Fracture-cavity oil and gas reservoir fractured well large karst cave well testing interpretation method

Abstract

The invention discloses a fracture-cavity oil and gas reservoir fractured well large karst cave well testing interpretation method. The method comprises the following steps: S1, establishing a fractured well fracture-cavity oil reservoir well testing physical model; s2, establishing a karst cave and karst cave oil drainage area radial seepage dimensionless mathematical model; s3, establishing a fracture linear seepage dimensionless mathematical model and a coupling model of the fracture linear seepage dimensionless mathematical model and the radial seepage model; s4, enabling the mathematicalmodel to be subjected to Laplace transformation and solving; s5, drawing a typical well testing double logarithm curve; s6, fitting explanation of actual test well data; s7, researching the influenceof the radius of the karst cave; and S8, researching the influence of the main fracture length. The beneficial effects of the invention are that: a fracture-cavity oil and gas reservoir fractured welllarge karst cave well test interpretation method is established; a large-scale fracturing crack seepage channel is formed by considering shaft fracturing; the pressure crack is communicated with thelarge karst cave; a large-scale karst cave is regarded as a potential body, a double-medium karst cave oil drainage area is formed with the karst cave as the center, a mathematical model is established through radial seepage of the karst cave oil drainage area and linear flow coupling of a fracturing fracture, Laplace transformation solving is conducted on the model, a typical well testing double-logarithm curve is drawn, and parameter sensitivity analysis is conducted on the model.

Description

technical field [0001] The invention relates to the technical field of geological exploration, in particular to a well test interpretation method for fracturing wells in fracture-cave oil and gas reservoirs. Background technique [0002] There are a large number of natural fractures, dissolved pores and large-scale dissolved caves in fractured-vuggy reservoirs, and these three types of media are good oil and gas storage spaces. The current seismic identification and drilling techniques cannot fully guarantee that fractured-cavity reservoirs will be encountered. In the case that production wells do not encounter karst caves, measures such as fracturing are often used to generate artificial fractures to communicate with effective fracture-cavity reservoirs. For such fractured-cavity reservoirs with fractured wells, identifying the volume of dissolved caves and the length of fractures has important guiding significance for guiding later production. [0003] Since the 1960s, m...

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Problems solved by technology

However, these models have simple fracture-cavity combinations and limited scope of application, so they cannot be applied to fracture-vuggy reservoirs in fractured wells.

In the production practice of fracture-cavity reservoirs, there are production wells that do not encounter effective fracture-cavity areas, resulting in low productivity of oil wells

To sum up, the assumption of incomplete multi-media continuity in fractured-cavity reservoirs with large-scale fractures and caves, and the existing drilling-encountered karst-cavity model and fracture-cavity combination well testing model cannot solve the problem of well testing in fractured reservoirs.

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