Casing Damage And Prevention In The Ordos Basin

The Ordos Basin oil is the second largest oil-and-gas-bearing in China, the Oil and gas reservoir has the special characteristics of low porosity and low permeability, low pressure and low-yield. Because of the complex geological conditions, the damage factor of the casing in the oil (water) well is extremely complex. Generally speaking, the main factor have four points that is the geological factors, production factors, the well-own factors of and the corrosive factors. Existence of these factors will make the oil(water) well into Serious damage, and lead to the area with casing damage into a piece of casing damage and the local district casing damage.Thus it will Seriously affect the implementation of development programs,threaten the stable production of the oil field,and greatly increase the difficulty of the workover construction.Through the casing damage information and data statistical analysis,this article has summarized the main casing damage type are mechanical damage and corrosion in the Ordos Basin. The Mechanical damage always performances for the casing deformation,which contains including expanding, reducing diameter, oval, bending and dislocation,and Corrosion contains internal corrosion and external corrosion. The external corrosion are the main types of casing damage, internal corrosion and scaling belongs to the secondary type of casing damage, deformation, dislocation and collar off is a small number of sets of loss type.this article mainly analysis the casing damage causes from the factors of geological, production,wellbore and corrosion. This paper focuses on the Changqing Oilfield Wangyao casing damage, and systematically analysis the impact of various factors on casing damage.To sum up, the poor quality and not enough cement return set the main reason for casing damage, the layers of sandstone water, rock intercourse interface and shale is a secondary cause of corrosion, the water cut, water pressure, the bending angle and the perforation parameters setsthe impact on the damage.In addition,this article do a more detailed description and instructions for the instrument, explaining software and methods.Nowdays Various oilfield casing damage logging equipment series caliper log series, magnetic logging series, acoustic imaging logging suite downhole television imaging logging series.useing the better casing damage instrument from the Changqing Oilfield,this article analysis the instrument characteristics, the principle and the methods for explaining. From the point of view of the injection profile,this article analysis of the injection profile curve anomalies may occur when the damaged casing, and a classified summary. Finally,combined with the dynamic data of the oil fields,this article prevents measures for different type of casing damage, analysis casing Countermeasures from the ways of drilling, well cementing process and perforation,take casing repair Measure for different sets of damage degree (deformation, dislocation and loss),and attempt to establish a dynamic monitoring process, qualitative identification the casing damage in the way of the crossplot; fuzzy mathematics method...