Sealing properties and structure optimization of packer rubber under high pressure and high temperature

Abstract

During hydraulic fracturing operations of low-permeability reservoirs, packers are the key component to ensure the success of multistage fracturing. Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure, one at a time, while the remainder of the wellbore is not affected. However, reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature (HPHT) conditions of reservoirs (such as 70 MPa and 170 °C). In this study, the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments. The optimization process starts from the packer rubber with a conventional structure, and then, the weakest spots are identified by ABAQUS and improved by slightly varying its structure. This process is iterative, and the final optimized structure of a single rubber barrel with expanding backup rings is achieved. For the structure of three rubber barrels with metallic protective covers, both HNBR and AFLAS fail under HPHT conditions. For the final optimized structure, the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting. The results show that the optimized structure of a single rubber barrel with expanding backup rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.

Multi-objective optimization and experiment of nylon cord rubber in expandable packer

“…For numerical simulation, Hu et al (2017Hu et al ( , 2018, Patel et al (2019a, b) studied the influence of three rubber materials on sealing performance of packing element in the compression packer. Wang et al (2017), Lan et al (2019) studied the structure of the packer rubber with different materials and optimized the structure of its sealing unit. Based on the simulation results, the best inner groove shape and the structure of shoulder protection were confirmed.…”

Investigation on the Depth of Slip Hanger Teeth Bite into Casing and the Mechanical Properties of Casing under Different Suspension Loads in Ultra-Deep Wells

“…There is increasing difficulty in controlling the setting load due to increasing large-size casing tripped into deep reservoirs in the Northwest Oilfield in China. Excessive setting loads and the high-pressure and high-temperature (HPHT) conditions of reservoirs (such as 70 MPa and 170 °C) will cause problems such as wellhead subsidence, and severe damage to the casing caused by slips and the sitting load is too small possibly lead to poor sealing of the casing head [1] and [2]. Tripping the liner hanger into the upper casing is completed through interaction between the liner hanger slips and the casing.…”

Influence of viscous-elastic properties of a cylindrical sealing element on its sealing ability

“…Achieving tightness with the least external load by sealers and improving their efficiency and determination of sealing parameters has an important scientific value. Some scholars have done relevant research on cylindrical sealers used in oil and gas production (Lan et al, 2019;Liu et al, 2020). Liu et al (2020) carried out theoretical calculation and experimental research through the finite element analysis on the contact with large deformation according to the design of the new seal structure.…”

“…Liu et al (2020) carried out theoretical calculation and experimental research through the finite element analysis on the contact with large deformation according to the design of the new seal structure. Lan et al (2019) investigated the packer rubber with a conventional structure and optimized the materials and the structure of the packer rubber by ABAQUS software simulation and experimental research. But in these works viscoelastic properties of the sealing element were not taken into account.…”