Well Cement Formulations for Increased Drilling Hardness
AssigneeSaudi Arabian Oil Company
InventorsAbdullah Saleh Hussain Al-Bari Al-Yami, Scott Steven Jennings, Abdulkarin I. Khafaji, Ahmed Saleh Al-Humaidi
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Abstract
A well cement composition for plugging a bore at the location for initiating sidetracking to bore a lateral well is formulated as a slurry of hydraulic cement that contains at least two, but preferably all three of the following additives: (1) a source of silicon dioxide, (2) fracturing proppants and (3) an expansion compound selected from the group consisting of 1%-5% crystalline silica and 60%-99% MgO or CaO, and their mixtures.
Claims12
A well cement composition containing hydraulic cement that includes the following additives to increase the hardness of the cured composition:
- a. silicon dioxide source;
- b. fracturing proppant;
- and
- c. an expansion compound selected from the group consisting of 1%-5% crystalline silica and 60-99% MgO or CaO, and mixtures thereof.
A cement plug set in a well bore at a predetermined drilling site for the initiation of a lateral well bore, the cement plug formed from a composition that comprises hydraulic cement and at least two of the following additives:
- a. a silicon dioxide source;
- b. a fracturing proppant;
- c. an expansion compound selected from the group consisting of 1% to 10% crystalline silica and 60-99% MgO or CaO, and mixtures thereof.
A well cement composition containing hydraulic cement and formulated for use as a plug at a predetermined position in a well bore passing through a rock formation, the cured cement composition having a rate of penetration (ROP) that is approximately equal to the ROP of the surrounding formation, the composition including the following additives:
- a. silicon dioxide source;
- b. fracturing proppant;
- and
- c. an expansion compound selected from the group consisting of from 1% to 10% crystalline silica and 60-99% MgO or CaO, and mixtures thereof.
A method of formulating a well cement composition containing hydraulic cement for use in forming a cured cement plug at a predetermined position in a well bore to provide a rate of penetration (ROP) value for the cement plug that is comparable to the ROP of the adjacent rock formation, the method comprising the steps of:
- a. determining and recording the ROP value for the rock formation at the predetermined well depth;
- b. comparing the value of the ROP of the rock formation from (a) to a table of ROP test values obtained by testing cured cement compositions that included the following additives to increase the harness of the cured cement:
- i. a silicon dioxide source;
- ii. a fracturing proppant;
- and
- iii. an expansion compound selected from the group consisting of from 1% to 10% crystalline silica and 60-99% MgO or CaO, and mixtures thereof;
- c. identifying an ROP test value for a cement composition that is the same as, greater than, or if neither is present in the table, the closest lesser value to the ROP of the rock formation that is to be drilled;
- and
- d. selecting and preparing a well cement composition corresponding to the ROP test value identified in step (c).
Dependencies are inferred from the claim text.