Evaluation and Modification of Fracture Treatments Showing Near-Wellbore Effects

Gulrajani, Sunil N.; Romero, J.

doi:10.2118/36901-ms

Cited by 14 publications

(2 citation statements)

References 3 publications

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“…Several researchers have conducted studies in order to investigate the mechanism of a hydraulic fracture creation in cased perforated wellbores [7][8][9][10][11][12]. They have shown that the wellbore inclination and azimuth as well as perforations spacing, phasing and orientations with respect to the in-situ stress directions play important roles in the process of fracture initiation and near wellbore propagation.…”

Section: Introductionmentioning

confidence: 99%

Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

et al. 2017

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Abstract:Hydraulic fracture initiation and near wellbore propagation is governed by complex failure mechanisms, especially in cased perforated wellbores. Various parameters affect such mechanisms, including fracturing fluid viscosity and injection rate. In this study, three different fracturing fluids with viscosities ranging from 20 to 600 Pa.s were used to investigate the effects of varying fracturing fluid viscosities and fluid injection rates on the fracturing mechanisms. Hydraulic fracturing tests were conducted in cased perforated boreholes made in tight 150 mm synthetic cubic samples. A true tri-axial stress cell was used to simulate real far field stress conditions. In addition, dimensional analyses were performed to correspond the results of lab experiments to field-scale operations. The results indicated that by increasing the fracturing fluid viscosity and injection rate, the fracturing energy increased, and consequently, higher fracturing pressures were observed. However, when the fracturing energy was transferred to a borehole at a faster rate, the fracture initiation angle also increased. This resulted in more curved fracture planes. Accordingly, a new parameter, called fracturing power, was introduced to relate fracture geometry to fluid viscosity and injection rate. Furthermore, it was observed that the presence of casing in the wellbore impacted the stress distribution around the casing in such a way that the fracture propagation deviated from the wellbore vicinity.

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Section: Introductionmentioning

confidence: 99%

Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

et al. 2017

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“…Near-wellbore measurement methods often use radiotracers to monitor wellbore data (Guo et al, 2019;Liu et al, 2018;Jin et al, 2021;Liu et al, 2020a). Different radioactive materials were put into the fracturing fluids, gamma spectrum was measured by using a logging instrument, the distribution of the proppant was obtained, and then the fracture height and width were calculated (Gulrajani and Romero, 1996;Shi et al, 2017;Liu et al, 2020b), as shown in Figure 1C. Near-wellbore measurement technology is limited by a small monitoring range, resulting in low accuracy of evaluation results.…”

Section: Near-wellbore Measurement Methodsmentioning

confidence: 99%

Research Advance on the Diagnosis Technology of Hydraulic Fractures in Shale Reservoirs

Chen

Wang

et al. 2022

Front. Energy Res.

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2D Modeling of Hydraulic Fracture Initiating at a Wellbore with or without Microannulus

et al. 2009

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The goal of this paper is to investigate the near-wellbore phenomena with respect to fracture initiation. The 2D numerical model was developed, which takes into account the interaction of steel casing, cement, and surrounding rock and allows for a curved path of the fracture. The model incorporates an effective finite-difference numerical method for solving a system of coupled differential equations: 1D equations of power law fluid flow along the fracture trajectory and 2D equations of the linear elasticity for rock massif. The model predicts and evaluates the near-wellbore fracture pinching effect as a function of fracture trajectory, perforation misalignment angle, cement/formation properties, stress contrast, and fracturing fluid parameters.The model developed has a limitation: it does not take into account the leakoff and pore pressure changes in nearwellbore zone during fracturing treatment. However, we believe that this limitation is not essential as it does not affect the quality of results obtained and can be eliminated easily.Several different scenarios of fracture initiation and propagation were considered. We modeled the initiation and propagation of the fracture through the narrow channel (microannulus) along cement-rock interface as well as along the misaligned perforation. We also investigated different geometries of microannulus development and made conclusions on the most probable situation for different formation conditions. We conducted the comparative analysis of pressure drops and fracture width reductions for different types of fracture propagation. We also modeled fracture propagation for different perforation phasing angles. Based on the results of numerical experiments, we are able to provide some recommendations on how to avoid the worst case of the fracture initiation scenario.

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Evaluation and Modification of Fracture Treatments Showing Near-Wellbore Effects

Cited by 14 publications

References 3 publications

Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

Research Advance on the Diagnosis Technology of Hydraulic Fractures in Shale Reservoirs

2D Modeling of Hydraulic Fracture Initiating at a Wellbore with or without Microannulus

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