Modeling Multistage Acid Fracturing Treatments in Carbonate Reservoirs

Dong, Rencheng; Wheeler, Mary F.; Su, Hang; Ma, Kang

doi:10.2118/204197-ms

Cited by 9 publications

(4 citation statements)

References 20 publications

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“…Reducing acid fluid filtration and acid rock reaction rate can effectively increase fracture length and conductivity. Most of the existing studies have evaluated the adaptability and process optimization of acid fracturing operations from two aspects: acid fluid combination [15] and acid fluid systems [16]. By adding a variety of additives to the acid fluid, the rheology of the acid fluid system is changed, and the liquid filtration and acid-rock reaction rate are reduced.…”

Section: Introductionmentioning

confidence: 99%

Study on Optimization of Stimulation Technology of Heterogeneous Porous Carbonate Reservoir

Zhao,

Xu,

Wang

et al. 2024

Processes

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Mishrif (M) reservoir of Faihaa (F) oilfield in Iraq is a heterogeneous porous carbonate reservoir. The reservoir properties of each reservoir unit differ greatly, and the distribution of porosity and permeability is non-uniform. Some reservoir units have the problem that the expected production cannot be achieved or the production decline rate is too fast after matrix acidification. This work optimized and compared the process of acid fracturing and hydraulic fracturing techniques. The Mishrif B (MB) and Mishrif C (MC) layers are selected as the target units for fracturing and the perforation intervals are optimized. The acid fracturing process adopted the acid fracturing technology of guar gum pad fluid and gelled acid multi-stage injection. According to the wellhead pressure limit and fracture propagation geometry, the pumping rate is optimized. The recommended maximum pumping rate of acid fracturing is 5.0 m3/min, and the optimized acid volume is 256.4 m3. The pressure changes during hydraulic fracturing and acid fracturing are different. It is recommended that the maximum hydraulic fracturing pump rate is 4.5 m3/min for MB and MC layers, and the amount of proppant in MB and MC layers is 37.5 m3 and 43.7 m3, respectively. The production prediction of two optimized processes is carried out. The results showed that the effect of acid fracturing in MB and MC layers is better than hydraulic fracturing, and it is recommended to adopt acid fracturing technology to stimulate MB and MC layers. Acid fracturing operation is carried out in the X-13 well, and better application results are achieved. The results of this study provide optimized reference ideas for reservoir stimulation in heterogeneous porous reservoirs.

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Section: Introductionmentioning

confidence: 99%

Study on Optimization of Stimulation Technology of Heterogeneous Porous Carbonate Reservoir

Zhao,

Xu,

Wang

et al. 2024

Processes

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“…Currently, the majority of mathematical models employed for simulating fracture propagation rely on linear elasticity theory [7]. The drawbacks of those models are that they cannot accurately describe the fracture propagation process and their simulation results are severely controlled by the mesh shape [8]. In addition, these methods only discretize the body boundary, and this phenomenon can cause serious problems during iterative calculations.…”

Section: Introductionmentioning

confidence: 99%

Study on the Fracture Propagation in Multi-Horizontal Well Hydraulic Fracturing

et al. 2023

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Multi-horizontal well hydraulic fracturing is a widely employed and highly effective method for stimulating tight and shale reservoirs. However, most existing studies primarily focus on investigating the impact of intra-well interference on fracture propagation while neglecting the influence of inter-well interference. Here, a multi-well hydraulic-fracture-propagation model is established to examine the effects of inter-well interference on fracture propagation within a multi-well system. In this study, based on the bilinear T-S criterion, the stiffness degradation is used to describe the damage and evolution process of fracture, the coupling process of fluid flow and solid damage and deformation is realized, and the dynamic distribution of inter-fracture flow is realized by using Kirchhoff function on the basis of the cohesive zone method (CZM) finite element model. Finally, the fracture-propagation model of multiple horizontal wells is established. Based on this model, the mechanism of inter-well interference on fracture propagation is studied, and the influence law of Young’s modulus and fracture displacement on fracture propagation in multi-wells is investigated. The results show that the reservoir can be divided into self-influence area, tension area and compression area according to the stress distribution state in the hydraulic fracture propagation of multi-wells. The propagation rate of hydraulic fractures in horizontal wells is significantly accelerated when they propagate to the local tension area generated by the fracture tip of neighboring wells, and rapidly decreases as the hydraulic fractures continue to propagate to the compression area of neighboring wells. Rocks with a lower Young’s modulus tend to be more plastic, forming hydraulic fractures with usually lower fracture lengths and usually larger fracture widths. The hydraulic fracture has an inhibitory effect on the propagation of fractures closer to each other in neighboring wells, and this inhibitory effect gradually increases as the distance decreases. The dominance of the dominant fracture to propagate in the self-influence area gradually decreases under inter-well and intra-well interference. As the dominant fracture propagates into the tension and compression areas of the neighboring well fractures, the feed fluid will show a brief rise and then eventually stabilize. This study quantifies the effect of inter-well interference on fracture propagation and lays the foundation for treatment optimization of small well spacing hydraulic fracturing.

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“…It can effectively remove inorganic scale but cannot remove organic scale. Organic solvent scale remover can effectively remove organic scale but cannot remove inorganic scale [ 21 ]. The organic solvent system dissolves the crude oil in the oil sludge by physical extraction according to the mechanism of extraction and plugging removal and the principle of similar phase solubility and disperses and strips the organic heavy components such as colloid asphaltene and paraffin attached to the surface of the oil sludge to achieve the complete separation of the two phases of oil and sludge [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

Wang

Zhou

Zou³

et al. 2023

Molecules

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Matrix acidification is one of the most effective stimulations to dissolve scales and remove damage in carbonate reservoirs. However, existing acid systems are difficult to dissolve organic and inorganic scales simultaneously, and complex multi-stage alternative injection often introduces new precipitation and damages the reservoir. Here, based on the retardation ability of emulsified acid and the stable structure of microemulsion, an oil-phase solvent was preferably selected, and the surfactant and cosurfactant were optimized to prepare an acid-in-oil type microemulsion acid capable of dissolving both organic and inorganic scales and high solubilizing for hydrochloric acid. Based on the rotating disc experiment, scale dissolution experiment and acid driving experiment, the acid-rock reaction kinetics, scale dissolution ability and acidizing and plugging removal performance of microemulsion acid in a carbonate reservoir were systematically studied and compared. The results show that Solvesso 150 (aromatic solvent) has the advantages of low toxicity, high flash point and high-scale dissolving ability. At NP−4: OP−10: A (cosurfactant) = 3:3:4, the microemulsion acid system has the strongest ability to solubilize hydrochloric acid and can solve the problem of low H+ concentration. The particle size of microemulsion acid is smaller compared to emulsified acid. At 60 °C, the mass transfer coefficient of microemulsion acid is 3.2 × 10−8 cm2/s, which is one order of magnitude less than that of emulsified acid. Microemulsion acid shows good solubility performance in dissolving organic and inorganic scales, and the comprehensive solubility of mixed scales can reach 98.28%. The stronger scale solubilization ability and lower acid-rock reaction rate enable microemulsion acid to form a thin and straight main wormhole, thus enhancing the acidizing and plugging removal effect. This study can solve the problem of poor hydrochloric acid solubilization ability of microemulsion acid to a certain extent, which provides theoretical and data support for the research and development of microemulsion acid and the efficient plugging removal technology for carbonate reservoirs.

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Modeling Multistage Acid Fracturing Treatments in Carbonate Reservoirs

Cited by 9 publications

References 20 publications

Study on Optimization of Stimulation Technology of Heterogeneous Porous Carbonate Reservoir

Study on Optimization of Stimulation Technology of Heterogeneous Porous Carbonate Reservoir

Study on the Fracture Propagation in Multi-Horizontal Well Hydraulic Fracturing

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

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