Liquid Nitrogen Foam Cementing Technology And Construction Technology Research

The area of Southwest Oil & Gas filed has a very complicated geological feature. The bad circulation loss or well kick occurs easily in drilling or cementing after meeting the absorption formations of low pressure, leakage zones or creviced formation. Now many oilfields home and aboard had successfully applied air/mist/foam drilling to deal with these accidents in drilling, but it had not mature technology in cementing. So it must carry out the study of cement and construction technology which is matching to UBD technology urgently.After analyzed many information, it has two disposal methods: one is two or multistage cementing, the other is reducing cement density. But these methods can't satisfy density demand in the formations whose pressure coefficient or fracture coefficient is less than 1.08. So it brings forward with using the ultra-lightweight cement, foamed cement in cementing. This paper will carry on the study of mechanical aeration foamed cement. It has many research contents and innovation points as follows:1. Main research contents1) The study of investigation analysis about foamed cement: it has many aspects about the performances, research methods and practical application in foamed cement.2) The study of cementing operation technologies with foamed cement: it has two methods: one is mechanical aeration; the other is chemical generated.Meanwhile it analyzes the construction methods, equipments and craftworks in these methods.3) The study of cementing operation parameters calculating method with foamed cement: it establishes the rational cement model, and deduces the computational process about annular density and pressure in detail. Meanwhile it optimizes the calculating method and authorizes the cementing construction operation parameters calculating software.4) The study of dynamic analysis in cementing process with foamed cement: it establishes the rational dynamic cement model, and deduces the different flow regime computing model in one or two phases flow. Meanwhile it designs the dynamic calculating and analyzing method, and authorizes the the cementing process dynamic analysis software.5) After had used foamed cement technology practical application in Guang'an 102 well, it has provided the cementing operation parameters and dynamic analysis results for construction unit. Practice proved that the cementing operation parameters are rational and dynamic analysis results are consistent with the cementing operation in field.2. Main innovation points1) This paper generalizes the history, current situation and development about cementing technique with foamed cement, and introduces the performances, research methods and application area in details. Meanwhile the construction method and process flow are determined by practices, and it can provide references for cementing.2) At the basis of considering the cementing operation technology, it founds the model about cementing technique with foamed cement, and solves the equations with finite element method. Then it forms a calculating method about cementing operation parameters, and authorizes the engineering software. Meanwhile it can provide the basic method for ascertaining the rational cementing operation parameters.3) This paper founds the dynamic model about cementing with foamed cement after considered the cementing Operation process. It analyses the flow state with two-phase flow knowledge in process, and authorizes the engineering software that is used for dynamic analysis. Using the dynamic analysis engineering software, it can simulate the flow process in down-hole timely and provide the ideal platform for mastering the cementing operation process fully.4) The research results have applied in production practice fully. In practice, the rational cementing operation parameters are determined by the cementing operation parameters engineering software.And the flow processes in down-hole are tracked timely by the dynamic analysis engineering software. It is proved that the research results are rational and practical which set a good foundation for the application of cementing technology with foamed cement.