Methods of separation of materials in an under-balanced drilling operation
First Claim
1. A method of separating fluids present in a hydrocarbon well in an under-balanced drilling operation wherein operating fluid circulating through the well during drilling is mixed with well materials flowing into the well from the well formation and is mixed with solids from the drilling operation and wherein a returning stream of mixed fluids and solids flowing out of the well is at an elevated pressure, comprising the steps of:
- lowering the pressure of the returning stream to a first pressure and removing well materials from the returning stream at the first pressure thereby creating a treated returning stream;
thereafter lowering the pressure of the treated returning stream to a second pressure and removing additional well materials from the treated returning stream at the second pressure; and
raising the pressure of the operating fluid and returning the operating fluid to the well.
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Accused Products
Abstract
Disclosed are improved methods of separation and control of drilling fluids in under-balanced drilling. The separated returning stream materials are measured and used to control the additive gas mixing process to maintain under-balanced drilling conditions. Separation is conducted at reduced pressures to improve gas separation efficiencies. Preferably, separation is performed in multiple steps of pressure drops to eliminate foaming and to enhance gas removal.
90 Citations
30 Claims
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1. A method of separating fluids present in a hydrocarbon well in an under-balanced drilling operation wherein operating fluid circulating through the well during drilling is mixed with well materials flowing into the well from the well formation and is mixed with solids from the drilling operation and wherein a returning stream of mixed fluids and solids flowing out of the well is at an elevated pressure, comprising the steps of:
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lowering the pressure of the returning stream to a first pressure and removing well materials from the returning stream at the first pressure thereby creating a treated returning stream;
thereafterlowering the pressure of the treated returning stream to a second pressure and removing additional well materials from the treated returning stream at the second pressure; and
raising the pressure of the operating fluid and returning the operating fluid to the well. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of separating fluids present in a hydrocarbon well in an under-balanced drilling operation wherein drilling fluid circulating through the well during drilling is mixed with hydrocarbon well materials flowing into the well from the well formation and is mixed with solid cuttings from the drilling operation and wherein a returning stream of mixed fluids and solids flowing out of the well is at an elevated pressure, comprising the steps of:
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lowering the pressure of the drilling fluid;
thereafterremoving the hydrocarbon well materials from the drilling fluid; and
raising the pressure of the drilling fluid and returning the drilling fluid to the well. - View Dependent Claims (29, 30)
there is a pressure drop between at least two sequential separators.
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Specification