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The principle of well integrity is primarily occurred with maintaining well control with sufficient barriers.
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listed. Algorithm for estimation of parameters with an arbitrary time interval are described. Program realization of the algorithm are illustrated.
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... In the mining industry, significant attention is paid to safety and production efficiency. In particular, this is reflected in the annual growth of efforts and costs aimed at ensuring the integrity of oil and gas wells [1][2][3]. The life cycle of a well includes several stages, such as design, construction, operation and abandonment. ...
One of the main problems of well operation is the risk of uncontrolled leakage of hydrocarbons into the environment. This problem is especially relevant for the long-term operation of wells. The idea for this study was inspired by a real industrial problem that the authors of the article were involved in solving. At several operating gas wells, an abnormal slope of the production tree occurred, which raised the question of the safety of their further operation. An analysis of known studies and current regulatory documents did not allow us to assess the safety of using a gas well based on the measured kinematic parameters of production tree deviations. A mathematical model for the deformation of a package of casing strings when the surface layer of the rock is displaced is developed in the article. A boundary value problem is formulated for differential equations of pipe bending on an elastic foundation. Based on the results of solving this problem, an unambiguous relationship was established between the maximum bending stress in the surface pipe and the angle of inclination of the production tree. The quantitative characteristics of the connection depend on the geometric and mechanical properties of the pipes and on the thickness and mechanical parameters of the formations. It was established that the existing inclination of the production tree can be achieved due to the beginning of the plastic bending of the surface pipe under the slickenside, which does not exclude the exhaustion of the safety margin of the surface pipe and indicates the possible operation of the casing string in a pre-emergency state. In general, the obtained results develop analytical approaches to assessing the behavior of underground structures of a production well in unstable soil bodies.
This paper discusses the common operation challenges when performing Coiled Tubing Cement Zonal Isolation in a well with integrity complications and offers probable solutions to mitigate the operational risks introduced by the well integrity issues.
Our case study, well Y is situated in the shallow offshore terrain in Balingian Basin. This well was completed as a Dual String Completion Oil Producer in the year 1986. After years of production, well Y experienced multiple leaks in its production tubing, and the leaks were successfully isolated by tubing patches.
During well intervention campaign, these multiple tubing patches need to be retrieved to allow Coiled Tubing to pass through the well inner diameter (ID) which leaves the well to be in a leaking condition again.
A comprehensive risk assessment was conducted to identify the feasibility of performing Coiled Tubing Cement Zonal Isolation in a leaking tubing and recommended solutions to achieve a successful Zonal Isolation. Few of the vital criteria that enabled this campaign to be executed were the location of tubing leaks that were ways above the intended top of cement, the Production Packer Integrity was intact, and the use of Cement Retainer in the operation.
The low-cost solutions recommended were to (1) fill up both production casing and tubing with fluid to enable Production Packer – Tubing Integrity / Cement Retainer Integrity to be evaluated appropriately, (2) use of Single Trip Cast Iron Cement Retainer to avoid difficulties in sting-in or (3) use of Modified Cement Retainer with Dual Flapper Check Valve (DFCV) and Pump Out Plug to facilitate Cement Retainer Integrity Test in case if result from solution (1) was misleading or not available.
This paper therefore details all the operation approaches taken by the project team in accessing the available well data and how the integrity problems were addressed. This paper intends to guide well engineer who might face similar well integrity challenges in their intervention campaign.
In the world, with the development of science, brand new technologies are being created to generate energy resources (e.g., hydrogen energy, electric car, etc.). These inventions will reduce the consumption and cost of hydrocarbon resources. This leaves oil and gas resource producers with only one option – accelerated development of oil and gas fields with low capital investment. This monograph is devoted to the development of oil and gas fields in a short period of time with a reduction in the volume of drilling operations and well quality by at least 50%. The developed technology of simultaneous split operation will give an impetus to volumetric production of hydrocarbons, accelerated field development and reduction of capital investments, as well as lead to the production of all recoverable and non-recoverable reserves from the subsoil. This monograph also delves into the technological aspects of operating wells in the Altyguyi gas condensate field. The scientific work examines the operational and technological aspects of hydrodynamic and thermohydrodynamic studies. To support this research, patents for invention No. 643 and 644, dated January 6, 2015, were obtained (application numbers 14/101317 and 15/101320). These patents cover the “Simultaneous method of separate and joint operation of several productive horizons by one chink and device for its realization” and the “Method of dual oil and gas production from one well in a multizone”. Based on the findings of the conducted analyses, studies, and calculations, the implementation of the intensification of the gas condensate field using the oil and gas DC method by one well is justified. This approach represents a first in global practice and aims to reduce capital investments and accelerate development.
70% of Indonesia's old oil and gas wells will have no economic value and have to be abandoned as ruled by the government as it comes to the end of the well life cycle. It's part of decommissioning an entire field with environmental preservation called Abandonment and Site Restoration (ASR). There are two kinds of approaches to abandonment, prescriptive-based and performance-based. Each country has its regulations but refers to one of those two approaches. Indonesia's permanent abandonment standard is prescriptive-based, this was compared and evaluated to international permanent abandonment standards for abandonment design, and the philosophy behind it.
Literature studies are performed to understand the abandonment philosophy for Performance-Based versus Prescriptive-Based to give proper suggestions or improvements. Based on the literature study, contrast gap analysis and suggestions provided to ensure a proper permanent abandonment approach to avoid any future leaks or re-abandonment operation as part of well integrity assurance after abandonment
This paper will define and evaluate the gap analysis between typical prescriptive-based abandonment standards, like Standar Nasional Indonesia 6910-2022, Section 19.2, Abandonment of Wells; ISO-16530-1, Chapter 10, Well Abandonment Phase; OGUK, 2015a, and NORSOK D-010, Rev. 4, Chapter 9 with a performance-based approach.
The gap analysis has shown significant abandonment improvement opportunities, especially in terms of materials that can be used for plugging/isolations, reservoir isolations barriers, annular barriers, also abandonment philosophy and practice.
Safe production from oil and gas wells always entails a two-barrier policy. In the well of interest, the primary barrier was breached while the secondary barrier was holding, and well fluids were observed in one of the tree ports during routine maintenance operations. The well was quickly made safe by closing a primary barrier, the downhole surface-controlled subsea safety valve (SCSSSV), and installation of a secondary barrier in the form of plugs downhole. To bring production back, the root cause was investigated, and it was determined that the straight-bore metal-to-metal seal, which seals the tubing at the interface of the tree and the tubing hanger, was compromised.
After a successful installation of a new seal, pressure integrity could not still be ensured as it was further determined that there was pitting corrosion, observed on the tubing hanger, which did not allow the seal to successfully seal the pressure across the tubing hanger neck. Restoration of the well would depend on the repair of the tubing hanger, which would have required a complete workover, an approach that was deemed prohibitively expensive.
A novel approach was implemented to machine out an additional groove on the tree body to provide an additional elastomer seal as a secondary barrier as opposed to the traditional metal-to-metal seal. This paper demonstrates the approach and successful restoration of the safety and well production. The approach can be widely utilized in establishing safety barriers in similar situations.
Cement sheath is a well barrier that prevents the unintentional and uncontrollable flow of fluids from, into a formation or back to its surface. However, during drilling and production operations, this cement is subjected to various stresses resulting from thermal stress, non-uniform geo-stress, compressive and tensile stresses. Therefore, this study describes a finite element analysis (FEA) simulation of a cement sheath of class G type under stress in a typical drilling and production scenario. With experiments, the rheological and mechanical properties of class G cement with varying water-cement ratio of 0.4, 0.5 and 0.6 were prepared and analyzed for their performance and workability. From the results, it showed that the cement system with the lowest water-cement ratio of 0.4, demonstrated the highest mechanical strength. This was attributed to lesser water in the mix triggering efficient interaction with cement. Hence, based on this study, 0.4 cement ratio is recommended if the ability to withstand compressive and tensile forces is desired. In cases where it is to be used for drilling and production operations characterised by fatigue and cyclic forces, its composition should be designed such that it is more ductile and flexible. An FEA software, ANSYS Mechanical APDL (ANSYS Parametric Design Language) was used to analyze stress to convergence. Material properties of 0.4 cement ratio was adopted for simulation based on experimental results. Also, well loading conditions were cycled at temperature and pressure of 0-104 0C and 250-290 bar simultaneously. Simulation results showed the time changes of equivalent (Von-Mises), maximum, minimum and shear stresses. Time changes of equivalent elastic strain, total deformation and stress intensity were also recorded. From the simulation results, it can be concluded that the yield point of the material occurred at a time (t) =1.3245×10−4 s under continuous stress. It is recommended that the contact point between the casing and the cement be monitored for deformation due to high stress response during stress analysis.
