Psi-type pipe multi-phase fidelity sampling method and device suitable for ultra-low permeability stratum

Abstract

The invention discloses a Psi-type pipe multi-phase fidelity sampling method and device suitable for an ultra-low permeability stratum. The device comprises a ground control system, a packer system, Psi-type sampling pipes, I-shaped sampling pipes, a temperature control system and an automatic multi-way valve. The Psi-type sampling pipes comprise first Psi-type sampling pipes and second Psi-type sampling pipes. According to the method, the combination of a set of Psi-type sampling pipes and a set of I-type sampling pipes is adopted for a general low-permeability stratum for gas-liquid sampling, and for the condition that gas samples of the ultra-low permeability stratum are sparse, two sets of Psi-type sampling pipes are used for gas-liquid sampling; the conditions such as downhole sampling amount and sampling depth are controlled by the ground control system and the temperature control system, high-pressure driving fluid is injected into the Psi-type sampling pipes through the groundcontrol system to form a section plug flow in the sampling process, a gas-liquid sample in the pipe reaches the ground in a discontinuous section plug flow mode, the sample amount in the pipe can be effectively reduced, the controllable range of the sampling amount is large, and the stratum disturbance is extremely small.

Description

technical field [0001] The invention belongs to the technical field of fidelity sampling of downhole fluid in deep ground engineering, and more specifically relates to a method for sampling formation multiphase fluid, and also relates to a device for sampling formation multiphase fluid, which is suitable for low-permeability formations especially Formation fluid fidelity sampling for multiphase sampling in ultra-low permeability formation drilling. Background technique [0002] With the advancement of science and technology, people are studying the depth of the subsurface higher and higher. In order to accurately study the subsurface conditions, it is very important to obtain in-situ fidelity gas-liquid fluid sample data. Petroleum, geothermal, CO 2 Geological storage, underground energy and waste underground storage, deep geological scientific research and other projects are facing the problem of in-situ fidelity gas-liquid fluid sampling under complex geological conditions...

AI Technical Summary

Problems solved by technology

Therefore, it is an urgent purpose to carry out fidelity sampling of downhole gas-liquid fluid and to study the physical properties of gas-liquid fluid. However, as the research progresses, the increase of depth makes the sampling of gas-liquid fluid more and more difficult. The technology has been thoroughly researched, and there are various sampling equipments: Bailer sampler, discontinuous interval sampler, groundwater sampling pump and directly propelling in-situ groundwater sampling with exposed filter mesh sampler and closed filter mesh sampler , Waterloo sampler, U-tube sampler and other sampling technologies. Although these samplers can sample downhole fluids, there are some technical problems that cannot be used for deep sampling of earth-permeable formations, especially ultra-low-permeable formations.

[0003] According to the classification of oilfields, China refers to reservoirs with a permeability lower than 50mD as low-permeability reservoirs, and further divides them into three categories: general low-permeability reservoirs (reservoir permeability 10-50mD), ultra-low permeability reservoirs ( Reservoir permeability is 1-10mD), ultra-low permeability reservoirs (reservoir permeability 0.1-1mD) have low permeability, small pore throats, high irreducible water, seepage characteristics of non-Darcy flow, and insufficient natural energy. Formation pressure drops slowly, and the invention patent "Fidelity Sampling Device for Stratified Gas-liquid Two-phase Fluid in Wells" (CN 102108861 A) provides a technical method based on downhole gas-liquid two-phase sampling. Although the sampling method can achieve fidelity sampling requirements, but it is impossible to control the disturbance of the sampling flow rate and pressure to the formation, and the liquid sample is easy to remain in the U-shaped tube. Weak replenishment ability leads to long sampling period. The liquid residue in the downhole device not only reduces the effective sampling volume but also causes cross-contact and mutual dissolution of samples with different sampling periods in the device, which reduces the representativeness of the sample taken. Therefore, it cannot be effectively analyzed. Multi-phase (gas, water, oil, etc.) multi-phase (gas, water, oil, etc.) fidelity sampling of ultra-low permeability formations, how to reduce the impact of sampling on low permeability formations, how to reduce residual liquid samples in sampling devices, and provide an effective guarantee for ultra-low permeability formations The true sampling device is the technical key to the fidelity sampling of ultra-low permeability formation fluids

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