bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Development Projects Optimization Integrated to Risk Analysis
Authors: Mezzomo C. C.
Published: December 2007

Field development planning is a very complex process due to uncertainties, related to the restricted amount of information available for the high number of variables with dynamic behavior. An appropriate evaluation of these uncertainties in the process often requires reservoir simulation associated to optimization algorithms for the optimization of a non-linear objective-function previously stated, regarding the objectives for the project.

Considering the main particular aspects of the objective-function, manual procedures usually are adequated for the optimization of a recovery strategy although they require excessive time from the professionals involved and may not consider all the necessary scenarios in order to avoid long times for projects planning. Some tests have been published with the objective of developing an automatic process but, until this moment, they demand a very large amount of simulations and are unfeasible for actual reservoirs.

The approach for field development plan selection proposed in this work takes advantages of both approaches and is composed by a sequence of manual and automated procedures. This enables to integrate the parameters definition for the development plan to a risk analysis (technical, operational, geological, economic, etc.). The procedure for field development plan selection can still be integrated with an adequate decision analysis using, for example, multi-attributes utility theory.

The main idea is to propose a procedure that can be applied to a large set of reservoirs, providing the fundamentals to choose the most adequate choice for the initial field development, regarding the risks related and objectives classification for the project. The procedure was applied to an example based on a real field and the results, obtained with a low computational cost, were adequate for decision taking respecting the objectives stated to the project.
Enhancing and Sustaining Well Production: Granite Wash, Texas Panhandle
Authors: Ingram Stephen , Paterniti Isaac , Pauls Richard , Rothkopf Brian , Stevenson Chris , Conner John
Published: December 2007

This paper will describe the ongoing Granite Wash completion project in the Buffalo Wallow field in Hemphill and Wheeler Counties, Texas. This study will discuss the reservoir development and characteristics, current and former completion techniques, and production comparisons. The goal for this study is to use best practices gained from a statistical analysis and new chemical technologies for completion procedures in the Granite Wash project utilizing a permeability core testing apparatus for optimized regained permeability in fracturing fluids.

Surface modification agents (SMAs) and their coating onto proppant have been applied in treatments of thousands of wells in the last 10 years and have undeniably improved their productivity in terms of production rates and duration. The coating of these SMA materials has been found to dramatically enhance the recovery of aqueous-based fracturing fluids during well cleanup after fracturing treatments. As a result, a significant improvement in gas production has been observed in treated wells. Friction-reduction polymer anti-flocculants have been developed to reduce the tendency of these polymers to damage the proppant pack/reservoir interface, resulting in a decreased effective fracture length. A nonionic, micro-emulsion surfactant has been developed to reduce capillary pressure in producing hydraulic fractures via surface tension reduction and contact angle modification. These chemicals have been used in various combinations; the field results as well as testing results will be presented.

A patented low-permeability core testing apparatus has tested two granite wash core samples from the Buffalo Wallow field for regained permeability using friction-reduction polymer anti-flocculants, SMAs (specifically diagenesis protective agents), and micro-emulsion surfactants. In addition, basic water-frac additive packages have been applied to continue the optimization of water fracs in the Texas Panhandle to increase long-term natural gas production.

The data from those tests and field case histories will be discussed.
Pressure and Separation Performance of Oil/Water Hydrocyclones
Authors: Jiang Minghu , Zhao Lixin
Published: December 2007

Hydrocyclone has many traits such as smaller volume, higher efficiency, simpler structure, and so on. It is found that tiny change of geometric parameters can affect separation efficiency to a great extent, although the structure of hydrocyclone is relatively simple. Several hydrocyclone prototypes were tested to investigate the effects of geometric parameters, mainly including lengths of vortex cavity and conical section, and operating parameters, mainly including flowrate and split ratio, on the separation performance of liquid-liquid hydrocyclones. Many tests were carried out in Daqing Oilfields, China. Test results for normal oil-water mixed fluid and those for polyacrylamide-containing oil-water mixed fluid were obtained. The results show that different geometric hydrocyclones should be designed for different application conditions. For a certain application, every hydrocyclone has its optimum flowrate range, and the ideal split ratio exists for getting better separation results.
Extendable Arm Drill Bit: A Novel Idea
Authors: Gupta Yash , Banerjee Sudeepto N.
Published: December 2007

In conventional vertical drilling, the drill string is tripped in, allowed to drill to the predetermined depth and tripped out so that a bit of a smaller diameter can be attached to continue drilling the hole.

Extendable arm drill bit is essentially a rotary drill bit in which the roller cones can be extended so that the diameter of the bit corresponds to the required diameter of the hole to be drilled. This extension is done hydraulically by diverting some of the pressure of the circulating drilling mud to compress an assembly which would push down the roller cones, thus increasing the diameter. Now as drilling continues, the diameter of the bit can be adjusted by diverting a lesser amount of circulating pressure on the bit thereby "contracting" it to achieve a smaller diameter. It could be imagined like a tripod standing on its three legs.

The idea behind this proposal is to save the time, power and the cost of tripping operations of the drill string to change the bit to a smaller diameter one, by reducing the frequency of tripping the string, if not completely eliminating the process. This would result in an increase in the overall rig efficiency, both in terms of time and mainly money. Thus, the time and money saved can be diverted, if required, towards problems arising due to unexpected hole problems and pipe stuck-ups.

This paper gives the description of the most suitable design of such a drill bit and the possible modifications of this concept to be applicable in future developments.
Louisiana Orphaned Reserve Pit Cost Assessment
Authors: Lewis Adam , Webre Travis , Wojtanowicz Andrew
Published: December 2007

In the oilfield, a reserve pit is any site (usually an earthen-pit) that is used for the collection of used drilling fluid. These sites must be closed (cleaned up and disposed off) in order to meet certain federal and local requirements. The costs associated with this are directly affected by environmental regulations, contamination levels, geographic/ecological location, and distance to an approved disposal site.

Since 1983, states have had the option to set unique standards for reserve pit closure. Louisiana enacted its standards in Act 404 of the 1993 Regular Legislative Session. The work presented in this paper can be used to estimate the cost to close a single, unique reserve pit in order to meet federal and Louisiana state regulations for reserve pit closures.

State approved contractors where contacted to obtain closure cost estimates for comparison with historical closure costs obtained from government records. Relationships for cost versus size and contamination levels were established. A computer program facilitates the cost estimation procedure. In the program, the state and federal regulations, and the cost estimates for various closure techniques have been compiled into a Visual Basic-driven Excel spreadsheet. All an individual user must do to generate a cost estimate for a particular reserve pit is to input data from samples taken from that pit. The study has shown that cost prediction is reasonably accurate for "normal" reserve pits that require little or no chemical remediation. However, when serious chemical remediation is needed for pits contaminated with salt or oil, the prediction loses precision due to the large number of variables and wide range of costs associated with those variables.

This work has become of paramount importance for the State of Louisiana because there are currently over 1,500 "orphaned" reserve pits in Louisiana, i.e. sites for which no liable party/company can be found. The State has had to assume financial responsibility for closing these orphaned reserve pits using the statewide tax on natural gas production. The State has expressed serious interest in understanding the scope and significance of the problem that they are currently dealing with.
Optimum Control of Unwanted Water Production in Stratified Gas Reservoirs
Authors: Yamali Nampetch , Nguyen Quoc P. , Srinivasan Sanjay
Published: December 2007

Minimizing production of water from gas reservoirs is one of the main strategies for enhancing primary hydrocarbon production. Advances in intelligent well technology and simulation of reservoir-production system enable optimum inflow allocation of produced fluids by controlling perforations and valve settings. However, real-time optimum control of flow is still a challenge. To this end, we have developed an advanced method for optimization of production based on a feed-back optimum control concept. The method allows optimization of inflow-control–device operation in conjunction with strategic updating of reservoir-smart well model under uncertainty.

In this work, we present a hybrid optimization method for improving optimum solutions. In this method, the response of production system to control variables is mathematically described by a high-order proxy model, which is developed using Response Surface Methodology (RSM) and Design of Experiments (DOE). The validity of this method was tested for the dynamic optimum control of gas and water coning observed in a physical two-dimensional layered bead-pack model with automatic inflow control valves. The valves were actuated by distributed flow or pressure sensors. Results showed that dynamic (time-dependent valve settings) and static (fixed valve setting) control exhibited advantages one over another, depending on operational conditions. It was also found that the heterogeneity of porous media strongly influenced the control effectiveness. Field implications are discussed.
Simulation Study of Drilling Horizontal Wells in One of Iranian Oil Fields
Authors: Azarkish Abbas , Kavkani Elham Khaghani
Published: December 2007

The objective of this study is to investigate the advantages of drilling horizontal wells on oil recovery improvement. To evaluate the effect of horizontal length, porosity, anisotropy, staggered-line well pattern with gas injection (in the top layer) and water injection (in the bottom layer), different scenarios were studied.

This study is focused on simulation of formation-A of a carbonate reservoir which consists of three layers; where horizontal well is going to be drilled in layer-2 of this formation. The average thickness of formation-A is about 167.64 meters (550 feet) and we also have tilted water oil contact in this formation.

This field has produced around 146.9 MMBBL until year 2002 for the last 12 years with the Recoverable Reserve of about 237.31 MMBBL. Up to now 40 wells have been drilled in this field.

IRAP/RMS software was used to generate geological model. Based on selected reservoir black-oil model, IMEX from CMG is used for simulation task. Sector model used for simulation as we only had one productive horizontal well in the formation (scale-down method).

This study confirms simultaneous use of overbalance method and horizontal well in this reservoir in order to: A) Increase production rate up to 3 to 4.5 times by boosting productivity index (PI). B) Communicate a large area leading to a better drainage area. C) Postpone the water breakthrough by minimizing the draw down pressure.
Reduction of Oil Droplet Breakup in a Choke
Authors: Kwakernaak Peter Jan , van den Broek Wim M. G. T. , Currie Peter K.
Published: December 2007

This paper reports on experimental work focused on modifying choke design with the aim of reducing oil droplet break-up in the choke in high water-cut production wells. Producing oil under such conditions, with the oil dispersed in the produced water, leads to severe break-up of the dispersed oil droplets. This break-up is caused by high energy dissipation in the choke. Previous work carried out in Delft indicated that, under identical process circumstances (tubing diameter, flow-rate, pressure drop, oil type and concentration), the break-up process is significantly influenced by the choke geometry. In this work we discuss possible ways of modifying the choke geometry to reduce droplet break-up. Three model chokes were tested in the laboratory: an orifice, a small choke consisting of 7 parallel tubes and a larger choke consisting of 13 parallel tubes. These chokes were tested at identical flow rates and with the same pressure drop across the chokes. The larger model choke was the superior one in the sense that in this device the least break-up of oil droplets took place. In the small model choke more break-up occurred, while the most severe break-up was observed for the circular orifice. A general conclusion of the investigation is that the intensity of the break-up process occurring in the (model) choke can be considerably reduced by adaptation of the choke design. A choke design based on parallel tubes gives opportunities for improving the choke performance with regard to oil droplet break-up, while still making it possible to vary and control the volume flow-rate as with a conventional choke.

This investigation suggests that it will be possible to construct chokes with improved characteristics with regard to oil-droplet break-up in high water-cut wells. This will result in easier separation and less emulsion-forming downstream of the choke.
Security Is Everybody's Business: Transforming Security Into a Core Business Practice in the SHE Model
Authors: Simmons Stephen B. , Robb Albert J.
Published: December 2007

A security focus in recent years has driven the recognition of synergies between security management and existing safety, health and environment (SHE) management programs in many industries. While safety has a long history as a core business practice within the petrochemical industries, several key roadblocks exist with a similar integration of security. The most effective oil and gas company safety programs are those that are implemented and owned at the field level. However, security-related issues have historically been managed by corporate/functional security departments, rather than at an operational level. We believe that integration of security into existing corporate SHE management programs and practices is key to effective implementation. As such, successful integration of security as a core business practice requires both ownership and implementation at the operations level, as well as technical functional guidance and quality assurance from competent security professionals within the organization. Reporting of meaningful security-related performance indicators still remains primarily in the realm of leading indicators (activity-based), whereas, useful analysis of robust safety programs require evaluation of causal relationships between leading and lagging indicators. This in part is due to the lack of long-term data for comparison, but more importantly the causal effect of external influences related to lagging indicators (incidents), and will slowly change with time. Efforts to increase security awareness by employees need to mirror safety awareness programs. Successful implementation strategies include mixed media packages (video, print, logos, web) along with training and workshops designed to promote security as a core business practice. Effective integration of security into core business practices has resulted in success stories involving employees exhibiting security conscious behaviors, as well as statistics illustrating both increased reporting/incident prevention and security vulnerability gap closures.
Reclaiming Lost and Forgotten Oil and Gas Through the Use of Solid Expandable Tubulars
Authors: Villemez Don
Published: December 2007

With the price of oil and gas at all time high levels, methods of harvesting previously un-recoverable reserves are an extremely lucrative value proposition. These methods attract operators looking to increase production to take advantage of the current prices and to increase production for a higher revenue stream should prices fall in the future. The use of solid expandable tubulars can enhance production in mature and declining fields by: Isolating perforationsRe-completing the wellRestoring wellbore integrityProviding full pressure capabilityAllowing for selected re-stimulationPreventing casing collapseRe-drilling or deepening the wellAttaining water shut off

Compared to the alternate solutions of cement squeezes and casing patches, solid expandable tubulars provide a more concise and conductive method to field enhancement with a proven technology that Is more reliableIs more flexibleHas a higher pressure ratingHas increased longevity

This paper will use case histories to demonstrate the increase in production achieved by isolating zones for the purpose of fracturing or which are now producing water. Case histories will also be used to illustrate how solid expandable tubulars enabled operators to isolate and later re-perforate zones to allow for stimulation of previously unproduceable zones.
Critical Conditions for Effective Sand-Sized Solids Transport in Horizontal and High-Angle Wells
Authors: Duan Mingqin , Miska Stefan , Yu Mengjiao , Takach Nicholas , Ahmed Ramadan , Zettner Claudia
Published: December 2007

Effective removal of small sand-sized solids is critical for successful drilling and completion operations in sand reservoirs. Recent experience in extended reach drilling also indicates that inefficient transport of smaller cuttings is a main factor for excessive drag and torque. This study was undertaken to determine two critical conditions for efficient transport of small solids. The two conditions are represented by the Critical Re-Suspension Velocity (CRV), the minimum fluid velocity necessary to initiate solids bed erosion, and the Critical Deposition Velocity (CDV), the minimum fluid velocity required to prevent bed formation.

Experiments were conducted in a field-scale flow loop (8×4.5 in., 100-ft long) to determine CRV and CDV, for 0.45 mm and 1.4 mm sands in different fluids over a range of bed heights and hole inclinations. The results show that, depending on sand size and fluid properties, CDV is approximately two to three times larger than CRV. Water is more effective than low concentration polymer solutions for bed erosion. However, polymer solutions are more helpful than water in preventing bed formation. This indicates the need for different drilling fluids for cleanout and drilling operations.

A mechanistic model was developed to predict CRV for a solids bed. Both experimental and theoretical results indicate the importance of inter-particle forces that are incorporated into the model. The model accounts for drill pipe eccentricity in any direction in an annulus, which is consistent with experimental observations. The model predictions are in good agreement with experimental results. Existing CDV correlations developed for larger cuttings were verified by experimental data for sands. The differences are around 25%. Results in this study will be useful not only in drilling and completion through sand reservoirs, but also in extended reach drilling and sand control.
Optimized Deep-Penetration Acid Fracturing Technology in Low-Permeability, Naturally Fractured, Complex Lithology Reservoirs
Authors: Xu Yun , Zou Honglan , Lei Qun , Liu Zhanjun , Ding Yunhong , Tian Zhuhong , Yang Yanli
Published: December 2007

This paper describes characterization and its successful applications of a deep-penetration acid-fracturing approach to enhance oil recovery in low-permeability complex lithology reservoirs. A kind of special but important low-permeability reservoirs are distributing widely in west of China, in which neither carbonate nor detrial rock is main content.It is named complex lithology, which has 1/3 of quartz and feldspar, 1/3 of carbonate, and 1/3 of clay mineral. Early attempts in stimulations got miserable results.Propped fracturing failed with little bauxite placed before job termination due to premature screen-out. In addition, less HCl consumption and rock dissolving power prevents deep penetration of acid into formation. In matrix treatments this results in compact dissolution with only marginal skin decrease.

To optimize acid system for this complicated formation condition, acid rock reaction experiments of gelled acid and emulsified acid were accomplished to get full understanding the kinetics of acid reaction with complex lithology cores. Acid conductivity experiments were conducted with a unique conductivity instrument using samples designed to simulate deep-penetration acid fracturing process. The lab results indicate acid reaction mechanism is quite different both from carbonate and sandstone that is not controlled by surface reactivity or mass transport, but by both of these two reactions modes in balance. A good way to improve conductivity is alternating stages of acid fracs and closed acidizing with a multi-component acid, which is available to dissolve quartz, feldspar and clay.

More than 63 treatments with new technologies in Yumen, Qinghai oil field have been performed with encouraging results, 74.5% efficiency with accumulated incremental oil of 254,900 tons. For example, well L8 had original oil production of 546 BOPD, and got production as much as 2016 BOPD after treatment.
Case Study from 12 Successful Years of High Temperature Fracturing in Bach Ho Field Offshore Vietnam
Authors: Jain S. , Prestridge A. , Dellorusso P. , Nghi N. C. , Lam D. D. , Hung V. Q.
Published: December 2007

This paper presents the results of propped fracturing operations conducted in the past 12 years in the Bach Ho (White Tiger) field offshore Vietnam. High temperatures (>275°F) and closure stress (>8,000 psi) combined with the fact that fracturing has to be performed from a vessel make the execution of fracturing treatments operationally difficult and challenging. More than 60 treatments have been performed in over 40 wells placing over 3 million lbm of proppant with a success rate greater than 85%. The wells targeted were both injector and producer wells. The post treatment results have been excellent with an average increase in Productivity Index (PI) of greater than 5 times.

This study discusses the properties of the various hydrocarbon-producing zones in the Bach Ho field. A general discussion of reservoir properties and damage mechanisms is included, which demonstrates the potential for stimulation and the associated benefits. The methodology adopted in the design, execution and evaluation of the fracturing treatments is discussed. Discussion on the rig-up of the fracturing vessel and the necessary modifications for efficient operation is also included.

A review of the treatments indicates that the majority of them are conducted at a flow-rate of 20–25 bbl/min (bpm), with a maximum proppant concentration in the range of 8–10 ppa (lbm of proppant added to 1 gal. of clean fluid) and proppant quantities of 60,000 to 80,000 lbm per treatment. High leak-off limits higher proppant concentrations and volumes. Higher rates are desirable but are limited due to limitation of equipment on the fracturing vessel.

Zones targeted are both the Oligocene (sandstone) and the naturally fractured Basement. Propped fracturing has been found to be very successful in the Oligocene whereas different types of treatments like propped fracturing, acid fracturing and acidizing have been tried in the Basement with limited success. Finally the lessons learned and the experiences gained in this field are shared.
An Integrated System for Risk Assessment of Drilling Operations in Oil and Gas Wells
Authors: Khatlan A. , Jafari A. , Milani A. A.
Published: December 2007

In this paper, a general, hierarchical, structured and flexible drilling operation risk assessment system (DORA) is presented. The model, which is presented in this paper, is generated form the operator's point of view and it is applicable for different wells in a range form wild cat to reentry types. In order to completely define the risk assessment system, its operation model is developed, the tools and methods for each phase are specified and the inputs and outputs are determined. The developed model has four main phases of beginning, preliminary risk analysis, secondary risk analysis and support. The inter-related position of these phases and their sub-phases with respect to the drilling operation steps, are also specified.
Use of New Rate-Integral Productivity Index in Interpretation of Underbalanced Drilling Data for Reservoir Characterization
Authors: Suryanarayana P. V. , Vaidya R. N. , Wind J. A.
Published: December 2007

The prospect of dynamic reservoir characterization using flow and pressure data gathered during underbalanced drilling (UBD) is a powerful driver for implementation of UBD. The mathematical aspects of this complex, ill-posed, inverse problem have been the subject of research in the past decade. This paper focuses on practical, field implementation of UBD reservoir characterization, and the problems that consequently arise. Interpretation of data from UBD is made difficult by transducer errors, operational transients, and noise in data. It is therefore often very difficult to interpret the reservoir characteristics from the instantaneous productivity index (PI). In this paper, we introduce a parameter known as the Rate Integral Productivity Index (RIPI), which borrows from the theory of rate-transient analyses. The mathematical and physical basis of RIPI and its relationship to the instantaneous PI are presented. The behavior of RIPI and its implications for reservoir characterization are discussed. RIPI de-noises the data, and scales the problem such that the trends in data are more obvious, enabling robust interpretation of UBD data, and increasing the confidence in calls made regarding reservoir characteristics. Application of RIPI to field data is illustrated through several examples. Data acquisition, processing, and preparation for UBD reservoir characterization are discussed. In particular, the importance of filtering, de-noising, and identifying and excluding operationally induced transients is described. Limitations imposed by the data gathering methods are highlighted. It is shown that the ability of RIPI to reduce noise in raw PI data allows trends to be read more easily. The use of RIPI for static and dynamic characterization of supermatrix features (such as fractures, thief zones, etc.) is illustrated. The limitations of the approach and future trends are discussed.
Expandable Liner Hanger Resolves Sealing Problems and Improves Integrity in Liner Completion Scenarios
Authors: Williford James , Smith Pete
Published: December 2007

Conventional liner-hanger systems typically rely upon the primary cement job as the main method of sealing the liner/casing overlap, and liner-top packers are run either integrally with the liner hanger or separately in a second trip. In certain applications, however, cementing the complete liner may not be feasible or obtaining a primary cement seal at the liner top may not be achievable; in these situations, a liner-top packer must be used as the primary seal. In cases where the top of cement is above the overlap but below the hanger, the liner top packer is used as a back-up seal for the overlap.

Almost all liner-top packers that are run integrally to the liner hanger are set through the application of weight applied through the drill-pipe or landing string. The capability of the liner-top packer to seal with a single element at the maximum pressure rating requires that a sufficient setting force of up to 100,000 lbf be applied through the drill pipe to the packer mechanism. Work performed in Latin America recently showed the limitations of this process and how shallow liner-top installations might not have the string weight to apply a sufficient setting force to the liner-top packer.

A conventional alternative to an integral packer design is a secondary tie-back packer, but this alternative requires at least two extra trips into the wellbore and picking up of a string of large drill collars to supply the significant force required.

A solution was found that was capable of resolving this problem, and the innovative technology applied will be the focus of this paper. An expandable liner hanger that allows a hydraulic setting force to be applied locally to the hanger was used. The setting force for the packer was measurable and consistent. With the success experienced on the first well, the expandable liner hanger was used in subsequent jobs, and in all of them, the operator saved several days of rig time in addition to experiencing a successful completion.
Success of Hybrid Fracs in the Basin
Authors: Coronado Juan Antonio
Published: December 2007

In recent years waterfracs have increased in popularity, providing relatively long fracture lengths without the polymer damage of conventional crosslinked gelled fracture treatments. The major disadvantages of waterfracs are proppant settling and bridging, which limits waterfracs to high pump rates and low sand concentrations. These disadvantages gave way to the creation of the hybrid fracture stimulation, which is a combination of a waterfrac prepad followed by a crosslinked gelled fluid.

This paper will compare the use of hybrid fracture treatments in the deep, high pressure, high temperature, tight gas formations of the Anadarko Basin in Oklahoma to the more conventional waterfrac and crosslink frac. Also the fracture geometry, cooling effects and cost savings of the hybrid will be discussed.
Plunger Lift Application and Optimization in the San Juan North Basin—Our Journey
Authors: Oyewole Peter O. , Garg Divyakumar
Published: December 2007

Plunger lift technology has been applied systematically and successfully to unload liquids from marginal tight gas and coalbed methane wells in San Juan North Basin. This article presents the recommended practices, case studies, and results of excellent plunger lift application and optimization.

A production increment of over 4 MMcfd has been achieved and sustained on about 40 plunger lift installations. Most wells that were chosen for plunger installations were either on a plug and abandon (P&A) list or on temporary abandon (TA) status. Neither gas production nor anticipated production uplift from wells could justify installation of a more costly artificial lift system such as sucker-rod pump to de-water wells. Amazingly, production uplift of more than 200 Mcfd, and/or production increment of over 300%, was realized on some wells. It important to note that many operations use the practice of surfacing plungers by auto-venting, thereby releasing greenhouse gas (GHG) into the atmosphere. Plungers were operated successfully in San Juan North operations without this practice.

All these results were achieved through applications of new plunger lift technology, efficient plunger type selection, monthly and quarterly reviews, proper maintenance, optimization and monitoring, i.e. effective utilization of plunger lift data.

The strong alliance that was formed with the plunger equipment provider was one of the important inputs to our plunger lift journey. This new approach is a significant departure from the conventional ways of operating plungers, whereby service companies traditionally supply plunger hardware to the producing companies to operate with little "service" involved. Also, the field operations' teams, with their perseverance, offered a very important contribution to this successful venture.
Intelligent Prediction of Reservoir Fluid Viscosity
Authors: Hajizadeh Yasin
Published: December 2007

Accurate information on phase behavior and properties of fluids is an essential element in proper management of petroleum reservoirs. These fluid properties which are usually determined by laboratory experiments performed on samples of actual reservoir fluid or using empirically derived correlations provide the information required to properly understand the phase behavior, evaluate various production scenarios, optimize reservoir production and IOR schemes, and to maximize ultimate recovery and optimize production economics. One of these properties is the petroleum reservoir fluid viscosity. Crude oil viscosity is an important physical property that controls and influences the flow of oil through porous media and pipes.

This paper introduces a new application of fuzzy logic and neural networks in petroleum engineering. Artificial intelligence techniques such as neural networks, fuzzy logic and genetic algorithms for data analysis and interpretation are an increasingly powerful and reliable tool for making breakthroughs in the science and engineering and it is becoming clear that our industry has realized the immense potential offered by intelligent systems. The introduced model in this paper can predict the reservoir fluid viscosity data with neural networks and fuzzy logic approach. We can use these techniques in order to recognize the pattern between the given data sets where this pattern may not be understood clearly or no precise mathematical relationship exists

Prediction of the proposed model has been tested against the measured reservoir fluid viscosity data. Results indicate that the proposed prediction model with recognizing the possible patterns between input and output variables can successfully predict and model reservoir fluid viscosity.
Investigation of Explosion Occurrence in Underbalanced Drilling
Authors: Shahbazi K. , Mehta S. A. , Moore R. G. , Ursenbach M. G. , Fraassen K. C. V.
Published: December 2007

The development of mature fields has led operators to use underbalanced drilling to benefit from advantages such as reducing formation damage and increasing penetration rate. In gasified liquids, a light oil can be used as the liquid phase and nitrogen with almost 5 percent oxygen as the gas phase. Due to the simultaneous presence of oil and oxygen in the drillstring, safety considerations are a major concern in these operations.

To study and simulate the occurrence of explosions, oil base liquids were aged at 150°C and 14 MPa initial pressure in rocking and stationary reactors for 2.5 and 5 days in the presence of a gas with different concentrations of oxygen. The presence of drilling cuttings was simulated by addition of calcium carbonate to the base liquids. To cover the real penetration rates encountered in the drilling industry, volume percentages of 0.3, 0.6, 1.2, 2.4, and 4.8 of calcite were employed.

The experimental results of the samples that experienced explosions show that a delay time of approximately 0.5 hours was observed. In the period leading up to an explosion, the vapor phase temperature remained relatively constant while the liquid phase temperature first increased gradually and then more rapidly. At the time of the explosion, a rapid rise in the vapor phase temperature accompanied by a sudden increase in the reactor pressure was observed. This behavior indicates that the explosion was triggered by liquid phase oxidation reactions but that the sudden energy release event was associated with combustion reactions in the vapor phase.

This study signifies the important impact of the liquid phase temperature on explosion occurrence. The liquid phase acts as an initiator or an ignition source for explosions. Furthermore, it can be used as a parameter to warn of an impending explosion.
Focused Oilfield-Specific Training Reduces Accident Costs by Over 10 Times
Authors: Chedsey George , Kaminski Donald , Kaufmann Jeff
Published: December 2007

In the fall of 2004, BJ Services Rocky Mountain Region (Colorado, Wyoming, Utah and Northern New Mexico) identified the need to grow their driver/equipment operator ranks to meet the growing demand of the oil and gas industry in the Rocky Mountain west. Although new hire safety training programs, detailed driving safety programs and training resources were in place, the volume of drivers/equipment operators needed could not be accommodated in a timely, efficient and effective manner. Working with Center for Transportation Safety, the two groups developed, implemented and successfully operated a program that trained 315 Equipment Operators (as of October 2006) to obtain their commercial drivers license (CDL) and safely operate BJ Services heavy vehicles. The training focused on creating a safer oil service industry driver and specifically;

Included use of driving simulators; Introduced and reinforced BJ Services driving, fatigue management and journey management policies; Included driver training in areas that replicate oil field conditions (mountains, tight oil well locations, dirt roads, etc.); and Included vehicles similar to oil field equipment, i.e., heavy equipment and bulk tankers.

This case study documents the training of the heavy vehicle driver/equipment operator and compares accident statistics and cost of two groups of drivers. "Existing Drivers" are drivers/equipment operators trained prior to 2004 or who joined BJ Services after October 2004 with a CDL, and a "New Program Driver" who were trained for their CDL in the new program. The data shows that even when new program trained drivers had a vehicle accident, the accident was less severe and even though new program drivers comprised approximately 40-43% of the total drivers, their cost of accidents represented only 2-4% of the total accident cost.
Making Personal Responsibility for Safety Work to Create Change
Authors: Lang Kenneth A. , Allan Derek , Adam Tracey , Chew Vanessa
Published: December 2007

As part of the process of attaining accident free operations, the UK Step Change in Safety organization has suggested that ‘Personal Responsibility for Safety’ (PRFS) (1) will build on the existing safe plant and equipment in addition to the safe systems that hitherto have been the mainstay of safety improvements creating a change in our safety behaviour and ultimately performance.

This paper demonstrates one organization's innovative approach to engaging staff in PRFS. It addresses the challenge faced in moving the nine key elements of PRFS from a paper based work pack to an inherent behaviour exhibited by the organization and our colleagues

PRFS is composed of a template of ideal behaviours by which the individual and the organization can assess their performance leading them to self evaluation and hence to improvement. Personal Responsibility for Safety cannot be a short term programme but must be undertaken as a continuing long term process of improvement or culture change.

It must be stressed that PRFS is not simply a programme for laying complete responsibility on those in the front line in the work place.

The methodology employed used a combination of live theatre, based on the elements of PRFS, and mirrored existing business processes. Through this the leadership team was introduced to their own behaviours and those of the PRFS model. The participants were invited to self evaluate their PRFS maturity before being given independent assessment based on the PRFS maturity matrix.

More traditional approaches of engagement had been previously rejected as they were not believed to be effective enough in communicating and involving the appropriate staff.

A number of important initial lessons can be learnt from this process which will be valuable even outwith the UK and for those wanting to stimulate change. These are shared regarding the engagement process and the participant's own preconceptions of their performance versus the independent assessment are discussed.
Surface Reactive Fluid's Effect on Shale
Authors: Grieser Bill , Wheaton Bill , Magness Bill , Blauch Matt , Loghry Ray
Published: December 2007

In general shale is thought to be relatively nonreactive to low pH or acidic fluids. This is because of the general belief the clay, silt, and organic materials comprising the major components of shale formations exhibit insignificant bulk solubility in acid. What we find however is that shale units are highly laminated and contain acid-soluble minerals homogenized in the shale bulk matrix and natural fractures. XRD analysis and SEM images of shale samples show a great diversity and distribution of soluble material in the shale producing unit. SEM images of the shale fracture face before and after exposure to certain reactive fluids show a remarkable amount of surface texture disruption and micro-etching of the fractured surface. Based on these observations, it is concluded that reactive fluids are capable of (1) enhancing gas diffusion into and through narrow-aperture induced fractures, and (2) increasing surface area for flow of gas from the shale matrix. Such fluids are also capable of enhancing flow through mineral-filled microcracks or other secondary porosity. Initial production response from wells treated with reactive low pH fluids has been promising.

This paper documents X-ray and SEM analyses of many shale plays in Oklahoma. Production enhancement mechanisms are proposed to explain the observed physical effects of these fluids on shale.
Working Hard To Work Hard Safely
Authors: Mode Nicolle , Conway George A.
Published: December 2007

The shortage of qualified rig workers, and the desire of workers to earn high wages, is pushing drilling companies to increase the number of overtime hours. The trend in this growing industry of increased demand with limited numbers of workers is likely to continue. Unfortunately, another trend in this industry is an increasing number of work-related fatalities – with the Bureau of Labor Statistics reporting 98 fatalities in the oil and gas extraction industry in 2005. Historically, increases in the number of fatalities has followed the number of actively drilling rigs, even more so than the number of current employees. Working typical 12-hour shifts for 7 to 14 days in a row can lead to fatigue, resulting in mistakes in judgment and handling of equipment. Mistakes on a drill rig can be costly, both financially and in worker injuries. Fatigue is not unique to the drilling industry, and lessons learned from other areas can help identify and alleviate some of the potential hazards. Companies can schedule shifts and breaks to minimize fatigue, put in place policies and practices for identifying and managing fatigued employees, and help employees learn how to plan their off-time to minimize work-time tiredness. A summary of findings from research and practices in the oil and gas drilling industry as well as other industries will be presented with practical recommendations for safety management. The conclusions in this presentation have not been formally disseminated by CDC/NIOSH and should not be construed to represent any agency determination or policy.
Treatment of Hydrocarbon-Based Drilling Waste Using Supercritical Carbon Dioxide
Authors: Street C. G. , Tesche C. , Guigard S. E.
Published: December 2007

Non-aqueous drilling fluids are essential in challenging drill operations. Their use, however, requires special treatment and disposal because of their potential for environmental damage. In light of increasing costs for common treatment technologies and ever tightening environmental legislation, alternative treatment technologies are being sought by the drilling industry. Supercritical fluid extraction is one such technology which employs a substance above its critical pressure and temperature as a solvent.

In this paper, the results of a study using supercritical carbon dioxide to treat synthetic based drilling waste are presented. Unlike typical supercritical fluid extraction studies where the process is optimized using changes in pressure and temperature, this study was undertaken to improve the extraction of hydrocarbons from drilling waste by increasing the supercritical fluid solvent to waste ratio. Efforts focused on improving supercritical fluid/drilling waste contact, eliminating system clogging with waste solids and minimizing solids carryover. Alterations to the waste using additives and alterations to the vessel both led to an increased amount of waste being treated effectively using the same amount of solvent. Optimization of the process has yielded efficiencies as high as 97%. Also, it has been determined that the extracted hydrocarbons are unchanged by the supercritical fluid extraction process. This result suggests that the collected hydrocarbons may be reused in the drilling process, resulting in significant cost savings to the industry.
Effective "Just In Time" Data Integration: The Cased-Hole/Openhole Composite Log
Authors: Davidson John P. , Rourke Marvin , Bootdee Sasithorn
Published: December 2007

More data, fewer people, and less time are universal problems in our industry today. There is a continuous search for ways to streamline processes and to improve efficiency. A wealth of data must be rapidly validated and interpreted so that value-based decisions can be made in a timely manner.

In a typical development environment, wells are drilled, formation evaluation data acquired, completions run, cement evaluated, perforations made, and later in the life of the well, additional perforating added. The workflow includes geologists, petrophysicists, reservoir and completion engineers, and well operations personnel. Well log data contains critical information used by various asset team members at different times throughout the workflow. Traditionally, open-hole and cased-hole logs, while representing the same well have been maintained separately, most often because of the differing data-users. In this paper, we demonstrate improvements in workflow efficiency and database quality control by bringing together most of the depth-based well data into a single user-friendly format that can be used by all disciplines.

The primary purpose of the cased-hole/open-hole (CH-OH) composite log is the correlation between open-hole logs, either LWD or wireline, cased-hole logs, and other depth-specific data. Users of this log select the perforation intervals, write well work orders, complete perforating operations, and expedite hydrocarbon delivery. This composite log saves time, promotes cross-functional understanding, and provides the first step toward an all-electronic interface between reservoir engineering and completions engineering operations.

This paper provides a detailed explanation of the process of building the CH-OH composite log and of the benefits realized by engineers, as well as the additional benefit of database quality control feedback for earth scientists in the asset team. We foresee a completely digital workflow in the future in which engineers select perforating intervals from a graphical composite log environment and work requested to the well site.