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Results
Flow of Hydrophobically Modified Water-Soluble Polymers in Porous Media: Controlled Resistance Factors vs. Flow-Induced Gelation in the Semidilute Regime
Dupuis, Guillaume (IPREM-EPCP and IFP Energies nouvelles) | Rousseau, David (IFP Energies nouvelles) | Tabary, René (IFP Energies nouvelles) | Grassl, Bruno (IPREM-EPCP and IFP Energies nouvelles)
Summary The associative properties of hydrophobically modified water soluble polymers (HMWSPs) are attractive for improved oil recovery (IOR) because of both their enhanced thickening capability, compared with classical water-soluble polymers (for mobility-control applications), and their permeability-reduction, or plugging, ability (for well-treatment applications). In previous works, we have studied the injectivity of HMWSP made of sulfonated polyacrylamide backbones and alkyl side chains in the dilute regime and have shown, in particular, that it was largely governed by adsorption. In this paper, we report new experimental data on the injectivity of the same class of HMWSP solutions in the semidilute regime. From membrane filtration tests at imposed flow rate, we have first observed the formation of a filter cake made of HMWSP physical gel, which remained largely permeable to polymers. Our observations are compatible with the creation of channels within the gel. This leads to a gel-filtration process, entailing modifications of the solution's viscosimetric properties, which can be explained by a rearrangement of the intra- and interchain hydrophobic bonds in the solution. The second part of our work consisted of injectivity tests in model granular packs. We have performed comparative experiments in porous media with variable permeabilities, but at the same shear rate in the pore throats. Results show that, above a critical permeability k, or a critical pore-throat radius , HMWSP injection led to stable resistance factors, with values close to the solution's viscosity, and that, at less than k or the very high resistance factors observed suggest that flow-induced gelation of the HMWSP takes place. Furthermore, resistance factors measured over the core internal sections are compatible with an in-depth formation of the gel. These insights could be of use for designing HMWSP better suited to mobility-control operations and for tuning HMWSP-injection conditions for profile/conformance-control operations.
- Asia > China (1.00)
- Europe (0.68)
- North America > United States > Texas (0.46)
- North America > Canada > Alberta (0.28)
- Asia > China > Henan > North China Basin > Zhongyuan Field (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)
Abstract From the point-of-view of a solutions provider the wastewater treatment should be straight forward: once given the composition of the feed and the required composition of the effluent, today's technology allows formulating a set of solutions which best meets the operator's and the regulatory criteria. The problem with wastewater in the unconventional gas exploration and production operations is that there are large volumes to be handled and treated. To add complexity, composition varies for the same well in time and varies even more from area to area of development. Also, the requirements for the cleaned fluid vary from operator to operator and by region. Moreover, management of the water based fluids is under the pressure and scrutiny of various regulating agencies: public, privately, or governmentally run. All these constraints make the vetting of treatment methods and technologies to be a very dynamic and intensive process. Our findings during the process of formulating a set of solutions shows that a deep understanding of the problems, combined with close collaboration with the operators and regulators along with solid basic engineering practices are the key to success. Our experience would benefit the new developments in other unconventional exploration and production area in Asia by showing the steps that were undertaken to insure solutions are up to the highest standards. The process of finding and testing various waste water treatment technologies to formulate a flexible comprehensive set of methods will be described. Laboratory results of various samples of water will be presented as well as the challenges that were overcome for obtaining consistent, reliable analytical data. The oilfield tough requirement presented to new technologies translates as: rugged, flexible, mobile, and low cost.
- Water & Waste Management > Water Management > Lifecycle > Treatment (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Abstract A new solution for determining the amount of mud loss during drilling operation in a fractured reservoir having a regular two- or three-dimensional radial fractured network with the novel inclusion of a convective transport of filtrate in the matrix is presented. Convective-dispersive filtrate transport along the network is modeled in which drilling mud can be filtered in existing matrix. The filter cake effect at the fracture-matrix interface in the network is simulated by means of an empirically decaying filter rate equation. The numerical solution is used in this study. The consistency of numerical solution is checked and the best situation is considered. The sensitivity analysis on all parameters in the model has been done and the effect of each parameters such as wellbore loss rate, reservoir thickness, fracture opening size, matrix porosity, matrix permeability and dispersivity, on the amount of filtration are inversitaged. By means of developed model, the amount of mud filtration can be plotted against position in different fractured network configurations for different wellbore conditions, reservoir properties and reservoir geometries at different times. The position in the fracture network at which the curve of concentration reaches zero can be considered to represent skin radius caused by drilling operation. This radius can be used for determining the acid volume which is needed for acidizing operation and accurate well-log interpretation.
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (21 more...)
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Formation Damage (1.00)
- Well Drilling > Drilling Operations (1.00)
- (8 more...)
Abstract Manganese tetraoxide is used as a weighting material in drilling deep wells (> 90 lb/ft). Removal of the filter cake that contains Mn3O4 is a difficult task. This is mainly because Mn3O4 is a strong oxidizing agent. Extensive lab work was done to: 1) study the reaction of glycolic acid with Mn3O4 particles (D50 =1 μm) as a function of time at 190°F in a batch reactor, 2) examine the solubility of the filter cake using a modified HP/HT filter press, 3) determine the compatibility and thermal stability of cleaning fluids with α-amylase using an HP/HT visual cell, 4) characterize the filter cake using computer tomography (CT), and 5) assess the retained permeability of limestone and sandstone cores. The results following the removal of the filter cake showed that 4 wt% glycolic acid (4 g Mn3O4 to 200 ml acid solution) dissolved 75 wt% of Mn3O4 particles at 190°F. Glycolic acid (5 wt%) had a removal efficiency of 85 to 90% of manganese tetraoxide-based filter cake after 20 hrs soaking time. The retained permeability was 100% for the Indiana limestone core and 125% for the Berea sandstone cores. CT results showed that glycolic acid was able to stimulate the cores and no formation damage was observed.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.49)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.49)
- Europe > Norway > North Sea > Northern North Sea > East Shetland Basin > PL 050 > Block 34/10 > Gullfaks Field > Statfjord Group (0.99)
- Europe > Norway > North Sea > Northern North Sea > East Shetland Basin > PL 050 > Block 34/10 > Gullfaks Field > Lunde Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > East Shetland Basin > PL 050 > Block 34/10 > Gullfaks Field > Lista Formation (0.99)
- (2 more...)
Biodiesel-based Drilling Fluids
Wang, Meishan (Senior Engineer, CNPC Technical Service Company) | Sun, Mingbo (Professor, China University of Petroleum(Western China)) | Shang, Hongyan (Professor, China University of Petroleum(Western China)) | Fan, Songlin (Senior Engineer, Petroleum Engineering Research Institute of Dagang Oilfield Company(CNPC)) | Liu, Meiquan (Engineer, CNPC Technical Service Company) | Liu, Fupeng (Engineer, Petroleum Engineering Research Institute of Dagang Oilfield Company(CNPC))
Abstract The rheological properties of biodiese and white oil were compared at normal temperature and high temperature in this paper. The ability of biodiesel to inhibit shale expansion was investigated. The results showed that the rheological properties of biodiese were better than white oil. Biodiese also showed better resistance to high temperature and shale expansion. Organo- lignite and vegetable pitch were used to reduce the filtration in biodiesel-based drilling fluids system. The optimum formulation of biodiesel-based drilling fluids was determined by experiments. In order to simulate the contamination of calcium and dry soil, CaSO4·2H2O and sodium-based bentonite were added to the system, and the experimental results showed that the tolerance of biodiesel-based drilling fluids to the contamination of calcium and dry soil is desirable.
Abstract Hydrochloric acid, organic acid, or a mixture of these acids is used to remove filter cake, which consists mainly of calcium carbonate. However, the use of these acids in horizontal and deep wells has some major disadvantages, including high and uncontrolled reaction rate and corrosion to well tubular. To overcome these problems, chelating agents are used in oil and gas wells. Extensive lab studies were done to determine: 1) the compatibility of various chelates with α-amylase at different pH values, 2) the optimum pH that should be used to remove filter cake, 3) the efficiency of filter cake removal using a modified HPHT filter press, 4) the return permeability of sandstone and limestone cores, and 5) assess the potential of formation damage using a computer tomography scanner. All of these tests were conducted at temperatures up to 225°F. The results obtained showed that chelate solutions, GLDA (pH of 3.3 - 13) and HEDTA (pH 4 and 7) were incompatible with α-amylase solutions over a wide range of temperatures. At high pH, various chelates had removal efficiency of 40% and retained permeability of 30%, which indicated formation damage. To solve this problem, 20 wt% of the chelating agents at low pH (3.3 - 4) were used to remove the filter cake without the enzyme stage. The results obtained showed that the retained permeability increased to 85% for limestone cores and 110% for sandstone cores. The removal efficiency of the filter cake was 100% for limestone and sandstone cores. CT results showed that no formation damage was observed when using chelating agents as a breaker to remove the filter cake.
- Europe (1.00)
- North America > United States > Texas (0.69)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.68)
Abstract A new stochastic model for suspension/colloidal transport in porous media is developed accounting for the retention mechanism of size exclusion. The medium is modelled by two-pore-size network with triangular pore shape. The micro scale model is established using distribution functions and the macro scale equation system is generalised. The analytical solution is obtained for deep bed filtration of distributed particles in bimodal media. Comparison between model prediction and experimental data shows good agreement, which validates the proposed model.
- Europe (0.68)
- North America > United States > California (0.28)
- Water & Waste Management > Water Management (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Information Technology > Communications > Networks (0.51)
- Information Technology > Modeling & Simulation (0.50)
Nanotechnology to Improve Sealing Ability of Drilling Fluids for Shale with Micro-cracks During Drilling
Li, Gongrang (Shengli Drilling Technology Institute, Sinopec) | Zhang, Jinghui (Shengli Drilling Technology Institute, Sinopec) | Zhao, Huaizhen (Shengli Drilling Technology Institute, Sinopec) | Hou, Yegui (Shengli Drilling Technology Institute, Sinopec)
Abstract Shale wellbore instability is a complex difficulty encountered during drilling all over the world. And the most important factor to determine shale wellbore stability is the distribution and expansion of micro-cracks in hard brittle shale. The usual ways to avoid collapse of shale wellbore mainly include increasing the inhibition of drilling fluid filtrate, improving the quality of drilling fluid cake and sealing the pores and micro-cracks near the wellbore surface. However, the shale wellbore collapsing difficulty was not solved effectively in field, which mainly because that the effective sealing is difficult to achieved in the case of crack width is unknown. Furthermore the drilling fluid cake is more difficult to be formed on shale sections because of the filtration rate is very low compared to sand sections under the same differential pressure. A kind of nanomaterial has been applied to achieve a sealing film rapidly, improve the sealing strength of the cake and reduce the mud cake permeability, which have been verified through the use of sound wave propagation speed, the pressure transmission experiment and cake strength. The technology had also been used in Well Exp1, which exhibited a smooth borehole and the borehole enlargement rate was below the wells in the same block.
- Europe (0.29)
- North America > United States (0.28)
Abstract Water-based drilling fluids consisting of xanthan gum, starch, sized calcium carbonate and salt particles have been used to drill horizontal wells. Available chemical methods of removing filter cake like mineral acids, esters, oxidizers, and chelating agents are limited at certain conditions. Drilling fluid was designed based on calcium carbonate particles and an ester of lactic acid. The objective of the latter is to remove calcium carbonate once the drilling operation is complete and there is a need to remove the filter cake. Extensive lab work was done to: 1) determine thermal stability of the drilling fluid (70-72 pcf) for 24 hrs, 2) characterize the filter cake using computer tomography, 3) assess potential formation damage for different rock types (limestone and sandstone) using a modified HPHT filter press, and 4) determine the removal efficiency of the filter cake and the return permeability. The results obtained showed that the drill-in fluid has stable rheological properties up to 250°F over 24 hrs. A CT scan showed that the filter cake contained two layers, one layer close to the rock surface, which contained a mixture of calcium carbonate and acid-precursor, and one layer close to the drilling fluid that contained a mixture of XC-polymer and starch. The polymer layer was removed by using 10% solution of alpha amylase. The rest of the filter cake was removed by lactic acid that was produced from the hydrolysis of the ester. The removal efficiency of the filter cake was nearly 100% and the return permeability was about 100%, when using a ratio of polylactic acid to calcium carbonate 3 to 1. The decrease in the CT number of the core after the removal process indicated that the filter cake was completely removed and no formation damage occurred. This paper will discuss the development of this new drilling fluid and will give recommendations for field applications.
- Europe (1.00)
- North America > United States > Texas (0.28)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Bioplastics (0.61)
Study of Particle Straining Effect on Produced Water Management and Injectivity Enhancement
Aji, K.. (Australian School of Petroleum, The University of Adelaide, Australia) | You, Z.. (Australian School of Petroleum, The University of Adelaide, Australia) | Badalyan, A.. (Australian School of Petroleum, The University of Adelaide, Australia) | Bedrikovetsky, P.. (Australian School of Petroleum, The University of Adelaide, Australia)
Abstract Theoretical and laboratory studies are performed aiming at the development of a predictive model for transport and retention of particles from produced water and crude oil/gas based on grain size distribution and particle sizes only. The particle capture by straining is thoroughly investigated. In the laboratory, injections of different sized particles suspended in fluid with different salinity and pH values have been carried out into the newly designed porous media holder with single-layer grains and into the column packed engineering porous media. The retained particles are filmed using microscope; their breakthrough concentrations are measured by particle counter. A new mathematical model accounting for pore connectivity and triangular pore throat shape is derived and applied to the experimental conditions. Agreement between test data and modelling results supports application of the model to the evaluation of straining effect on the produced water management and injectivity enhancement.
- North America > United States (0.93)
- Europe (0.69)
- Water & Waste Management > Water Management (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Production and Well Operations > Well Operations and Optimization > Produced water management and control (1.00)
- Health, Safety, Environment & Sustainability > Environment > Water use, produced water discharge and disposal (1.00)
- Information Technology > Modeling & Simulation (0.54)
- Information Technology > Data Science (0.34)