Changes

! Problems

! Problems

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| Type 1. Fractures provide essential porosity and permeability

| rowspan = 4 | Type 1. Fractures provide essential porosity and permeability || Rapid decline rate

| Rapid decline rate

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| Often limited reserves

| Often limited reserves

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| Rapid coning

| Rapid coning

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| Fracture intensity and width must be very high

| Fracture intensity and width must be very high

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| Type 2. Fractures provide essential permeability

| rowspan = 4 |Type 2. Fractures provide essential permeability || Poor fracture and matrix interaction can isolate matrix hydrocarbons

| Poor fracture and matrix interaction can isolate matrix hydrocarbons

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| Rates often need to be controlled to not pull water preferentially along fractures and not through matrix

| Rates often need to be controlled to not pull water preferentially along fractures and not through matrix

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| Permeability contrast between fractures and matrix reduced sweep efficiency in flooding

| Permeability contrast between fractures and matrix reduced sweep efficiency in flooding

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| Development must be highly tailored to the reservoir Matrix block size should be small

| Development must be highly tailored to the reservoir Matrix block size should be small

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| Type 3. Fractures provide a permeability assist

| rowspan = 3 | Type 3. Fractures provide a permeability assist || Nonrecognition of the fracture system leads to poor estimations of drainage area and reserves per well and unusual response in secondary recovery

| Nonrecognition of the fracture system leads to poor estimations of drainage area and reserves per well and unusual response in secondary recovery

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| Apparently isolated reservoirs are often really interconnected

| Apparently isolated reservoirs are often really interconnected

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| Fracture system must have good continuity or “connectedness”

| Fracture system must have good continuity or “connectedness”

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| Type 4. Fractures create only permeability anisotropy

| rowspan = 4 | Type 4. Fractures create only permeability anisotropy || Reservoir often highly compartmentalized

| Reservoir often highly compartmentalized

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| Flow predictions from standard core or log analyses do not match reservoir performance

| Flow predictions from standard core or log analyses do not match reservoir performance

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| Wells may display a larger skin factor than anticipated

| Wells may display a larger skin factor than anticipated

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| Best to have fractures of one orientation than multiple intersecting trends

| Best to have fractures of one orientation than multiple intersecting trends

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