Overview

OG_OV1

Oil and Gas ReservoirsPorous rock (sedimentary)

Rocks mainly carbonate or sandstone

Unconventional gas (shale, coal bed, tight gas)

Trap is needed

A source of carbon (micro-organisms in seawater)

On- or Off-shore

Economics

OG_OV2

OG_OV3

Off-Shore Rigs and Platforms

How to Produce HCs?

Drill a well (gas or liquid)

Pressure difference

Mining (oil sands)a

OG_OV4

a. Oil is extracted by heat and caustic, Canada

How to Maintain Pressure Difference?

Reservoir pressure

Gas injection

Water injection

Pumps (surface or submersible)

Gas lift

Minimize damage

OG_OV5

Oil Recovery ModesPrimary

Secondary

Tertiary Chemical

CO2

Steam

In-situ combustion

OG_OV6

Types of Injection Water

Seawater (SRB, SO4 scale)

Aquifer water (fines migration, SO4)

River water (fines migration, TSS)

Produced water (TSO, SRB, H2S)

Commingled water (scale formation)

OG_OV7

a. There are problems with all types of waters

Oil Processing Oil gas separation plant (GOSP)

Separate dissolved gases

Separate free and emulsified waters

Water contains salts (scale, corrosion)

Gases contain hydrogen sulfide

OG_OV8

Problems with Produced Waters

Loss of production Lifting, separation, disposal Scale CorrosionBacteriaEmulsionsSanding

OG_OV9

Chemicals NeededCorrosion inhibitors

Scale inhibitors

Demulsifiers

Biocides

Drag reducing agents

OG_OV10

OG_OV11

Types of Wells - FunctionOil producerWater injectionWater disposalWater supplyGas producerGas injectionObservation (T, P, OWC, GOC, GWC)

OG_OV12

Types of Wells – Geometry VerticalHorizontalShort radiusExtended reachMulti-lateral

OG_OV13

Types of Wells – Completion

Open holePerforatedScreensGravel packedSmart completions

OG_OV14

LithologyCarbonates SandstonesMixedShales

OG_OV15

Carbonate ReservoirsCalcite (CaCO3)Dolomite CaMg((CO)3)2

Ankerite Ca(MgFe)((CO3)2)Small amounts of clays, pyrite Middle East, Brazil, USA, UK

OG_OV16

Carbonate Rocks (2)

Dissolve in HClDensity of Calcite = 2.7 g/cc Density of Dolomite = 2.85 g/ccNatural fracturesPositively chargedNever use HF, H2SO4, H3PO3

OG_OV17

Sandstone Rocks Quartz (sand)Feldspars and claysCarbonatesSulfatesIron oxides (hematite)Pyrite (iron sulfide)

OG_OV18

Sandstone Rocks (2) Density = 2.65 g/ccNegatively chargedCementing material Sand production Fines migration HF acid for silica/silicatesNever use HF alone

OG_OV19

Drilling Fluids (Mud)

Water-based All oil Oil-based

OG_OV20

Function Well controlCool-down the drilling bitCarry drilling cuttings Form filter cake Left drilling cuttingsSuspend solids if bit stops

OG_OV21

FormulationWater XC-polymer (xanthan gum)Starch, Poly-anionic celluloseWeighting material KClKOH, Ca(OH)2

Drag reducing agents

OG_OV22

Weighting Materials

Bentonitea

Barite, BaSO4a

Calcium carbonate, CaCO3

Hematite, Fe2O3

Manganese tetraoxide, Mn3O4

a. Insoluble in HCl acid

OG_OV23

Casing Mainly low-carbon steel Joints Examples: J-55 and C-95Letter stands for heat treatmentNumber is the minimum yield

strength of steel

OG_OV24

CementPlaced between rock and casing Zone isolation Water shut-off

OG_OV25

Formulation

Water Class G cementAdditivesLight weight cementFlexible cement

OG_OV26

Sand ProductionWeak rockHigh drawdownWater productionChemical treatments

OG_OV27Unconsolidated Sandstone

Rock Integrity

OG_OV28

ProblemsAccumulation in the well boreErosion to surface valvesErosion to pumpsAll kinds of problems