CN-122021395-A - Shale oil new well layout parameter determination method based on response time-varying oil drainage volume

CN122021395ACN 122021395 ACN122021395 ACN 122021395ACN-122021395-A

Abstract

The invention discloses a shale oil new well layout parameter determining method based on a response time-varying oil drainage volume, and belongs to the field of oil and gas field development. The method comprises the steps of S1, constructing a geomechanical-seepage coupling model, calculating dynamic response time-varying oil drainage volume, S2, simulating crack expansion and oil drainage volume curves under different cluster distances, determining optimal cluster distances, S3, differentially adjusting the lengths of new well fracturing sections according to the positions of old well cracks, realizing staggered joint distribution, verifying an optimization effect through the oil drainage volume curves, S4, simulating contact relation of the new well cracks and the old well cracks under different azimuth angles, and selecting azimuth angles which realize 'crack micro-lap joint' and optimal oil drainage volume expression. The invention breaks through the static evaluation limitation, realizes the determination of well distribution parameters such as cluster spacing, section length, azimuth angle and the like under the background of multi-field dynamic coupling and inter-well interference, and remarkably improves the well group reserve control and long-term stable production capacity.

Inventors

WANG WENDONG
SUN HAO
SU YULIANG
LV CHUNSHUANG
FENG DIAN
JIA MINGWEI
LI LEI
HAO YONGMAO

Assignees

中国石油大学(华东)

Dates

Publication Date: 20260512
Application Date: 20251225

Claims (6)

1. The shale oil new well layout parameter determining method based on the response time-varying oil drainage volume is characterized by comprising the following steps of: S1, constructing a multi-field coupling time-varying drainage volume characterization model; Establishing a geomechanical-seepage coupling numerical simulation model, simulating dynamic evolution of a pressure field, a saturation field and a stress field of a target block in the shale oil failure development process, and calculating response time-varying oil drainage volumes under different production times based on simulation results; s2, determining the optimal cluster spacing; based on the characterization model, setting a plurality of groups of different cluster spacing schemes, respectively carrying out fracturing crack expansion simulation, analyzing the morphological characteristics of the cracks under each scheme and the corresponding time-varying oil drainage volume change curves in response, selecting cluster spacing corresponding to the schemes which can lead the cracks to expand uniformly, avoid strong stress shadows and reserve blank areas and have high peak value and slow attenuation of the time-varying oil drainage volume as the optimal cluster spacing or the optimal interval; s3, optimizing the differential section length to realize staggered cloth seams; acquiring space distribution information of fracturing sections of an adjacent old well, taking the old well fracturing sections as references, unevenly adjusting and designing the length and the position of each fracturing section of a new well, so that the starting point of a main fracture of the new well is spatially aligned to a matrix area between adjacent fracturing sections of the old well; S4, determining the azimuth angle of the optimal horizontal well; Setting multiple azimuth schemes, respectively carrying out fracturing crack expansion simulation to obtain the space contact relation between the new well crack and the old well reconstruction area, and selecting azimuth angles which can enable the new well crack and the old well crack area to realize 'crack micro lap joint' instead of direct penetration and enable the response time-varying oil drainage volume to represent the optimal azimuth angle of the optimal horizontal section of the new well by combining the response time-varying oil drainage volume change curves of the new well under the schemes.
2. The method according to claim 1, wherein in step S1, the calculation formula of the responsive time-varying drainage volume at time t is: ; In the formula, The response time-varying oil drainage volume at the time t is expressed as m 3 ; The oil phase saturation of the grid block corresponding to the moment t; Is along with the formation pressure The effective modified volume of the change is m 3 ; a reservoir-pressure response function for characterizing the response of reservoir parameters as a function of formation pressure; is a fluid-pressure response function for characterizing the response of a fluid parameter as a function of formation pressure; The production pressure difference at time t is expressed in MPa.
3. The method according to claim 1, wherein in step S2, the specific condition for determining the optimal cluster pitch comprises: the crack expansion form is relatively balanced, and the length of the supporting crack is moderate; the crack system can realize moderate lap joint without obvious blank areas; the corresponding response time-varying drainage volume curve decays at a rate below a preset threshold after reaching a peak.
4. The method of claim 1, wherein in step S3, the segment length optimization principle of the staggered joints is that main joints of new wells are spatially avoided from the main joint high interference area of old wells, and the main joints of new wells are directed to the unused residual oil enrichment area between the old well joints.
5. The method of claim 1, wherein in step S4, the "micro-lap joint" of the fractures is in such a manner that the extended ends of the new well fracture are in limited communication with the edge of the old well reconstruction zone through the secondary fracture or the natural fracture network, and the new well main fracture is not in direct communication with the old well main fracture to form a high diversion channel.
6. The method of claim 1, wherein in step S4, the criteria for optimal performance of the responsive time-varying drainage volume includes a higher peak of the curve and a slowest rate of decrease after reaching the peak.

Description

Shale oil new well layout parameter determination method based on response time-varying oil drainage volume Technical Field The invention belongs to the technical field of development of petroleum and natural gas fields, and particularly relates to a shale oil new well layout parameter determination method based on response time-varying oil drainage volume. Background As shale oil development expands to deep and complex structural areas, development difficulty and cost are remarkably increased. The core of efficient development is the formation of complex slotted networks by horizontal well multi-stage fracturing to maximize the mobilized reservoir volume. However, in the case of a freeze well or new block well placement, the placement parameters (e.g., cluster spacing, segment length, azimuth) of the new well design directly relate to the fracturing effect, the extent of reservoir control, and the interference strength with neighboring old wells, ultimately affecting the long term stability and ultimate recovery of the well group. The traditional well distribution parameter design is mostly dependent on geostatistics, numerical simulation and engineering experience, but has obvious limitations that firstly, the common oil drainage volume evaluation method is mostly based on static evaluation of fracturing fluid wave and range or proppant distribution, and omits dynamic evolution of the oil drainage range caused by multiple physical field coupling such as pressure failure, stress field redirection, fluid phase change and the like in the development process. This static evaluation cannot distinguish between "fracture modification volume" and "effective flow volume of crude oil", which is quite different from actual use. Secondly, the existing method ignores a dynamic interference mechanism between new and old wells. The stress field of the pressure funnel and stress shadow formed by long-term production of the old well can be obviously changed, so that a new well crack is induced to unevenly spread to a low-pressure area, and the crack is easy to directly pass through, so that energy ineffective dissipation and yield mutual loss are caused. In the prior art, there have been some approaches to try to optimize well pattern or well placement parameters. For example, patent CN107506948a discloses a shale oil gas comprehensive yield analysis method based on dynamic drainage volume, but focuses on single well history fitting and prediction, and does not deeply solve the problem of parameter optimization of new and old wells collaborative well layout. Patent CN117454755A relates to the optimization of parameters of a three-dimensional well pattern, but mainly starts from macroscopic well spacing and horizon layout, and lacks a method for determining fine parameters such as cluster spacing, segment length differentiation, azimuth angle and the like based on dynamic physical field coupling. Therefore, a method for accurately characterizing the dynamic change of the effective drainage volume in the development process and scientifically determining the well distribution parameters of a new well based on the dynamic change is needed, so that the interference among wells is effectively managed while the control degree of reserves is improved, and the maximization of the overall development benefit of a well group is realized. Disclosure of Invention The invention aims to overcome the defects of dependence on static evaluation, neglecting multi-field dynamic coupling and fine inter-well interference management in the existing shale oil well distribution parameter design method, and provides a new well distribution parameter determination method based on response time-varying oil drainage volume. In order to achieve the above purpose, the present invention adopts the following technical scheme: a shale oil new well layout parameter determining method based on response time-varying oil drainage volume comprises the following steps: S1, constructing a multi-field coupling time-varying drainage volume characterization model; Establishing a geomechanical-seepage coupling numerical model, simulating dynamic evolution of a pressure field, a saturation field and a stress field of a target block in the shale oil failure development process, and calculating response time-varying oil drainage volumes under different production times based on simulation results; s2, determining the optimal cluster spacing; based on the characterization model, setting a plurality of groups of different cluster spacing schemes, respectively carrying out fracturing crack expansion simulation, analyzing the morphological characteristics of the cracks under each scheme and the corresponding time-varying oil drainage volume change curves in response, selecting cluster spacing corresponding to the schemes which can lead the cracks to expand uniformly, avoid strong stress shadows and reserve blank areas and have high peak value and slow attenuation of the t