Study On Optimization Of Well Completion Method In Deep Water Oil And Gas Field

The exploration and development of the deep water oil and gas field are high investment, high risk, also need to be highly productive and rapid recovery of funds. It will cause a lot of waste about manpower, material resources and financial resources, even lead to the abandoned wells, to ignore any details. Well completion is an important part of the well construction in deep water oil and gas wells also it is the foundation of deep water oil and gas field development. The goal is to ensure the safety of oil and gas wells in normal production and extend the life of the oil and gas wells. At present it has not yet formed a complete system of theory and technology for well completion method optimization in deep water. Therefore, the research on well completion method optimization in deep water oil and gas field is very necessary.In this paper, the well completion method in deep water oil and gas wells was carried on the system analysis and evaluation. Characteristics of well completion methods in deep water wells such as premium screens, expandable sand screens, open hole gravel pack, high rate water gravel pack and cased hole frac-pack and the factors that affect the well completion methods choice such as the control of edge water and bottom water, gas cap, shale content, sand production prediction, mechanical stability of borehole was studied. First, the principle of deep water oil and gas well completion optimization and optimization methods are identified for the well completion methods in deep water wells at well completion engineering system point. Secondly according to the calculation formula of skin factor under different well completion method different well type of productivity equation was deduced. Based on many times indoor sand production simulation experiment for different well completion methods, the accuracy of grit and the different effect of sand control completion was determined. According to the basic theory of petroleum technology economics, completion economic evaluation model is established. By collecting basic risk events of deep water sand control completion, completion homework fault tree is established. Different deep water well completion life data is collected. Considering the uncertainty of parameters such as economy, geology, engineering, comprehensive initial production, cumulative production, well completion costs, financial net present value, the dynamic payback period of investment, the effect of sand control, accident risk, life of completion, simulation and sensitivity analysis was carried out on the eight indexes by risk evaluation simulation software Crystal Ball. Finally comprehensive weighted osculating value completion optimization mathematical model and risk analysis and evaluation model was established by using the multi-objective decision-making osculating value method, and combining the comprehensive weights to consider the influence of different evaluation indexes,. In the end the deep water oil and gas well completion methods were optimized.According to the geological characteristics of LW3-1deep water gas field, by using risk evaluation simulation software Crystal Ball for simulating evaluation index and the qualitative analysis. Comprehensive weighted osculating value completion optimization mathematical model and risk analysis&evaluation model is compiled into program by computer. Quantitative analysis was calculated by this program. Finally the vertical wells, directional well and horizontal well completion method of LW3-1gas field were optimized. The recommended completion method and grit precision are being adopted and applied by oil fields.This thesis is the research content of the corpus "drilling and completion in deep water and it’s relief wells application technoloy research " which belongs to he national major project (project number:2011ZX05026-001-04)"Large oil and gas fields and coal bed methane development"...