Patent ID: 7165616

Claim:
A method of controlling the direction of propagation of injection fractures in a permeable formation ( 1 ), from which oil and/or gas is produced, comprising: drilling in the formation ( 1 ), first and second drilled production wells ( 105 , 110 ) next to each other; drilling at the drilled production wells ( 105 , 110 ), a further drilled well ( 115 ) that extends between the first and the second drilled production wells ( 105 , 110 ); initiating production of oil and/or gas; while oil or gas is being produced, conveying a liquid to said further drilled well ( 115 ) and out into the formation ( 1 ) for a first period of time T 1 ; performing at least an approximated determination of the maximally allowable injection rate I max for the period T 1 in order to avoid producing fracturing ruptures in said further drilled well ( 115 ) when liquid is supplied therein; keeping the injection rate I for the liquid supplied to the further drilled well ( 115 ) below said maximally allowable injection rate I max for said time period T 1 ; and increasing the injection rate I to a value above I max after expiry of the period of time T 1 when the relation σ′ hole,min <=σ′ h has been complied with along the further drilled well ( 115 ), wherein σ′ h is the minimum horizontal effective stress component and σ′ hole,min is the minimum effective compressive circumferential stress at the wall of the further drilled well ( 115 ).