bluuebunny/crossref_metadata_2025 huggingface dataset:
First Successful Selective Stimulation With Coiled Tubing, Hydrajetting Tool, and New Isolation Sleeve in an Openhole Dual-Lateral Well Completed in a Saudi Arabia Carbonate Formation: A Case History
Authors: Garzon F. O. , Franco C. A. , Ginest N. H. , Sierra L. , Surjaatmadja J. B. , Izquierdo G.
Published: July 2010

Drilling and completion of extended reach (ER) or multilateral wells (MLT) in open hole carbonate reservoirs to maximize the reservoir contact and exploitation has become routine in Saudi Arabia. Initial deep gas development wells were conventional vertical wellbores that were perforated an either acid matrix or fracture stimulated. Experience with the more complex ER and MLT well completions has shown that these wells also require stimulation to remove induced damage or to enhance well productivity. Selectively accessing and stimulating these complex well types completed with open hole laterals is extremely challenging utilizing existing conventional intervention technologies.

A recently drilled dual lateral well completed in the Khuff-C formation with open hole horizontal sections exceeding 3,000 ft was successfully selectively stimulated. This paper describes how each lateral was accessed with coiled tubing (CT) and selectively stimulated using a hydrajetting tool and a new isolation sleeve, which was used for the first time in the world. The excellent post-treatment results achieved are also discussed.
Corrosion Control of Drilling Tools Through Chemical Treatments – Effectiveness and Challenges
Authors: Asrar Nausha
Published: July 2010

With increasing demand for energy, the production of oil and gas must increase. However, increasing production is challenging because the wellbore fluids in many new fields are typically multiphase in nature with harsh chemical compositions and conditions, such as high hydrogen sulfide, carbon dioxide, and occasionally dissolved oxygen, in a high temperature and pressure environment. All this makes corrosion control a major concern, especially in the present challenging economic climate, where the risks and cost associated with corrosion may have significant impact on Health, Safety and the Environment (HSE), capital expenditure (CAPEX) and operation expenditure (OPEX) in oil & gas exploration and production. This paper addresses the chemical treatments of drilling mud for corrosion control. Corrosion mechanisms, such as mud deposit attack (pitting), corrosion due to corrosive gases of formation, stress corrosion cracking, and microbiologically influenced corrosion (MIC) are reviewed to emphasize the failure mechanisms through which the drilling fluid parameters, such as, dissolved oxygen, pH, hydrogen sulfide, carbon dioxide and chloride contents may aggravate the corrosion problem and adversely affect the reliability of the downhole equipment. These corrosion issues are addressed by design and control options such as material upgrade, coatings, cladding, and chemical treatment. However, the focus is on chemical treatments, the mechanism through which they can effectively control corrosion and their limitations. Finally, prevention and mitigation measures are discussed to address the limitations of chemical treatments, such as control measures by the drilling company for mud treatment and the development of sensors for monitoring mud chemistry during drilling operations.
Research of Conductor Setting Depth Using Jetting in the Surface of Deepwater
Authors: Jin Yang , Shujie Liu , Jianliang Zhou , Pingshuang Wang , Haixiong Tang , Junfeng Luo , Bailing Zhang , Changsuo Zhou
Published: July 2010

The tripping technology using jet conduit in construction of deepwater drilling is a key technology, In this paper, the relationship between the jet catheter lateral friction and the properties of the seabed soil is studied through theoretical research and analysis and field simulation test, The relation model of lateral friction in the sandy soil and clay conduit and the consolidation time has been established. Combined with construction process of deep-water jet catheter, an analysis of force situation during the process of drilling pipe jet was carried out, and a calculation model of the tripping in depth of jet catheter. To combine a deep-water exploration well in the South China Sea with the specific circumstances of, from the depth into the mud of drilling jet catheter, drilling assembly, Optimization of drilling parameters and the main points of the construction of jet catheter tripping in, Etc. Explored the technical skill under the jet method surface casing, shows the construction of drilling jet catheter site specific measures.
Pipework and Vessel Review and Risk Based Assessments of the North Sea Forties Assets
Authors: Barson R. , Spicer K.
Published: July 2010

The North Sea Forties assets, consisting of five platforms, have been in operation for 35 years. Extensive exploration of the Forties field in 2003 indicated that the field life could be extended by 20 years. Consequently, the Operator made substantial investments in these assets for the necessary upgrades to improve efficiency and infrastructure integrity.

The pipework and vessel information and inspection history for the assets was stored in an asset database. This database had not been updated for several years and therefore could not be used as an efficient inspection tool. For the Operator to introduce Risk-Based Inspection (RBI) to the assets, a thorough review of the topside pipework and vessel information was required.

The main scope of work was: An update of the pipework and vessels equipment list to include upgrades and archiving removed or redundant itemsCompiling a deadleg registerAllocating pipework to corrosion circuitsIdentifying insulation status changesPerforming Risk-Based Assessments (RBA) on corrosion circuits and vessels to facilitate RBI

Comparisons of the assets’ updated P&IDs with the database equipment list were made to identify the new, redundant or removed items and other changes.

The updated asset equipment lists were uploaded into the database, overwriting the outdated information. It was then possible to start the RBA process using the database.

The RBA sessions were attended by a panel of experts; the Integrity Authority, two Corrosion Engineers, an Inspection Engineer and a Pressure Systems Engineer. Qualitative RBAs were performed on all corrosion circuits and vessels with only limited records of inspection history and with reliance on the knowledge and judgment of the experts.

On completion of the topside assets update/review, together with the RBAs, the Forties field Operator was able to perform full Risk-Based Inspections (RBI) on pipework and vessels, thereby providing an improved operational regime.
Possibilities of the Methane Utilization from Mined and Unmined Coal Seams in Poland
Authors: Stopa Jerzy , Nawrat Stanislaw , Rychlicki Stanislaw
Published: July 2010

The potential in coal seams gas resources in Poland is estimated to be similar to known conventional reserves (about 150 bln s.cu.m) but present efficiency of utilization is much lower. Many coalmines utilize this gas for a small-scale heating and electricity generation, but global utilization efficiency is as low as 60%. In Poland, methane is recovered mainly for safety reasons from coalmines. This paper presents new possibilities for methane production from abandoned coalmines and from unmineable, deep coal seams. In the first case the gob gas ventholes can be drilled from the surface, in the second case multilateral wells technology can be employed. In the paper, the simulation models of mined and unmined coal seams are presented and discussed. The results are evaluated from both technical and economical point of view. Economical analysis showed positive NPV and IRR=10%. Two case studies presented in this paper show that both abandoned coalmines and unmineable coal seams could be effectively utilized for coalbed methane production using advanced drilling technologies. During the last decade many coalmines over the Europe have been abandoned for both economical and environmental reasons, others are in the terminal state of production. However, some of these mines still contain large resources of methane that could be used for the local purposes like heating or electricity generation. The case study of the Moszczenica coalmine in Poland, including computer simulation of the coal and methane production shows that gob gas can be successfully recovered using new wells drilled from the surface. Presently, the deep unmineable coal seams are often not utilized from economic reasons. The case study presented in this paper shows that they can be effectively utilized for coalbed methane production using advanced drilling technologies like multilateral wells.
Comparison of Different Deliverability Testing Techniques in Low Permeability Gas Reservoir and Its Impact on the Absolute Open Flow (AOF) Estimation
Authors: Khalifa Mohammed , Yemez Ivan , Stigliano Horacio , Vicente Sekulin Mario , Angulo Reinaldo
Published: July 2010

Several deliverability test techniques are being used in the oil industry to generate a reservoir inflow performance relationship (IPR). The IPR curve describes the relationship between surface production rate and the flowing pressure at the bottom of the well (BHFP). The Absolute Open-Flow potential (AOF) represents a hypothetical gas flow rate that may be produced if the BHFP value were equivalent to the atmospheric pressure, i.e. the maximum flow rate that the reservoir may produce.

The most commonly known techniques for deliverability testing are: Flow-after-flowIsochronalModified IsochronalSingle-point

Although, these techniques are aimed to evaluate the production capacity of wells, most of them (the Isochronal, Modified Isochronal and Single-point tests) were developed to reduce the flared/vented gas and to minimize well testing cost. The flow-after-flow method requires stabilized flow for each of the flow periods, while the rest of the techniques only require stabilized flow at the last flow period test.

In this study, a radial simulation model was used to simulate the flow behaviour observed during application of the different well deliverability techniques mentioned above and to analyze and compare their flow stabilization times. These simulation results indicate that the stabilized flow condition is the main factor which influences the AOF results for any of the deliverability testing techniques used. Furthermore, the results emphasize that the use of a non-stabilized flow test may lead to an over estimation of well deliverability, especially for low permeability reservoirs.
New Generation Software Integrates Intrusive and Non-intrusive Systems for Corrosion and Sand/erosion Monitoring
Authors: Wold Kjell , Hopkins Sean , Jakobsen Tommy , Lilleland Svein Erik , Stoen Roar , Brandal Øystein
Published: July 2010

On-line corrosion and sand/erosion monitoring increases the amount of data to be handled significantly, and new monitoring technologies also generate more complex information than before. The importance of reliable and efficient systems for data management and for the reporting and analysis of monitoring data has therefore never been higher.

Roxar has developed software which combines intrusive and non-intrusive systems for corrosion monitoring, as well as intrusive and acoustic systems for sand/erosion monitoring into one integrated solution. Together with new measurement technology features, the new system will improve user ease-of-use and the reliability of data, in particular for the non-intrusive field signature method technology.

This paper will describe and present field data from the first on-line electric field signature systems, and demonstrate how the new software can improve the use and presentation of the data. Finally a new measurement feature for electric field signature measurements will be introduced and the paper will demonstrate how this feature can improve the detection and quantification of localized corrosion and sand/erosion attacks in all directions.

The paper will provide an overview of the move towards on-line and integrated corrosion and sand/erosion monitoring solutions; an overview of today's sand monitoring and corrosion measurement technologies; the growth of the electric field signature method (FSM); and details on the new software. The first field installation of the new software was carried out at Statoil's Heidrun field. Experience and field data from this installation will be presented and discussed.
Changing the Injection Water on the Blane Field, North Sea: A Novel Approach to Predicting the Effect on the Produced Water BaSO4 Scaling Risk
Authors: McCartney R. A. , Burgos A. , Sørhaug E.
Published: July 2010

The Blane Field, North Sea, has one injection well and two production wells and is tied back to the Ula Field platform. The original scaling risk assessment was based on injection of platform produced water (PW) with minor seawater (SW) (~90:10 PW:SW). However, after injection of 25:75 PW:SW for only 6 weeks, a change in operational circumstances on the Ula Field meant that only 10:90 PW:SW injection water could be supplied for the next 18 months. There was a risk that this might result in unmanageable BaSO4 scaling conditions in the production wells but the alternative would be to cease injection, leading to reservoir pressure decline and loss of oil revenues.

The need for a rapid decision negated the use of reactive transport reservoir simulations to predict the future BaSO4 scaling risk under the new injection scenario so a novel, alternative approach was adopted. A history matched ECLIPSE model served as the basis for predicting the types of water entering the production wells over time and their rates. A 1-D reactive transport model was then used to predict the Cl, Ba and SO4 composition of these waters after accounting for the effects of reservoir reactions. These results were integrated in a spreadsheet to provide predictions of Cl, Ba and SO4 concentrations in the produced water from each well over time.

The results for future injection water scenarios indicated that the scaling risk would increase over time in the wells but, due to deposition of BaSO4 and CaSO4 in the reservoir, the BaSO4 scaling risk would be manageable even allowing for uncertainties associated with this approach.

Based on these results, and those of associated studies, a decision was made to continue water injection resulting in avoidance of loss in oil revenues. This novel scaling prediction approach may be useful on other fields where reactive transport reservoir simulations may not be possible.
Advances in Subsea Well Intervention BOP Qualifications
Authors: Deshotels S. J. , McClanahan P. , Douty J.
Published: July 2010

Performance Verification Testing (PVT) is performed on prototypes on production models to verify the performance requirements specified for temperature, pressure, load, mechanical cycles, and standard test fluids are met in the design of the product.

I will outline the PVT requirements as given in API 6A (ISO 10423), API 16A (13533), API RP-17G (ISO 13628-7) and draw attention to what is required for a subsea well intervention coiled tubing/wireline BOP rams. I will go through some of the qualifications that have been performed for some products, difficulties and challenges with certain sections and conclude with a summary.

We all want to be provide a safe environment during a well intervention project or campaign. The industry standards set guidelines for us to follow so that we have a reassurance that the equipment we put on our wellheads will keep everyone safe. We are challenged as the wells get higher pressure, higher temperature and deeper waters. The risk increases and any small accident could be catastrophic. We are therefore faced with challenges during well intervention operations, we must have confidence the equipment we are putting on our wells is sufficient, adequate and will work when we need it to work.

Performance Verification Testing is one of the major steps we take to ensure the equipment is fit for purpose. We perform a range of tests on the equipment to ensure that it will work when we need it to. Some equipment is used on a daily basis, other tools are used only during certain situations and then you have the tools that are used as the last step to contain the well.

The steps I am going to go through are the steps taken to qualify equipment for well intervention. I will go through the requirements for API 6A, 16A, and 17G and some challenges we have faced and conclude with some suggestions.
Merging Tapered in Coiled Tubing (CT) and Well Tractor Technologies to Effectively Stimulate Extended Reach Open Hole Horizontal Wells
Authors: AlDhufairi Mubarak , AlGhamdi Saleh , Noya Vidal , Al-Aradi Khaled , Al-Sarakbi Samer , Al-Dossary Ahmed , Krueger E. , Moore B.
Published: July 2010

The M field development involves one of the largest drilling projects in Saudi Arabia, targeting various carbonate reservoirs, and with an extraordinary amount of extended reach wells (ERWs) requires meeting the expected oil production rate, at the lowest development cost possible. More than two-thirds of the wells fall under the extended reach drilling classification, and the majority of the wells have measured depths (MDs) between 24,000 ft and 31,000 ft. These wells are open hole completions where acid stimulation is highly needed to overcome reservoir damage and improve the well's performance after drilling operations terminate.

The placement of the treatment fluids requires a uniform distribution along the open hole section. Among the different techniques considered, namely bullheading, using the rig drill pipe and coiled tubing (CT), the last one offered the soundest technical and cost option. However, the CT technique alone did not show the ability in reaching the maximum depth in most ERWs of this field. Therefore, the tractor1 was required to provide the significant amount of pull force needed to operate inside these long distances, not seen before in open hole completions.

The first eight well campaigns, using a combination of CT, a hydraulic tractor and friction reducer fluids, have achieved the main objectives. Moreover, a new intervention world record2 was set when the CT bottom-hole assembly (BHA) reached the maximum depth of 28,257 ft inside open hole in two different occasions, to place the stimulation fluids, and to record an injection profile. During the campaign, a total of 41,774 ft accumulated footage has been operated with the tractor, allowing over 3,400 bbls of acid to be placed in direct contact with the formation. As a result, the average injection rate has increased more than tenfold, reducing the drilling requirements for injection wells originally projected.

The job preparation, technology, results, learning curve experience and best practices are discussed in this paper, including proposed operational enhancements. This experience demonstrates the feasibility of the operations with CT required for full zone coverage, yielding optimum water injection rates at the lowest development cost.
A Transient Multi-Phase Flow Simulation using Steady-State Correlations for Coiled-Tubing Applications – New Insights to Old Problems
Authors: Salim P. , Aitken B. , Li J.
Published: July 2010

In the past four decades, several computer programs have been developed to predict steady-state fluid flow in coiled tubing (CT) applications. They are useful in designing the ultimate treatment phase of an intervention but questions remain concerning how their results are affected by the transient nature of the overall job. Any change in the operating conditions on surface or down hole will introduce a transient response. Common treatments such as liquid unloading, under balanced drilling with nitrified fluid, well control, cementing and hole cleaning may never reach a steady state. Only a transient simulation can determine whether a steady state is achieved. If it is not, the simulation can be used by job programmers to develop procedures that will deal with transient phenomena.

This paper describes a transient multi-phase flow simulation that has been developed based on the correlations used to describe steady-state multi-phase flow. The software was extensively validated against data collected on a full scale flow loop, field operations, and other transient software. Several field cases are used to illustrate the transient nature of CT applications and the benefits of using the transient simulation for the operational design, training and job execution.
Fishing Live Perforating Guns Stuck in the Wellhead: The Challenges and Obstacles
Authors: Powers J. L.
Published: July 2010

The Piceance Creek field is a high pressure gas field located in the northwest corner of Colorado and production is from multiple zones at depths in the order of 12,000ft. Standard well construction in the field takes the form of monobore completions with several sets of perforations producing commingled. Typical exploitation techniques involve the perforating, fracturing and cleanup of the lowest zone followed by each successive zone being completed in the same manner by running a composite bridge plug and perforating guns on the same run in the well using electric line methods.

In a recent well completion procedure the same techniques were used however, on one of the later runs, the composite bridge plug preset at a depth of 75ft while going in the hole resulting in a fish at surface straddling the lower part of the tree with the perforating guns still attached to the bridge plug and with high pressure at the wellhead. The only alternative available was to pull out of the e-line rope socket and attempt to fish the guns. Subsequent attempts to fish the guns with wireline techniques designed to shear out the plug setting tool resulted in two additional fish being left in the hole with the upper end straddling the tree and the swab valve. This presented a unique set of circumstances which required extremely careful handling in order to prevent a major well control problem.

In this paper the author will describe the subsequent operations which were performed to remedy the situation and bring the well back to a productive condition and all the challenges associated with it. This included freezing the wellhead to allow removal of the wireline lubricator and the upper part of the wireline fish followed by the installation of additional upper master/swab valves and a fishing operation using coiled tubing. Finally the plug was milled and full access to the well achieved, all without any HSE incident.
A General Coupled Kinetic Adsorption/Precipitation Transport Model for Scale Inhibitor Retention in Porous Media: I. Model Formulation
Authors: Sorbie K. S.
Published: July 2010

The application of scale inhibitors to prevent mineral scale formation downhole is performed routinely in the oil industry in chemical "squeeze" treatments in water producing wells. The retention of scale inhibitor (SI) within the formation is central to a squeeze treatment having a long lifetime. Scale inhibitors are retained within porous media by the two main mechanisms of "adsorption" (Γ) and "precipitation" (∏). There is not complete agreement in the literature about when we should use one mechanistic description or another. Field observations are not sufficiently accurate to distinguish between different retention models/mechanisms and a detailed analysis of a given retention mechanism requires carefully designed laboratory experiments at "field relevant" conditions. In previous experimental and modelling work (SPE 114108), we have demonstrated for static (equilibrium) "apparent adsorption" tests where the system exhibits either (a) adsorption only or (b) it is in the coupled adsorption/precipitation (Γ/∏) regime. Results from an extensive series of "apparent adsorption" experimental measurements were presented for various mineral separates to illustrate these points.

In addition to experiments, we must also have well developed models which can describe these retention processes both for equilibrium Γ/∏ cases and also for kinetic flowing situations where the processes are not at equilibrium. That is, a complete model of SI retention must have (i) an equilibrium description of the coupled Γ/∏ process (SPE 114108); (ii) a kinetic model of coupled Γ/∏ which correctly limits to the equilibrium case (i.e. the kinetics must be consistent with the equilibrium Γ/∏ model as t → ∞); (iii) the full kinetic Γ/∏ model must then be embedded in a transport model for flow through porous media. In this paper, the two tasks in (ii) and (iii) are carried out; a fully cononsistent coupled Γ/∏ is developed and then incorporated into a transport model (a 1D core flood simulator) and a number of example simulations are carried out. In the related Paper II (SPE 130703), the application of this coupled model in a sensitivity study of field squeeze treatments is described.
Material Selection for HP/HT Developments
Authors: Marsh J. , Zvandasara T. , Macgill A. , Kenny J. , Kenny J. P.
Published: July 2010

This publication examines the material selection challenges for offshore High Pressure (HP) and High Temperature (HT) developments, both present and future. The materials are examined from corrosion/cracking, mechanical performance and economic perspectives. The scope of this publication includes subsea equipment and pipelines and is oriented towards subsea developments. It does not include wells, wellheads and trees, though the material selection experience and literature for these have been reviewed. The parameters examined include material resistance to corrosion and cracking from a variety of mechanisms, costs of materials, mechanical strength, retention of mechanical properties at elevated temperatures, and requirements for dealing with forces associated with longitudinal stress such as upheaval buckling. Methodologies for control of temperatures and pressures, such as cooling spools, are also discussed. Different operators have different philosophies towards material selection for HP/HT developments, and the chosen materials range from carbon steel to super duplex stainless steels and nickel alloys. The duplex type stainless steels can offer excellent corrosion resistance and mechanical strength, especially 25% Cr super duplex. However, as temperatures increase, these materials suffer from a steep decline in mechanical strength. Also, the susceptibility to hydrogen induced stress cracking (HISC) can place severe limits on the allowable stress levels. They are also expensive materials with long delivery times. Carbon steel suffers in terms of corrosion resistance, even with corrosion inhibition, as inhibition becomes problematic at elevated temperatures. However, the loss of mechanical strength is less marked, and corrosion can be mitigated by the use of corrosion resistant alloy (CRA) cladding if required. The super modified Martensitic 13% Cr materials have excellent mechanical strength, very good retention of strength even at high temperatures, and low cost. However, they are less resilient in terms of corrosion and cracking resistance and are highly susceptible to HISC. Materials selection is affected by a large number of variables, and by the relative conservatism of the operator. Pipeline and subsea equipment design needs to be flexible in response to these requirements. This becomes especially challenging for future developments, where increased temperatures may require solutions out with those traditionally utilized.
Application of Thermal Recovery and Waterflood to Heavy and Extra-heavy Oil Reservoirs: Analog Knowledge from More Than 120 Clastic Reservoirs
Authors: Lu X. G. , Sun S. Q. , Xu J.
Published: July 2010

More than 120 clastic reservoirs were examined to extract knowledge of application of thermal recovery and waterflood to heavy or extra-heavy oil (less than or equal to 25 °API gravity). The thermal recovery methods discussed include cyclic steam injection, steam flood, in-situ combustion, hot water injection and SAGD. Key parameters of reservoir and fluid properties and production engineering are summarized in detail for reservoirs where one or more of the above EOR methods or waterflood are applied. These include: (1) reservoir characteristics such as sandbody facies type, permeability, porosity, oil saturation, reservoir depth, net pay thickness and net to gross ratio; (2) crude oil properties including API gravity, viscosity, GOR, and FVF; (3) well spacing and ultimate recovery factor; and (4) controls on incremental recovery and ultimate recovery factor.

Controls on ultimate recovery factor for each of the above methods were analyzed. It was found that the basic controls are API gravity, viscosity, reservoir depth, net to gross ratio and well spacing. Thermal recovery methods are mainly applied to reservoirs less than 1100 m deep with crude oil API gravity less than 20°, and typical well spacing of 2–5 ac. The ultimate recovery factor is variable, ranging from 9% to 79%. The most commonly applied thermal recovery methods are cyclic steam injection and steam flood. In-situ combustion has also been successfully applied to some reservoirs with ultimate recovery up to 45%. SAGD technique applied to extra-heavy oil reservoirs is able to improve recovery by 45% to 50% of STOIIP.

Waterflood, which has been widely applied to relatively "light" heavy oil with API gravity greater than 15°, can yield good recovery provided that well spacing is close and throughout injection is sufficient. The secondary recovery method is usually implemented in reservoirs at depths greater than 600 m with well spacing of 6–50 ac. Typical ultimate recovery factors for reservoirs with waterflood ranges from 20% to 45%.
A Study for Redevelopment Trends after Polymer Flooding and Its Field Application in La-sa-xing Oilfield
Authors: Dandan Hu , Wei Tang , Yuwen Chang , Yuanbing Wu , Songhao Hu
Published: July 2010

La-sa-xing oilfield of Daqing in China, which accomplished polymer flooding in quick succession, had now entered into subsequent water flooding stage with yearly increase reserves, so various development contradiction were serious, the effect of conventional measures by water flooding were poor, the potential oil-bearing areas became complicate and were increasingly difficult to be produced.

The paper proposed redevelopment trends after polymer flooding for La-sa-xing oilfield, on the basis of analysis of residual oil distribution and present technologies of EOR after polymer flooding, includes subdivision of layer series of development, well pattern reconstruction, application of horizontal well to producing residual oil in the top of thick layer, using high concentration polymer, comprehensive implementation of various optimization measures and accelerating tertiary oil recovery technique etc.

The paper took the typical block of North 1 Area in Sazhong oilfield as a case study, established detailed reservoir geological model and carried out reservoir numerical simulation, made clear residual oil characteristics and residual oil distribution law after polymer flooding and calculated residual oil potential after polymer flooding. The paper provided a technical strategy and ideology for recombination of layer series of development and combined well spacing of horizontal and vertical wells, and formed a set of post-polymer-flooding's optimization and adjustment technology of vertical well infilling, combination of horizontal and vertical wells and re-polymer-flooding. The paper developed EOR mechanism simulation research for further enhanced recovery optimization. Numerical simulation results of optimization plan indicated that recombination of layer series of development and combined production by using horizontal-vertical wells is a feasible and effective way to improve further development effectiveness and the incremental recovery rate can reach to 5%.
A New BHA's Thoeretical Analysis and Its Successful Applications
Authors: Zhu Xiaohua , Jia Yanjie , Tong Hua
Published: July 2010

This paper presents a new Flexible Bottomhole Assembly (BHA), which is classified as a coupled driven drilling BHA of the power anti-deviation, with the technical superiority of anti-deviation and high ROP. The coupled driven drilling has simultaneously two driving powers: one is from kelly/rotary-table or top-drive; another is from positive downhole motor (PDM). Comparing with the traditional BHA, the new BHA for coupled driven drilling uses a short flexible sub and the appropriate PDC bits with high hydraulic efficiency and high cleaning and cooling capacity, which has rationally distributed the stabilizers' spacing, and has scientifically designed the structure of PDM centralizer's size.

The new BHA used for coupled driven drilling is based on an integrated mechanical model. Through the analysis on the kelly/rotary-table and rotor centrifugal force and their transmission efficiency, the fulcrum role to PDM centralizer and its leverage ratio, the formation force and the geometric anti-deviation force, and the coupling analysis on the above factors, this paper has set up an anti-deviation force's calculation model of the coupled driven drilling, a relationship model between the allowable well-deviation and the critical WOB, a PDC bit gauge length design model, and the structural designed model of PDM centralizer. According to the above integrated model from the view of the whole system, a set of software moduli, a coupled driven drilling BHA mechanical analysis and drilling parameters optimization, is developed to determine the optimum BHA through different formation parameters, drilling parameters, the design requirements to well-deviation and ROP. The new BHA and the matching technology have been in successful application in the part of oil blocks of the Bohai Sea in China, the ROP and well-deviation meet the design requirements, and borehole quality has been improved significantly.
Studies on Fracture-identification of the Igneous Rock Reservoir by Well Logging
Authors: Wang Jianguo , Liu Hongqi , Zhao Xuan
Published: July 2010

This paper mainly focuses on the igneous rock reservoirs of Yingcheng group in Xushen gas field, Daqing. According to plenty of data in field (Core description, conventional logging, FMI, drilling data), this work presents the general development characteristics of core fractures, the response feature of fractures in conventional well logging and FMI, then, an quantitative fracture-identification criteria has been established with the method of curve unit-principle and algorithm.

Compared with the identification results of conventional well logging, FMI shows a significant advantage of fracture characterization in most cases. In some local low-resistivity formations, conventional well logging could serve as an assist method in collating the results of FMI to distinguish the low-resistivity caused by fractures.

Results provided through practices and research in this paper demonstrates that combining FMI with the conventional well logging can lead to a creative and feasible method in identifying fractures in the igneous rock, and shed some light on related researches on other complex reservoirs, such as metamorphic rock, carbonate rock, and tight sand oil gas reservoirs.
Rebuilding Existing Geological Models
Authors: Da Veiga S. , Le Ravalec M.
Published: July 2010

Reservoir models must be fully updateable: when new data become available, the optimal model identified from a first matching process must be modified to honor also these newly collected data. Therefore, a new matching process has to be run starting from the previously matched model.

A facies realization can be modified by varying either facies proportions or facies spatial distributions. The gradual deformation method was introduced to perturb facies distributions (Hu, 2000). This parameterization technique involves a reduced number of parameters and allows for preserving the spatial variability of facies. The resulting changes can be global or localized over a target sub-domain. Local gradual deformation is possible only when applied to the random numbers used to generate the facies realization. Therefore, a prerequisite is to know the random numbers used to produce the existing matched reservoir model.

However, in many cases, especially when the second matching study is performed a significant time after the first one, the random numbers are no longer available. The only known object is the realization describing the spatial distribution of facies. At this point, the problem to be solved consists of identifying random numbers, which allow for generating a stochastic realization close to the one populating the existing geological model. In this paper, we develop different methods for identifying the required random numbers and reconstructing the existing reservoir model. Three cases are considered: the existing model was generated from the Sequential Indicator Simulation algorithm, the truncated Gaussian method, or the pluri-Gaussian method.

The potential of our methodology is illustrated from a few realistic examples. A particular application shows how an object-based facies realization can even be modified, while considering a reconstruction process based upon the truncated Gaussian method.
Research and Application on CO2 and Dissolver Assisted Horizontal Well Steam-injection to Develop Super Heavy Oil
Authors: Hui Li , Jianfang Sun , Junping Shi
Published: July 2010

The Super heavy oil in the Shengli Oilfield is commonly higher than 20×104mPa•s in ground degassing viscosity and deeper than 1000m in depth, and therefore the traditional development techniques such as steam-injection is not effective due to the high steam-injection pressure and little heat radius. The study of flow shows that the super heavy oil is dilatant fluid in porous media, the temperature transform to Newton fluid and the startup pressure gradient are higher than other heavy oil, and the oil drainage radius inferior to the heating radius. In order to improve the injection steam quality and enlarge steam sweep, proposed new technique that combing the steam injection with horizontal well assisted by CO2 and dissolver agent to develop super heavy oil. Lab experiment shows that the high efficient dissolver agent may decrease the viscosity of the heavy oil around the well hole and increase the injection steam quality; meanwhile, the CO2 may enhance the injection steam volume and enlarge the drainage radius effectively. By means of the plug injection of dissolver agent and CO2 assisted horizon well the super heavy oil may be recovered effectively. Moreover, well pattern and distance and the economic-technique limit are studied by numeric simulation. Based on the research, the thermal chemical technique is completely developed, and is very effective for the development of super heavy oil. Moreover, it is of practical significance which has been evidenced and applied in the field such as Zheng 411 block, Tuo 826 block and Shan 113 block with about 5000×104t reserve being developed.
Comparison of Oil Displacement by Water Between Naturally Fractured Reservoir and Vuggy Fractured Reservoir Based on Streamline Technique
Authors: Zhang Xuelei , Hu Yongle , Fan Ru , Li Baozhu , Zhang Shouliang
Published: July 2010

The differences between naturally fractured reservoir and vuggy fractured reservoir are apparent in the aspect of oil displacement by water. In fractured reservoir, the oil displacement by water is the governing recovery mechanism known as capillary imbibition, which allows the recovery of matrix oil that cannot be reached by the externally applied pressure gradients of waterflooding. The main difficulty is the problem of choosing the well pattern. While oil displacements in the vuggy fractured reservoir are dependent on the single well huff-and-puff because of its higher permeability and the nonexistence of the coning, thus its displacement is to inject water by production well, and the mechanism is to complement formation energy and replace rather light oil with water by gravity segregation.

In this paper, the displacement models of naturally fractured reservoir, which are based on streamline numerical simulation method, are developed and discussed on the well pattern, well type, recovery rate, injection rate, injection cycle, etc. The result shows that design of well pattern plays a dominating role in the waterflooding, followed by the optimization of injection rate. While for the vuggy fractured reservoir, injection cyclic deserves prior consideration. The other factors such as critical recovery rate, critical injection rate, injection opportunity, aquifer, etc. are also taken into account in the study, which make the development scenario of vuggy fractured reservoirs more reasonable and economic.

In the end, an example of comparison between Fuyu oilfield(naturally fractured reservoir) and Tarim oilfield (vuggy fractured reservoir) is presented to illustrate the differences of the displacement, and scenarios suited for the reservoir are put into implementation. The study provides an important technical support for similar reservoirs development, especially when confronted with the problem of oil displacement at the secondary recovery stage.
Improved Scale Inhibitor Assay for Sulphonated Polymers in Oilfield Brines
Authors: Graham Gordon M. , Munro Ian , Harvison Nicola , Marshall Kirsty , Kyle Mark
Published: July 2010

Residual scale inhibitor analysis in produced waters, particularly for the sulphonated co-polymers is recognised as an ongoing challenge for many offshore production environments. Although methods have been well documented (e.g. dialysis / hyamine based techniques), there are a number of known difficulties when assaying residual ppm and sub ppm levels of sulphonated polymers where separation of the inhibitor from the brine phase can be a time consuming, labour intensive and often difficult operation. This paper describes a number of recent developments made to enable rapid, accurate, reliable and robust analysis of sulphonated polymers in oilfield brines. The work focuses primarily on those inhibitors which are not readily separated by conventional C18 techniques. This includes more appropriate solid phase extraction, SPE, techniques which demonstrate near 100% retention of sulphonated polymers from brines of different salinities and therefore negate the requirement for dialysis. The work couples these newly developed separation techniques to different assay methods including conventional post separation Hyamine derivitisation as well as direct analysis using appropriate HPLC detection systems. The paper will describe the challenges faced with residual scale inhibitor analysis in oilfield produced waters. Present advances made in the separation and assay of these and other polymeric species include the ability to obtain reliable separation and when required concentration using SPE methods as well as the utility of a variety of different detection systems. Extensive validation tests in a range of high salinity brines demonstrating the limits of detection and repeatability at ppm and sub ppm level for a variety of different polymers including PVS, VS-Co and more conventional polyacrylate as well as phosphorus containing polymers. In short, the results will demonstrate the ability to accurately assay a range of different polymers in different brine systems and mark a significant advancement over previously employed dialysis / Hyamine approaches. The paper will also illustrate the potential application of the techniques for separation and individual assay of different polymers from mixtures, which still represents a significant challenge for produced water analysis in many situations.
The Evolution and Effect of Information Application Technology about Oilfield development of ShengLi
Authors: Yang YaoZhong , Zhou Yongyi , Zhang Mingan , Sun Yeheng
Published: July 2010

The information technology has been the key supporting technology for the oilfield development. The routine information application technology of the oilfield development has obtained tremendous advancements such as structure interpretation, reservoir forecast, and reservoir simulation, etc. It has played a pioneering role in the engineering of EOR, detailed reservoir modeling, thermal injection of heavy oil reservoir, and chemical flooding. At present, the target of information application in the oilfield has been in the stage of data sharing in the whole field, and integral application and the modeling of the tracking application. In this paper, we propose some ideas to enhance the development performance for the mature and very mature oilfield, and indicate the necessity of technical development and the future direction for the development of information technology, especially in the field of conglomerate, shoal and bar sandstone reservoir, and the geological modeling and tertiary recovery advancement. Moreover, we also reviewed the applications on the detailed geological modeling, foaming flooding and in-situ combustion, and integrated reservoir description that is facies constrained, and the significance for the EOR of mature oilfield.
The Effect of Sulfide Scavengers on Scaling Tendency and Scale Inhibitor Performance
Authors: Williams Helen , Dyer Sarah , Bezerra Maria Carmen , Graham Gordon , Wright Rob
Published: July 2010

Use of continually injected sulfide scavengers has become more widespread in recent years with increased requirement for sulfide scavengers to be injected directly into water producing streams. The chemicals used, especially those based on common triazine chemistries, impact the pH of the produced water, leading to much more severe scaling tendency and impaired scale inhibitor performance. We have found this to be the case with both water-soluble and oil-soluble scavengers, although the effect is less severe with oil-soluble chemicals. The paper describes the results from a range of tests to examine the performance of a number of different scale inhibitor chemical types in the presence of different scavenger chemicals and different brine systems. We also describe the results of scale prediction modelling, as compared to the lab results and show methodologies which improve the reliability of the scale prediction programmes.