A new numerical method for evaluating the variation of casing inner diameter after strike‐slip fault sliding during multistage fracturing in shale gas wells

Abstract

Casing shear deformation has become a prominent problem in the process of completion in shale gas wells. It was believed that the slide of strike‐slip fault induced by multistage fracturing was the main reason. This paper presented a new numerical investigation for evaluating the casing inner diameter after strike‐slip fault sliding based on the microseismic data. A 3D finite element model, considering the mechanical anisotropy of shale and heat‐fluid‐solid coupling effect during multistage fracturing, was developed to calculate the variation of casing inner diameter after fault sliding under different engineering and geological conditions. The calculation result was verified by comparison with the measurement result of the multi‐finger caliper survey. Sensitivity analysis was carried out and the results showed that decreasing the sliding distance, maintaining high pressure, increasing the casing thickness, and increasing the elasticity modulus and decreasing the Poisson ratio of cement sheath were beneficial to protect the casing integrity. Finally, the engineering verification demonstrated that the numerical method has an accuracy up to 85.9%. Numerical model in this study was expected to provide a better understanding of casing shear deformation and an evaluation method of casing inner diameter after fault sliding during multistage fracturing in shale gas wells.

Statistical analyses of reservoir and fracturing parameters for a multifractured shale oil reservoir in Mississippi

“…The central part of Tuscaloosa is composed of dark gray, fissile, and sandy marine shale . Multifractured horizontal wells (MFHW) have enabled commercial production of oil from shale reservoirs . More than 80 multifractured horizontal wells were drilled in the TMS play during 2012 and 2015 .…”

“…2 Multifractured horizontal wells (MFHW) have enabled commercial production of oil from shale reservoirs. 5,6 More than 80 multifractured horizontal wells were drilled in the TMS play during 2012 and 2015. 4,7 Some wells were reported to have appealing initial production rates of greater than 1000 stb/day.…”

Development and application of transient gas‐liquid two‐phase flow model considering sudden density change

“…It is directly related to safety and efficiency, and also to the success of drilling operations. [1][2][3] In order conduct safe drilling for a narrow pressure window in deepwater, research institutions and scholars studied several dual-gradient drilling technologies, such as dual-gradient drilling with light medium (gas, hollow sphere), 4 submarine pump lifting drilling, 5,6 mud cap control drilling, 1,7,8 and deepwater multi-gradient drilling, 9 while developing corresponding core technologies, matching equipment, and drilling theories. In recent years, based on the idea of injecting a light medium (gas, hollow sphere) into the annulus to realize dual-gradient drilling, a new deepwater dual-gradient drilling technology based on downhole separation was developed and a new downhole cyclone separator was designed.…”

“…Narrow pressure margins are a significant factor during deepwater drilling. It is directly related to safety and efficiency, and also to the success of drilling operations . In order conduct safe drilling for a narrow pressure window in deepwater, research institutions and scholars studied several dual‐gradient drilling technologies, such as dual‐gradient drilling with light medium (gas, hollow sphere), submarine pump lifting drilling, mud cap control drilling, and deepwater multi‐gradient drilling, while developing corresponding core technologies, matching equipment, and drilling theories.…”

Numerical investigation of casing shear deformation due to fracture/fault slip during hydraulic fracturing

“…[1][2][3] The influence of in situ stress field redistribution and asymmetric treatment on casing deformation was calculated by estimating the spatial distribution of microseismic events as stimulated rock volume. 4,5 Based on comprehensive analysis of field microseism, well logging, and lead model, the main casing damage mode corresponds to shear failure due to the formation slip that is reactivated in the process of fracturing fluid injection, [6][7][8][9][10][11][12] as shown in Figure 1. 13 Guo et al 13 noted that the casing failure rate near the natural fracture/fault (hereafter, fault is replaced with natural fracture) was as high as 56.76%, which included 37 total natural fractures.…”