CN-122021222-A - Optimization method for thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well

CN122021222ACN 122021222 ACN122021222 ACN 122021222ACN-122021222-A

Abstract

The invention provides a preferred method for a thick oil viscosity reduction, driving, throughput and efficiency leading process measure well, which comprises the steps of 1, calculating the sweep range r of a viscosity reduction system according to oil reservoir parameters and injection parameters, 2, establishing a target block driving pressure gradient regression formula, 3, calculating driving pressure Pr required by the sweep region, 4, calculating the driving pressure of a water well to be P wat , 5, calculating the oil reservoir range r 1 which can be swept by the water injection displacement pressure of an unswept region of the viscosity reduction system, and 6, judging whether a production well is a measure well according to the relation between the total distance r+r 1 which can be driven by the water well and a well distance L. The optimal method for the thick oil viscosity reduction driving throughput efficiency guiding process measure well mainly considers the influence of viscosity reducer property, well pattern well spacing and water injection pressure on the productivity of the oil well, avoids viscosity reduction throughput of only low-liquid-amount oil wells, and has the characteristics of high pertinence and high accuracy in well selection.

Inventors

HE XU
GUAN JINGTAO
LIU MING
LIU TINGFENG
YIN FANGHAO
LI LINXIANG
ZHANG ZHAOXIANG
HAO TINGTING
CHEN ZHIYING

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胜利油田分公司

Dates

Publication Date: 20260512
Application Date: 20241108

Claims (11)

1. The preferred method for the thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well is characterized by comprising the following steps of: step 1, calculating the sweep range r of a viscosity reduction system according to oil reservoir parameters and injection parameters; Step 2, establishing a target block driving pressure gradient regression formula; Step 3, calculating the driving pressure Pr required by the sweep region; Step 4, calculating the driving pressure of the water well as P wat ; Step 5, calculating an oil reservoir range r 1 which can be swept by water injection displacement pressure in an unswept area of the viscosity reduction system; And 6, judging whether the production well is a measure well according to the relation between the total distance r+r 1 which can be driven by the well and the well distance L.
2. The method for optimizing a thick oil viscosity reduction, flooding, throughput and efficiency initiation process measure well according to claim 1, wherein in the step1, when calculating the sweep range r of a viscosity reduction system, the daily water injection quantity of a water injection well is q, the injection duration is t days, the oil reservoir thickness h and the permeability phi are the sweep range of the viscosity reduction system is
3. The preferred method for a thick oil viscosity reduction, flooding, throughput and efficiency inducing technological measure well according to claim 1, wherein step 2 comprises: Step 21, establishing an injection and production model by using numerical simulation software; Step 22, calculating critical driving pressure gradient under a certain crude oil fluidity; step 23, changing the fluidity of crude oil, repeating step 22, and determining critical driving pressure gradients under different fluidity; At step 24, a regression equation is established that drives the pressure gradient.
4. A preferred method for a thick oil viscosity reduction, flooding, throughput and efficiency inducing process measure well according to claim 3, characterized in that in step 22, a critical driving pressure gradient at a certain crude oil fluidity is obtained by continuously changing the bottom hole pressure of the production well until a critical production pressure difference is obtained, wherein the liquid production volume is directly increased.
5. The method according to claim 4, wherein in step 24, the critical driving pressure gradient is plotted in a graph with fluidity as abscissa and critical driving pressure gradient as ordinate, and power function regression is performed to obtain a regression formula of driving pressure gradient: wherein: To initiate a pressure gradient, MPa/m; k is permeability, 10 -3 μm 2 ; mu is the viscosity of crude oil and mPa.s; a and b are the regression coefficients of the starting pressure gradient.
6. The method according to claim 1, wherein in step 3, the regression formula for the driving pressure gradient is integrated to obtain the driving pressure Pr required by the sweep zone in the sweep range of the viscosity reduction system.
7. The method for optimizing a thick oil viscosity reduction, flooding, throughput and efficiency-inducing technological measure well according to claim 6, wherein in step 3, with the viscosity of crude oil near a water well being μ 0 , the viscosity of crude oil in a reservoir being μ 1 , the sweep radius of a viscosity reduction system being r, the viscosity μ l of l < r at any l distance from the water well within the sweep range of the viscosity reduction system is: mu l =cl+d (equation 2) Wherein the method comprises the steps of Integrating the formula 2 along the length to obtain the driving pressure required by the viscosity reduction system in the sweep range: Wherein P r is the driving pressure required by the viscosity reduction system in the wave range and MPa; a, b is a starting pressure gradient regression coefficient; c, d is the coefficient in formula 2; k is permeability, 10 -3 μm 2 ; r is the sweep range of the viscosity reducing system and m.
8. The method according to claim 1, wherein in step 4, when calculating the driving pressure of the well as P wat , assuming that the injection pressure of the well is P inj and the depth of the well is H, the driving pressure provided by the well is: P wat ＝P inj +H/100-P r (equation 4).
9. The method for optimizing a heavy oil viscosity reduction, flooding, throughput and efficiency-inducing technological measure well according to claim 1, wherein in step 5, when calculating a reservoir range r 1 that can be reached by the flooding displacement pressure in an unswept area of the viscosity reduction system, the reservoir range that can be reached by the residual pressure is: Wherein r 1 is the oil reservoir range which can be covered by the residual pressure; P inj is the wellhead pressure of the water injection well and MPa; H is the well depth; a, b is a starting pressure gradient regression coefficient; k is permeability, 10 -3 μm 2 ; mu is the viscosity of crude oil and mPa.s; P r is the driving pressure required in the range of the viscosity reduction system, and MPa.
10. The method for optimizing a measure well of a thickened oil viscosity reduction, flooding, throughput and efficiency inducing process according to claim 1, wherein in step 6, the relation between the total distance r+r 1 which can be driven by the well and the well distance L is judged, wherein when L > (r+r 1 ), the well is a measure well, and otherwise, the well is a non-measure well.
11. The system for optimizing the thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well is characterized in that the system for optimizing the thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well adopts the method for optimizing the thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well according to any one of claims 1-10 to screen out measure wells needing throughput and efficiency guiding in a well pattern.

Description

Optimization method for thick oil viscosity reduction, driving, throughput and efficiency guiding process measure well Technical Field The invention relates to the technical field of oil extraction processes, in particular to a preferable method for a thick oil viscosity reduction, flooding, throughput and efficiency guiding process measure well. Background The crude oil of the heavy oil reservoir has high viscosity, and serious fingering phenomenon can be generated during water flooding, so that series of contradictions such as short water injection validity period, low recovery ratio and the like are caused, and the recovery ratio of the water flooding heavy oil reservoir is generally lower than 20%, even some reservoirs are lower than 10%. To overcome this difficulty, viscosity reduction flooding techniques reduce crude oil viscosity, increase crude oil mobility, and increase production well productivity by injecting a viscosity reduction system into the formation. The viscosity reduction and driving technology of the heavy oil reservoir is mainly applied to the heavy oil reservoir after multi-pass huff and puff and common water drive heavy oil reservoir, for the oil reservoir in the middle and later period of development, the well pattern is shaped and is difficult to change, the production well with small well spacing and good physical property in the well pattern takes effect preferentially, and the viscosity reduction system takes effect only between the preferential effect well and the water injection well after effect, so that great difficulty is brought to balanced displacement and comprehensive effect of the viscosity reduction and driving technology. In order to make the viscosity reduction drive become full-scale, a cold/hot production throughput efficiency-inducing process is implemented on site in the production well in a matched manner, and the purpose is to reduce the viscosity of near-wellbore zones without taking effect, improve the crude oil flowing capacity of the near-wellbore zones, dredge the seepage channels of the near-wellbore zones, reduce the bottom-hole flowing pressure of the production well, accelerate the transmission of stratum driving energy and the migration of fluid, and finally enable the communication between the non-effective well and the water injection well to be established. In the implementation process of the throughput efficiency-inducing process, scientific well selection is a foundation and is also an important technical link for guaranteeing balanced effects of viscosity reduction and flooding. At present, for the well selection link of the throughput efficiency-leading process, the technical means is single, mainly based on the production dynamics of the oil well, and the visual decision is made by using the parameter of the daily liquid production of the oil well. The daily liquid yield reflects the development degree of an dominant water flow channel of an oil well in the water injection development process of an earlier-stage oil layer to a certain extent, but the daily liquid yield is used as a huff-puff well selection decision to have three defects, namely, factors influencing the productivity of the oil well such as permeability and well spacing are ignored, the sweep range of a viscosity reduction system is not considered, and driving capability provided by a water injection well is not considered. The method comprises the steps of obtaining a characteristic model of a reference well according to a first production parameter and a second production parameter of the reference well, obtaining a wellhead oil pressure difference value of the well to be evaluated according to the characteristic model, the first production parameter and the second production parameter of the well to be evaluated, and if the wellhead oil pressure difference value is smaller than a preset value, the well to be evaluated is the measure potential well, wherein the first production parameter comprises a production time parameter, a unit period gas production parameter, a unit period liquid production parameter and a wellhead temperature parameter, and the second production parameter comprises a wellhead oil pressure parameter. The method for determining the measure well is not suitable for the viscosity-reducing displacement well group of the heavy oil reservoir, and the influence of the pressure of the water injection well and the injection system on the physical properties of crude oil is not considered. The Chinese patent application with the application number of CN202210553102.0 relates to a heavy oil exploitation method of push-pull linkage of a water well oil well, which comprises the steps of determining a target oil reservoir, determining a target block, analyzing the development current situation and the residual oil distribution of the target block, screening viscosity reducer and flooding agent according to the oil reservoir characteristics of the target block, injec