Inherently safer sustained casing pressure testing for well integrity evaluation

2014 ◽  
Vol 29 ◽  
pp. 209-215 ◽  
Author(s):  
Tony Rocha-Valadez ◽  
Ray A. Mentzer ◽  
A. Rashid Hasan ◽  
M. Sam Mannan
Keyword(s):  
Pressure Testing ◽  
Well Integrity ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Implementation of Factory Cementing Concept in the High-Intensity Drilling Environment of Khazzan, Sultanate of Oman

2021 ◽  
Author(s):  
Emmanuel Therond ◽  
Yaseen Najwani ◽  
Mohamed Al Alawi ◽  
Muneer Hamood Al Noumani ◽  
Yaqdhan Khalfan Al Rawahi ◽  
...  
Keyword(s):  
Shallow Water ◽  
High Intensity ◽  
Sultanate Of Oman ◽  
Cement Slurry ◽  
Short Term ◽  
Lost Circulation ◽  
Well Integrity ◽  
Sustained Casing Pressure ◽  
Zonal Isolation ◽  
Casing Pressure

Abstract The Khazzan and Ghazeer gas fields in the Sultanate of Oman are projected to deliver production of gas and condensate for decades to come. Over the life of the project, around 300 wells will be drilled, with a target drilling and completion time of 42 days for a vertical well. The high intensity of the well construction requires a standardized and robust approach for well cementing to deliver high-quality well integrity and zonal isolation. The wells are designed with a surface casing, an intermediate casing, a production casing or production liner, and a cemented completion. Most sections are challenging in terms of zonal isolation. The surface casing is set across a shallow-water carbonate formation, prone to lost circulation and shallow water flow. The production casing or production liner is set across fractured limestones and gas-bearing zones that can cause A- and B-Annulus sustained casing pressure if not properly isolated. The cemented completion is set across a high-temperature sandstone reservoir with depletion and the cement sheath is subjected to very high pressure and temperature variations during the fracturing treatment. A standardized cement blend is implemented for the entire field from the top section down to the reservoir. This blend works over a wide slurry density and temperature range, has expanding properties, and can sustain the high temperature of the reservoir section. For all wells, the shallow-water flow zone on the surface casing is isolated by a conventional 11.9 ppg lightweight lead slurry, capped with a reactive sodium silicate gel, and a 15.8 ppg cement slurry pumped through a system of one-inch flexible pipes inserted in the casing/conductor annulus. The long intermediate casing is cemented in one stage using a conventional lightweight slurry containing a high-performance lost circulation material to seal the carbonate microfractures. The excess cement volume is based on loss volume calculated from a lift pressure analysis. The cemented completion uses a conventional 13.7 - 14.5 ppg cement slurry; the cement is pre-stressed in situ with an expanding agent to prevent cement failure when fracturing the tight sandstone reservoir with high-pressure treatment. Zonal isolation success in a high-intensity drilling environment is assessed through key performance zonal isolation indicators. Short-term zonal isolation indicators are systematically used to evaluate cement barrier placement before proceeding with installing the next casing string. Long-term zonal isolation indicators are used to evaluate well integrity over the life of the field. A-Annulus and B-Annulus well pressures are monitored through a network of sensors transmitting data in real time. Since the standardization of cementing practices in the Khazzan field short-term job objectives met have increased from 76% to 92 % and the wells with sustained casing pressure have decreased from 22 % to 0%.

Annular Barrier as an Alternative to Squeezes in Challenging Wells: Technology Review and Case Histories

2016 ◽  
Author(s):  
Joseph Bagal ◽  
Gbenga Onadeko ◽  
Paul Hazel ◽  
Vibjørn Dagestad
Keyword(s):  
Hydraulic Pressure ◽  
Case Histories ◽  
Regulatory Requirements ◽  
Pump Failure ◽  
Advantages And Disadvantages ◽  
Second Stage ◽  
Well Integrity ◽  
Open Hole ◽  
Sustained Casing Pressure ◽  
Casing Pressure

ABSTRACT The drilling industry has always relied on cement as a primary barrier. Although the cement represents about 5% of the well cost, when squeezes are required, cementing averages 17% of the well cost. Only 50% of the squeezes achieve the objective of establishing a barrier for well integrity. A little bit more than half of the failures can be attributed to operational challenges (pump failure, cement contamination), or design oversights (cement recipe, centralizers). However there are still cement failures with perfect design and field execution. These failures typically exhibit some of the following characteristics: high deviation, high pressure, washouts, natural fractures, long casing section, heterogeneous sands. For these specific conditions, it is beneficial to add an assurance that would maintain the integrity of the well even in case of bad cement. Some of the assurances used include port collars, external casing packers (ECP) and swell packers. Port collars allow a squeeze above the first stage cement, while ECP serves as a base for a second stage cement, and swell packers provides a baffle for sustained casing pressure. A more recent technology is the well annular barrier that can form a combined barrier with cement, and can also be used as a stand-alone primary barrier. The well annular barrier is a metal-expandable barrier that is expanded with hydraulic pressure. It is full bore, highly customizable, and qualified to ISO 14310. The metallurgy allows the packer to shape fit into either an open hole with irregular geometry or inside a casing to preclude annular pressure build up by giving a life-of-well reliable seal. The well annular barrier has been deployed in a variety of wells to achieve well integrity with and without cement, protect the B-annulus from sustained casing pressure, or serve as a barrier between reservoirs that cannot be commingled. This paper performs a review of the technologies used for cement assurance, their advantages and disadvantages. Case histories of well annular barrier deployments are presented, including a case where the well annular barrier was used as a stand-alone well barrier element without the need for dispensation. This paper also discusses how the well annular barrier fits into the regulatory requirements for well construction providing to the drilling industry an alternative to cement for the purpose of well integrity.

Well Integrity Enabled by Digital Workflow

2021 ◽  
Author(s):  
B. Brechan (Wellviz) ◽  
A. Teigland ◽  
S. Dale ◽  
S. Sangesland
Keyword(s):  
Fiber Optics ◽  
Risk Level ◽  
Gas Migration ◽  
Digital Workflow ◽  
Well Integrity ◽  
Digital Format ◽  
Standard Procedures ◽  
Safety Margins ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Abstract Emerging technologies are expected to provide step changes in many areas within planning, making and production of wells. The main topic of this paper covers in a digital workflow, where the different disciplines contributions to well integrity are expected to be on a fully digital format. All phases in the lifecycle of wells are integrated into one digital process, where possible improvements are enabled by the transition from a human oriented work process to a software oriented (human supported) process. This transition has taken place in several other comparable energy and capital-intensive industries. Today, some wells have the new fiber optics that enables a range of opportunities for improvement of well integrity. Distributed Acoustic Sensing (DAS) has measurements for every meter, which provides new aspects such as in situ measurements during cement jobs and drilling. Other applications of the new fiber optic technology are monitoring of gas migration, source of sustained casing pressure and other measurements which have the potential to develop into standard procedures or even regulatory requirements. With gas migration, corrosion and other changes affecting the integrity of the well construction, integrity can be re-modelled and updated automatically in a fully digital workflow to understand the safety margins. A part of this digital process is automating the risk level for each well and the entire asset. These processes and the prototype of the automated risk assessment are possible in a fully digital process, where planning and well construction commence with support from modern well planning and integrity software.

scholarly journals Public data from three US states provide new insights into well integrity

2021 ◽  
Vol 118 (14) ◽  
pp. e2013894118
Author(s):  
Greg Lackey ◽  
Harihar Rajaram ◽  
James Bolander ◽  
Owen A. Sherwood ◽  
Joseph N. Ryan ◽  
...  
Keyword(s):  
New Mexico ◽  
Oil And Gas ◽  
The United States ◽  
Gas Leakage ◽  
Integrity Testing ◽  
Well Integrity ◽  
Regional Trends ◽  
Public Data ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Oil and gas wells with compromised integrity are a concern because they can potentially leak hydrocarbons or other fluids into groundwater and/or the atmosphere. Most states in the United States require some form of integrity testing, but few jurisdictions mandate widespread testing and open reporting on a scale informative for leakage risk assessment. In this study, we searched 33 US state oil and gas regulatory agency databases and identified records useful for evaluating well integrity in Colorado, New Mexico, and Pennsylvania. In total, we compiled 474,621 testing records from 105,031 wells across these states into a uniform dataset. We found that 14.1% of wells tested prior to 2018 in Pennsylvania exhibited sustained casing pressure (SCP) or casing vent flow (CVF)—two indicators of compromised well integrity. Data from different hydrocarbon-producing regions within Colorado and New Mexico revealed a wider range (0.3 to 26.5%) of SCP and/or CVF occurrence than previously reported, highlighting the need to better understand regional trends in well integrity. Directional wells were more likely to exhibit SCP and/or CVF than vertical wells in Colorado and Pennsylvania, and their installation corresponded with statewide increases in SCP and/or CVF occurrence in Colorado (2005 to 2009) and Pennsylvania (2007 to 2011). Testing the ground around wells for indicators of gas leakage is not a widespread practice in the states considered. However, 3.0% of Colorado wells tested and 0.1% of New Mexico wells tested exhibited a degree of SCP sufficient to potentially induce leakage outside the well.

Avoiding Sustained Casing Pressure in Gas wells using Self Healing Cement

2011 ◽  
Author(s):  
Salim Taoutaou ◽  
Jorge Andres Vargas Bermea ◽  
Pietro Bonomi ◽  
Bassam Elatrache ◽  
Christian Pasturel ◽  
...  
Keyword(s):  
Self Healing ◽  
Gas Wells ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Sustained Casing Pressure Calculation of A Annulus Induced by Downhole Operation Load

2012 ◽  
Vol 430-432 ◽  
pp. 2067-2070
Author(s):  
Zhang Zhi ◽  
Tai Ping Xiao ◽  
Zheng Mao Chen ◽  
Tai He Shi
Keyword(s):  
Internal Pressure ◽  
Safety Evaluation ◽  
Calculation Model ◽  
Extrusion Force ◽  
External Diameter ◽  
Gas Well ◽  
Seal Failure ◽  
Theoretical Support ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Currently the annulus pressure of gas well becomes more common, so the safe production of several wells has been seriously affected. The annulus pressure mechanism is relatively complex, and it can be approximately classified into annulus pressure induced by temperature effect, by ballooning effect and by leakage or seal failure etc. The article mainly focuses on the annulus pressure mechanism induced by ballooning effect and the corresponding calculation model. For the tubing column with two ends fixed and closed, when tubing internal pressure is larger than the external extrusion force, the external diameter of the tubing column balloons (i.e. ballooning effect). It reduces the annular volume between the tubing and the casing, and consequentially induces annulus pressure. Based on the fundamental theory of elastic-plastic mechanics, the tubing column is simplified into the thin walled cylinder so as to deduce the relation models between the internal pressure and its swell capacity and A annulus pressure value, which provide theoretical support for safety evaluation on annulus pressure and the next treatment program.

Study of Ultrasonic Logs and Seepage Potential on Sandwich Sections Retrieved from a North Sea Production Well

2021 ◽  
pp. 1-15
Author(s):  
Hans Joakim Skadsem ◽  
Dave Gardner ◽  
Katherine Beltrán Jiménez ◽  
Amit Govil ◽  
Guillermo Obando Palacio ◽  
...  
Keyword(s):  
Gas Flow ◽  
Fluid Migration ◽  
Production Well ◽  
Offshore Production ◽  
Extensive Test ◽  
Sustained Casing Pressure ◽  
Zonal Isolation ◽  
Seepage Characteristics ◽  
Casing Pressure ◽  
Well Cement

Summary Important functions of well cement are to provide zonal isolation behind casing strings and to mechanically support and protect the casing. Experience suggests that many wells develop integrity problems related to fluid migration or loss of zonal isolation, which often manifest themselves in sustained casing pressure (SCP) or surface casing vent flows. Because the characteristic sizes of realistic migration paths are typically only on the order of tens of micrometers, detecting, diagnosing, and eventually treating migration paths remain challenging problems for the industry. As part of the recent abandonment operation of an offshore production well, sandwich joints comprising production casing, annulus cement, and intermediate casing were cut and retrieved to surface. Two of these joints were subjected to an extensive test campaign, including surface relogging, chemical analyses, and seepage testing, to better understand the ultrasonic-log response and its potential connection to rates of fluid migration. One of the joints contained an apparently well-defined top of cement (TOC) with settled barite on top. Although the settled material initially provided a complete seal against gas flow, the sealing capability was irreversibly lost as part of subsequent testing. The two joints have effective microannuli sizes in the range of tens of micrometers, in agreement with previous reports on SCP buildup in wells. On a local scale, however, we observed significant variations in cement quality from both the log results and the seepage testing. Further, we found qualitatively very good correlations between seepage-test results and the log results for the bond between cement and casings. The best bonded cement was found directly above a production casing collar, where a short segment of well-bonded cement prevented measurable steady-state seepage of nitrogen. Additional tests involving internal pressurization of the production casing suggested that certain annular-seepage characteristics are well-described by an effective microannulus at the cement/casing interfaces. We consider the two sandwich joints to be highly representative and relevant for similar mature wells that are to be abandoned.

Successful Remediation of Sustained Casing Pressures in Gas Cap Injector Wells with the Use of Flexible and Self Healing System

2021 ◽  
Author(s):  
Bipin Jain ◽  
Abhijeet Tambe ◽  
Dylan Waugh ◽  
Moises MunozRivera ◽  
Rianne Campbell
Keyword(s):  
Self Healing ◽  
Injection Wells ◽  
Coiled Tubing ◽  
Cement System ◽  
Sustained Casing Pressure ◽  
Casing Pressure ◽  
New Generation ◽  
Prudhoe Bay ◽  
Production Tubing

Abstract Several injection wells in Prudhoe Bay, Alaska exhibit sustained casing pressure (SCP) between the production tubing and the inner casing. The diagnostics on these wells have shown communication due to issues with casing leaks. Conventional cement systems have historically been used in coiled-tubing-delivered squeeze jobs to repair the leaks. However, even when these squeeze jobs are executed successfully, there is no guarantee in the short or long term that the annular communication is repaired. Many of these injector wells develop SCP in the range of 300-400 psi post-repair. It has been observed that the SCP development can reoccur immediately after annulus communication repair, or months to years after an injector well is put back on injection. Once SCP is developed the well cannot be operated further. A new generation of cement system was used to overcome the remedial challenge presented in these injector wells. This document provides the successful application of a specialized adaptive cement system conveyed to the problematic zone with the advantage of using coiled tubing equipment for optimum delivery of the remedial treatment.

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