Study Of Parameter Calculation And Technology Of Foam Drilling In Block 1of Yemen

Block 1 in Yemen is the 1^st independently operational project of SINOPEC International Petroleum Exploration & Production Corporation (SIPC) overseas strategic exploration and development. Low ROP,Lost Return and Drift Sand Formation are the main problems of this block. As a new drilling technique, air drilling technology has many advantages such as rapidly increasing ROP, leakage prevention and decreasing contamination, etc. It can be used for dealing with the drilling difficulties of Block 1.So the air drilling technology has become the priority of Block 1 to speed up the exploration schedule.Air Drilling Feasibility Study of Block 1 has been performed. Referring to the basic geological structure, lithology distribution, the pore pressure and formation fluid of Yemen block 1,?the hole stability is analyzed by laboratory experiment and theory calculation, the rock hydrating stability of Block 1 judged through researching the flow principle of aqueous solution, the effect to lithomechanics strength of the hydration, the effect to the near wellbore wall's effective stress of the hydration,the effect of formation fluid to entrainment through researching the effect of water breakthrough and gasing to the entrainment. Analyze the feasibility of air drilling in Block 1 and recommend the scheme of foam drilling. The findings demonstrated that the geological feature and the hole stability is fit for air drilling. After analyzing the respective? distinguishing feature of several kinds of air drilling,? the foam drilling is recommended in Block 1 in Yemen.The foam drilling system has been chosen and its performance been evaluated. The foam system which is suitable for the Block 1 has been optimized in laboratory through the Waring Blender experiment method. And we judged its performance, such as oil and cuttings pollution prevention, salt proof, heat resistance and reutilization. The laboratory findings showed that half foam life and foam quality of FMA-100 and S-FOAM is good, the optimal dosage of FMA-100 and S-FOAM is 0.4%-0.6%, and comparatively, the antipollution of FMA-100 is better than S-FOAM. After debubbling, the base fluid could be re-utilized in order to save the drilling budget.The research of foam drilling multiphase theory model has been performed. Pressure and temperature are the most considerable parameters in the multiphase fluid flow? field. The traditional theoretical model neglected the effects of cuttings and the heat change between the fluid and the layer, so its error is obvious. The paper analyzes the flow field of downhole multiphase flow based on the rule of fluid mechanics. The model of pressure field has been amended through analyzing the gravity pressure drop, the acceleration pressure drop, and the rub pressure drop. The conceptual model of temperature site has been established using the theory of thermal conduction study. A new computational method of minimal gas and liquid injection has been researched and verified in the well site. Using the new method in the Well Reema-1 of Block1, the computational solution showed that the model was dependable to calculate in the foam drilling.A systematical technical scheme of foam drilling has been established based on the theory research in the former and the actual drilling condition of Block 1 in Yemen. The technical scheme consists of the well profile design, the BHA design, the foam drilling parameter design, the work fluid optimization, the foam drilling equipment optimization, ground equipment circuit and the?well-site operation technology etc. Based on the technical scheme, a detailed operation and maintenance measures of foam drilling has been made. Referring to the characters of float sand layer of Block 1, the"foam drilling operation regulation in float sand layer of SIPC"was established.We finished the field experiments successfully in Well Abyed-2 and Reema-1 of Block 1 in Yemen by means of foam drilling technical research. By the experiments, The ROP was raised obviously and the loss circulation was cured,and meanwile, drift sand layer successfully drilled. The field experiment demonstrated that foam drilling could resolve the drilling problems of large hole section in Block 1 in Yemen which exist loss circulation, low ROP and drift sand layer etc.