Evaluation method for refracturing stimulation potential of horizontal wells in low permeability heterogeneous reservoirs

Abstract

The invention discloses an evaluation method for low permeability heterogeneous oil reservoir horizontal well repeated fracturing yield increasing potential. The evaluation method sequentially comprises the following steps that (1), a crack expansion model is built by utilizing Meyer software, and inversion of first-time fracturing hydraulic crack parameters is conducted; (2), an oil reservoir heterogeneous geological model is built by utilizing oil reservoir numerical value simulation software Eclipse, the first-time fracturing hydraulic crack parameters are planted into the heterogeneous geological model to conduct production dynamic history fitting, and remaining oil saturation field and stratum pressure field distribution is obtained; and (3), quantitative evaluation is conducted on the horizontal well repeated fracturing yield increasing potential according to the remaining oil saturation field and stratum pressure field distribution, first-time fracturing hydraulic cracks are classified, and pertinence repeated fracturing modes are proposed. The problems of the stress sensitivity phenomenon and poor pertinence of the repeated fracturing modes and the like existing in evaluation of the low permeability heterogeneous oil reservoir horizontal well repeated fracturing yield increasing potential are effectively solved, the effect of repeated fracturing transformation is improved, the risk of engineering construction is reduced, and the evaluation method has wide market application prospects.

Description

technical field [0001] The invention relates to the field of petroleum and natural gas development, in particular to a method for evaluating the production potential of a horizontal well in a low-permeability heterogeneous reservoir by repeated fracturing in the field of hydraulic fracturing. Background technique [0002] Most low-permeability reservoirs in my country have the characteristics of poor reservoir properties, strong heterogeneity, strong stress sensitivity, and low natural productivity. Some of these reservoirs cannot be developed by conventional water injection to form an effective injection-production well pattern. Flexible development of large-scale multi-stage multi-cluster volume fracturing technology for horizontal wells. However, due to various factors such as geology and engineering, insufficient initial fracturing stimulation and failure of hydraulic fractures, the production declines rapidly, which seriously affects the development effect. In order to r...

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Problems solved by technology

[0005] (1) Wei Chenji et al. (a method for selecting refracturing target wells in tight oil and gas reservoirs, patent number: 201510324579.1) determined the completion efficiency of the screening well and the unit reservoir quality of the screening well, taking the unit reservoir quality as horizontal coordinates, the completion efficiency is a scatter diagram on the ordinate, and the scatter diagram is divided into four parts by using the horizontal and vertical dividing lines to form an intersection diagnostic diagram, so as to complete the selection of the target well for refracturing, but only the geological reserves and Completion efficiency is used to select refracturing target wells, ignoring factors such as formation pressure

[0006] (2) Xu Hongxing et al. (A low-permeability gas reservoir shifting to refracturing process, patent number: 201510144184.3) divided the process implementation process into pre-fracture analysis and evaluation of the reasons for initial fracturing failure or inefficiency, and turning to refracturing selection. Well selection decision-making, modeling and simulating the change of stress field when turning to refracturing, optimization of fracture geometry parameters and conductivity, and design of refracturing operation parameters are three parts to realize the transition from low permeability gas reservoirs to refracturing technology, but the storage capacity is not considered. The influence of layer heterogeneity on the distribution of remaining oil, no targeted refracturing method for each hydraulic fracture

[0007] (3) Pang Peng et al. (Pang Peng, Liu Zhenyu, Wang Huzhen. Numerical simulation of refracturing timing [J]. Daqing Petroleum Geology and Development, 2015, 34(6):83-87) using the reservoir numerical simulation method, Considering the influence of fracture conductivity changes on the production performance of horizontal wells, the timing of refracturing stimulation is optimized, but the influence of the actual shape of hydraulic fractures on productivity is not considered, so as to simulate the difference between the distribution of remaining oil saturation field, the distribution of formation pressure field and the actual situation bigger

[0008] None of the above methods considered the influence of reservoir heterogeneity on the distribution of remaining oil saturation field to study the evaluation of refracturing stimulation potential of horizontal wells.

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