南海西部地区异常高压气井套管防磨技术

南海西部地区高压区域分布广泛，高压井在各种工况下，内外压比常压井要高，对套管强度的要求更高。海上开发井主要采用定向井和水平井开发，套管磨损问题突出，加大了套管挤毁或破裂的风险。针对以上问题，通过不同磨损带磨损实验，得到不同工况下套管磨损系数，建立了考虑磨损的高压井套管强度校核方法。针对南海某D气田套管磨损问题，选取了井深最大的B井，根据其井身结构、井眼轨迹计算了钻井过程中钻具组合对套管的侧向力，评估了磨损对套管强度的影响。综合考虑钻井过程中磨损、抗内压和抗外挤安全系数，提出了基于磨损风险剖面和套管校核安全系数的配套防磨技术方案。该方案已经用于D气田的套管设计和招标采办中。

An integrated wear prevention technology for casing of the abnormal-pressure gas well in the western South China Sea

High-pressure areas are widely distributed in the western South China Sea. In various working conditions, the internal and external pressure of high-pressure well are higher than those of normal-pressure well, so its casing strength has to reach a higher level. As offshore development wells are mainly directional wells and horizontal wells, casing wear is prominent enough to increases the risk of casing collapse or rupture. The casing wear coefficient in different working conditions was obtained by conducting the wear test on different wear bands. The method to check the casing strength of high-pressure well considering the wear was established. To deal with the casing wear in D Gas Field in the South China Sea, Well B, the deepest well was selected as the research object. Based on its casing program and well trajectory, the lateral force of bottom hole assembly (BHA) to the casing in the process of drilling was calculated, and the influence of wear on casing strength was evaluated. Considering the safety factors of wear, anti-internal pressure and anti-external pressure in the process of drilling comprehensively, a set of wear prevention technical scheme based on wear risk profile and casing check safety factor was proposed. And this scheme has already been applied in D gasfield for casing design, bid and procurement.