Experimental Research On Foam Drilling Defoaming Methods And Simulation Of Cuttings Transport With Foam

Due to Complex reservoirs and complex geological conditions, the highpressure on oil and gas resource development, the transformation of the old oil andgas fields and heavy oil, etc., in this21stcentury has led to a higher demand forexploration and development. Foam drilling technology has come to stay and can wellovercome the technical problems normally encountered in drilling operations, andreduce damage to the reservoir, and can also ensure effective protection of thereservoir, oil and gas well production, real-time detection of geological anomalies,timely evaluation of the low pressure reservoir. This can also effectively control theleakage, reduce and avoid the occurrence of the down hole pressure differentialsticking, etc., which will in turn improve the drilling rate, shorten drilling cycle andreduce drilling costs.For nearly five decades now, although the technology has been widely used, butthere are still many problems and technicalities that need to be resolved; especiallydefoaming and horizontal wells cutting Transport with Foam particularly beingprominent.Since there is no reasonable method for defoaming, foam drilling fluid foam usesa large amount of disposable repeated low rate drawback; which not only increase thecost of drilling but a significant source of pollution to the environment. Therefore,how to save the use of foam agent to reduce foam drilling costs and meetsincreasingly stringent environmental requirements has become a major problem offoam drilling.The theoretical research on foam cuttings is seriously lagging behind in terms ofprocess of development, all studies published mainly for the description of the FoamCuttings Transport process is in terms of vertical well drilling at about flow rate of0.3m/s, which is sufficient.Therefore, no much problem exists in the vertical well drilling process for foam Cuttings Transport. However, in the horizontal well drilling,because of grain settling velocity the foam flow direction is vertical, resulting indebris deposited at the bottom of the wellbore.Against The above problems, this paper carried out experimental and numericalstudies and obtained following conclusions:1. One chemical defoamer has gone through four replacements, but so far stillthere is not a panacea defoamer applicable to all areas of anti-foaming, defoamersdefoaming mechanism also has no uniform conclusion. A defoamer dosage tested byexperiment, the type of foaming agent, the temperature influence of defoamersdefoaming and antifoaming performance. Defoamer dosage proved optimal value. Italso shows that the type of foaming agent to defoamer defoaming ability have a greatimpact. In this experiment, the anionic foaming agents, defoaming better suppressionfoam blowing agent compound is found to be better. Therefore, we recommend theuse of chemical defoamer should be done before the experimental test to determinethe applicability of the defoamer. In addition, as the defoaming system temperatureincreases, defoamer defoaming speed is also cause to accelerate, but the temperatureis above60℃, defoaming velocity does not change; and this will increase defoamingtime proportionally to defoaming system temperature trend.2. In response to these issues, this paper carried out experimental and numericalstudies, to draw the following conclusion; the experimental results show that thedefoaming rate is closely related to foam stability. As the foam stability decreased, thedefoaming rate is reduced; a linear relationship between the defoaming pressure anddefoaming rate is achieve at an experimental length of about1m and20cm indiameter storage pipe, gas-liquid ratio of α100to200, the gasket thickness of0.6mm.The antifoaming effect conditions were measured in addition with the FLUENTsoftware. Defoaming device diffusion tubes and storage pipe internal pressuredistribution and storage can take control of the flow velocity of the foam and the foampressure changes in the numerical simulation and analysis and simulation results areconsistent with the experimental conclusion.3. Developed for large diameter Water Well foam drilling XP-400foam breaking device used in the drilling of deep wells foam drilling to solve a series of drillingproblems, and achieved good application. In arid areas and mountains water supply isdifficult and low pressure loss and permafrost regions, the bubble is a fast, efficientdrilling, promising drilling methods. The development of the defoaming (XP-400)will effectively address the impact of foam drilling in recent years in the Water Welldefoaming research.4. The level of foam in the annulus to bring the rock capacity is the key to thesuccess of foam drilling. In the horizontal drilling process, due to particle settlingvelocity and bubble flow direction is vertical to horizontal wells, this brings a hugechallenge. This paper first describes the basic properties of the foam fluid, includingthe foam quality, foam viscosity of the fluid, corrosiveness of the bubble, the filtrationof the foam, foam thermal physics, electrical conductivity of foam, foam stability,foam fluid flow degeneration and other aspects of foam drilling. Horizontal wellcuttings transport model is used to analyze the mechanism of foam to bring rock lawinto place. Annular bubble density, bubble pressure of the annulus, the effectiveviscosity of the annulus foam fluid, foam fluid annulus fluid friction and other factorswere all considered on the ability of foam to bring the rock to horizontal wells. Inaddition, the process of horizontal wells foam to bring rock cuttings settlement andthe relationship between annulus velocities were calculated and analyzed. To bringrock ratio derived foam fluid foam annulus velocity increases improve, but the ringempty return the speed to a certain extent after erosion sidewall, and when this getssevere may lead to the well collapse, so there is a critical annulus velocity. Numericalsimulation shows that, with the foam annular return velocity increases, the particlevolume fraction decreases. We believe that horizontal drilling annulus velocity atabout0.8m/s is more reasonable.5. Experimental study will be carried out on the design of a simulated wellboredevice that affects the foam to bring rock and this will be processed. In particular,foam annular speed, the rotation of the drill string, foam density, eccentric drill string,drilling speed and foam rheology and cuttings size, among other factors.In short, these aspects of innovation in foam drilling development will promote the use of a new concept of creative thinking. In particular, this provides a theoreticalbasis for the new joint anti-foaming method, proposed a new defoaming machinerybased chemistry, supplemented by joint anti-foaming method. In addition all theexperimental results, conclusions and the simulation results are consistent with whatis in the literature, which also verified the correctness of this line of research methodsand techniques.