High-pressure Wells Research Articles

Finite element analysis of fracture of a ram BOP for deep gas wells

Abstract In order to prevent well leakage in high temperature and high pressure (HTHP) wells, pressure test is a very important leak prevention operation that causes artificial high-pressure environment in wellbore. However, failure of wellbore equipment due to harsh condition is a common problem that brings great economic losses. Ram blowout preventer (BOP) is an important component of wellbore integrity, which is subjected to heavy loads from the test gas and the push rod during the pressure test. Therefore, the serious stress concentration of ram BOP induced by heavy loads and complex geometry is a major reason of fracture. Hence, the focus is to find out the fracture mechanism of ram BOP with experimental method and finite elements (FE) model in this paper. A series of damage inspection and strength test of ram BOP is carried out to find out the fracture characteristics. Based on detection information, FE analysis is conducted to analysis stress distribution and fracture reason of ram BOP. The results show that the maximum stress exceeds the yield strength (705 MPa) of the material under the actual working condition. Serious stress concentration at the notch root of the ram BOP can be easily caused by test pressure (from test gas) and contact pressure (from push rod). Both experimental method and FE analysis show the characteristics of ductile fracture obviously. Stress concentration at notch root is very sensitive to the test pressure. The work presented in this paper can provide basis and reference for preventing failure of ram BOP and improve efficiency and production.

A New Dynamic Fracture Plugging Evaluation Method and Its Application in Cementation for Mudstone and Sandstone Formation with Narrow Pressure Range in China South Sea

One of the difficulties in high temperature and high pressure wells and deepwater well cementation in China South Sea is that the pressure range is very narrow. In the drilling or cementation process, the formation is easy to form sharp crack leakage. In general, the traditional simulation of bottom-hole mud or cement slurry leakage is to use the mesh plate or fixed width at a certain temperature and pressure difference. However, when there are wedge cracks in the formation, it will cause repeated "huff and puff" dynamic leakage of fluids. Dynamic leakage puts forward higher requirements for evaluation methods and plugging materials. In view of the problems, a new dynamic fracture plugging evaluation instrument was developed, and the new hydraulic wedge plugging material and matching cementing technology were optimized, which solved the problem of cement slurry leakage and return in China South Sea. The results of this paper have been successfully applied in cementing operations of high temperature and pressure wells and deepwater wells in the China South Sea, effectively solving the problem of hydraulic wedge leakage in sandstone formation cementing with narrow safety pressure window.

The study of hydraulic automatic pressure regulating technology in water injection well

According to the energy waste, bigger burden and the different requirements of different injection pressure in the process of injecting pressure, this paper has conducted an in-depth study and put forward a series of new and improved technologies based on the original technologies, and the new techniques are validated, using modelling and simulation, and ultimately a set of hydraulic and automatic pressure regulating energy-saving water injection technologies for ground water injection are formatted, which can transfer a low-pressure well's surplus energy to high-pressure well without adding new equipment's energy consumption, complete the redistribution of the water injection pressure between high- and low-pressure wells, and realise the reasonable energy conversion between wells. All in all, it is of great significance to further improve the qualified rate of interval, saving energy, and reducing consumption of water resources.

The study of hydraulic automatic pressure regulating technology in water injection well

According to the energy waste, bigger burden and the different requirements of different injection pressure in the process of injecting pressure, this paper has conducted an in-depth study and put forward a series of new and improved technologies based on the original technologies, and the new techniques are validated, using modelling and simulation, and ultimately a set of hydraulic and automatic pressure regulating energy-saving water injection technologies for ground water injection are formatted, which can transfer a low-pressure well's surplus energy to high-pressure well without adding new equipment's energy consumption, complete the redistribution of the water injection pressure between high- and low-pressure wells, and realise the reasonable energy conversion between wells. All in all, it is of great significance to further improve the qualified rate of interval, saving energy, and reducing consumption of water resources.

A comprehensive investigation on the performance of durian rind as a lost circulation material in water based drilling mud

Abstract Oil and gas operators worldwide are expecting service companies to deliver integrated techniques to minimize, if not prevent, drilling problems. Drilling fluids perform vital functions to ensure the success of drilling operations. The technical challenges often associated with water-based drilling fluids are loss of critical properties, such as fluid loss control and rheology, under demanding conditions, such as in drilling deeper, high-temperature and high-pressure wells. Fluid loss during drilling operations has a very significant effect in both reservoir formation damage and monetary terms. The use of durian rind (DR) as a new additive in controlling lost circulation would provide another opportunity to reduce waste and avoid pollution. Therefore, DR was used to improve the rheological properties of water-based mud, and it was prepared for use as a fluid loss additive. For a better understanding of the influence of pectin on drilling mud properties, the rheological evaluation of untreated DR was compared to that of mud samples containing treated DR. The pectin in DR was extracted using four different solvents, namely, ethanol, methanol, sodium hydroxide and hydrogen peroxide, and the most effective solvent to remove the pectin was then determined. The Fourier transform infrared spectroscopy (FTIR) results showed that NaOH was the best solvent for removing pectin from DR. Thermogravimetric analysis (TGA) was used to determine the thermal stability of DR before and after treatments. The TGA results demonstrated that the treated DR had improved thermal stability compared to untreated DR. The sizes of DR used were coarse, medium, and fine. The untreated DR presented better rheological properties than the treated DR. The experimental investigation showed that a concentration of 20 lb/bbl of intermediate-sized DR was the best concentration among the tested samples.

Comments on: The flow and heat transfer characteristics of compressed air in high-pressure air injection wells [Arabian Journal of Geosciences (2018) 11: 519

High pressure has been widely used in the petroleum industry. The commended paper presented a model that can be used to simulate air flow in a vertical wellbore. The novelty and usefulness of the model is good, and the paper deserves to be published in the Arabian Journal of Geosciences. However, we pointed out some critical points that should be noticed by the authors as well as the following researchers who are involved in this area. The comments will show usefulness in pointing out future research direction in wellbore modeling.

Technical Note: A Review of Assessment of H2S Environmental Severity in Field and Lab—Why Use Fugacity?

In the context of the ever harsher production conditions encountered in the oil and gas industry, there is a need for improved materials qualification methods for sour (H2S) environments. The classic approach, based on H2S partial pressure, does not adequately characterize the corrosive severity of, in particular, high-pressure environments such as high-pressure high-temperature wells. This paper describes the introduction of non-ideal thermodynamics in the characterization of environmental severity. The focus is on sour exposure and using H2S fugacity or H2S aqueous concentration rather than H2S partial pressure. Experimental work has shown that these approaches are valid, at least for sulfide stress corrosion cracking of steel, and some of the benefits are demonstrated. It is recommended to extend this work to other materials and degradation mechanisms and also to upgrade laboratory test methods and industry standards for this purpose.

Optimization schemes extraction of inert and acid gases from a trade flow

To increase the efficiency of gas-lift method of gas condensate and oil recovery nitrogen canbe used as a natural gas substituting agent. It should be noted at problem actuality because at“mature” gas-condensate and oil fields high-pressure wells drop in pressure with duration of fieldlife or there is no sources of high-pressure natural and associated gases at all (eg, oil fields).When using nitrogen gas as an operating agent for gas-lift operation the possibility ofincreasing the volume fraction of nitrogen in natural gas composition grows to maximum at theproduction wells wellhead. In these cases it should further pursue the collection and systematizationof natural gas physical and chemical parameters data at the outlet of the gas producing facilities asthe results of necessity of complying with the qualitative indicators for commercial gas transmittedto pipelines. Operator needs to predict the maximum concentration of nitrogen in the gascomposition after the gas-lift operation for individual wells and define the optimal nitrogen contentand net calorific value of marketable gas feeding to customers. For gathering systems with maintransported product: natural gas artificially enriched with nitrogen for technological operations of   improved condensate or oil recovery, the authors propose to apply a centralized scheme for gasgathering during production instead of gas gathering at group gas-oil separation plant.In the article the basic aspects of such schemes, construction of production and processingequipment for nitrogen removing are represented. The algorithm of nitrogen content calculation,optimum capacity of nitrogen units are created and prospects for their further use are shown.The authors argue that the optimization of gas gathering schemes in the fields ofcentralization of equipment will save investment and operating costs.

A CRITICAL REVIEW OF DRILLING WASTE MANAGEMENT TOWARDS SUSTAINABLE SOLUTIONS

Drilling waste management for oil and gas industry involves collection, transportation, processing, recycling, disposal, and monitoring of waste materials in order to reduce their effects on health and environment. In the Exploration and Production industry, environmental concerns have made effective management of drilling waste at well sites a great priority. Effective waste management is thus a key element in a successful drilling project. The industry therefore relies on effective expertise and newer technologies to maintain a balanced trade-off between healthy business activities and environmental effects. Over several decades, the industry has recorded remarkable progress in reducing the effects of drilling activities on the environment. The progressive development and adoption of sustainable drilling waste management protocols by operating and servicing companies have been partly responsible for this success. However, new challenges are emerging due to advances in drilling techniques such as extended reach wells, deep water drilling, multi-lateral drilling, and high-pressure wells. Recently, advanced drill waste treatment methods such as nanotechnology based approach, supercritical fluid extraction, and microwave treatment process have been explored and tested in the laboratory and on pilot scale to see if they can help overcome these challenges and increasingly stringent regulations. This paper reviews the shortcomings of the conventional approaches, their treatment technologies, advantages, and applications. This article enhances understanding of waste management and its treatment process based on sustainability concept. Researchers can find this review useful as an update on the state of drill waste management in the oil and gas industry. It can also serve as a useful guide to develop new rigorous sustainable models, protocols, and techniques to manage drilling waste using the noble concept.

The Impact of Casing Damage Critical Condition on Marker Bed With Differential Internal and External Pressure in Daqing Oilfield

During long-term development of Daqing oilfield of marker bed has been affected sliding between layers, causing a large area of casing damage. The marker bed casing damage mechanism has been basically clear at present, but the influencing factors of casing damage are not yet consummate. There is fluid impact of pressure on the casing on the marker bed, and fluid pressure on the critical conditions of casing damage has not yet been carried out in research. To research the critical conditions, taking into account the mechanics characteristics of the formation and elastic-plastic the finite element model has been established, and different sets of pressure differential as critical condition impact on casing damage were studied in this paper. The results showed that the internal and external casing liquid pressure difference has little effect on the formation of critical slippage. High internal casing pressure wells, with small casing damage critical slippage, are more likely to damage.

Technology Focus: Drilling and Completion Fluids (November 2015)

Technology Focus This year marked the second year after completing my tenure as the deputy director of the University of Malaya (UM) Center of Innovation and Commercialization (UMCIC). UMCIC is the technology-transfer office in the UM, which is responsible for protecting UM’s inventions through intellectual-property registration such as patents and copyrights. Despite that, this year remained a busy year for me because it is time to restrategize my research and teaching endeavors. What I miss the most is that I am still not able to invest in more relaxing rounds of golf. As an academic lecturer and researcher in a Malaysian public university, I am often asked about the future of the upstream oil and gas industry. Most students are worried about the uncertainty of the industry. With unstable and low oil prices, which has led to massive job cuts for companies to stay afloat and remain relevant, many students are skeptical about pursuing petroleum engineering degrees. Not long ago, petroleum engineering bachelor’s degrees promised a bright and well-paid career. It used to bring in a six-figure salary. Unfortunately, now the luster has vanished with the slide in oil price. The rest, as they say, is history. Gail Tverberg, who is an actuary interested in finite world issues, has listed 10 reasons that a severe drop in oil price is a problem. At the top the list is, “If the price of oil is too low, it will simply be left in the ground.” Low oil prices translate to a rapid drop in production. They will also lead to a series of secondary effects such as debt defaults from deflation, loss of jobs, collapse of oil exporters, and loss of credit needed for exports. These will eventually lead to a rapid decline in oil production. In addition, secondary and tertiary recovery, specifically enhanced oil recovery (EOR), will be out of reach. I feel the industry needs to reinvent itself. It needs to think out of the box and make use of novel ideas and technology to maneuver during the challenging time. This year, the Federal Institute for Geosciences and Natural Resources, which is based in Germany, in its annual report, highlights a fascinating microbial EOR (MEOR) project that uses microorganisms in a conventionally depleted reservoir. It is a pilot reservoir project south of Beijing to determine “what microbes occur in the deposit and what metabolites they secrete (i.e., the substances that improve oil solubility).” The contemplated MEOR process marks a distinct departure from conventional wisdom. One of the major findings from the pilot project shows that microbes are normally undesirable intruders in oil reservoirs. They transform hydrocarbons into tar-like heavy fuel oil. In addition, oil producers ought to productively make use of something that is in the reservoir to begin with. It makes the tertiary-recovery process more environmentally friendly and, under specific conditions, perhaps even less costly. So, is petroleum engineering a sunset industry? If Tiger Woods can change his game, why not we? I hope you enjoyed and benefited from the selected and highlighted papers. There are other interesting papers on the recommended-reading list. For further reading, the OnePetro online library has additional papers. JPT Recommended additional reading at OnePetro: www.onepetro.org. IPTC 17801 Innovative Nonaqueous- Fluids Technology Improves Drilling Efficiency Significantly in Dealing With Divalent Complex Salt Formation Under HP/HT Conditions by Da Yin, PetroChina, et al. IPTC 17913 Successful Application of Customized Fluid Using Specialized Synthetic Polymer in High-Pressure Wells To Mitigate Differential-Sticking Problems by Minimizing Pore-Pressure Transmission by M.S. Al-Muhailan, KOC, et al. IPTC 18133 Stable Fracturing Fluids From Waste Water by Sarkis Kakadjian, Trican Well Service, et al. IPTC 18217 Successful Application of Innovative Technology Improves Lubricity of High-Performance Water-Based-Mud Systems in Challenging Environments by A. Maliardi, Eni, et al.

Application of Ejector Technology to the Efficient Exploitation in the Low-Pressure Gas Well

According to the research status of spray and drainage technology at home and abroad, based on the basic design of the ejector, this paper designs the ejector geometry, and do numerical simulation and analysis for ejection and combination flow field inside the ejector by using computational fluid dynamics method, building structure design of ejectors with pressure-gain for low-pressure gas wells. Verified by numerical simulation and field tests, the results showed that ejector design method is reliable. The operation of the device at the scene is safe and stable, achieving such goals as using energy from high-pressure wells to drive the low-pressure wells to work stably; delaying pressurization and exploitation for gas wells, reducing the cost of production and management. Field experiment is very effective, providing a new channel for us to increase the pressure of low-pressure gas wells and exploit them.

Technology Focus: Subsea Technology (August 2013)

Technology Focus My, what a difference a year makes as I look back at last year’s interest vs. this year’s. Improved-oil-recovery (IOR) technology and remotely-operated-vehicle support were in the forefront last year. This year, the buzz is around high pressure/high temperature (HP/HT). This is not to say that IOR technology has vanished or become passé; far from it. But this year’s group of papers heralds a technical sense of urgency to focus on tougher long-term basic science and research rather than quick-return near-term application engineering projects. HP/HT has been simmering as a long-term technical concern for the last 8 years. But HP/HT is a tough nut to crack, needing a lot of research-and-development funding for basic research that is only starting to show long-term benefits from understanding. This urgency is being fueled by industry, which is increasingly uncovering its own shortcomings in terms of current technology as it encounters new, challenging sources of hydrocarbons in deepwater, shale, and heavy-oil formations. Many of this year’s HP/HT technical papers reflect the progress of efforts and the urgency to solve remaining barriers in Fundamentals in design methodology, from simple 1D pressure-containing and -controlling designs and codes to multidimensional complex loading (combined pressure, temperature, tensions, and moments) combinations. These combinations are often beyond a single existing design code and will require new practices that combine several codes and methods to create a hybrid code that both industry and government can use. Material and fabrication hurdles, including lack of material properties at elevated temperatures, joining and seal technology that is far more rigorous and exacting than what the industry currently employs, and higher strength/hardness vs. ductility/toughness. The latter are two material/fabrication properties that are often diametrically opposed, but they need to be merged for the material to survive extreme sour HP/HT conditions. Predicting design life, from static maximum-load design criteria to addressing random cyclic loads (internally and externally), and how we monitor these predicted loads to determine the remaining life through in-situ sensing equipment. Clearly, this year’s crop of subsea technical papers reflects the heightened interest in HP/HT while still recognizing continued advances in IOR technology. Recommended additional reading at OnePetro: www.onepetro.org. OTC 24057 Design and Verification of High-Load-Bearing Interfaces by Nigel McKie, FMC Technologies, et al. OTC 24150 Composite-Reinforced Steel Drilling Riser for Ultradeepwater High-Pressure Wells by C.A. Cederberg, Hexagon Lincoln, et al. IPTC 16796 Flow-Assurance Study for a Subsea Production System With a Large-Scale Seabed Storage by Juneyoung Kim, KAIST, et al. OTC 23968 Large-Diameter-Riser Laboratory Gas Lift Tests by G. Zabaras, Shell, et al. OTC 24021 Wellbore Thermal Performance and Its Impact on Flow-Assurance Design of a Subsea Production System by Leon Liu, Intecsea, et al. OTC 24052 Subsea-Pipeline Repair by Composite System: One Step Deeper by S. Boulet d’Auria, 3XEngineering, et al.

Numerical Modelling Study of Oil–Gas–Water Three-phase Transient Bubbly Flow in HTHP Wells

A coupled system model of partial differential equations concerning pressure, temperature, and velocity of gas–liquid–liquid three-phase transient flow in high-temperature, high-pressure (HTHP) wells is presented, according to mass, momentum, and energy balances as well as the stated equation of gas. A solution framework shared by the basic models is built, which makes it convenient to perform the solution process. The finite difference method was adopted to simulate the model. Based on the unified solution framework, the singular value decomposition (SVD) algorithm is employed to solve the large linear equations for the proposed model. The average value is adopted to solve the redundancy of model. The basic data for X Well (a 7,110-m-deep HTHP well in Sichuan, China) were used for case history calculations. Pressure, temperature, and velocity curve graphs along the depth of the well were plotted at different times, intuitively reflecting the flow law and the characteristics of heat transfer along a formation. The results can provide technical reliability in the process of designing well tests for HTHP gas wells and a dynamic analysis of production.

Analysis on Casing Size and Steel Grade and Application in High-Temperature High-Pressure Gas Wells

Analysis on casing size and steel grade and application in high-temperature high-pressure gas wells are important in natural gas production engineering. This paper presents the standard casing size series, casing steel grade standard and code, types of casing steel grade, main problems in high-temperature high-pressure gas wells, using casing material suitable as solving means for high-temperature high-pressure gas well and application. For application, the study above is good and easy for on-the-spot application.

Study on Technical Limits of Single-Pipe Concatenation Gathering Process during High Water-Cut Stage

In order to optimize the gathering system and reduce the energy consumption in the production, single-pipe concatenation process has been widely used after the tertiary oil recovery technique is applied and development enters into high water cut stage in the oilfield. Aiming at condensate oil in gathering pipeline and obvious increase of the high circle pressure wells in the operation of the process, the adaption relationship between oil gathering pipeline size and flow, as well as the temperature limit of the gathering system start are studied, through the hydraulic and thermodynamic calculations of oil-gas-water multiphase flow. It has directive function for making effective schemes to solve the production problems caused by the high back pressure of wells.

Predicting on Distribution of Temperature, Pressure, Velocity, and Density of Gas Liquid Two-phase Transient Flow in High Temperature-High Pressure Wells

The authors present a predicting model concerning pressure, temperature, density, and velocity of gas liquid two-phase transient flow in high-temperature–high-pressure wells, according to mass, momentum, and energy balances. The finite difference method is used to solve the model. A high-temperature–high-pressure gas well (6,115 m deep) in Sichuan Province of China is used to check the efficiency of the proposed model and the algorithms.

Rheological properties of polymer-gel drilling fluids at high temperature and pressure

Free-radical polymerization in solution was used to synthesize a terpolymer consisting of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and styrene sulfonate. Drilling fluids based on the terpolymer were prepared for use in high-temperature and high-pressure wells. The rheological properties of the drilling fluids based on the terpolymer were analyzed by the regression method. We found that the rheological properties of the drilling fluids at high temperature and high pressure can be described by the Casson model. A mathematical model is proposed for predicting the downhole viscosity of drilling fluids containing the terpolymer at high temperature and high pressure.

Finite Element Numerical Simulation of Tubing Premium Connection

The environment and load condition of tubing is severe in high pressure wells. The sealability and joint strength of tubing string plays an important role in production operation. In this study, the makeup, sealability and joint strength was analyzed from conditions of make-up loading, tension loading, compression loading and internal pressure loading by finite element method. The makeup torque, the contact pressure distributions of metal seal along the axis and the stress distributions of threaded connection are given. The results show that under tension loading, compression loading and internal pressure, the overall stress level of threaded connection is lower than of pipe. The anti-compression performance and joint strength of threaded connection is greater than of pipe. The contact pressures of metal seal maintain relatively high level of contact pressures under tension loading, compression loading and internal pressure. Tension loading and compression loading reduces the sealing performance and the internal pressure increases the sealing performance from the integral of the contact pressure.

Efficient Perforation of High-Pressure Deepwater Wells

This article, written by Editorial Manager Adam Wilson, contains highlights of paper OTC 21758, ’Efficient Perforation of High-Pressure Deepwater Wells,’ by William Sanders, SPE, Carlos Baumann, SPE, and Harvey Williams, SPE, Schlumberger, and Flavio Dias de Moraes, SPE, Jonathan Shipley, Martin Bethke, SPE, and Scott Ogier, SPE, Petrobras, prepared for the 2011 Offshore Technology Conference, Houston, 2-5 May. The paper has not been peer reviewed. Thousands of perforating jobs are conducted successfully worldwide each month. However, for a small number of jobs, typically high-pressure deepwater wells, gun shock is a real and significant risk. The Cascade and Chinook projects presented the two largest deepwater high-pressure perforation jobs to date in the Gulf of Mexico (Fig. 1). These Lower Tertiary well completions have gross perforation intervals greater than 800 ft and downhole pressures higher than 19,000 psi. Perforating all intervals with long gun strings and then frac packing multiple zones in a single trip saves substantial rig time compared with performing conventional stacked frac-packed completions requiring multiple trips per perforated zone. Introduction Perforating several intervals in one run was required to complement a single-trip multizone frac-pack system in which all downhole packers, screens, and service tools are run at once and all zones are stimulated in a single trip. Planning, mobilizing, executing, and reviewing multizone perforating jobs at wellbore pressures higher than 19,000 psi and in water depths greater than 8,000 ft presents many challenges. Operational risks inherent to perforating multiple zones in a high-pressure deepwater environment were minimized by using a simple and reliable approach built on previous experience from high-pressure deepwater perforation jobs. Cost reduction is the main driver because of the very high daily cost of deepwater operations. With a one-way-trip time of 18–24 hours, eliminating just one trip in the well would save up to USD 2 million. Perforating three or four zones at once multiplies the savings. Planning Planning for these jobs began with evaluating the casing design configuration to ensure that the perforating bottomhole assembly (BHA) could be run in and retrieved from the well with no damage and that the casing could withstand the pressure requirements of the perforating operations.