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Collaborating Authors
Water Management
Abstract In scale inhibitor squeeze treatments, precipitation of the inhibitor within the formation can lead to extended squeeze lifetimes. However, such processes also have the potential to cause formation damage unless they are carefully designed and controlled. The formation of a partially soluble inhibitor/metal complex within a reservoir is the objective for almost all precipitation squeeze packages. However, historically there are numerous ways this is achieved almost all of which require a limited operational window to be deployed successfully. In this paper, we describe the development of a novel dual chelant system which provides a method for controlling both the "wanted" and "unwanted" precipitation of the scale inhibitor package within the formation. The highly tunable nature of the system allows for ease of pumping at more extreme conditions (higher and low temperatures, calcium levels etc.) than have previously been possible. By using the dual chelant mechanism described in this paper, a package can be tuned to precipitate within a certain time frame both at low and high temperatures in brines with varying degrees of salinity and hardness. The scale inhibitor (SI) itself is a chelant or ligand for divalent ions present (mainly Ca) and this is denoted L2 and the second chelant, L1, is added to the system at certain design concentrations, as explained in the paper. In many situations, the high divalent metal ion content of a produced brine, or formation water can limit the successful pumping of a scale inhibitor due to high levels of calcium, for example. Under these conditions the dual chelant mechanism can also be deployed to prevent scale inhibitor phase separation. This paper discloses the theory of how the dual chelant mechanism works using computer modeling and the subsequent confirmation of the simulations by laboratory testing. The importance of the pKa of the SI (L2) and the added chelant, L1, and the relative metal binding constant interactions between L1/ L2 and Ca are explained and investigated. The comparison of the dual chelant mechanism versus conventional packages is demonstrated by core flood experiments. The dual chelant mechanism gives a clear improvement in squeeze lifetime and controllability and provides a platform for the development of many types of controlled solubility scale inhibitor treatment.
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Abstract In a deepwater West African field the relatively small number of high-cost, highly productive wells, coupled with a high barium sulfate scaling tendency (upon waterflood breakthrough of injected seawater) requires effective scale management along with removal of near-wellbore damage in order to achieve high hydrocarbon recovery. The nature of the well completion strategy in the field (frac packs for sand control) had resulted in some wells with higher than expected skin values due to drilling fluid losses, residual frac gel, fluid loss agents, and fines mobilization within the frac packs. The paper will present how the challenges of managing impaired completions and inorganic scale forced innovation in terms of when to apply both stimulation and scale inhibitor packages to deep water wells. This paper will outline a novel process for non-conventional batch chemical applications where bullhead stimulation treatments have been displaced deep into the formation (>20ft) using a scale inhibitor overflush. Not only does this benefit the stimulation by displacing the spent acid and reagents away from the immediate wellbore area, but the combined treatment provides a cost savings with a single mobilization for the combined treatment. The paper will describe the laboratory testing that was performed to qualify the treatments. The five field treatments that were performed demonstrate how these coupled applications have proven very effective at both well stimulation/skin reduction and scale inhibitor placement prior to and after seawater breakthrough. The term "squimulation" is used by the local operations team to describe this simultaneous squeeze and stimulation process. Many similar fields are currently being developed in the Campos basin, Gulf of Mexico, and West Africa, and this paper is a good example of best-practice sharing from another oil basin.
- Africa (1.00)
- Europe > United Kingdom > North Sea (0.28)
- North America > United States > Texas (0.28)
- Geology > Mineral > Silicate (0.94)
- Geology > Geological Subdiscipline (0.93)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.68)
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment (0.46)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Texas > East Texas Salt Basin > Alba Field (0.99)
- Europe > United Kingdom > North Sea > North Sea Basin (0.99)
- Europe > Norway > North Sea > North Sea Basin (0.99)
- (5 more...)
Abstract Silicate scaling is often induced by alkaline surfactant polymer (ASP) flooding in sandstone reservoirs. Scaling of the production tubing, rod or progressive cavity pumps, and other surface equipment causes frequent workovers, resulting in increased costs to the operator and non-productive time. The formation of silicate scale is complicated by its dependence on multiple factors including pH, silica concentration, and magnesium concentration, which vary as the flood progresses (Gill 1998). These factors affect silicate scaling tendency, and consequently, severity of the problem. Silicate scale inhibitors have been developed to mitigate problems in oilfields afflicted with silicate scaling due to ASP flooding (Qing et al. 2002). A new test method using an optical scanning device was developed to better characterize inhibition and dispersant qualities of the developed products on silicate scale in brine under static conditions. The advantage of this method is more comprehensive data generated by multiple-point measurements. Scaling reactions are more easily modified and differentiated. Water chemistries from several wells in an ASP-flooded field in Southern Alberta with known silicate scaling issues defined the tested synthetic brine. By allowing the mixed synthetic brine to react before adding inhibitor, the effect of delayed chemical injection may be studied. Performance of the tested inhibitor was significantly reduced by slight injection delay and may be attributable to the discrepancy between laboratory performance data and failures observed in the field. It is proposed that the performance of silicate scale inhibitors may be improved when applied by squeeze, where the inhibitor can inhibit silica polymerization within the formation and may provide substantial improvement over conventional continuous down-hole injection, where inhibitor reaches the water after the perforations.
- North America > United States (1.00)
- Asia (0.94)
- North America > Canada > Alberta (0.55)
- Geology > Mineral > Silicate (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.69)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.94)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)
Successful Deployment of a Green Multifunctional Scale Inhibitor, A Case Study From the Rockies
Spicka, K. J. (Nalco, an Ecolab Company) | Hirst, M. C. (Nalco, an Ecolab Company) | Hochhalter, G. E. (Nalco, an Ecolab Company) | Steppler, D. J. (Nalco, an Ecolab Company) | Haag, J. T. (Nalco, an Ecolab Company)
Abstract This paper will highlight the effectiveness of a novel, environmentally friendly multifunctional polymeric scale inhibitor that inhibits carbonate and sulfate scales as well as halite. The deposition of halite in the oilfield can present a challenge for operators in fields with high TDS brines. The large amounts of halite that can deposit in a short amount of time can lead to reduced production as well as a costly and logistically cumbersome remediation. A customer was controlling halite deposition by injecting a low salinity water source to dilute/dissolve the deposits. However, this remedial solution also presented an additional problem to the customer as the injection of the fresh water source led to calcium carbonate deposition due to brine incompatibility. This paper will present laboratory test results which highlight the effectiveness of this novel multifunctional scale inhibitor against halite, carbonate and sulfate scales. These results will be compared to traditional scale inhibitors. Following laboratory testing, this environmentally acceptable scale inhibitor product was deployed in high TDS wells where halite deposition was occurring. This paper will also demonstrate the successful implementation of the product, which provided calcium carbonate inhibition and a reduction in the volume of fresh water needed for control of halite deposition. This reduction in water consumption led to significant cost savings for the customer. The value this case study brings to the industry is an overview of the challenges halite and associated scales present to hydrocarbon recovery and the development/implementation of a multifunctional molecule rather than a chemical blend for scale control. Results of this paper have implications for other fields across the world where halite scale is a flow assurance challenge.
- North America > United States > Texas (0.29)
- North America > United States > Louisiana (0.28)
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Phosphorus Functionalised Polymeric Scale Inhibitors, Further Developments and Field Deployment
Todd, M. J. (Clariant Oil Services) | Thornton, A. R. (Clariant Oil Services) | Wylde, J.. (Clariant Oil Services) | Strachan, C. J. (Clariant Oil Services) | Moir, G.. (Clariant Oil Services) | Goulding, J. R. (J. Goulding Consultancy)
Abstract As the oil and gas industry strives to replace ageing, environmentally undesirable scale inhibitors there is an ever increasing use of polymeric inhibitors. Incorporation of phosphorus functionality into a polymer backbone has been shown to improve inhibition efficiency, enhance adsorption characteristics and allow the polymer concentration to be analysed by elemental phosphorus. It is known that some phosphorus tagged polymers can be problematic to analyse in oil field brines as they typically have a low phosphorus content which is difficult to determine from the background. The development of novel phosphorus functionalised polymeric scale inhibitors was previously described (SPE 130733). This paper follows the development of the inhibitor class. Utilising extensive laboratory testing the interactive nature of the scale inhibitors and reservoir lithology was studied. These novel phosphorus functionalised inhibitors were compared to a number of other available P-containing polymers. Following successful development, one of the phosphorus functionalised polymeric inhibitors was subject to sequential field-trial in a harsh BaSO4 scaling, highly naturally fractured North Sea carbonate reservoir. The phosphorus functionalised inhibitor provided improved performance compared to the incumbent product. Following the successful deployment in a carbonate reservoir the novel inhibitor class was also deployed in a number of North Sea sandstone reservoirs and one field wide case study is reported with details on the innovative management and implementation strategy presented. Focus has been given to the application of these products and a detailed analysis of field proven benefits given. This paper concludes with a detailed comparison of these Phosphorus functionalized scale inhibitors with the incumbent products they have replaced in the case histories described. The benefits that these novel, innovative products have given to the operator are described along with a technical synopsis of incremental performance benefits.
- Research Report > New Finding (0.46)
- Overview > Innovation (0.34)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Effective Laboratory Simulation of Scale Inhibitor Squeeze Treatments -Core to Field II
Graham, Gordon (Scaled Solutions Limited) | Stalker, Robert (Scaled Solutions Limited) | Hoeth, Laurien Wichers (Scaled Solutions Limited) | Kidd, Samuel L. (Scaled Solutions Limited) | Lagarde, Frederic (Total) | Orski, Karine (Total)
Abstract Coreflood experiments are an integral part of the selection and optimisation of scale inhibitor treatments, providing information on formation damage, inhibitor return profiles and dynamic retention isotherms. However, significant discrepancies can arise between core and field due to test methodology. In a previous paper (SPE131131), we demonstrated that test methodology can have significant consequences for the comparative inhibitor returns, particularly with respect to oversaturation. The paper showed that many of the limitations can often be overcome through appropriate simulation techniques. We extend this work and present further results of laboratory core flood tests specifically designed to examine the effect of core flood test methodology on the derived return isotherm, particularly examining the effect of injection of different volumes of main treatment ranging from ~ 0.5 pore volume (under saturated) to 20 pore volumes (over saturated) for a series of different generic scale inhibitors. This work clearly identifies the significant detrimental artefact of inhibitor oversaturation. This paper differs from the previous works (SPE 131131) in that examples are shown where core flood oversaturation can not be overcome with effective isotherm derivation and upscaling. This is due to significant differences in the isotherms derived as a function of the level of oversaturation with main treatment chemical. This paper will also demonstrate the impact of low concentrations of impurities and or the use of chemical blends when testing with poorly designed core flood tests. Thus the paper directly addresses the procedures involved in core flooding, recommends approaches and test protocols which allow more appropriate product ranking and allow improved simulation from core to field.
- North America > United States > Texas (0.46)
- North America > United States > Louisiana (0.46)
- Europe > United Kingdom > North Sea (0.28)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.84)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 29/5b > Elgin Franklin Field > Fulmar Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 22/30c > Elgin Franklin Field > Fulmar Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 22/30b > Elgin Franklin Field > Fulmar Formation (0.99)
- (7 more...)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
Understanding the Co-deposition of Calcium Sulphate and Barium Sulphate and Developing Environmental Acceptable Scale Inhibitors Applied in HTHP Wells
Liu, Xuan (aSouth West Petroleum University) | Chen, Tao (bChampion Technologies) | Chen, Ping (bChampion Technologies) | Montgomerie, Harry (bChampion Technologies) | Hagen, Thomas (bChampion Technologies) | Wang, Bin (aSouth West Petroleum University) | Yang, Xu (aSouth West Petroleum University)
Abstract Calcium sulphate and barium sulphate are two major scales experienced in the oil and gas fields, especially when sea water breakthrough in the waterflood supported HTHP wells. Normally, studies have been focused on a single scale component. Seldom studies have focused on the co-deposition of calcium sulphate and barium sulphate. The importance of interference between calcium sulphate and barium sulphate deposition in the field, especially for the HTHP wells, has been ignored. In this paper, the interference between calcium sulphate and barium sulphate deposition has been studied based on a field case in the North Sea. The mechanisms of co-deposition have been addressed using both scale prediction and laboratory tests. Environmentally acceptable scale inhibitors have also been developed. The scaling tendency and mass deposition of calcium sulphate and barium sulphate have been predicted with sea water breakthrough at different levels. The difference between calcium sulphate and barium sulphate, and the consequences of both types of scale deposition are discussed. Dynamic scale loop tests have been carried out. It demonstrated that a small amount of barium sulphate deposit substantially accelerates the co-deposition of barium sulphate and calcium sulphate. Linked to the scale prediction, the mechanism of co-deposition of calcium sulphate and barium sulphate has been addressed. Several scale inhibitors, including phosphonate and polymer based inhibitors, along with an amine based polymer have been tested under the worst case scaling condition. Environmentally acceptable scale inhibitors have been developed and are suitable for squeeze application. This paper will give a comprehensive study of co-deposition of calcium sulphate and barium sulphate, including scale prediction, laboratory evaluation, mechanism discussion and inhibitor selection. It will contribute to understand calcium sulphate and barium sulphate scale deposition in HTHP wells and find effective inhibitors for field application.
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Understanding Mechanisms of Scale inhibition Using Newly Developed Test Method and Developing Synergistic Combined Scale Inhibitors
Liu, Xuan (aSouth West Petroleum University) | Chen, Tao (bChampion Technologies) | Chen, Ping (bChampion Technologies) | Montgomerie, Harry (bChampion Technologies) | Hagen, Thomas (bChampion Technologies) | Wang, Bin (aSouth West Petroleum University) | Yang, Xu (aSouth West Petroleum University)
Abstract Static jar and dynamic loop tests are two major test methods used in the oilfield scale industry to evaluate the performance of scale inhibitors. The minimum inhibitor concentration (MIC) under the test conditions can be determined, but with a certain amount of assumptions and theoretical analysis of the mechanism of scale inhibition, especially for scale inhibitors with dispersive effects. Unlike these traditional test methods, a newly developed test method, using an ultrasonic technique along with turbidity measurement, has been used to evaluate scale inhibitors and understand the inhibition mechanisms. In comparison with traditional test methods, this test method provides a quick and effective way to understand the scale inhibitors, including the effect of scale inhibitors on the induction, nucleation and growth stages of scale formation, and also the dispersion functions of scale inhibitors. Several typical commercial scale inhibitors, including phosphonate and polymer based chemistries have been tested using this newly developed test method. Different scale inhibitors demonstrated different inhibition mechanisms and will be addressed in detail in this paper. Results showed a polymer based scale inhibitor has good inhibition on the induction time of scale formation and a phosphoric based scale inhibitor showed a major dispersive effect on scale inhibition. The combined formulation based on these two inhibitors has been evaluated and a synergistic effect was observed and later confirmed by both the traditional static jar test and dynamic loop test, where the mixture of 75% polymer based scale inhibitor and 25% phosphoric based scale inhibitor showed much better performance than both neat scale inhibitors. In this paper, this newly developed test method will be introduced in detail and the benefits and limitations will also be discussed. By understanding the mechanism of the scale inhibitors, this technique might provide a new and alternative route of developing and formulating scale inhibitors.
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
Development of Test Method and Environmentally Acceptable Inhibitors for Zinc Sulfide Deposited in Oil and Gas Fields
Wang, Bin (South West Petroleum University) | Chen, Tao (Champion Technologies) | Chen, Ping (Champion Technologies) | Montgomerie, Harry (Champion Technologies) | Hagen, Thomas (Champion Technologies) | Liu, Xuan (South West Petroleum University) | Yang, Xu (South West Petroleum University)
Abstract Zinc sulfide (ZnS) is an exotic scale formed in the oil and gas fields, especially in HT/HP wells. It is relatively difficult to test ZnS formation and inhibition in the laboratory using traditional static jar and dynamic loop tests due to the oxidization during the test and its naturally ‘soft’ scale characteristic. Limited studies have been focused on ZnS and the detailed inhibition mechanisms are still unknown. In this paper, a newly developed stress test method has been applied to evaluate the performance and mechanisms of ZnS inhibition. Compared with the traditional test methods, it shows good reproducibility and provides a quick and effective way to evaluate the performance of inhibitors and information to understand the mechanisms of inhibition. More than 15 typical scale inhibitors, representing several different types, have been tested using this newly developed method. The ZnS scale inhibitors were classified as three types based on the inhibition mechanisms from this work: Type 1: Dispersion and nucleation inhibitors. These scale inhibitors showed nucleation and growth inhibition effect at low concentrations of sulfide and dispersion effect at high concentrations of sulfide. Type 2: Nucleation and growth scale inhibitors. These scale inhibitors inhibit nucleation and growth of ZnS formation, where the test can be stressed further. Type 3: Scale inhibitors with poor performance on ZnS inhibition. The turbidity and stress curve did not change obviously in the presence of scale inhibitors. This paper will give a comprehensive study of ZnS formation and inhibition, including scale prediction, development of test method and inhibitors, insight into the mechanism of ZnS inhibition and identification of environmentally acceptable inhibitors.
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 29/5b > Elgin Franklin Field > Fulmar Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 22/30c > Elgin Franklin Field > Fulmar Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Central Graben > Block 22/30b > Elgin Franklin Field > Fulmar Formation (0.99)
Abstract Addition of scale inhibitor into the reservoir allowing its adsorption and or precipitation into the rock formation and subsequent release during production is one of the most common treatments used in oil field industries to avoid scale formation. Little is known however about the surface chemistry of scale inhibitor interaction with the various mineral phases present in subsea rock formations. This paper presents some recent work investigating these interactions with the spectroscopic techniques commonly employed in surface chemistry. Uptake of NTMP, a model scale inhibitor, by kaolin, halloysite and montmorillonite has been monitored by liquid phase P NMR spectroscopy. P NMR has also been used to follow the release of scale inhibitor during desorption experiments. The adsorbed inhibitor has been detected directly and quantified with X-ray photoelectron spectroscopy (XPS). XPS combined with argon ion etching has also been able to distinguish between inhibitor adsorbed onto the external surface of the clays and occluded into the interlayer spacing.
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Europe > United Kingdom > North Sea > North Sea Basin (0.99)
- Europe > Norway > North Sea > North Sea Basin (0.99)
- Europe > Netherlands > North Sea > North Sea Basin (0.99)
- Europe > Denmark > North Sea > North Sea Basin (0.99)