Formation damage, skin and the skin treatable techniques.

petroleum for gate.

1. Formation damage Saturation changes; Invasion od mud in the reservoir increase the saturation,,,thus HC of the relative permeability decresase I know… saturation of water is incread there by elative permeability of oil isdecreased.hence,,production decreased.

2. Skin Relation b/w delta p skin and skin. The more permeable the reservoir,, the more skin value. High skin value------- high pressure drop High pressure drop---- less production.. The additional pressure drop must me substracted to obtain actual flowing pressure or drawdown pressure. Pressure drop due to skin must be substracted .

3. Formation dammage - ve skin –enhancement of flow + ve skin degradation of flow.

4. Formation dammage Mechanical plugging____+ ve skin Chemical swelling___+ ve skin Chemical swelling ..,,,( montmorillonite, illite )—swelling in nature Flocculation__--clay particles joing together and forming – mudda Clay deflloculation — happens in salt Clay flocculation –happens in acid medium. Wettability___- ve skin Generally all the reservoirs are water wet…

5. Formation damage parafins asphaltanes St.branch Ring-(asphalult-8 lo anni rings vesrtaru ) Carbon nunb . Less than 20 Contains O,N,S and various metals. Soluble in Kerosine and Diesel Soluble in Aromatic components Burns rapidly with less smoke Burns with Smokey flame. Paraffin wax he chemical formula for paraffin is CnH2n+2 Asphaltenes clogging

6. To remove the parafinns rod scrapers wireline scrapers flowline scrapers balls, pigs, and/or soluble plugs free-floating pistons hollow rods for circulating hot fluid Phenol-formaldehyde  -- coat inside pipes Epoxy phenolic Polyurethan

7. Accumulation of parafinn Presure drops at at a certain point---called CLOUD POINT C.P- the point liquid becomes vapour.. C.P of petrol—Wax crystal start to form in the crystal.( petrolled is cooled) C.P– the temp. below At which parrafins are formed. C.P– Fuel shows visible cloudiness.. (( Diese >> gasoline,petrol )) Diesel has higher carbon number( approximately 12–20 carbon atoms and 170 to 360 ° C) gasoline (4-12 carbon atoms and 30 to 210 °C).  diesel fuel is more prone to wax formation and solidification at lower temperatures, resulting in a higher cloud point.  Wax Appearance Temperature-cloud point.

8. Liquid temp. ni tagginchali ….1 st C.P vastadi …(wax formavvudii ) inka taggincheste …P.P vastad ( liquid lost its pour properties. i.e …pour avvadu (below the pour point… paaradu ) C.P. 1 st vastadi ………then P.P P.P –The lowest temp at which… liq can flow.. B elow pour point— liq becomes semi solid and losses it fluid properties Lower P.P—fluid remain fluid (above P.P– fluid remain )) Higher p.p – fluid becomes solid ((below P.P—fluid becomessolid )) Low C.P– fluids/lubricants remains clean i.e no parafinns are formed.(above –no) High c.p – may solidifies…((below– C.P—cloudy) i.e (low=above) (high=below)

9. Cloud---fuel to form wax(when cooled) i.e parafins are formed.. Pour point– fuel to form form solid (at lowest temperature) Cloud point pour point I ncreasing order of cloud point is  petrol < kerosene < diesel < black oil . (becomes too viscous to flow) increases in the following order:  petrol < kerosene < diesel < black oil (fuel oil) .  1 Kerosene 40) - 21.9 (cloud ) - 25.8(solid) 2 Diesel 40 ) - 9.3 - 11.4 3 Stanadyne 40) - 33.3 - 36.3 4 Diesel+Kerosene 40+40 ) -25.3 -29.5 4petrol 35 to (-60) 35 to (-60)

10. Formation dammage Acid Dissolvig minerals NaCl Delaying decomposition of gel polymer chains Polyacrylamide Minimize the friction b/w fluids and pipes Ethelene Glycol Preventing scale formation within the pipe Boric Acid salt Maintainfluid viscocity Naco / Kco Crosslinkage Guar gum Water viscocity keep th sand flow Citric acid Prespitation of metallic acids Isopropane Decreases the velocity of fracturing fluid

11. Formation damage Removal Ultasonic and Chemical reaction—removes long chain of carbons. Mechanical Removal : Scrappers and Cutters.-from tubing . kerosene &diesel are ( st chained i.e parafinns are dissolved.) Toulene & xyelene (for asphaltants .) Hot oil – parafinns are dissolved.(steam dissolves the paraffin.. Pour point Depresser ..(PDD) Surfactant well treatment : raise or low surface IFT weaken an emulsion change the wettability disperse or flocculateclays . Oil wetting of Formation Rock. Water blocks Viscus emulsion blocks

12. Sand control methods Mechanical solution Chemical solution Mechanical solution… Sand screens Gravell packing Slotted liners layer of gravel is placed between the wellbore and the reservoir formation.

13. Chemical solution Chemical consolidation.---to bind the sand(consolidate with the help of the sand.) Chemical sand treatment---using chemical to modify the properties of sand.

14. Formation damage Removal Matrix Acidization : (HCL+HF) solution. Carbonated and Sand stone formations. Formation damage and removal of Permibility . (HCL)- for carbonated reservoirs. HCL+HF)-for sand stone reservoirs. Emulsion block: formation of stable water in water that stops the flow.

15. Water-Bloc k: Near-Well bore..With high water saturation.(drilling chesinappudu vastadi .) Hydraulic-oil Pnumatic -air Surfactant treatment: reducing-IFT, change Wettability, Improving oil Mobility. Reducing (Pc).