Quantitative predication method applicable to formation water production before drilling of gas drilling

Abstract

The invention relates to a method for accurately predicating the size of a formation water production amount before drilling of gas drilling, which is characterized by comprising the following steps of: (a) judging formation fluid; (b) explaining formation porosity; (c) explaining formation permeability; (d) explaining formation pressure; and (e) calculating the water production amount. According to the method disclosed by the invention, the formation pore pressure is explained and a seepage mechanics principle is finally combined to realize the quantitative predication of the produced water by utilizing an output formula; with the adoption of the method, the size of the formation water production amount can be accurately calculated before frilling and evidences can be provided for reasonable region selection and layer selection of the gas drilling; a water production complicated condition is avoided during the gas drilling and the success rate of the gas drilling is improved; the method is successfully applied to the Qingxi region of Yumen, the Sulige region of Changqing, a deep layer of Songliao basin, Sichuan-Chongqing region and the like; and a predicated result is matched with a field actual condition and an engineering application prospect is good.

Description

technical field [0001] The invention relates to gas / underbalanced drilling technology in oil and gas drilling, in particular to a method for quantitatively predicting formation water production before gas drilling. Background technique [0002] Gas drilling technology is a drilling technology in which gas equipment injects gas into the wellbore on the ground as a drilling circulation medium. It is mainly used in deep well drilling with complex geological structures. It began to be tested abroad in 1950. However, due to the technical level, equipment and understanding at that time, it has not been applied on a large scale. This technology was not widely used until the 1980s due to the development and maturity of underbalanced drilling equipment represented by rotary blowout preventers and rotary control heads. Overseas applications have found that compared with conventional drilling technology, gas drilling technology has greatly improved drill bit life and ROP under the sa...

AI Technical Summary

Problems solved by technology

In 2003, when Weatherford Company tested gas drilling in Qingxi Oilfield, Yumen, they encountered water layers in the nappe body and the lower Cretaceous, and had to switch media, failing to achieve the expected gas drilling goals

In 2007, deep gas drilling in Songliao caused complex accidents such as pipe sticking and reaming due to formation water problems, which reduced the efficiency of gas drilling

However, at present, there is no technical method capable of quantitatively predicting formation water production before gas drilling at home and abroad.

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