Well-to-seismic integration paleo-formation pressure prediction method

Abstract

The invention relates to a well-to-seismic integration paleo-formation pressure prediction method. The method includes the steps that a velocity cube, a density cube and a porosity cube of a formation are obtained through the fine reservoir wave impedance inversion technology; time domain and depth domain conversion of a three-dimensional model is completed by means of the velocity cube; a geologic model of the geological time of a pool-forming period is obtained by subtracting the thickness of a formation needing to be eroded away in the pool-forming period from the thickness of the current formation; a paleo-porosity cube is obtained according to the erosion compaction restoration thicknesses of grids in the longitudinal direction of the geologic model of the pool-forming period and the porosity and depth relation; the paleo-density of the formation is restored by means of the density and depth linear relation; a paleo-formation interval velocity cube is obtained through the paleo-porosity cube; the rock matrix velocity and relations between pore fluid velocities with depths are obtained through logging information; ancient overlaying formation pressure is obtained through a paleo-density cube; a formation pressure cube of the ancient geological time is obtained through the ancient overlaying formation pressure, the rock matrix velocity, the relations between pore fluid velocities with depths and the paleo-formation interval velocity.

Description

technical field [0001] The invention relates to the technical field of oil and gas accumulation dynamics research, in particular to a method for predicting paleo-formation pressure combined with well and seismic. Background technique [0002] Paleo-stratigraphic pressure in sedimentary basins is an important parameter in the study of oil and gas accumulation. Paleo-pressure affects various aspects of oil and gas generation, storage, capping, migration, accumulation, preservation, and distribution. [0003] At present, the methods for restoring paleo-formation pressure in sedimentary basins mainly include fluid inclusion method, basin simulation method and acoustic time difference method. Fluid inclusion method is an effective method used to restore paleopressure earlier. The trapping pressure of secondary inclusions formed by trapped fluid during reservoir formation represents the paleopressure of reservoir formation. However, obtaining this pressure has a large Difficulty,...

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Problems solved by technology

Fluid inclusion method is an effective method used to restore paleopressure earlier. The trapping pressure of secondary inclusions formed by trapped fluid during reservoir formation represents the paleopressure of reservoir formation. However, obtaining this pressure has a large Difficulty, the traditional method is often to use brine inclusions or carbon dioxide inclusions, use the chart method or formula method to calculate the capture pressure, limited by core sampling, the number of samples in the study area is limited, the obtained paleofluid pressure information is discrete point information, it is very difficult It is difficult to reflect the overall heterogeneity characteristics of the formation paleopressure in the study area; the basin simulation method is also one of the effective methods for studying paleopressure. During the evolution of the basin, the abnormal pressure is mainly due to the burial and compaction of sediments. The recovery of paleo-formation pressure in the abnormally high-pressure area is mainly to restore the current thickness and formation pressure of a certain formation to The thickness and pressure at a certain moment during deposition or burial. Its basic assumption is that during the development of the entire basin, it is ideally considered that the volume of rock particles remains constant (due to the small compressibility of the rock), so that in the evolution of the basin During the process, due to the increase of the overlying strata, the porosity and thickness of the stratum decrease, and the change of stratum thickness is mainly realized by the change of pore flow volume and porosity. This method relies on geological data to establish a geological model, and the calculation process does not use Seismic data, the lack of lateral information of seismic data, and imperfect models cause large errors between simulation results and actual geological conditions. At present, the paleopressure of single well (one-dimensional) and profile (two-dimensional) is mainly recovered; Based on the time difference data, using the irreversible principle of mudstone compaction, the normal compaction trend line of porosity-depth and porosity-time of the single-layer formation can be established, and the ancient pressure of the formation can also be calculated and restored by the method of reverse stripping. This method obtains The paleo-formation pressure is mainly the formation pressure at the well point of a certain layer, and the lateral information of the seismic data is also not fully utilized.

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