Feasibility of foamed acid treatment in upper stimulation of fractured-vuggy dolomite reservoirs with bottom water

Su, Xuhang; Qi, Ning; Shi, Xiangke; Zhang, Zehui; Zhang, Zhenjun; Luo, Pandeng; Yu, Zhigang

doi:10.1016/j.geoen.2023.211552

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…In such cases, the single-well, water-free oil production period is short, and the production decline type is mostly rapid decline. The recovery factor for this type of reservoir ranges from 8% to 14%, with an average of only 11.7%, which is significantly lower compared to other types of reservoirs both domestically and internationally [13]. Consequently, improving development efficiency remains a pressing challenge [14].…”

Section: Introductionmentioning

confidence: 98%

Mechanistic Study and Optimization of High Water Cut Phase Management Strategies in Fracture-Vuggy Carbonate Reservoirs with Bottom Water

Zhao,

Xin,

et al. 2023

Processes

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Fracture-vuggy carbonate reservoirs commonly exhibit sufficient bottom water energy and are characterized by fractures or other interconnected channels with bottom water, which can easily cause high water cut in oil wells during production. The main reasons are as follows: firstly, bottom water coning leads to water flooding. Secondly, artificial water injection flooding fails and shows high water cut in oil production. This paper further clarifies the causes of high water cut in fractured-vuggy carbonate reservoirs and explores rational and feasible management strategies to improve the current water flooding situation and reduce the comprehensive water cut in oil wells. In this paper, numerical simulation technology is used to establish a mechanism model based on the actual reservoir conditions. By comparing the development effects of four bottom water suppression measures, including the adjustment of flow channel, artificial barriers, adjustment of flow potential and gas injection, the optimal measure is selected and the relevant parameters are optimized. Building upon this, further optimization of water injection methods is conducted to explore comprehensive management strategies for enhancing the water flooding effect during high water cut periods. The research demonstrates that bottom water can be effectively inhibited by artificial barriers, leading to an expansion of the swept volume of water injection and achieving the goal of improving the high water cut condition in carbonate reservoirs. Optimal implementation of artificial barriers occurs when the water cut reaches around 80%. Specifically, positioning barriers at the bottom of perforations and setting the barrier radius at 0.15–0.2 times the well spacing obtain the most favorable results. Additionally, short-term injection with long-term shut-in, identified through cyclic water injection simulations, exhibits superior oil recovery enhancement. Validation conducted in a practical field of a fractured carbonate reservoir over a five-year period has led to a substantial increase in oil production by 5.6 × 104 t and a 12% reduction in water cut. The research approach and methodology presented in this paper can provide valuable insights and serve as a reference for the development of high water cut periods in fractured-vuggy carbonate reservoirs.

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Section: Introductionmentioning

confidence: 98%

Mechanistic Study and Optimization of High Water Cut Phase Management Strategies in Fracture-Vuggy Carbonate Reservoirs with Bottom Water

Zhao,

Xin,

et al. 2023

Processes

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“…With 15% hydrochloric acid and 10% acetic acid in 100 mL/min under the dynamic dissolution experiments and water-based foam penetration into the rock matrix and tectonic surfaces, nitrogen ventilation into the mixing makes the foam occur; with the foam compressive aggregation, more pressure of acid, and acid steering breakthrough of the low-permeability filter cake, the foam is persistent, penetration distance is long, and the steering rate is high. However, the foam thermal stability is poor and sensitive to temperature and has limited influence in engineering applications. , Guo et al studied the nonhomogeneous reservoir of Longwangmiao in Sichuan Basin; they drew on the volumetric fracturing technology, using the reduced-resistant acid as the main acid, under high displacement to reduce friction, and propping open the natural fractures, so that the acid filtration loss along the fractures was deep into the reservoir, relying on its high reactivity to dissolve the foreign pollutants in the fracture and the primary and secondary fill minerals. It can indeed establish a few mesh flow channels with considerable flow-conducting ability to eliminate near-well damage.…”

Section: Introductionmentioning

confidence: 99%

“…However, the foam thermal stability is poor and sensitive to temperature and has limited influence in engineering applications. 14 , 15 Guo et al 16 studied the nonhomogeneous reservoir of Longwangmiao in Sichuan Basin; they drew on the volumetric fracturing technology, using the reduced-resistant acid as the main acid, under high displacement to reduce friction, and propping open the natural fractures, so that the acid filtration loss along the fractures was deep into the reservoir, relying on its high reactivity to dissolve the foreign pollutants in the fracture and the primary and secondary fill minerals. It can indeed establish a few mesh flow channels with considerable flow-conducting ability to eliminate near-well damage.…”

Section: Introductionmentioning

confidence: 99%

Study on the Spatial Damage Characteristics of Working Fluid in a Sandstone Reservoir and an Unplugged Fluid System

Xin,

Zhao,

et al. 2024

ACS Omega

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Due to its good physical properties and low pressure coefficient, the K75 reservoir is prone to leakage and intrusion of drilling and completion fluids during well construction, resulting in plugging of the borehole throat, which will inevitably affect the injection and recovery capacity of the gas well. In order to ensure the strong injection and production capacity of the K75 reservoir, this paper clarifies the reservoir space damage characteristics under different pressure differences and different entry fluids by establishing physical simulation of the damage, selecting the optimal system of the decongestant, and conducting dynamic flow decongestion experiments, as well as combining with the characterization means of the continuous scanning system of the core and the permeability test of the gas measurement. The test results show that the degree of damage of the same working fluid increases with the increase of differential pressure of repulsion, and the degree of damage of sequential working fluids (drilling fluid, completion fluid, and perforating fluid) is greater than that of drilling fluid damage under the same differential pressure of repulsion. In order to relieve the damage of wellbore working fluids, a set of multifunctional, low-corrosion composite acid system formulas was selected through rock powder, mud cake dissolution experiments, and dynamic flow unblocking experiments; the permeability recovery rate of this acid system after unblocking was more than 90%, which is widely applicable, and it is useful for the acidizing and unblocking practice in similar reservoirs.

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“…Sandstone reservoirs with bottom water drive are important parts of unconventional petroleum resources, which are characterized by early water breakthrough, short water-free oil recovery period, rapid water cut increase, and strong heterogeneity. − With large scale and high abundance, bottom water reservoirs are strictly controlled by structure, stratum, and other conventional traps. Since natural interbeds between sandstone reservoirs and the bottom aquifer are usually weak or absent, water can easily intrude the production wells and the oil/water interface moves toward the wellbore. , Once water breakthrough occurs, the water cut increases significantly, which inhibits the flow of oil, and a large amount of residual oil remains in the middle and upper part of the reservoir, reducing production efficiency. − Therefore, the exploitation of sandstone reservoirs with bottom water drive suffers from the bottom water coning and huge production cost issues. − …”

Section: Introductionmentioning

confidence: 99%

Laboratory Evaluation on the Water Flooding Characteristics in Bottom Water Reservoir Containing Interbeds

Lee,

Tang,

Yan

et al. 2023

ACS Omega

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Sandstone reservoirs with bottom water drive are widely distributed all over the world, which are characterized by the complex process of oil and water storage and transmission. At present, the research on the water flooding process and oil–water evolution characteristics in bottom water reservoirs containing interbeds needs to be strengthened. In this study, water flooding experiments with different placements of the interbeds were conducted using a two-dimensional (2D) vertical model. The results demonstrated that the interbeds make the bottom water flow upward more evenly, resulting in decreased incursion speed, increased displacement area, and better displacement effect. Moreover, compared with the tilted interbed model, the horizontal model has a 6% higher oil recovery rate, exhibiting a better oil displacement effect. The results presented herein will provide important guidance on water control in bottom-aquifer oil reservoirs containing interbeds and will promote unconventional petroleum resources recovery.

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Feasibility of foamed acid treatment in upper stimulation of fractured-vuggy dolomite reservoirs with bottom water

Cited by 8 publications

References 19 publications

Mechanistic Study and Optimization of High Water Cut Phase Management Strategies in Fracture-Vuggy Carbonate Reservoirs with Bottom Water

Mechanistic Study and Optimization of High Water Cut Phase Management Strategies in Fracture-Vuggy Carbonate Reservoirs with Bottom Water

Study on the Spatial Damage Characteristics of Working Fluid in a Sandstone Reservoir and an Unplugged Fluid System

Laboratory Evaluation on the Water Flooding Characteristics in Bottom Water Reservoir Containing Interbeds

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