Plug and Abandonment for Gas Wells: A Case Study from Baghjan Oilfield, India

2021 ◽  
Author(s):  
Rishabh Bharadwaj ◽  
Bhavya Kumari ◽  
Astha Patel

Abstract The economic end of the life-cycle of a well is dynamic and it varies with the oil & gas market conditions and advances in extraction technologies. If production declines or the need for a workover arises, plugging and abandonment operations are followed. In case the wellsite has encountered accidental releases, systematic abandonment and remediation becomes even more crucial to avoid further environmental damage and capital investment. This paper analyzes the Baghjan oilfield blowout of the Assam-Arakan basin and provides abandonment practices for gas wells. The mobile workover rig was stationed at the Baghjan Well-5 with the aim to plug the lower producing zone at 3871 m and complete the well in the upper Lakadong+Therria sand at a depth of 3739 m. Baghjan Gas Well No.5 blew during the temporary abandonment which was planned to mitigate the leakage in the wellhead. Improper depth for the placement of cement plug, failure to check the plug integrity, and shortcomings in the regular inspection of annular casing pressure led to the well control situation at the Baghjan gas well. While pulling out the tubing conveyed perforation gun after perforating the Lakadong+Therria I+II sand, Shut-In Tubing Pressure of 4400 psi and 3900 psi Shut-In Casing Pressure was observed which indicated a leak in the Tubing Seal Assembly. The well was killed with a 9.76 lbm/gal sodium formate brine and in the middle of pulling the tubing, leakage in the W.F. Spool was identified which changed the priority of the operations. Therefore, a temporary abandonment operation was planned to mitigate the leakage problem in the primary and secondary seals, during which the well started flowing gas profusely after nipple-down of the blowout preventer. The shortcomings of the abandonment process can be conquered by the selection of an appropriate isolation material such as resin-based sealants or bismuth and thermite, which shall act as a primary barrier and provide enhanced zonal isolation. The isolation material should mitigate micro-fractures, minimize treatment volume and fluid loss, provide ample pumping time, and not degrade in the presence of wellbore fluids. The study discusses resin-based sealants, cement slurry designs, advances in conventional, unconventional, and rigless abandonment techniques, and suggests the most efficient method for the temporary and permanent abandonment operations to avoid further such incidents in the oil and gas industry.

2015 ◽  
Author(s):  
Mahmoud Asadi ◽  
Brain Ainley ◽  
David Archacki ◽  
Eric Aubry ◽  
Harold Brannon ◽  
...  

Abstract Historically, leak-off analyses of stimulation fluids have been performed using in-house laboratory procedures. The lack of industry standard procedures to perform leak-off and wall building coefficient analyses of stimulation fluids has introduced inconsistency in both results and reporting for many years. A technical standard adopted in 2006 by both API and ISO for static conditions has provided the oil and gas industry with the first standardized procedure to measure and report leak-off1. However, the more complex testing under dynamic conditions was not addressed. As a result, a group of industry experts have compiled their years of experiences in developing a new technical standard to measure the leak-off characteristics of stimulation and gravel-pack fluids under dynamic flow conditions. Stimulation and gravel-pack fluids are defined, for the purpose of this technical standard, as fluids used to enhance production from oil and gas wells by fracturing and fluids used to place filtration media to control formation sand production from oil and gas wells. Leak-off is the amount of fluid lost to porous media during these operations. The leak-off procedure was developed through the colaberation of several industry companies by evaluating numerous in-house laboratory techniques and conducting round robin testing to ensure that any modifications to these procedures were reliable and repeatable. The new standard provides a step-by-step procedure that includes fluid preparation, experimental equipment design, testing procedure and data analyses for fluids exhibiting viscosity controlled leak-off or wall building characteristics. Example calculations are reviewed within this paper.


2020 ◽  
Author(s):  
Mohammed Abdo Alwani ◽  
Mohammed Ahmad Soliman

Abstract The objective of this paper is to showcase successful and innovative means and techniques to improve and enhance centrifugal gas compressors (CGCs) performance, using methods to minimize power consumption, with no need for capital investment. These techniques will assure, if effectively followed, considerable reduction of the consumed energy. CGCs are the most widely used equipment in the oil and gas industry to boost gas, mainly hydrocarbons, to satisfy process treatments and pipeline requirements. In addition, CGCs are one of the major energy consumers, and therefore present an exceptional opportunity for saving energy. Focusing on lowering inlet gas temperatures, considering suction throttling of discharge pressure instead of the traditional discharge throttling, will help to reduce energy consumption. In this paper, a detailed analysis of factors aggravate or lead to undesired CGCs performance will be discussed along with solutions to minimize adverse impact. For example, operating the gas compressors at relatively high inlet temperature will result in higher energy consumption. After performing need analysis, results prove that we would save 3-7% of running compressors consumed energy. In addition, during compressor design phase, it was found that most motor driven compressor system uses discharge throttling, which incurs high-energy consumption. Instead, it is recommended to consider suction throttling to control discharge pressure, as will be explained. This paper will focus on a detailed case study in one of the running CGCs in an upstream gas-oil separation plant (GOSP-A). This paper proves the effectiveness of the proposed techniques in reinstating the CGCs in GOSP-A, to ensure better performance and save energy. This innovative technique is based on extensive process data analysis — evaluating operating, design data, related performance curves, and reviewing international standards. It will be illustrated that this type of analysis and techniques is a valuable tool for saving energy, in most cases, at oil and gas industries


2021 ◽  
Author(s):  
Abiola Oyatobo ◽  
Amalachukwu Muoghalu ◽  
Chinaza Ikeokwu ◽  
Wilson Ekpotu

Abstract Ineffective methods of increasing oil recovery have been one of the challenges, whose solutions are constantly sought after in the oil and gas industry as the number of under-produced reservoirs increases daily. Water injection is the most extended technology to increase oil recovery, although excessive water production can pose huge damage ranging from the loss of the well to an increase in cost and capital investment requirement of surface facilities to handle the produced water. To mitigate these challenges and encourage the utilization of local contents, locally produced polymers were used in polymer flooding as an Enhanced Oil Recovery approach to increase the viscosity of the injected fluids for better profile control and reduce cost when compared with foreign polymers as floppan. Hence this experimental research was geared towards increasing the efficiency of oil displacement in sandstone reservoirs using locally sourced polymers in Nigeria and also compared the various polymers for optimum efficiency. Starch, Ewedu, and Gum Arabic were used in flooding an already obtained core samples and comparative analysis of this shows that starch yielded the highest recovery due to higher viscosity value as compared to Ewedu with the lowest mobility ratio to Gum Arabic. Finally, the concentration of Starch or Gum Arabic should be increased for optimum recovery.


2019 ◽  
Vol 2019 (4) ◽  
pp. 160-175
Author(s):  
Anna Popova

The author studies environmental insurance in nature management as a lever of management measures to prevent and eliminate environmental pollution by oil products during their transportation and oil fields development. The research aims to develop recommendations for environmental risks insurance in Russian oil and gas industry on the basis of economic and mathematical model that allows to estimate the scale of environmental pollution by oil products. Such methods as system and comparative analysis, expert assessments, forecasting, modeling used in this work helped the author to identify Russian environmental insurance features; to propose a method for solving the problem concerning the lack of statistical data on the frequency and scale of accidents and the environmental damage magnitude by mathematical modeling of the accident, which allows to estimate the radius and depth of the underlying surface pollution. These developments will help insurers to make more adequate insurance premiums and tariffs, as well as to improve the underwriting procedure for unique oil and gas projects. But in order for the obtained achievements to find their application, it is necessary to have legislation obliging oil companies to compensate for environmental damage, and due to the scale of such damage, oil companies will be obliged to insure the relevant risks.


2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Alex W. Mwang’ande ◽  
Hualin Liao ◽  
Long Zeng

Annulus pressure buildup (APB) is still a serious problem in offshore gas wells, which threatens the safety of wells for the entire phases of drilling, completion, and production. The existing methods for mitigating APB are technically complex and highly costly. Setting top of cement (TOC) below the outer casing shoe to mitigate APB is easy to implement and can significantly reduce costs. However, there are no unified methods of determining TOC for this purpose. Nevertheless, existing petroleum standards give ambiguous regulations on the setting of TOC. This article brings a new and cheap method of mitigating APB by determining best TOC settings using a mathematical model for calculating APB from both annulus fluid expansion (AFE) and sustained casing pressure (SCP). Field data from gas well X are inputted to the model to describe how it serves this purpose. Calculation results for well X show that setting TOC's above and below the upper casing shoes for production and intermediate casings annuli, respectively, can greatly avoid the problem of APB and the costs associated with the existing mitigation methods. This technique can be used to other wells following the same procedures. The developed model reduced greatly the ambiguity of TOC determination as it helps to get the clear TOC combinations that control APB at the lowest cost of well construction while maintaining good and safe well operation.


2014 ◽  
Vol 34 (5) ◽  
pp. 405-413
Author(s):  
Xianru He ◽  
Qian Chen ◽  
Chunhui Feng ◽  
Liang Wang ◽  
Hailong Hou

Abstract High performance cement slurry polymer modifiers are increasingly in demand in the cementing process of oil and gas. A new polymer modifier with outstanding fluid loss control and high strength and toughness was synthesized by the main monomers butyl acrylate (BA), methyl methacrylate (MMA), acrylamide (AM), the functional monomers vinyltriethoxysilane (VTS), glycidyl methacrylate (GMA) and the initiator of ammonium persulfate (APS) through emulsion polymerization. By using Fourier transform infrared (FTIR) spectrometer, a laser particle analyzer, a scanning electron microscope and a differential scanning calorimeter, we studied the mechanism of fluid loss control and microstructure of polymer latex cement slurries. The experimental results showed that the copolymer could be crosslinked at 160°C and have the lowest fluid loss control, 12 ml, when the polymer content reached 5%. Acrylate latex modified by the silane coupling agent VTS had excellent performance on fluid loss control, as well as mechanical properties for oil well cement. These results have a potential significant value for the development of a new polymer cement modifier with high thermal stability and durability.


2016 ◽  
Vol 847 ◽  
pp. 485-489
Author(s):  
Xing Cai Zhang ◽  
Xiao Wei Cheng ◽  
Xiao Yang Guo

With the exploration of oil and gas in depth, shallow wells already can’t satisfy the requirement, therefore to explore and develop deep reservoirs is necessary. In the case of deep wells the loop temperature of bottom can reach to 150°C-200°C, which put forward a higher requirement for the high temperature resistance property of cement slurry. At present, many problems existed in the most of high temperature cement slurry. For example, high temperature resistance is not well, cement thickening time can’t adjust easily, mega-thermal sedimentation stability is unsatisfactory, and ultra-retarding phenomenon appeared for the top prone. After research indoors, we developed the ultra-high temperature slurry system by means of the investigation on cementing additives and select proper materials from high temperature resistant fluid loss additives, retarders, flowable agent at the same time. This system needs a lots of properties, such as, adjustable slurry thickening time below 200°C, great slurry sedimentation stability, API loss can be controlled at the range of 0-50ml, insensitive to temperature and density, could be used in low-density and conventional density cement etc. This system be used successfully in the well that loop temperature of bottom reaches to 185°C and get a good effect finally.


2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Abo Taleb T. Al-Hameedi ◽  
Husam H. Alkinani ◽  
Mohammed M. Alkhamis ◽  
Shari Dunn-Norman

Abstract Practically, to regulate filtration characteristics of drilling fluid, non-biodegradable materials used commonly have a high cost with side effects on personnel safety and the environment. Hence, eco-friendly additives are needed as an alternative to replace or at least support the commonly used filtration control agents. This experimental investigation examines the possibility of using date tree seeds’ powder (DTSP), as a new eco-friendly fluid loss agent. Under surface and sub-surface conditions (fresh and aged conditions), experiments were executed utilizing low-temperature and low-pressure (LTLP) and high-temperature and high-pressure (HTHP) American Petroleum Institute (API) filter press to comprehend the influence of DTSP on the seepage loss characteristics. The findings were compared with a commonly utilized chemical additive to regulate filtration characteristics of drilling fluid (low viscosity sodium carboxymethyl cellulose (CMC-LV)). Two concentrations of DTSP and CMC-LV were added separately to a reference fluid (RF) to understand the effect of concentration variations on filtration properties. The findings revealed that both DTSP and CMC-LV significantly improved the filtrate and the filter cake when comparing them with the RF under fresh and aged conditions. The findings for fresh conditions also showed that LTLP filtration measurements for CMC-LV additives had almost similar performance as DTSP additives, while HTHP filtration measurements exhibited that the two concentrations of DTSP additives were marginally better than those of CMC-LV additives. For aged conditions, CMC-LV additives were relatively more efficient than DTSP additives for LTLP filtration control experiments. However, DTSP additives were more efficient in improving the filtration characteristics as compared to CMC-LV additives for HTHP filtration control experiments. These results are in aid of shifting the oil and gas industry from using conventional harmful additives to using unconventional eco-friendly additives. This also helps in transforming unwanted food wastes into valuable commercial products, which can revolutionize the domestic and international industries and create new job opportunities, hence minimizing the total cost of drilling fluid and the wastes disposed to the environment.


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