Three-hole rock core kettle and ultra-low-permeability reservoir fluid damage evaluation test apparatus and method

Abstract

The present invention is a three-hole rock core kettle and an ultra-low-permeability reservoir fluid damage evaluation test apparatus and method, the three-hole rock core kettle takes upper and lower cover bodies for clamping a rock core sample, and the upper and lower cover bodies are respectively provided with through holes communicating rock core sample surface. The ultra-low-permeability reservoir fluid damage evaluation test apparatus includes the three-hole rock core kettle, an upstream simulated formation fluid intermediate vessel, a downstream simulated formation fluid intermediate vessel, a to-be-tested fluid intermediate vessel, a plunger pump, a vacuum pump and a nitrogen bottle; the various components are connected by pipes, and corresponding control valves, gas pressure regulation valves and back-pressure valves are arranged. The ultra-low-permeability reservoir fluid damage evaluation test method is as follows: simulated reservoir fluids with same activity are contacted with upper and lower surfaces of the rack core sample, meanwhile the simulated reservoir fluid continuously flows on the upper surface of the simulated reservoir fluid, osmotic pressure transmission is eliminated, and by monitoring of the change with time of downstream fluid pressure, penetration rates of the sample before and after contamination can be obtained, and further damage degree can be evaluated. The three-hole rock core kettle is simple in structure, the test apparatus and method are easy to use, the test pressure is reduced, and experimental data is reliable.

Description

technical field [0001] The invention relates to an oil and natural gas reservoir damage evaluation technology, in particular to a three-hole core kettle and an ultra-low permeability reservoir liquid damage evaluation experimental device and method. Background technique [0002] At present, low-permeability and ultra-low-permeability reserves account for about two-thirds of the proven oil and gas reserves. Low-permeability and ultra-low-permeability reserves will be the focus and difficulty of exploration and development for my country's oil production replacement. In the process of exploration, development and production, low-permeability and ultra-low-permeability reservoirs are more vulnerable to damage than medium and high-permeability reservoirs during production operations, and the damage caused by the reservoir is more harmful. To eliminate the damage Also more difficult. Therefore, to improve the exploration and development effect of ultra-low permeability reservoir...

AI Technical Summary

Problems solved by technology

It is clearly stated in the SY / T5358-2010 standard that this standard applies to air permeability greater than 1×10 -3 um 2 The experimental method for sensitivity evaluation of rock samples in clastic rock reservoirs, while the gas permeability of ultra-low permeability reservoirs is generally lower than 1×10 -3 um 2 , using the above evaluation method will have the following problems: On the one hand, it needs a high displacement pressure difference and a long flow rate stabilization time, which requires high equipment, and the permeability is 0.1×10 -3 um 2 Take a rock sample as an example. Under the conditions of 2.54 cm in diameter, 5 cm in length, 1 ml / min flow rate, and water as the displacement medium, the displacement pressure difference exceeds 16 MPa, and the flow rate basically stabilizes for more than 5 hours.

On the other hand, this steady-state method based on Darcy's law mainly calculates the corresponding permeability by measuring the flow rate under steady-state conditions. The current flow measurement method is greatly affected by environmental and human factors. As far as the layer is concerned, the steady-state flow rate during the experiment is very low, which further increases the measurement difficulty and error

[0004] In addition, ultra-low permeability reservoirs have certain semi-permeable membrane characteristics, which allow water molecules and some ions or molecules to pass through, and induce a certain osmotic pressure on both sides. The existing liquid permeability measurement methods usually do not consider the osmotic pressure. influence, which will further increase the error of permeability measurement and reservoir damage assessment results

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