Simulation experiment method of acidizing production stimulation under temperature and pressure of 7 cm diameter core formation

Abstract

The invention discloses a method for performing acidizing yield-increasing stimulation experiment under 7-cm diameter rock core stratum warm pressure. The method comprises the following steps: (1) drilling a 7-cm diameter rock core column in a direction perpendicular to the rock core; (2) placing a sample rock core column into a reaction kettle; putting saline and an acid liquid into a container;starting a ring pressure pump and a temperature control system, so that the pressure of the rock core column in the reaction kettle is consistent with the pressure and the temperature of the rock corecolumn under a real stratum; starting an inner pressure pump, setting pump speed, starting to record the inner pressure value periodically until the experiment ends and obtaining the time of the experiment from the beginning to the end, the inner pressure pump speed and the inner pressure value; (3) calculating permeability k under the rock core stratum warm pressure; obtaining the daily liquid production rate of a reservoir section before and after acidification by utilizing the pump speed, the inner pressure and the sample section area. According to the method, the true level filtration capability and the acidifying yield-increasing effect of the rock can be reflected truly and directly, the natural filtration capacity and the acidifying yield-increasing potential of a reservoir can beeffectively evaluated, and import theory and practical significance in reserve utilization of a tight sand rock is achieved.

Description

technical field [0001] The invention relates to a simulating experimental method for acidizing and increasing production under temperature and pressure of a rock core formation with a diameter of 7 centimeters. Background technique [0002] With the deepening of exploration fields, tight sandstone reservoirs have gradually become the main energy replacement reservoirs in eastern my country. One of the main problems at present is that tight sandstone oil layer exploration wells generally have low oil test production or no amount of production, and encounter great difficulties in increasing reserves and upgrading reserves; using fracturing or acidizing to fully excavate and expand tight sandstone hard-to-produce reserves, It is one of the main directions to rely on to realize the strategic succession of oil and gas energy in the future. How to accurately evaluate the rock seepage capacity and acidification stimulation potential under formation temperature and pressure is very...

AI Technical Summary

Problems solved by technology

The current methods mainly include: ① Permeability test using 2.5cm rock samples on the ground or under overburden conditions. The measurement medium mainly uses gas. For example, the measurement of air permeability is to dry the fluid in the core in an oven, and then Air is passed into the core holder to measure the air permeability of the core, but in the actual oil layer, the fluid in the pores is often not a single phase, but two phases of oil and water or three phases of oil, gas and water coexist , at this time, the percolation effect of the rock on each phase will be very different from that of the single-phase fluid; in addition, it is impossible to evaluate the permeability under the condition of acid flooding

②The 2.5cm diameter core was used to carry out the flow simulation experiment of brine or acid rock injection flooding. Firstly, this method is poorly representative for the simulation of strongly heterogeneous tight sandstone. It can only simulate a quick reaction of the formation near the wellbore and apply the simulation results to the primary selection of the acidizing fluid, but it is impossible to judge the impact of the secondary sediment on the formation after the acid-rock reaction

Therefore, the current evaluation of rock seepage capacity is difficult to directly and accurately reflect the seepage capacity of rock formations.

In addition, the above two methods are not suitable for experiments on glutenite because the particle diameter of some of the glutenite exceeds the sample diameter or occupies the main volume of the sample.

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