Well layout method for carbonate interlayer karst reservoir

Abstract

The invention discloses a well spacing method for a carbonate interlayer karst-type reservoir. The well spacing method comprises the following steps that 1, borders of an oil and gas pool are depicted through tectonic lines, fault lines, stratum lines, physical property lines and oil-water border lines according to the geologic characteristics of the interlayer karst-type carbonate reservoir; 2, a while-drilling marker bed is recognized according to prediction and description of special lithology, and the position and the interlayer of the reservoir are defined through division and comparison of geological small layers and prediction of the reservoir; 3, the seismic reflection types of the reservoir are divided and evaluated, and the interlayer karst-type reservoir is divided into the 'beaded', 'schistose' and 'disordered' reflection types; 4, the trajectory of a horizontal well is optimized by applying ground stress field prediction and engineering geological mechanics research, and the effect that the trajectory direction is heterotropic with the maximum ground stress in a perpendicular mode or a large angle mode is determined; and 5, well spacing is conducted in the well spacing mode that the well trajectory penetrates through 'schistose' seismic reflection and penetrates through 'beaded' seismic reflection as much as possible. The well spacing method for the carbonate interlayer karst-type reservoir is reasonable and capable of increasing the drilling ratio of the reservoir.

Description

technical field [0001] The invention relates to the technical field of natural gas exploitation, in particular to a well layout method for carbonate interlayer karst reservoirs integrating seismic, geological and gas reservoir engineering. Background technique [0002] Carbonate oil and gas reservoirs in Tazhong have entered the development stage from the exploration stage. At present, wells are mainly deployed in cave-type karst reservoirs. Uncovering fracture-cavity and inter-cavity karst reservoirs has not yielded industrial oil and gas flow, and the 17 wells deployed have not been drilled, making it more difficult to deploy wells in Tazhong. [0003] Wells in cave-type karst reservoirs are well-screened for reservoirs with large caves and well-developed fractures. The initial effect is very good, but there are not many good cave-type reservoirs. If the remaining fractures are underdeveloped and the caves are small in scale, Single wells are difficult to be efficient. ...

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Problems solved by technology

[0006] However, the prior art represented by the above-mentioned patent documents cannot be directly applied to the well layout of carbonate interlayer karst oil and gas reservoirs in Tazhong, and has the following defects: it does not consider the division marks of oil and gas reservoirs, and cannot accurately divide oil and gas The type of reservoir brings inconvenience to the later production; without special lithology prediction, the well trajectory cannot be guaranteed to pass through the reservoir; without seismic reflection type division, the design well will miss the dissolved cave development area of ​​seismic "beads" reflection

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