Optimal Design Of Horizontal Well Structure For Tight Sand Gas

Horizontal well is one of the advanced well types to develop the unconventional oil and gas reservoirs including the tight sand gas.The development and application of horizontal well promotes the high-efficiency development of the tight sand gas.However,the tight sand gas in our country has the characteristics,such as the big bury depth and high abrasiveness.It's easy to come across some complex problems,such as low rate of penetration,high friction and drag,and difficult to control the well trajectory.In order to settle these matters,it's necessary and has engineering significance to do the research on the optimal design of well path and well structure.According to the drilling data obtained from Well A,the real drilling time and relative drilling time is studied.Finally,the efficiency of the slim-hole drilling is demonstrated.Therefore,the slim-hole drilling is a feasible direction for the optimization of well structure for tight sand gas.In the well structure design,the slimhole with a diameter of 6 in is used in the horizontal section and the production casing with a size of 4-1/2 in is tripped down.Consequently,the rate of penetration is enhanced and the drilling economic benefit is improved.In the thesis,a horizontal well with two build-up profiles is set as an example.Then obtained the mathematic models aiming at the shortest well trajectory and the minimal friction.The weight concept is introduced.Then the multi-objective optimization model for the horizontal well path is built.At last,solve this model by MATLAB.