Method for interpreting multiple parameters through stagewise down discharge testing

Abstract

The invention discloses a method for interpreting multiple parameters through stagewise down discharge testing. The method comprises the following steps of step 1: by combining with a pressure meter arranged at the bottom of a fracturing string before construction, testing the change of shaft bottom pressure in the fracturing construction process, and selecting the construction discharge and the shaft bottom pressure corresponding to a stagewise down point in the discharge reduction stage of fracturing construction; step 2, according to the shaft bottom pressure and the construction discharge,building a mechanical balance model of the shaft bottom pressure, the hole friction resistance pressure drop and the near shaft bending friction resistance pressure drop; step 3, substituting data collected in the step 1 into the mechanical balance model to build a model solving equation set; and step 4, solving unknown numbers in the equation set by solving the model, and obtaining the result ofthe multiple parameters. The method provided by the invention has the advantages that the precise fracture closing pressure, the perforating bore friction resistance coefficient and the near shaft bending friction resistance coefficient can be obtained at the same time.

Description

technical field [0001] The invention relates to the technical field of hydraulic fracturing, in particular to a multi-parameter method for step-down discharge test fracturing interpretation. Background technique [0002] The exploration and development field of the world's oil and gas industry is undergoing tremendous changes, continuing to extend from conventional oil and gas development to unconventional reservoir oil and gas development. The proportion of low-permeability and unconventional oil and gas in global oil and gas production continues to increase, resulting in rapid growth of oil and gas production. However, these reservoirs are low-permeability-tight, and a single well generally has no natural production capacity, and certain technical means are required to achieve commercial exploitation. Hydraulic fracturing plays an important role in improving the seepage capacity of the reservoir and can meet the requirements of unconventional reservoirs. Reasonable and ef...

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Problems solved by technology

The calculation of hole friction resistance mostly adopts the traditional calculation formula, but there is a big gap between the hole flow coefficient measured by indoor test and the field construction data, and the results obtained by the calculation formula cannot be applied to the field construction (Zhang Yanjie, Wang Yongqing, Zhang Shuanglong. Limit Research on Perforation Friction Change in Flow Fracturing[J]. Petrochemical Technology, 2015, 22(01): 120-121.)

Bending friction can generally be obtained by testing fracturing, but when interpreting near-wellbore fracture bending friction under the assumption that formation closure pressure is known, the accuracy of closure pressure seriously affects the accuracy of interpretation results

The pressure drop curve analysis method after the pump is stopped can explain the fracture and formation conditions after fracturing, but requires a long test time to record, which limits its field application, and the assumptions of this method are too ideal, which is not consistent with the actual formation conditions. There are differences

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