bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial Studies on Dissolved Gas Flotation
Authors: Oliveira R. C. G. , González G. , Oliveira J. F.
Published: December 2007

The removal of emulsified residual oil from water is an important issue due to the increasing concern with the environment. In the present paper various surface chemistry aspects of dissolved gas flotation were studied aiming at a better understanding of the mechanisms of the process. These studies included surface and interfacial tension measurements of a model system composed of n-dodecane in the presence and absence of nonyl-phenol.

After bubble/drop contact and rupture of the water film, oil drops have a tendency to spread over the bubble surfaces. Critical micelle concentration and spreading coefficients determinations were undertaken at different NaCl concentrations. The spreading coefficient proved to be a critical parameter in oil droplets flotation. The spreading coefficient increased with increasing salt concentration.

An experimental setup was designed to measure the induction contact time between single n-dodecane droplets and air bubbles. Induction time decreased with increasing salt concentration. In the presence of the nonyl-phenol aqueous solution, induction time decreased with time of stabilization. On the other hand, induction time increased with time of stabilization when nonyl-phenol was added to the organic phase. The mechanisms involved are discussed and some results obtained in a dissolved air flotation batch unit in which bubbles size was measured and controlled are also presented.
The Influence of Divalent Cations on the Performance of BaSO4 Scale Inhibitor Species
Authors: Boak L. S. , Graham G. M. , Sorbie K. S.
Published: December 2007

One of the most common methods of preventing downhole and topside mineral scale formation in oilfields is through the use of chemical scale inhibitors. Several aspects of the brine composition may affect the performance of the various scale inhibitors used in oilfield applications. In this paper, we focus on the influence of divalent cations such as calcium and magnesium. The concentration of such divalent cations is shown to effect the barium sulphate inhibition efficiency of generically different species of scale inhibitors by varying degrees, and in different directions. In previous work,1 the effect of calcium cations on the performance of various inhibitor species was demonstrated. In this paper, these observations are extended to include the effects of the magnesium cations in solution.

The influence of divalent cations such as Ca2+ and Mg2+ on the barium sulphate inhibition efficiency of generically different inhibitor species has been examined here in a variety of brine systems including low scaling "Brent type" and medium scaling "Forties type" brines. In addition, low salinity "ideal" brine systems have also been examined. The scale inhibitors studied include: penta-phosphonate (DETPMP), hexa-phosphonate (TETHMP), phosphino-poly carboxylate (PPCA) and poly-vinyl sulphonate (PVS). Results are presented from a series of static barium sulphate inhibition efficiency tests conducted at 95°C over 2 and 22 hour residence times.

The results presented here demonstrate how phosphonate inhibitors are significantly improved in the presence of [Ca2+] and also that their effectiveness is considerably reduced, or poisoned by increased [Mg2+]. The performance of the phos-phonate species are shown to be controlled by the performance of inhibitor/Ca2+ complexes, whereas the formation of inhibitor/Mg2+ complexes effectively poisons the phosphonate species ability to inhibit. The polymeric species (PPCA and PVS) are shown to be less influenced by increased [Mg2+]; indeed, marginally improved performance is obtained. This paper significantly extends the findings reported previously in SPE 37273.1
Application of a Mineral-Dispersion System to EOR
Authors: Li Jiyong
Published: December 2007

This paper presents a new technology for oil recovery enhancement in heterogeneous waterflooding under high tempterature and high water salinity the method mainly is to inject a mineral dispersion system(SMD) to improve the sweep effciency and recover the residual oil by emulsification-entrainment. This system is a pseudoplastic fluid with temperature tolerance,shearing resistence and good stability. Core flooding tests show the oil recovery is increased by 10%. The displacement nechanisms have been studied by microscopic modeling technique. After a successful pilot test,The commercial field test are conducted and the initial results are obtained.
Field Test Measures Amount and Type of Iron in Spent Acids
Authors: Taylor K.C. , Nasr-El-Din H.A. , Al-Alawi M.J.
Published: December 2007

This paper was prepared for presentation at the 1999 SPE International Symposium on Oilfield Chemistry held in Houston, Texas, 16-19 February 1999.
Solids-Free H2S Scavenger Improves Performance and Operational Flexibility
Authors: Schieman Susan R.
Published: December 2007

HCI Travis has developed an H2S scavenger that offers the advantages of enhanced performance and a reacted material (scavenger + H2S) that is completely free of solids. Consequently, this product is suitable for use in a wider range of applications than many of the liquid scavengers currently available to the industry. The fact that the spent material consists of two liquid phases is of special interest to producers who want to scavenge H2S by using packed contact towers or continuous injection either directly into the flowline or into the annulus of a well. These application techniques generally allow for increased contact time and therefore optimize the use of the scavenger. However, it is imperative that solid formation does not occur in these scavenging systems as solids could lead to potentially serious operational problems.

This new material, SULFAGUARD™ 4531, was developed in 1995 and has been extensively field tested. Several case histories where SULFAGUARD™ 4531 was used to overcome operational limitations and where improved effectiveness over traditional triazine scavengers was demonstrated will be discussed.
Chemical Treatment vs. Mechanical Operations in Tank Cleaning: Who Won?
Authors: Shaheen S. E. , Ibrahim H. M. , Raoul P. G.
Published: December 2007

Sludge removal from a storage tank is an easy task if the objective is just to increase the storage capacity. However, sludge transformer in crude oil is much desirable in order to benefit from the value of the recovered crude. Desludging approaches used could be chemical or mechanical. The objective of this paper is to evaluate both these approaches and propose the most cost effective methodology in tank cleaning operations.

No doubt that performing the cleaning task without opening the tank is of advantage. Also working without adding chemical products, heating or applying steam is safer for the facilities and the workers.

Other aspects that are discussed in the paper include the need to eliminate pollution of air and soil, in addition to changing the sludge into crude which can be sold in the international market. Furthermore, real examples are discussed in the paper where the sludge in the tank was about 30.7 ft and the cleaning process is explained in detail. One of the examples shows how 74 676 barrels of sludge changed to crude in only 37 days by optimizing the applied technique.
The Advancement of the Petroleum Engineering Professional: Establishment of Professional Competency Guidelines
Authors: Bobo James E. , Reece Cindy
Published: December 2007

An SPE Task Force (Task Force) was established to define the criteria for minimum competency for petroleum engineers. The original scope of the task force was to apply minimum competency requirements to the U.S. Principles and Practice Examination for Petroleum Engineers (Exam). However, the resulting criteria can be used in more global endeavors. This includes the establishment of professional guidelines for continued professional development for petroleum engineers as well as integration with petroleum engineering degree curricula. This systematic approach will help foster efforts to elevate engineering to a recognized profession such as law or medicine.
Identification and Distribution of Natural Fractures
Authors: Song Xinmin , Zhu Yixiang , Liu Qinghuai , Chen Jun , Ren Dianxing , Li Yanlan , Wang Bo , Liao Mingshu
Published: December 2007

Identification and distribution of natural fractures are important in development of oil and gas fields. On the basis of detailed observation and description of core fractures and their comparison with advanced imaging well-logging fractures, natural fractures can be distinguished from induced fractures. Due to conventional well-logging responses to the high conductivity of fractures, all kinds of fractures may be recognized. Lithology and lithologic association control on the distribution and behavior of natural fractures under concurrent structural settings, natural fracture distribution is indirectly predicted by searching for lithologic combination, which is implemented by seismic inversion under the control of well- logging quality. In addition, fracture distribution is forecasted by extracting fracture information from compressional wave data after excluding lithologic factor.

P. 45
Research, Test and Application on Enhancing Working Reliability of Pump Head for High-Pressure Water Injection Pump
Authors: Yang Fangyun , Wu Zhenya
Published: December 2007

The key factor to guarantee high-pressure water-injection pump's working reliability is operating life of pump head (valve box). This paper presents the pump head compound intensifying process, which is based on researches on fracturing mechanics, metallics, fatigue damage, metal intensification, finite element analysis and machinery manufacturing process. The process consists of two steps. Firstly, a hardening treatment is practised to the inner surface of pump head so that the surface has a compression stress field. Secondly, a sand blast treatment is practised to the inner surface to acquire optimal residual compression stress field. The process will highly enhance its fatigue fracturing resistance and stress corrosion (including hydrogen brittleness) fracturing resistance. The study shows the residual compression stress field formed by the sand blast treatment and -a phase change caused by plastic deformation are the key factors to enhance the fatigue resistance of pump head.

To develop deep zone reservoir, particularly the faulted block field, normally needs water-injection pressure of 40MPa. H i-pressure reciprocating water-injection pump manufactured by Zhong Cheng Company, Dagang Oil Field Group Co. Ltd., can perfectly meet the requirement. Nearly 2,000 units have been provided to domestic users in China, with a market share of 85%. Hekou Oil Production Headquarter of Shengli Petroleum Administration Bureau has taken a comparison test to our pump, which showed the pump increased averagely 11 t/d per pump. In Wennan Area of Zhongyuan Oilfield, the pump increased by 6 t/d. The applications have demonstrated that the key factor to influence the pump's working reliability is the working life of the pump head (valve box). On the basis of analysis the intrinsic rule and related factors affecting pump head working reliability, we put forward the self-enhancement process by thin shell hardening. The process prolongs its working life but the life clearance was not satisfied. Then we take some measures to imporve the process, inculding metallurgy quality and management, its working life is extended. Then after, the process is taken a test study, smallscale industrial test and large-scale extended application and finally reach a breakthrough.

P. 111
Developing Another Heavy Oilfield with Combination Directional Wells and Horizontal Wells -- Development program of QHD32-6
Authors: Jiang Wenxue , Li Yanbo , Chen Guofeng , Ji Ning , Chen Peng
Published: December 2007

Based on the detailed reservoir description, a reservoir simulation model has been built for the selection of production schemes, the division of layer developing series, and optimizing well patterns, well spacing and horizontal wells etc. The combination of both directional wells and horizontal wells is recommended for the development of QHD32-6 oilfield after the study.

P. 135
Evaluation of Horizontal Well Development in Ansai Extra Low Permeability Oilfield
Authors: Wu Zhiyu
Published: December 2007

Ansai oilfield is a marginal oil field with an extra low permeability in the economic and geologic viewpoint. The air permeability is 1.29 md and Kilinkenberg permeability is only 0.49 md. It is difficult to increase individual-well flow rate and to obtain economic benefits because of formation geology. In 1993, the first horizontal well SP-l was drilled in the South of the field with oil production equivalent to that of 4.5 vertical wells in the same block. In 1996, five horizontal wells were drilled and development test of horizontal well group was carried out in the North of the oilfield, in which the reservoir physical property is much poor.

This paper discusses the reservoir characteristics, oil production technology, injection-production performance and so on. The key point of the paper is the comprehensive evaluation of development results of horizontal wells, the main factors affecting production rate of horizontal wells are analyzed, and the feasibility of employing horizontal well to develop extra low permeability, thin pay zone in Ansai is also discussed.

P. 187
Research on the Method of Determination for Remaining Oil at Late Period of High Water Cut Stage
Authors: Du Qinglong , Qing Lu , Cheng Baoqing , Wang Quanlin
Published: December 2007

The method discussed in this paper is to research the relationship between water-out degree of various layers at different waterflood stage and influential factors (well location, sandbody type, communicating states with surrounding injectors and water injection distance) based on water-out behavior analysis of various layers in inspection wells drilled at different period, and to evaluate water-out degree by severe, mediate and weak or no levels for each layer in any well by using fuzzy comprehensive evaluation method and neural network pattern recognition technology, then to further determine remaining oil distribution in each layer. Practical verification of other inspection well and separate layer testing data are conducted. The coincidence rate is high. This method has been successfully applied in remaining oil research of Lamadian oilfield at late period of high water cut stage.

P. 197
Development Practice of Es3 2+3 Marginal Reservoir in Gaoshangpu Oilfield
Authors: Yu Shoude , Chang Xuejun , Liu Quanhai , Yuan Junxiang
Published: December 2007

Es3 2+3 reservoir in Gaoshangpu oilfield is a typical field with complex faulted block marginal. In the past ten years, we achieved scale development and gained better economical in Gaoshangpu oilfield by adopting modem reservoir description technology and characterizing the geological features accurately. At the same time, we used completing injection and production system step-by-step through encrypting well pattern and dividing layer series reasonably making practical development technology projection, and applying advanced technology.

P. 203
Flow Mechanism Investigation and Field Practice for Low Concentration Flowing Gel
Authors: Han Dong , Yang Puhua , Luo Youshong , Qingxia Weili , Qingxia Lin , Cheng Shaozhi , Shong Zhengyu , Tang Jinxing , Tang Xiaolei
Published: December 2007

The applications of flowing gel for modifying the water injection profile is a novel EOR technique developed in recent year. The features of this system are low cost, large application and it can solve the problems of short effective period, quick polymer production in polymer flooding. Therefore, it is of certain use in China. In the paper, the low concentration flowing gel was obtained by using organic metallic Cr3+-polyacrylamide system for the first time. The structure and properties of the gels were identified by modern analytical techniques of atomic force microscopy and dynamic rheological method. The large diameter sand pack displacement tests were carried out to investigate the flow mechanisms in the porous media. The results show that: flowing gel is a aggregate of cross-linked molecules with a radius of 30 m. Low concentrations gellant system can form into gel during its flow in porous media. And the gel formed is capable of flowing, and different from that formed from solutions. The flowing behavior of low concentration flowing gel in porous media is different from conventional polymer flooding. It can be described by the first, maximums and residual resistance factors. The field practice of injectivity test was carried out in Henan oil field. The radius of injection was 70m, injection period 60 days. After injection, pressure increased 2MPa, with an incremental oil production of 4 ton/d. It shows the injectivity is good.

P. 483
Liquid Carbon Dioxide Fracturing for Increasing Gas Storage Deliverability
Authors: Harris Ramon P. , Ammer James , Pekot Lawrence J. , Arnol Daniel L.
Published: December 2007

During the summer of 1995, National Fuel, through a Department of Energy (DOE) sponsored project for storage deliverability enhancement, began a stimulation project on three wells in Galbraith Storage Field. Galbraith, located in Jefferson County, Pennsylvania, consists of 26 active injection/withdrawal wells completed in the First Sheffield Sand at an average depth of 2,800 feet. Three of the active wells were fractured in the early 1980's using a gelled water fluid and approximately 20,000 pounds of sand. Several years of cleanup were required in all of these wells before the peak stimulation deliverability was experienced. The combined delivery from two of these wells was responsible for more than 40% of the field total. The fracture stimulation provided a significant increase from pre-frac deliverability. However, roughly 10 years of storage use and a coiled tubing cleanout were required before this level of increase was realized.

Three wells from the remaining 23 active were selected for the first liquid carbon dioxide fracture stimulations conducted in a storage field. Preliminary well test analysis indicated that permeability in the field was greater than anticipated, and deliverability was being adversely affected by a large skin. The fracture procedures were designed to produce short propped fractures to extend beyond near wellbore skin damage. The fracture gradient experienced was greater than 1, pushing the treating pressure to the maximum allowable for all of the jobs. As a result, the sand concentrations did not get as high as designed. The formation breakdown in one well was not sufficient for proppant to be run and very little deliverability increase was achieved at this well. However, deliverability increases at the other two wells were about 5 fold, roughly 5 MMcfd. Concerns that the carbon dioxide would not be recovered in a timely manner were put to rest after a few days as the concentration in the gas quickly fell below 3% and the wells were put back into service.

The level of immediate deliverability increase is what makes this technique attractive to storage operators. Because the pumped proppant was lower than anticipated, the longevity of the increase is suspect. Eighteen-month follow-up well testing has shown good maintenance of deliverability at the two propped wells and an increase in the deliverability at the unpropped well. Flow testing was conducted in July 1998, to evaluate the third-year performance. Additional details regarding the planning, testing, pumping, and evaluating of these jobs are discussed in the paper as well as a general review of the costs.
Collapse Behavior of Casings: Measurement Techniques, Numerical Analyses and Full Scale Testing
Authors: Assanelli A. P. , Toscano R. G. , Johnson D. H. , Dvorkin E. N.
Published: December 2007

The production of steel OCTG products with guaranteed external collapse pressure (high collapse casing) requires the implementation of an accurate process control. To develop that process control it is necessary to investigate how different parameters affect the external collapse pressure of pipes. Two dimensional finite element models provide an useful tool for performing the "first approach" parametric studies; however a bidimensional representation of the tube geometry (as used in many analytical and semi-empirical formulas) is not enough for determining the external collapse pressure of casings. We use three dimensional models to further investigate the effects of the casing geometry on its external collapse pressure. To acquire the data that dscribes the geometry of casing samples, we have developed an imperfections measurement system following previous developments by Yeh and Kyriakides. We also present finite element models of OCTG connections which are used as a tool for the evaluation of connections collapse pressure.
Incorporating Sequence Stratigraphy in Reservoir Simulation: An Integrated Study of the Meren E-01/MR-05 Sands in the Niger Delta
Authors: Cook Gerald , Chawathe Adwait , Larue David , Legarre Henry , Ajayi Ebenezer
Published: December 2007

This paper was prepared for presentation at the 1999 SPE Reservoir Simulation Symposium held in Houston, Texas, 14-17 February 1999.
A Streamline Based Approach to Solution of Three-Phase Flow
Authors: Ingebrigtsen L. , Bratvedt F. , Berge J.
Published: December 2007

Two methods for calculation of three-phase compressible flow in a porous media using streamlines are presented. For simplicity, gravity and capillary effects are neglected.
Relationship Between Polymeric Fragment Damage and Damage Removal and the Original Rock and Proppant Pack Permeability
Authors: DeVine C. S. , Tjon-Joe-Pin R. M. , Rickards A. R.
Published: December 2007

Fluid viscosity reduction is an important gauge of polymer degradation, and, although viscosity reduction does indicate that polymer degradation has occurred, reduced viscosity does not necessarily indicate that the proppant pack and the formation are undamaged. Polymer fragments which are "broken" from the gelled fluid no longer contribute significantly to fluid viscosity but may contribute to proppant pack and/or formation permeability damage, i.e. fragments may be "stuck" in pores and pore throats.

Carbohydrate analysis of post-fracturing flowback fluids yields valuable information regarding the abundance of mobile polymer fragments which are recovered subsequent to fracture stimulation. Gel breaker efficiency is characterized based upon the size distribution of generated polymeric fragments from both linear and cross-linked guar based fracturing fluids. Previous studies have demonstrated that a correlation exists between formation rock permeability and the degree of damage resulting from residual polymer fragment deposition -the greater the formation rock permeability, the greater the degree of damage to the formation.

In this study, results of core flow and fracture conductivity testing are presented in an effort to correlate clean up effectiveness to original rock and proppant pack permeability. Degraded and cross-linked low, near neutral, and high pH frac fluids were tested. In general, a greater percentage of regained permeability was noted for more severely (i.e. permeable) damaged rocks. Proppant pack studies showed a similar effect. Rocks tested in this study exhibited permeabilities from 3 md to over 2 darcies. Conductivity proppant pack baseline ranges were 250 to 500 darcies.

Data yield a semiquantitative model of the extent of formation permeability and conductivity damage and clean up that can be expected based upon the original rock permeability. Laboratory carbohydrate content data are compared with fracture flowback data, and field case histories, as applicable, are discussed.
Stripper Field Performance Comparison of Chemical and Microbial Paraffin Control Systems
Authors: Giangiacomo Leo A.
Published: December 2007

This paper reports the field performance results of a comparison of chemical and microbial paraffin control systems. The two systems were selected based on laboratory screening work. Well selection was based on production rates, produced fluids, and prior paraffin treatment history. The treatments were performed on similar groups of wells over the same period of time, using quantities and techniques recommended by the supplier specifically for the wells to be treated. The tests were conducted by the U. S. Department of Energy's Rocky Mountain Oilfield Testing Center at Naval Petroleum Reserve #3 in Natrona County, Wyoming.

The chemical system was applied to three stripper wells. The treatments utilized paraffin solvent and diesel and were pumped down the casing annulus of the wells. Initially, a smaller treatment was performed to clean up the wellbore and tubulars. Shortly thereafter a larger treatment was performed to clean up the perforations and near-wellbore area.

The microbial system was applied to four stripper wells. A dry medium containing microbes was mixed with produced water and pumped down the casing annulus. The wells were treated monthly for three months.

Production was monitored closely on all the treated wells prior to the treatment and for eight months thereafter. The study makes recommendations for choosing wells for paraffin treatments and for treating wells with microbial systems. It concluded that solvent treatments were capable of yielding larger production increases. Microbial treatments required lower capital investment and yielded lower initial production increases, but had a more sustained effect.
Downhole Capillary Soap Injection Improves Production
Authors: Awadzi Jacqueline , Babbitt Jess , Holland Steve , Snyder Kent , Saucer Tom , Latter Kelly
Published: December 2007

Liquid loading is an ever increasing problem as gas wells age and deplete. In tight gas reservoirs, liquid loading can adversely effect well performance for 3/4 to 7/8 of a well's 20 to 30 year life. A relatively new approach to unloading liquids had been to inject soap via a downhole capillary injection system. This approach has resulted in substantial and sustained production increases in East Texas Cotton Valley gas wells at depths of 8,500' to 11,000'. The production increases will impact both well life and reserve recovery. The East Texas Cotton Valley gas area contains 3500+ wells and it still continues to be an active development area.

The capillary stainless steel 1/4"-3/8" tubing is snubbed into the well inside the tubing. A downhole injection/check valve assembly is run on the end of the capillary tubing. Soap is then injected or siphoned from a chemical storage tank through filters to maintain solids-free fluids for injection. Injection can be easily maintained on a continuous basis to ensure consistent foaming action for unloading efficiency. The capillary string is easily installed and can be transferred from one well to another. In many cases the soap injection from capillary tubing has out performed the more conventional plunger lift.

The injection system is also very effective in treating downhole corrosion, paraffin and scale, buildup and in dissolving salt buildup. This capillary injection system could provide a new approach to solving many oil and gas well operating problems worldwide.
CO2 Gas Lift – Is It Right For You?
Authors: Martinez John
Published: December 2007

Gas lift can be installed in producing wells within a CO2 flood utilizing the nearly pure injection CO2 or the mixed hydrocarbon/CO2 gas returning to the production station. Lift gas injection rates can be varied to correspond to the water content resulting from the water-alternating-gas (WAG) results.

The lift equipment configuration options are:

standard installation with gas on the casing passing through a valve mandrel(s) gas conveyed by coiled tubing (strapped to the main tubing) to the valve mandrel coiled tubing hanging inside the main tubing with production flow in the annulus of these strings

Field installations of the two options at the top of the list have given good service and the last option is a common configuration for velocity strings in gas wells.

Gas lift as an artificial lift method can eliminate failures in pumps due to the CO2 or due to the gassy nature of the produced fluid. Chemical treatments can be transported downhole with the lift gas and used to control corrosion, paraffin, or asphaltine.

Gas lift is a flowing process, which must have adequate reservoir, and wellbore pressure to flow the fluids to the surface facility, whereas the pumping process has energy transmitted downhole to raise the fluid pressure. Wellbore pressure for pumps can be lower since the fluid need only flow from the reservoir to the pump intake.
Using Stimulation Expert System to Design Hydraulic Fracturing Treatments – Field Examples
Authors: Xiong Hongjie , Rahim Zillur
Published: December 2007

Stimulation Expert has been developed to aide the engineer design a stimulation treatment. The process involves calculation of injection and tubing pressure and tubular movements, selection of appropriate mode and methods of stimulation, and correct choice of treatment fluids, proppant, and pumping schedule. The program is user-friendly and the numerous databases and expert help facilities included in STIMEX™ make this program readily accessible to all level of engineers and experts in solving stimulation problems.

The Stimulation Expert system has been used for the design of stimulation treatments for oil and gas formations for a wide range of reservoir property. The expert help and technical advice received during the design process have been successfully used for the treatment designs. In the final phase of the design, the optimization method is used to predict the optimal treatment that should be carried out in the field.
Deepwater Well Control: Circulate With Both C&K Lines?
Authors: Christman Stan A.
Published: December 2007

In deepwater well control, choke and kill line friction becomes an increasingly important factor, particularly when the margin between mud density and the equivalent casing shoe fracture gradient is small. Using both C&K lines for flow is one of the options to reduce the friction loss, but the decision involves considerations that are affected by well and rig conditions. This paper reviews these considerations, including an interesting phenomenon called the ‘BOP Separator Effect’ that alters the flow distribution when two lines are used and the kick has free gas. This effect has been studied with computer modeling and appears to have the beneficial effect of reducing hydrostatic surface pressure fluctuations and hence facilitating choke adjustments. Also, the value of a pressure sensor in the BOP stack is addressed.
Modern Use of Closed-Loop Hydraulics for Controlling and Powering of Cylinder-Based Hoisting Systems
Authors: Rudshaug B. , Skibelid T.
Published: December 2007

The Maritime Hydraulics A.S RamRig© drilling concept is based on hydraulic cylinders as actuators powered by up to 3.4 MW of hydraulic power in a closed loop hydraulic system. This synthesis of well-known technology allows for the use of integrated active and passive heave compensation, as well as the storing and reuse of energy from the lowering phase of an operation. The RamRig concept makes mechanical brakes and clutches obsolete, since hoisting and lowering of the load is controlled solely by the closed loop hydraulics. This decreases the number of critical mechanical components in the hoisting system to a minimum. Safe handling and emergency shut down of extreme amounts of hydraulic power is taken care of by cartridge valves, which make rerouting of hydraulic power possible with minor losses of transferred effect.
A Radical Approach to Offshore Activities in the New Millenium
Authors: Mitchell C. , Chiesa G.
Published: December 2007

The high costs of offshore activities, particularly deepwater drilling, are currently forcing oil companies to consider new technologies and new ways of operating in an effort to reduce costs of finding oil in even deeper waters. Shell and Saipem have been working together for the last 18 months considering the idea of a Subsea Drilling rig. This work has indicated that subsea drilling is a feasible concept, which has a number of benefits over conventional drilling, although the cost to construct a fully capable rig, coupled with the technical risk associated it, means that it is unlikely to happen today. However, for rank exploration work, where success is on average very low (20-30%), it is proposed that a very small subsea rig, with the capability to gather a minimum of reservoir data through a minimum diameter hole, might be an economically attractive solution, which will enable true low cost exploration drilling.
Electric Coiled Tubing Drilling: A Smarter CT Drilling System
Authors: Turner D. R. , Harris T. W. R. , Slater M. , Yuratich M. A. , Head P. F.
Published: December 2007

The paper describes the ongoing development of an electrically powered bottom hole assembly for use in coiled tubing drilling (CTD) applications.

Electric coiled tubing drilling (E-CTD) offers many distinct advantages over conventional CTD which are considered in more depth within the paper. These may be summarised to include: Drive power provided independent of fluid flowHigh tolerance of energised drilling fluids–ideal for underbalanced drilling–ideal for subsea drilling applicationsHigh temperature operationFlexible control of electric power with instantaneous feedback for closed loop drilling and optimisation of drilling efficiencyMotor operation is scalable. The same drive may be used for auxiliary actuation, e.g. orientation, active traction and formation testing.Real-time transmission of data to surface using power cableExtended longevity of motorReduced vibration (affects gyro placement, reliability of other equipment, eg NMR magnets)Reversible direction of rotation (passive or active traction capabilities)

It is these advantages that have driven the development of the electric BHA in a European Drilling Engineers Association [DEA(E)] joint industry project. This paper reviews prototype bottom hole assemblies from phases 1 and 2 of the project. Surface components, the electrical transmission system and its consequences for an integrated drilling package are also considered.

Phase 2 of the project, currently ongoing, has delivered a purpose-built, electric downhole motor (EDM) design suitable for drilling a 3.75" hole. This motor is currently being incorporated into an electric BHA which incorporates pressure, temperature and vibration sensors. The proposed test program is reviewed with some earlier results presented from phase 1 for illustrative purposes.

The ultimate goal of this project is to integrate the electric motor into a ‘smart’, closed-loop drilling system. It is envisaged that, based upon feedback from near-bit sensors, such a system would be able to automatically adjust drilling parameters to optimise drilling performance.

The paper concludes that not only is electric coiled tubing drilling a practical and effective alternative to conventional CTD, but that the system delivers many additional benefits.
New Open-Hole Displacement Procedure Dramatically Reduces Loss of Synthetic Fluids in Deepwater GOM
Authors: Courtney Greg , Elliott Karl , Smothers Neal , Humbles David , Toups Bret
Published: December 2007

Synthetic drilling fluids have evolved into the systems of choice for deepwater drilling, particularly in the Gulf of Mexico. As these systems are proportionately more expensive than their traditional counterparts, the loss of even a few barrels can impact well economics significantly. Historically, it has been commonplace to leave hundreds of barrels of synthetic drilling fluid in the wellbore during open-hole displacements. Attempts to retrieve synthetic muds with water-base systems have proved counter productive. When exposed to water-base muds in open hole, the formation becomes extremely unstable and will literally cave in, resulting in a number of operational problems.

This paper describes the development and application of a new displacement procedure and a modified water-base mud that successfully recovered 961 bbl of synthetic fluid on the Manatee project in the deepwater Gulf of Mexico. When compared directly with conventional open-hole completions in the deepwater GOM, the new procedure resulted in savings of $228,718, not including saved rig time. Furthermore, no additional rig time was required to condition the water-base system used in the successful open-hole displacement. More importantly, the wellbore remained stable and no problems were encountered while tripping through the 4,462-ft of open hole exposed to the re-engineered water-base fluid system.

The authors will describe both the new procedure, which included a casing shoe with an extremely high leak-off test and realigned pumps, and the new 15 lb/gal water-base displacement fluid. The modified system was both inhibitive to reactive shales and could also withstand the contamination effects of the calcium employed in synthetic muds.
New Permeability Plugging Apparatus Procedure Addresses Safety and Technology Issues
Authors: Davis N. , Mihalik P. , Lundie P. R. , Growcock Fred , Calloni G. , Davidson E.
Published: December 2007

For the past nine years, the drilling industry has used the Permeability Plugging Apparatus (PPA) to assist in evaluating and resolving differential sticking and lost circulation problems which may arise while drilling depleted, weak or fractured zones. The increasing use of open hole completions in horizontal wells also means that more attention has to be paid to the cake forming properties of drilling fluids. The PPA is a high pressure, high temperature filtration device designed to evaluate fluid loss and "spurt loss" of drilling fluids under filtration conditions that more closely approximate those encountered downhole than the filter paper normally used. Although filtration occurs under static rather than dynamic conditions, pressures as high as 5000 psi (34,500 kPA) and temperatures of up to 500°F (260°C) may be investigated. The main feature of the PPA is the use of ceramic disks as the filtration medium. These are available in a wide range of porosities and permeabilities to match those properties of the formation much better than filter paper can. There are currently five PPA types with different pressure ratings that are in use in the laboratory and the field. In response to concern about the safe use of these devices, and the reproducibility of the data generated with them, the American Petroleum Institute initiated a program to investigate these issues, and to produce a standardized test procedure.

The new API procedure addresses the safety issues of the PPA cell designs. Further, to provide consistency between users, the procedure outlines a new method of calculating spurt loss and total filtrate volume parameters based on the test data. The new procedure has been used, both in the laboratory and the field, to evaluate seepage loss additives as well as traditional lost circulation additives. Case histories are provided which demonstrate successful use of the device in evaluating lost circulation material and in the prevention of differential sticking problems while drilling depleted zones as well as designing pills for severe lost circulation.
Novel Lime-Free Drilling Fluid System Applied Successfully in Gulf of Thailand
Authors: Harrison James R. , Stansbury Mark , Patel Jay , Cross A. Todd , Kilburn Mark
Published: December 2007

A lime-free, high-temperature invert emulsion drilling fluid has been developed and applied successfully on 53 wells in the Gulf of Thailand (GOT). The subject drilling program included 24 wells in a field with static bottom hole temperatures (BHT) of 400°F. The fluid is run with a pH of less than 7.0, which is accomplished with the introduction of 1 lb./gal of citric acid and the elimination of the alkaline source (lime).

The fluid was mainly developed in search for a high quality drilling mud resistant to heat degradation, therefore allowing stable borehole conditions under which to execute the open hole wireline logging program. The fluid was also developed in part to allow the possibility of logging CO2 formation gas at the surface by utilizing a conventional mud logging unit. The ability to log CO2 gas with surface equipment would help eliminate wireline RFT sampling runs. This could provide significant savings during the course of an extensive drilling program.

The paper will discuss the development of the lime-free emulsifier package, the introduction of a new HTHP fluid loss reducer (stable in excess of 450°F) and low-end rheology modifier, the extensive lab testing, the introduction of the system to the GOT and the drilling of 53 wells.

Data from 250-plus GOT slimhole wells using invert systems were studied prior to the introduction of the new system. The numerous problems that prompted the investigation for a new cost-effective fluid system will be discussed.
Shallow Kick-off Extended Reach Drilling in GOM
Authors: Meize B. , Chesebro’ S. , Stubblefield A. , Lenamond C. , Miller R.
Published: December 2007

Anadarko Petroleum Corporation spudded a shallow kick-off extended reach well from the High Island A-376 "B" platform in December of 1997. The well successfully drilled 8208’ of horizontal displacement to a 3388’(TVD) reservoir target adjacent to the environmentally sensitive Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico. The 9767’MD/3388’ TVD well required significant planning to ensure technical feasibility and execution. Geological control was based on seismic data with no pilot hole planned prior to landing in the target. This required the use of geological steering and measurement-while-drilling techniques to perform the pinpoint landing.

The paper details predicted vs. actual torque and drag numbers for high-angle drilling conditions. The use of pressure-while-drilling tools identified circulating pressure losses associated with synthetic drilling fluids and pressure changes due to hole cleaning. The well features a number of today's technical advancements in extended reach drilling and includes: A 17-1/2" sea water kick-off with build rates of 6 degrees/100’Displacement to true vertical depth ratio greater than 2.5:1Use of top-drive fill-up tool while running 9-5/8" casing allowed greater annular velocities, increasing holecleaning effectiveness and successfully washing casing to bottomRotating a 7" liner in high angle hole made possible due to synthetic mud and use of solid-body centralizersFirst one-trip, weight-set liner top isolation packer run in the Gulf of Mexico on an extended reach well.

The paper concludes that seismic technology and geological steering can eliminate the need for pilot holes. Extended reach drilling through soft sediments to small shallow amplitude events can be economically accomplished from existing structures in the Gulf of Mexico.
A Case Study in Improving Capital Efficiency
Authors: Jackson K. L. , Brennan R. M. , Aranaga R. , Hawker R. , Montaña J. P.
Published: December 2007

The initial phase of Venezuela's first large-scale horizontal development drilling program in the Faja del Orinoco will soon be completed. This project is known as the Venezuela Extra Heavy Oil Project (VEHOP) and is operated by Petrozuata, C.A., a strategic association between Petroleos de Venezuela, S.A. (PDVSA) and Conoco, Inc. The planning process began in 1994 with the evaluation of worldwide heavy oil operations. A test well was drilled which incorporated design changes to improve well productivity and allowed the operator to gain experience in Venezuelan operations.

The Petrozuata development program was based on drilling and completing 95 horizontal wells of identical design as efficiently as possible in order to maximize the project economics. To accomplish this goal, a minimum well design was established based on managed risk. Discrete operations were then analyzed to establish breakthrough targets for drilling performance. To ensure targets were met, a well manufacturing process, including fit-for-purpose drilling rigs, contracting strategy, procurement strategy, and detailed operational plans were developed.

Performance improved significantly from an initial 19.2 days to 5.4 days per well. The basis of design included 4000 foot lateral sections with actual lengths exceeding 6000 feet measured depth (MD). A capital efficiency improvement of 18% is projected based on current performance. This paper details how shared goals, teamwork, and continuous improvement initiatives between the contractors and operator resulted in world-class drilling performance, record setting horizontal completions, and a new standard for future Venezuelan operations.
Drilling and Completion of Depleted Carboniferous Reservoirs in the U.K. Southern North Sea
Authors: Bourassa K. A. , Bujnoch J. A.
Published: December 2007

The objective of this paper is to outline and discuss the learnings which improved the drilling and completion process of horizontal wells in depleted Carboniferous reservoirs.

The learnings were derived from three replacement wells drilled and completed on the Conoco (U.K.) Limited operated Murdoch Field, which is a mature development in the Quadrant 44 area of the United Kingdom Southern North Sea (UK SNS) (refer to Figure 1). The replacement wells were drilled in an effort to restore production volumes that were lost when two of the original wells mechanically failed due to downhole conditions.

The paper will summarise the following: Failure analysis of the original wellsBasis of design for the three replacement wells including sand control issues of depleted reservoirs

Operational summaries for three wells will be thoroughly discussed.

The learnings gained from the failure of the first well was applied to the planning and implementation process of the two remaining wells. The wells were successfully drilled and completed. The initial production rates of these two wells were equal to or greater than the original development wells even though the reservoir pressures were significantly reduced.
GLOMAR HULL 456 CLASS Ultra-Deepwater Drillship
Authors: Dreith Mark W. , Garvin Michael D. , Thorson John A.
Published: December 2007

This paper describes how the Global Marine Hull 456 Class ultra-deepwater drillship is able to improve on conventional floating drilling operations and highlights advances that have been made to maximize efficiency and minimize downtime. The paper will document how the 456 Class uses a unique thruster specification to greatly reduce the amount of downtime due to weather or equipment failure. In addition, Global Marine's unique horizontal/vertical enhanced pipe handling technique will be discussed in depth, with a focus on how this will increase both up time and rig efficiency.