Research On The Online Testing Technology And The Residual Life Assessment Method For The Stream Assisted Gravity Drainage (SAGD) Wellhead

Stream Assisted Gravity Drainage (SAGD) technology is a technology of super heavy oil's therrnal recovery, and has become an important method for the thermal recovery of heavy oil. SAGD wellhead of Xinjiang oilfield is easy to lead some accidents such as the steam leakage, equipment failure and steam injection break, because it has been suffered from severe conditions and affected by erosion and thermal stress. For solving these failure problems of Xinjiang oilfield's SAGD wellhead, the on-line testing and residual life assessment of in-use wellhead should be implemented, and the specific reasons of the leaked wellhead also should be determined through failure analysis, and some reasonable prevention measures should be proposed.The method of on-line testing and residual life assessment of SAGD wellhead's equipment are studied by the combination of the field test data and numerical simulation analysis. According to the particularity of SAGD wellhead's equipment, a suitable device and method of high temperature on-line testing is used to measure the thickness of SAGD wellhead's equipment, and some safety measures are proposed for this online testing. The reasons of the SAGD wellhead equipment's failure are determined through the failure analysis, and some reasonable prevention measures are proposed. Based on the ANSYS numerical simulation, the effects of oil's sediment concentration on the erosion rate of wellhead's equipment is analyzed. The minimum wall thickness which is meet the strength requirements, and the safety margin of the wellhead's equipment are determined by the thermal stress analysis and strength evaluation method. The residual life and the checking period of the in-used wellhead's equipment are proposed.Field test data shows that the the on-line testing technology and the residual life assessment method of SAGD wellhead is feasible.This paper not only determines the failure reasons of the leaked wellhead, but also proposes some reasonable prevention measures of the in-used wellhead, which effectively ensure the safety of oil production in the SAGD wellhead.