Different Methods To Avoid Annular Pressure Buildup by Appropriate Engineered Sealant and Applying Best Practices (Cementing and Drilling)

Abstract

Summary Many wells that have been successfully cemented initially are showing annulus pressure buildup because of damaged cement- sheath integrity by post-cementing operations/conditions. This has been a concern by many operators where wellbores may be exposed to severe conditions and/or production regimes over a period of time. Sometimes this problem can be temporarily dealt with by releasing the annulus pressure, if environmental conditions and well type will allow. However, this method of annular gas production relief is not a long-term solution to the problem. In addition, it is not always possible to reduce the annulus pressure by releasing the trapped pressure into the environment on a regular basis, even if all other conditions permit this operation. An engineered cement-slurry system can save the operator from facing this situation by applying a lifetime zonal isolation remedy through the proper cement job design. Gas injection in specific areas in the UAE is performed to help maximize the production from these development fields. This paper will discuss the process of engineering a cementing system for these gas-injection wells and the development of a solution that has successfully protected wellbores in gas-injection areas where high pressures are applied to the wellbore. By treating the cement under defined wellbore conditions and studying the mechanical behavior of the cement sheath, it was possible to design a cement- slurry system that could withstand the high pressures applied through gas-injection operations. The mechanical behavior was evaluated using 3D finite element analysis (FEA) that considers mechanical properties such as Young's modulus, Poisson's ratio, and tensile strength in addition to confined compressive strength. The importance of complete zonal isolation is of high order. Elastic cement designs have provided a resilient nonfoamed, or conventional, system that successfully isolated the wellbores for more than a dozen gas-injection wells.

Integrity Evaluation of Cement Ring during Fracturing and Flowback of Horizontal Well in Jimsar Shale Oil

“…Since the mechanical model of casing/cement ring/ formation assembly is axisymmetric, the physical and mechanical model is a plane strain problem in the polar coordinate system (Figure 1). The relevant variables include radial displacement, radial stress, circumferential stress, and shear stress [12][13][14][15][16][17]. Among them, the inner surface of the casing bears the radial stress caused by the increase of wellbore temperature and pressure caused by wellbore fluid.…”

Study on sealing integrity of cement sheath in ultra deep well reservoir reconstruction

“…Using experimental devices, more in‐depth research has been conducted on the impact of changes in downhole construction conditions on the integrity of the cement sheath. They believe that the cement sheath should meet the short‐term and long‐term production tasks of the well and ensure its necessary strength requirements 10–14 . The convergence constraint method is applied to model the casing, cement sheath, and formation rocks as independent parts.…”

“…They believe that the cement sheath should meet the short-term and long-term production tasks of the well and ensure its necessary strength requirements. [10][11][12][13][14] The convergence constraint method is applied to model the casing, cement sheath, and formation rocks as independent parts. The integrity of the cement sheath is determined by the intersection of the load-bearing characteristic curves of each part, avoiding the complicated problem of directly calculating the failure of the first and second interfaces.…”

Development and application of on-line calibration device for water injection flowmeter

“…But the accuracy migration of high-pressure flow automatic controller must appear with the use of automatic controller. For example, the factory calibration accuracy is 0.5, but the accuracy error may be increased to ±10 ~ 20% due to pipeline changes caused by the corrosivity or scaling of the fluid medium and water injection pressure fluctuations in the process of using and different levels of other performance changes, and there isn't any kind of flow meter that can maintain long-term accurate and reliable measurement without any calibration after use [1][2][3][4][5].…”