CN-117127948-B - System and method for evaluating air pressure water cone injection effect of bottom water sandstone reservoir

CN117127948BCN 117127948 BCN117127948 BCN 117127948BCN-117127948-B

Abstract

The invention discloses a system for evaluating the air pressure water cone effect of a bottom water sandstone reservoir, which comprises a core device, a displacement device and a measuring device, wherein an experimental core is arranged in the core device, a plurality of injection points are arranged along the axial direction of the experimental core, pressure measuring points and probe measuring points are arranged on the section of the core at each injection point, the displacement device is connected with the core device and is used for injecting water into the experimental core which passes through saturated stratum water and displacement crude oil to simulate a strong bottom water driving process and injecting gas into any injection point at different speeds and/or different amounts to simulate an air pressure water cone process, and the measuring device is connected with the core device and is used for measuring pressure changes of different injection points and ultrasonic signal changes of different probe measuring points in the strong bottom water driving simulation process and the air pressure water cone simulation process respectively, and determining the gas wave and range through comparison of the same position and same type of measured data. The invention solves the problem of simulation of the air pressure water cone injection process of the bottom water sandstone reservoir.

Inventors

CUI MAOLEI
XU TING
XIAO PUFU
LUN ZENGMIN
TANG YONGQIANG
ZHAO CHUNPENG
HU WEI
YANG YANG

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司石油勘探开发研究院

Dates

Publication Date: 20260508
Application Date: 20220518

Claims (8)

1. A system for evaluating the effectiveness of a gas-injection water cone of a bottom water sandstone reservoir, comprising: The core device is internally provided with an experimental core, and a plurality of injection points are arranged along the axial direction of the experimental core, wherein a pressure measuring point and a probe measuring point are arranged on the core section of each injection point, each pressure measuring point is configured as a gas injection port and is used for simulating different gas injection positions of a bottom water reservoir, and the experimental core is formed by splicing a plurality of columnar cores selected from a target reservoir in a vertical direction to form a long core system; The displacement device is connected with the core device and is used for injecting water into the injection end of the experimental core which is subjected to saturated formation water and displacement crude oil to simulate a strong-bottom water flooding process, and injecting gas into any injection point at different speeds and/or different amounts to simulate an air injection pressure water cone process; The measuring device is connected with the core device and is used for measuring pressure changes of different pressure measuring points and ultrasonic signal changes of different probe measuring points in a strong-base water drive simulation process and an air injection pressure water cone simulation process respectively, and determining the gas sweep range through comparison of the same position and the same type of measurement data, wherein the measuring device comprises: Judging the lifting position of the bottom water according to the pressure change of different pressure measuring points and the ultrasonic signal change of different probe measuring points in the strong bottom water drive simulation process, calculating the water yield per unit time in the strong bottom water drive simulation process by measuring the liquid yield of the output end of the core for experiment, then determining the sweep range of gas according to the pressure change of different pressure measuring points and the ultrasonic signal change of different probe measuring points in the gas injection pressure water cone simulation process, calculating the water yield per unit time in the gas injection pressure water cone simulation process by measuring the liquid yield of the output end of the core for experiment, obtaining the change rule of the water yield before and after gas injection, determining the sweep range of residual gas and the change of the water yield under the residual gas condition, thereby determining the influence rule of the residual gas on the bottom water coning to evaluate the effect of the gas injection pressure water cone, The injection end and the output end are respectively positioned on two side end faces of the experimental rock core.
2. The system of claim 1, wherein the core device comprises: the experimental core; The rock core holder is vertically arranged on the experimental platform, and an annular space is formed between the inner wall of the rock core holder and the outer wall of the experimental rock core and is used for accommodating and fixing the experimental rock core; The pressure sensors are arranged on the outer wall of the experimental rock core, and each pressure sensor is correspondingly arranged on a pressure measuring point; A plurality of ultrasonic probes arranged on the outer wall of the experimental rock core, each ultrasonic probe is correspondingly arranged on a probe measuring point, and And the gas injection valves are arranged at each injection point, and each valve is used for realizing the independent communication between the displacement device and the corresponding injection point.
3. The system of claim 1 or 2, wherein the core device is rotatable to simulate different dip angle side bottom water reservoirs.
4. The system of claim 2, further comprising a switching valve disposed between the displacement device and the production end of the experimental core for switching from the strong base water drive simulation process to the gas injection pressure water cone simulation process when closed, wherein the gas injection pressure water cone simulation process ends and enters a continuous base water drive process when the switching valve and all gas injection valves are closed.
5. The system of claim 1 or 2, wherein the displacement device comprises a ring pump in communication with a sidewall of a core holder within the core device, the ring pump for applying ring pressure to the experimental core to simulate a saturated formation water process.
6. The system of claim 5, wherein the displacement device further comprises a gas injection pump in communication with the production end of the experimental core and a gas injection pump in communication with the injection end of the experimental core, wherein during the simulating of the displacement of crude oil, The gas injection pump is used for simultaneously applying annular pressure and production pressure to the experimental rock core when the gas injection pump and the annular pressure pump are simultaneously opened until the pressure of each pressure measuring point reaches the target reservoir pressure; and the oiling pump is used for injecting the experimental displacement crude oil into the experimental rock core when the pressure of each pressure measuring point reaches the target reservoir pressure, and the experimental displacement crude oil is petroleum ether.
7. The system of claim 5, wherein the displacement device further comprises a water injection pump in communication with the injection end of the experimental core, the water injection pump configured to inject water into the experimental core in a constant pressure mode to simulate a bottom water flooding process.
8. A method for evaluating the effectiveness of a gas injection cone of a bottom water sandstone reservoir, wherein the method is for implementing a system as claimed in any one of claims 1 to 7, the method comprising: Arranging an experimental core in the core device, and arranging a plurality of injection points along the axial direction of the experimental core, wherein a pressure measurement point and a probe measurement point are arranged on the core section of each injection point; simulating a strong-base water flooding process by using the displacement device to inject water to the experimental rock core which passes through saturated stratum water and displacement crude oil, and measuring pressure changes of different pressure measuring points and ultrasonic signal changes of different probe measuring points in the strong-base water flooding simulation process and the air injection pressure water cone simulation process by using the measuring device; the displacement device is used for injecting gas into any injection point at different speeds and/or different amounts to simulate the gas injection pressure water cone process, pressure changes of different pressure measuring points and ultrasonic signal changes of different probe measuring points are measured in the gas injection pressure water cone simulation process, and the gas sweep range is determined through comparison of the same position and the same type of measurement data.

Description

System and method for evaluating air pressure water cone injection effect of bottom water sandstone reservoir Technical Field The invention relates to the technical field of petroleum development experiments, in particular to a system and a method for evaluating the air pressure water cone injection effect of a bottom water sandstone reservoir. Background The tri-stack bottom water sandstone oil reservoir of the Tahe oil field has the characteristics of sufficient natural energy and large water body, and the oil reservoir yield is larger than the whole area yield. The oil field mainly adopts natural energy development, the coning of bottom water in the middle and later stages is obvious, the water content rises fast, the oil well is generally high in water content, the extraction degree is low, and the development potential is large. The oil reservoir has high stratum temperature, high stratum water mineralization degree, difficult application of a chemical flooding system and short effective acting time of a chemical plugging system, the gas injection has the effect of controlling water and increasing oil which is verified on an oil field site, and meanwhile, the capability of dissolving CO 2 under high-pressure conditions is strong due to large water body of bottom water, so that the aim of carbon burying is fulfilled, and the method has important significance for the application of a CCUS technology in northwest deep hydrocarbon reservoirs. The formation pressure of the tri-stack bottom water sandstone oil reservoir of the Tahe is high, the density of CO 2 in the oil reservoir is greater than that of crude oil, under the action of gravity difference, CO 2 can be transported to an oil-water interface, the bottom water lifting can be inhibited theoretically, the formation of a water cone is relieved, and in order to further know the effect of the air injection pressure water cone and the air flow law, an air injection pressure water cone effect evaluation experiment is very necessary to be carried out, so that important theoretical support is provided for the air injection of the bottom water oil reservoir and the recovery ratio improvement technology. At present, the bottom water reservoir gas injection effect evaluation method mainly adopts a technical means of numerical simulation method and core physical simulation experiment method based on a geological model from the angles of oil (or gas) increasing and water content reducing analysis. The numerical simulation method is to establish an ideal geological model or an actual geological model aiming at an actual block, develop oil displacement effect simulation research under different gas injection modes on the basis, quantitatively analyze by comparing dynamic parameters such as oil increment, water reduction and the like of different simulation schemes, qualitatively analyze the cone pressing effect from the dynamic simulation process of the three-dimensional geological model, and cannot quantify the cone pressing effect. The core physical simulation method is to compare and analyze dynamic characteristics of produced fluid (oil, water and gas) by developing core displacement experiments under different gas injection modes, and analyze the effects of oil increasing and water controlling, and can not simulate the formation of a water cone and the cone pressing effect. In the prior art, the scheme for evaluating the bottom water reservoir gas injection cone effect is few, so that gas injection parameters and the flow rule of stratum fluid after gas injection are ambiguous, the bottom water reservoir gas injection effect is affected, and the deep reservoir gas injection investment risk is increased. Disclosure of Invention The invention aims to provide an experimental device and method for evaluating the air pressure water cone injection effect of a bottom water sandstone reservoir, which are used for simulating the air pressure cone injection process under the condition of a strong bottom water reservoir, analyzing the flow rule of stratum fluid after air injection and clearly injecting CO 2 cone compression effect. In order to solve the technical problems, the embodiment of the invention provides a system for evaluating the air pressure water cone effect of a bottom water sandstone reservoir, which comprises a core device, a displacement device and a measuring device, wherein an experimental core is arranged in the core device, a plurality of injection points are arranged along the axial direction of the experimental core, a pressure measuring point and a probe measuring point are arranged on the core section of each injection point, the displacement device is connected with the core device and is used for injecting water into the experimental core which passes through saturated stratum water and displacement crude oil to simulate a strong bottom water driving process, and injecting gas into any injection point at different speeds and/or different amou