In underbalanced drilling ubd, even if the pressure gradient is generally negative between the wellbore and the reservoir, drilling fluid invasion into the reservoir can still occur due to the presence of. Drilling fluids serve to balance formation pressures while drilling to ensure wellbore stability. If cavings occur, utilise good hole cleaning practices. The influence of individual clay minerals on formation damage. A special concentration was made to inspect and characterize the phenomena of various cuttinginduced damage promoted in the material drilling. Jul 07, 2017 drilling and drillin fluids can cause damage to the reservoir section of a borehole. Formation damage due to drilling and fracturing fluids and its. The work focused on the study of the influence of cutting parameters on the distribution and extent of hole damage formation.
Jun 07, 2016 formation damage presentation group f 1. This is an inherent problem in sandstone that contains watersensitive clays. Stressinduced formation damage, sanding tendency, and prediction chapter 21. Formation damage caused during the drilling process and during the completion which is influenced by the drilling fluid.
Analysis of formation damage during the drilling of. A simple nmr methodology for evaluating filter cake. Two elements of drillinginduced damage will be reported in this paper. Drilling induced formation damage stress and temperature. This paper presents an integrated approach, combining a nearwellbore modeling with laboratory experiments for data acquisition as input for the model, to evaluate the performance of oil and gas wells after drillinginduced formation damage. Acid stimulation ebooks society of petroleum engineers. Common formation damage mechanisms bennion, 1999, bennion and thomas, 1991, bishop, 1997 4. It is shown that mechanical agitation provided by the acoustic waves effectively resuspends the paraffin and restores the effective permeability of the core to oil to its. Pdf a comparison of underbalanced and overbalanced drilling. A comparison of underbalanced and overbalanced drilling. The stage 2 experiment described a comprehensive investigation on the machinability effects of cd parameters, drill diameters and chips formation on the same drillinginduced damage on an optimal specimen of 19hfrp and mtm 441cfrp composite laminates, using the same specimen dimensions, drills, drilling parameters and condition. Evaluate the formationdamage potential of drilling fluids.
When a freshwater filtrate invades the reservoir rock, it will cause the clay to swell and thus reduce or totally block the throat areas. Do not plan a reduction in mud weight after exposing shale. Mud design criteria that call for maximizing penetration rate and maintaining wellbore stability often overlook the formation damage potential of drilling mud. In a different context, formation damage is defined as the impairment to reservoir reduced production caused by wellbore fluids used during drilling completion and workover operations. Tensional failure can occur where tangential stresses are lowest, in the direction of shmax, with the formation of drilling induced tension fractures ditfs. Initiation and propagation of drilling induced fractures. Phase trapping and blocking water entrapment in gas reservoirs 5. Near wellbore damage impairs the formation1s ability to conduct hydrocarbons to the wellbore formation damage lowers well productivity, defers production revenues and is difficult to repair. Natural or induced production impairments that can develop in the reservoir, the nearwellbore area or the perforations.
Underbalanced drilling using horizontal well technology has also increased in frequency as a means of attempting to increase productivity from horizontal wells by reducing formation damage, improve rop and reduce drilling and stuck pipe problems in severe lost circulation zones. Whether formation damage can be prevented, removed economically, or must be accepted as the price for drilling and producing a well will depend upon many factors. Spe 60325 formation damage processes reducing productivity of. The influence of individual clay minerals on formation. Pdf formation damage caused by oilwell drilling fluids. Permeability reduction due to formation damage by drilling fluids. Underbalanced drilling using horizontal well technology has also increased in frequency as a means of attempting to increase productivity from horizontal wells by reducing formation damage, improve rop and reduce drilling and stuck pipe problems in severe lost.
Therefore, the delamination tendency needs greater attention during drilling of composites. This paper discussed the possibility that a clay free microfoamed drilling fluid could be stabilized by silica nanoparticles cfmdfnp so as to avoid formation damage of cbm drilling. Dec 03, 2017 formation damage caused during the drilling process and during the completion which is influenced by the drilling fluid. Among the problems caused by drilling, the delamination is considered to be a major defect in composite structure. Both drilling fluids and completion fluids are composed of liquids, particles, and chemicals, so solid and polymer plugging of pores is the main formation damage mechanism.
The formation damage due to mud filtration is explained by erosion. Pdf permeability reduction due to formation damage by drilling. Reservoir formation damage, third edition, provides the latest information on the economic problems that can occur during various phases of oil and gas recovery from subsurface reservoirs, including production, drilling, hydraulic fracturing, and workover operations. Reservoir formation damage, second edition is a comprehensive treatise of the theory and modeling of common formation damage problems and is an important guide for research and development, laboratory testing for diagnosis and effective treatment, and tailorfit design of optimal strategies for mitigation of reservoir formation damage. Drilling and fracturing fluids can interact with reservoir rock and cause formation damage that impedes hydrocarbon production. Experiments were conducted that evaluate the feasibility of using high intensity acoustic sources to remove near wellbore formation damage caused by organic deposits paraffins and asphaltenes and polymers hec. Concerns for formation damage have been with our industry from the early days. Induced overpressured shale collapse preventative action. Permeability reduction due to formation damage by drilling. Tight sandstone reservoir with welldeveloped natural fractures has a complex pore structure where pores and pore throats have a wide range of diameters. American rock mechanics association june 28, 2015 fracturing experiments were conducted on cylindrical berea sandstone samples using syntheticbased mud sbm with a new experimental setup ut mudfrac. The basic principles of laboratory evaluation of drilling induced formation damage are as follows. In drilling operations, the fine drilled cutting are mixed with the drilling fluid. Coalbed methane cbm reservoirs in china are featured in remarkable nanosized pores below 200 nm, acknowledged natural cleats, and tectonic fractures.
Drilling mud filtrate and solids invasion and mudcake formation chapter 19. Solid and liquid particles dispersed in the drilling fluid mud are trapped by the rock porous medium and permeability decline takes place during drilling fluid invasion into reservoir resulting in formation damage. Effect of formation cuttings mechanical properties on. Combining largesized model flow experiment and nmr. Drilling mud filtrate and solids invasion and mud cake formation. In accordance with the experimental results of foaming. Formation damage indicators include permeability impairment, skin, damage and decrease of well perform. Fluid sensitivity damage, phase trapping damage, and the formation damage induced by oilbased drillin fluids were evaluated by a serious of modified experimental methods.
The experimental investigation of formation damage due to the induced flocculation of clays within a sandstone pore structure by a high salinity brine, spe 38156 paper, presented at the 1997 spe european formation damage conference, the hague, the netherlands, june 23 1997, pp. Drilling cfrps involve penetrating through several plies of laminate, which causes high stresses and strains in the vicinity of the drilled hole. A brief account is given of several problems associated with the management of drilling fluids. These primary considerations do not include well productivity concerns. Drilling bits depending on the formation type, hardness and abbrasiveness a proper bit has to be selected to optimise. Non water based muds prevent inducing overpressure in shale. Spe 60325 formation damage processes reducing prodlk. A comparison of underbalanced and overbalanced drillinginduced formation damage using reservoir conditions core flood testing conference paper pdf available october 1995 with 796 reads. Natural damage occurs as produced reservoir fluids move through the reservoir, while induced damage is the result of external operations and fluids in the well, such as drilling, well completion, workover operations or stimulation treatments. Pdf download reservoir formation damage free unquote books. Transport of particle suspensions in oil reservoirs is an essential phenomenon in many oil industry processes. In terms of standard, there are three main steps by which the formation damage can be indicated figure 1. Ultrasonic removal of organic deposits and polymer induced. A growing recognition of the importance of drilling induced formation damage has led to the use of drillin fluids fluids used to drill through the pay zone that.
Predictability of formation damage by modeling chemical and. Induced overpressured shale collapse rig site indications. Machinability analysis of a drillinginduced damage. Two elements of drilling induced damage will be reported in this paper. Damage induced by drilling and completion fluids exists in the majority of oil and gas wells and generally occurs at the first stage of well production, resulting in great. It is shown that mechanical agitation provided by the acoustic waves effectively resuspends the paraffin and restores the effective permeability of the core to oil to its undamaged. Formation damage due to drilling and fracturing fluids and. Damage in producing wells will reduce the oil and gas production rates and may leave some intervals inadequately drained. Mar 22, 2005 this paper presents an integrated approach, combining a nearwellbore modeling with laboratory experiments for data acquisition as input for the model, to evaluate the performance of oil and gas wells after drilling induced formation damage. Previous studies investigated the effect of rock type with different loadings on the drilling fluid properties. In vertical wellbores, localized damage induced by invading drilling fluids and solids can often be bypassed through cementing and perforating. The potential of the near wellbore formation permeability being reduced damaged exits from the minutes the drilling bits enters the formation until the wells is abandoned. Formation damage is a condition most commonly caused by wellbore fluids used during drilling, completion and workover operations.
This paper, which predated the development of scanning electron microscopy, showed that in nonsmectitic sandstones, loss of permeability was associated with the migrating and poreplugging characteristics of euhedral illite and kaolinite particles following water movement within the. This book investigates the limits of formation damage encountered with the various types of drilling fluids components. Chapter 14 drillinginduced nearwellbore formation damage. This paper is a contribution to i understand mechanisms of drilling mud and mud filtrate invasion, ii quantify drillinginduced permeability damage and iii evaluate the. Drilling mud is the first foreign fluid that contacts the reservoir section of a borehole. A growing recognition of the importance of drilling induced formation damage has led to the use of drillin fluids fluids used to drill through the pay zone that minimize formation damage. Evaluation of horizontal well performance after drilling. Damage mechanisms how are sandstones and carbonates damaged, how do formation mineralogy and clay chemistry influence damage, what about scale, paraffin etc. Drilling and drillin fluids can cause damage to the reservoir section of a borehole. Formation damage is important in both production and injection wells. An experimental investigation on cuttinginduced damage. However, the effect of cuttings mechanical properties. It was reported that, in aircraft industries, the rejection of components due to drilling induced delamination was as high as 60% stone 1996. Thus, the machining process not only affects the overall hole quality but also initiates discrete damage phenomena such as microcracking, matrix burning.
A parametric study to numerically analyze the formation. Formation damage overview professor dr abdel sattar dahab petroleum engineering department cairo university 1 the. Drilling fluid suspensions advances in chemistry acs. Reservoir formation damage, third edition, provides the latest information on the economic problems that can occur during various phases of oil and gas recovery from subsurface reservoirs, including production, drilling, hydraulic fracturing, and workover operations the text helps readers better understand the processes causing formation damage and the factors that can lead to reduced flow. In injection wells, formation damage adversely affects sweep efficiency and recovery factors. This model can be used for diagnosis, evaluation, and simulation of reservoir formation damage during drilling, production, and chemical. Formation damage evaluation from specific laboratory tests becomes a large part of the scal activities and many papers have focussed on this area of research. They also carry cuttings to the surface and cool the bit. A growing recognition of the importance of drillinginduced formation damage has led to the use of drillin fluids fluids used to drill through the pay zone that minimize formation damage. Formation damage is defined an impairment to the reservoir caused by the invasion of wellbore fluids during any interval of well. Experimental results indicate that the drilling fluid causes the major damage, and the chosen. Producing formation damage has been defined as the impairment of the unseen by the inevitable, causing an unknown reduction in the unquantifiable. Understanding and anticipating drilling problems, understanding their causes, and planning solutions are necessary for overallwellcost control and for successfully reaching the target zone.
Formation damage seems to be inevitable and it is costing your company money. Practical model for chemically induced formation damage. Formation damage, prevention, mechanisms training course. Practical model for chemically induced formation damage the model parameters are determined by an optimum history matching of the model predictions to laboratory core test data. As a supplement, the rock physics and surface property were analyzed deeply. Because the operator intended to complete the reservoir open hole, it was critical to select a drillin and completion fluid that would minimize formation impairment caused by. The material balance of the t 2 values for a rock sample that has undergone the three experimental stages is explained in eqs.
The capability and validity of the model are demonstrated by comparing the model predictions with experimental data. Several injection cycles were carried out on each rock sample to measure the fracture initiation pressure fip and the stable fracture propagation pressure fpp at various confining. A large number of formation damage mechanisms arising from the interaction of drilling mud solids and fluids with the reservoir solids and fluids can occur. Formation damage removal through acidizing of an oil well. Tmty of low permeability reservoirs 3 occurring insitu particulates within the pore system caused by high interstitial fluid velocities induced by differential pressure gradients. Estimating drilling induced formation damage using reservoir simulation to screen underbalanced drilling candidates spe 86465. Quantification of uncertainties for drilling induced. Can lead to severe damage to bit and drillstring different designs to overcome this.
By the way of material balance, indepth analysis of the filtration loss properties of a drilling fluid can be made as well as the evaluation of the associated drilling fluidinduced formation damage. Formation damage assessment, con trol, and remediation are among the most important issues to be resolved for efficient exploitation of hydro carbon reservoirs 1. In overbalanced drilling obd, formation damage is caused by the presence of filter cakes and invading drilling fluid in porous media. Quantifying the degree of existing formation damage. Investigation of formation damage induced during drillin. Damage is caused by drilling fluids and subsequently by cement slurry by two mechanisms. Mechanisms of formation damage and permeability impairment. Characterization of reservoir rock for formation damagereservoir. Removal of formation damage induced by drilling and. This page discusses the formation damage that may be associated with various types of drilling fluids. To mitigate formation damage due to the waterinoil drilling mud, it has been found that. As a result, the properties of the drilling fluid, such as density and rheological properties, will change based on the cutting properties. Formation damage can be defined as the reduction in the original permeability of the reservoir rock close to the wellbore. Several injection cycles were carried out on each rock sample to measure the fracture initiation pressure fip and the stable fracture propagation pressure fpp at.
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