dimensional geological modeling and serve as the constraint conditions to enable the model consistency rate to be increased by 10%, and the effect is obvious.

Description

[0001] 【Technical field】 [0002] The invention belongs to the field of geological analysis of oil and gas field reservoirs, and relates to a method for identifying an underground single paleo-channel under dense well pattern conditions. [0003] 【Background technique】 [0004] Fluvial facies reservoirs have always been one of the key fields of oil and gas exploration and development in China. Vertical multi-stage single paleo-channel sand bodies are cut and superimposed one after another, and horizontally different single paleo-channel sand bodies in the same stage are spliced ​​with each other, forming a layered and complex structure. The fluvial facies river reservoirs have strong heterogeneity inside the reservoirs, which seriously restricts the further improvement of oil and gas recovery. [0005] With the deepening of the development of fluvial oil and gas fields, oil and gas field stable production and enhanced oil recovery technologies have become the focus of domestic ...

AI Technical Summary

Problems solved by technology

For example, inter-fluvial deposits between channel sand bodies. The premise of this model is that the sedimentary facies must be interpreted on a single well, and the channel sand bodies and inter-channel deposits must be identified before the next step of analysis can be carried out; another example is the channel sand bodies. The difference in elevation of the top layer, this model takes into account the difference in elevation of the top layer of sand bodies deposited in different channels. If it is smaller, the two may be confused in the same channel, and this method does not consider the key factor of sand body thickness; in addition, these methods often emphasize the differences between different single paleo-channel sand bodies, and field outcrop observations show that most of the single paleo-channel sand bodies The paleo-channel itself has a flat top and a convex bottom. The thickness of a single paleo-channel is stable in the middle and gradually becomes thinner towards both sides. These methods do not pay too much attention to the characteristics of a single paleo-channel itself

Images