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A new perforating technique employing the integration of conventional shaped charges and solid propellant was described by Albert, et.al. (SPE 197185-MS). The innovative propellant deployment method allows the propellant deflagration to occur in the perforation tunnel rather than gun body and casing, thus delivering maximum energy to improve perforation tunnel performance. Shaped charges utilizing high energy explosives perforate casing and formation with high speed metallic jets that displace by sheer force. The explosive events are fast (20-30 microseconds) high impact events (as high as 1.5 million psi at the rock face) that can collapse large pores in the formation along the surface of the perforation tunnel. This crushing along the tunnel reduces permeability and increases skin and can impact the flow of fluids into and out of the reservoir rock. A number of methods have been developed to improve perforation tunnel flow efficiency, but all suffered limits on either deployment or effectiveness.
Propellants have been used for decades to improve perforation performance. Propellants are energetic materials with slower burn rates that can micro-fracture the formation and break-up the crushed zone around perforation tunnels. Prior methods deflagrated the propellant materials within the gun bodies, or casing and lost a significant amount of energy before delivering impact to the perforation tunnel. The new method with a composite cap of solid propellant on the face of the shaped charge, displaces the propellant into the perforation tunnel before deflagration, thus delivering maximum energy to the formation. This helps break up the crushed zone and micro-fracture the formation.
The improved perforation tunnel will reduce frac fluid tortuosity. Frac jobs can get better fracture initiation and better proppant placement, resulting in better production. This paper will focus on additional lab testing at an Advanced Perforating Flow Laboratory plus several USA onshore completions (horizontal and vertical). The field data will show the effect of the composite perforation method on frac performance and well production.
Naik, Sarvesh (Chevron Energy Technology Company) | Dean, Mark (Saudi Arabian Chevron) | McDuff, Darren (Chevron Energy Technology Company) | Ranson, Andrew (Saudi Arabian Chevron) | Jin, Xiao (Texas A&M University) | Zhu, Ding (Texas A&M University) | Hill, Alfred Dan (Texas A&M University)
Saudi Arabian Chevron (SAC) partnered with the Texas A&M University Petroleum Engineering Department and Reservoir Productivity Geomechanics Team of Chevron's Energy Technology Center (ETC) to perform acid fracturing conductivity tests on the Ratawi Limestone core samples. These tests were also performed on an analog limestone from an onshore USA field and Indiana Limestone samples for comparison with the results from the Ratawi Limestone samples. This paper shows the results of the acid fracture conductivity tests using various acid treatment systems on three different limestone formations and compares the acid etching and conductivity responses between homogeneous and heterogeneous mineralogy.
The success of acid fracturing treatment depends on the creation and sustainability of fracture conductivity under reservoir conditions. The fracture conductivity depends on the reservoir rock & acid reactivity, acid-etched pattern, closure stress on the fracture face and the pore pressure depletion.
Laboratory testing shows that acid fracturing is a viable option for large-scale development of the Ratawi Limestone. Its heterogeneous mineralogy plays an important role for sustaining the fracture conductivity after acid injection. Composed primarily of calcite and dolomite, limestone dissolves positively in acid. However, the insoluble minerals, such as the clay streaks with higher mechanical properties, acted as pillars to partially prop the fractures open as closure stress was applied. Essentially, the heterogeneous mineralogy of this formation assists with sustaining fracture conductivity as the reservoir pressure depletes.
As resource owner and enabler, PETRONAS's Malaysia Petroleum Management (MPM) is entrusted to ensure maximizing recovery efforts from more than 1000 oil reservoirs under production in its portfolio. Performance and recovery from oil reservoirs depends on many factors that can be broadly classified into Reservoir Complexity and how the reservoir has been developed and managed. To undertake a development gap analysis and expectation setting the exercise was undertaken to benchmark reservoir performance against reservoirs of similar complexity. The objective was to take the learnings from better performing reservoirs and explore potential replication in poor performing reservoirs of similar complexity. The main challenge was to establish a single term to define Reservoir Complexity. This term should encompass all the factors like geological, petro physical, rock & fluid etc. that could potentially make the reservoir complex and at the same time also decide on the relative weightage of these parameters posing recovery challenges. Data analytics has been used to accomplish this task and the calibration with reference reservoirs has been achieved. This benchmarking tool can help to internally set targets for all fields where the recoveries have been lower than normally observed, help set EUR numbers for green fields and drive additional development strategies to maximize recoveries in existing fields where they are falling short.
When reservoirs of similar complexities are grouped together, they show varying performance indicators viz. recovery factor, decline rates etc. The gap analysis between the reservoirs of similar complexity has helped in identifying poor performing reservoirs and the underlying reasons for underperformance. Learnings from the better performing reservoirs have been incorporated and a detailed action plan has been prepared to improve the performance of these reservoirs. Considering the various ways in which this information can be used, a reservoir complexity benchmark would be a great asset to any major operator or regulator.
The workflow has been developed to calculate complexity based on the parameters that are affecting microscopic displacement efficiency, horizontal displacement efficiency and the vertical displacement efficiency. Data analytics has been used to assign weightages to each component posing recovery challenges and derivation of a single number defining complexity on a scale of 0 to 1. This is major improvement on all previous works of this nature attempted in various parts of the world and provides the user with not only the complexity per se but also its distribution. This benchmarking tool has been used for selected fields and has enabled development gap analysis and helped in initiating course correction to unlock more values from the underperforming reservoirs.
Polymer flooding is one of the most broadly implemented chemical EOR processes due to its low injection cost and its success in prolific production increments. This work develops an artificial-neural-network based expert system by utilizing numerically generated training data using a high-fidelity numerical simulation model. Injection-pattern-based reservoir models are structured to establish the knowledge-base that serves for the ANN training. The injection process starts with water injection and switches to polymer injection when the water cut reaches to a threshold value. The chase-water is followed after a prescribed amount of polymer slug is injected. The expert system is generalized in terms of reservoir rock and fluid properties, rheological properties of the polymer solution, and critical engineering parameters to adjust to the complexities exhibited in the polymer injection projects. In developing the inverse model for project screening and design purposes, we have used an engineering design protocol employing inverse and forward-looking expert systems with the goal of exploiting the non-unique nature of the inverse problems. In this work, we employ the expert system as a forecasting and screening tool that is capable to predict time series based response in terms of oil production, water production and injection well sandface pressure data. The validity of the forward-looking expert system is confirmed via extensive blind test applications within a 5.83% error margin. More importantly, we present a project screening protocol that couples the expert system and particle swarm optimization (PSO) methodology to maximize the net present value (NPV) of polymer injection projects. In this way, we take the advantages of the fast computational speed of the ANN model to evaluate the finesses of project parameters. In the application of the inverse expert system, we observe that the proposed design protocol is capable to establish a catalogue of polymer injection design parameters that satisfy an expected hydrocarbon recovery performance. The work described in this paper exhibits the robust nature of the proposed expert system in adapting to strong non-linearities encountered in the polymer flooding projects. The coupled utilization of the inverse and forward-looking modules, enables the design engineers to find solutions that are unique to the problem being studied by simultaneously satisfying the imposed constraints effectively. The expert system proposed in this paper is one of the modules of a comprehensive artificial-neural-network based toolbox that includes a large spectrum of EOR processes.
Gossselin, Randy E (CEO, Inventor - Longhorn Casing Tools Inc.) | Montgomery, Trevor (VP Operations,Longhorn Casing Tools Inc.) | Muriby, Abdul S (General Manager - Wildcat Oilfield Services) | Yussef, Moataz (BDM, Wilcat Oilfield Services) | Karrani, Saud (Abu Dhabi Marine Operating Co.) | Khamis, Ahmed (ADMA)
With the innovation of ERD and directional drilling and the challenges these wells impose due to complicated and difficult wells’ paths, advanced well profile, Deep and HPHT wells and Horizontal wells, running casing and liner strings has become increasingly problematic.
Conventional casing running methods have not given full confidence of landing at TD every time a casing orliner job is run, especially with difficult and challenging wells.
Not much has been done to address these challenges which vary with wells and fields such as: ledges & obstructions, washouts, swelling shale, bridging, high doglegs, difficult well profiles, fill on bottom and well collapse, etc.
To overcome the challenges, the inventors developed the Fill Drill Product Line as a new technology to facilitate casing operations especially for long horizontal strings, production strings, and intermediate casing strings.
The authors will describe the innovative system utilized to improve the casing run supported by extensive field data. Case History will be presented and the benefits of the application of this technology in these wells will be explained.
The Fill Drill can rotate independently from the casing when encountering obstructions and hanging. The rotation is done by reciprocating the casing through 3 to 5 foot strokes which cause the Fill Drill shoe to act as a bit and ream. It “drills off” the obstruction and guides the casing string through ledges, tight swollen sections and dog legs, allowing effective removal of fill and debris from below the casing/liner shoe to land at the intended TD.
The Fill Drill is made of two main components: the tool body which is made similar to the casing grade being run, and the second part (the internal mechanism) which is made from industrial grade aluminum alloy for the mandrels and bronze components for the bit, both of which lend to the strength and durability of the tool in tough downhole conditions, yet facilitating a smooth clean drill-out with a standard PDC bit
The Fill Drill is customizable and comes in various types to suit the typical anticipated obstructions.
The first Fill Drill job was conducted on august 2010, since then, approximately 400 tool runs have been conducted achieving impressive success in landing casing at the desired depth.
Effective well management and a productive wellwork program are valuable and integral business objectives. Wellwork involves various well interventions and optimisation activities for enhancing and extending hydrocarbon production. These remedial processes involve substantial CAPEX and OPEX, as well as other resource allocations.
Failure to prioritise objectives and improper selection of candidate wells can have significant implications on both derived value and potential risk. A primary challenge is to ensure that wellwork is delivering production growth while maintaining cost efficiency. Well-by-well reviews with actionable decision support information will provide the best method for identifying potential production improvements. The selection and prioritisation of candidate jobs is a critical investment decision. This paper illustrates the use of data-driven models for estimating key performance indicators for wellwork jobs and predicting the likely outcome for a new planned job using pre-determined success criteria. Nine different machine learning and advanced analytics learning schemes were applied to the training dataset of wellwork history. The competing models performance was evaluated on separate hold-out testing set for best fit and prediction accuracy. The application of developed models provided intelligent augmentation for the decision-making process. This methodology embeds learning from past wellwork activities to streamline and guide complex workflows. The business value for embedding quantitative predictions into strategic and operational decision-making processes is realised in reducing less-favourable investments and maximising the value of wellwork.
Drilling the hard/abrasive Travis Peak/Hosston and Cotton Valley formations in East Texas/North Louisiana creates a distinctive challenge for polycrystalline diamond compact (PDC) bits. Conventional PDC cutters fail quickly due to abrasive wear/spalling and/or delamination of the diamond table. Most bits are typically pulled in poor dull condition graded 1-2-WT or worse. The situation has caused stagnation in PDC performance and limited additional gains in total footage and rate of penetration (ROP). Recent scientific studies have indicated that thermal fatigue of the diamond table is the main contributing factor leading to cutter failure and is restricting further advancement of PDC drilling in East Texas and other hard and abrasive applications. To improve cutter performance the industry must:
1. Manufacture a cutter to resist abrasive wear and retain a sharp edge for an extended amount of footage
2. Reduce/maintain temperature at the cutter edge to minimize thermal fatigue
To accomplish the objectives, engineers refined and implemented several new processes to increase abrasion resistance and maintain temperature at the cutter tip. This technology platform includes:
1. Enhanced High Temperature/High Pressure (HTHP)sintering process
2. Refined post-pressing process to improve thermal stability
3. Optimized hydraulics to maximizing cutter cooling
In laboratory experiments, the next generation O2 cutter has demonstrated approximately 15% improvement in resistance to abrasive wear compared to the previous generation of premium cutters (O1). Laboratory tests also confirm that optimizing cutter cooling has enhanced the life of the new shearing element. In East Texas field tests, PDC bits equipped with the new cutter and optimized hydraulics have achieved an average ROP increase of approximately 25% while producing improved dull bit condition. These new technologies are expected to have a positive economic impact in the East Texas/North Louisiana Haynesville shale play and in other hard and abrasive applications worldwide.
Information security is the bedrock of any information risk-management system, and oil and gas companies are becoming more adept at minimizing risk by bolstering these systems across their organizations. Information technology (IT) is becoming such an important facet to these businesses and their disaster-recovery and business-continuity planning that the security issues now often spread to the upper echelons of many organizational charts, even to boards of directors and audit committees.
In fact, the industry is seeing an increase in the number of executives in charge of company IT assets. Such arrangements play a powerful role in IT security and can result in strategically aligning IT-security issues with business objectives. Oil and gas companies should evaluate the following as global priorities when assessing information security:
Some of the regulatory changes that have taken place over the last few years, particularly related to the Sarbanes-Oxley Act in the United States, have caused companies to move from a reactive to a more proactive mode. While many energy companies still would rather spend capital on commodity assets than on information assets, they are slowly shifting as they recognize that information security is a top business driver. IT security is becoming a part of the discussion in the context of a company’s priorities. Whether those priorities include adding new acreage or adding rigs, E&P companies are leveraging technology more and more, and, as that technology is leveraged, the need for IT security rises.
As Technology Is Leveraged, Risk Rises
As companies grow through expansion or from mergers and acquisitions, computer networks can multiply and expand like cell division. Gradually adding bits and pieces to a network, especially when knowingly or unknowingly commingling sensitive data, increases risks and elevates the need for IT security. Not long ago, petroleum engineers, for example, examined geology assets in a back room, working safely within a secured computer network. Today, more and more of these professionals are performing such work on broader company networks, a move that saves companies money, but also elevates the possibility of data being compromised.
The notion of E&P companies leveraging communications technologies is not new, but they are constantly breaking new ground where applications are concerned. Fiber-optic networks, for example, are commonplace, and energy companies are now investing billions of dollars to lay these systems in the Gulf of Mexico and at other offshore asset locations. They know that as they go out into deeper water, the fiber-optic network will offer better communications capabilities for current and future processing facilities and drilling activities.
This paper discusses a segment of drilling engineering -- drilling analysis -- that is assumed to be practiced routinely, but in many cases is not given the necessary attention, time, and resources required.
Routinely acquired drilling, geologic, mud-log, and logging data, are shown to be amenable to organization into a knowledge-based structure that permits:
Use of statistical analysis to develop challenging but achievable technical limits, or best composite time (BCT), for similar wells - location, depth, hole size.
Statistics-based best composite cost (BCC), the dollars equivalent of BCT. Both the BCC and BCT represent practical, challenging but achievable benchmarks that are continuously upgraded, providing significant steps in the process of drilling costs reduction.
Specialized learning-curve analysis, trouble-time analysis, flat-time analysis, time vs. depth analysis, cost vs. depth analysis, rig and crew performance evaluation, bit-on-bottom and tripping analysis, time distribution plots, etc.
Convenient drilling data cross-correlation with wireline logs, geology and mud-log data, to further delineate drilling problem zones and improve drilling
A historical understanding of well construction that can contribute to continuing drilling improvement, and a method to provide feedback and collaboration with company drilling personnel, rig contractors, and service companies.
This paper reviews existing variations, key elements, and typical field applications of drilling analysis, and puts forth the case that drilling analysis should become an integral part of drilling engineering, the same way well-test analysis is an integral part of reservoir engineering. The need for a university curriculum and training on this key discipline is stressed, along with the necessity for management to champion the use of drilling analysis as an on-going process to improve organizational drilling performance.
Lost circulation problems are often encountered when drilling or cementing highly permeable formations (e.g., sandstones), naturally fractured formations (e.g., limestones), or through depleted zones. Curing these problems is critical if the operator is to control the well and drill and complete it effectively. Failure on a primary cement job due to lost circulation not only increases well costs but also can jeopardize well integrity.
The use of cement plugs to cure the losses is well-known, and these plugs are often used as a last resort. Lost circulation materials (LCM) are usually added to the cement slurry to maximize the chance of successfully stopping the losses. LCM can also be added to the cement slurry during a primary cementing job if losses are expected in a particular well section. However, the design of such cement slurries is not obvious and may not completely solve the problem. It is often uncertain whether the use of an LCM will help to completely cure the losses. Lastly, the appropriate LCM is often difficult to identify.
This paper shows that it is possible to formulate effective cement slurries to solve most lost circulation problems. The technology can be used either for a cement plug or during primary cementing operations by adding specifically designed fibers in a controlled manner. A laboratory setup was built to evaluate the fibers' efficiency in this application. We present the main results obtained and discuss the mechanism of action of the fibers. We also show that the combination of an enhanced particle size distribution cement slurry with this specific type of fiber allows the use of ultralightweight slurries, which leads to even better control of the losses and therefore increases the likelihood of success. These systems can be pumped with the standard cementing equipment used for typical primary cementing jobs. Several recommendations are made on the most effective way to use the fibers. We present Case histories that demonstrate improved slurry placement in traditionally difficult situations.